Content:
Presentation type:
PS – Planetary & Solar System Sciences

EGU23-1707 | ECS | Orals | MAL27 | PS Division Outstanding Early Career Scientist Award Lecture

Tectonics and magma oceanography of rocky exoplanets 

Tim Lichtenberg
The scarcity of geochemical constraints on the Hadean climate limits our understanding of the planetary environment that gave rise to life on the earliest Earth. I will describe how rocky exoplanets open a novel observational window into the geodynamic evolution of terrestrial worlds that is unavailable in the Solar System. Some of these planets orbit so closely to their star that they lack an atmosphere, which gives direct access to their surfaces. Geodynamic simulations of the super-Earths LHS 3844b and GJ 486b suggest that solid but tidally-locked rocky exoplanets undergo a hemispherically-forced tectonic regime, unknown in the Solar System, with volcanic activity focused either on the day- or nightside, potentially driving asymmetric outgassing. The dense sub-Earth GJ 367b, on the other hand, likely hosts a day-side magma ocean, enabling inferences on accretion regime and the evolution of melting geometry and surface composition over geologic time. Scheduled high-resolution observations with JWST of these and similar exoplanets will enable novel tests of fundamental models of planetary geodynamics, atmospheric formation, and planetary accretion.

How to cite: Lichtenberg, T.: Tectonics and magma oceanography of rocky exoplanets, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-1707, https://doi.org/10.5194/egusphere-egu23-1707, 2023.

EGU23-8554 | Orals | MAL27 | Runcorn-Florensky Medal Lecture

Fluid Planets: from Theory to Observations and Beyond 

Tristan Guillot

A planet which is warm enough so that it lies above the gas/liquid critical point and above the solidification line of its main constituent is a fluid planet. This is the case of Jupiter and Saturn, and of all planets in the Universe that are dominated by hydrogen, due to its very cold critical point (33K) and low melting temperature. Planets mainly made of other elements than hydrogen and helium, such as water, may also be fluid, if they are close enough to their star. Hydrogen, helium and oxygen being the most abundant elements in the Universe, fluid planets hold some of the keys to understand our origins.

Being fluid implies that these planets have low viscosities and few barriers to convection and mixing. They are governed by the same hydrostatic equations as stars. The progressive transition between the gaseous atmosphere and the fluid interior allows one, in principle, to infer bulk composition from the atmospheric one. Behind their apparent simplicity, complications arise rapidly: How do these planets rotate? How efficiently would they mix other elements, particularly in the presence of condensation and clouds, but also when this is energetically unfavored? What is the effect of intense irradiation on the global heat transfer? 

Over the past 30 years, solutions or partial solutions to these questions have been provided thanks to a combination of theoretical studies and observations. Simple theories of the evolution and atmospheric properties of exoplanets have proven relatively successful. Advances in gravitational sounding of Jupiter and Saturn have provided the basis to understand and predict how fluid planets rotate. Constraints on the structure of the planets and on the presence of primordial dilute cores have been provided.  

Yet, recently, thanks to the Juno and Cassini observations, evidence of imperfect mixing and stable regions have arisen both in the deep atmosphere and interior of Jupiter and Saturn. Observed latitudinal and temporal variability in composition, lightning or general atmospheric properties have remained unaccounted for. Modeling atmospheric properties of fluid planets based on Earth parameterizations, not fully accounting for their abyssal nature and moist convection inhibition has failed. Fluid planets are more complex and challenging than previously envisioned. 

Progress will come from the continuation of a combination of studies: theoretical and numerical studies to understand heat transfer and mixing in the presence of condensation, observations of a large variety of exoplanets and measurements in solar system fluid planets. But the next milestone lies in the outer solar system, with the exploration of Uranus and Neptune. These planets are only partially fluid and may have a solid interior. This increased complexity matches what is to be expected for other planets in the Universe. Their atmospheres, made of hydrogen and helium and large amounts of methane, are laboratories to test models of heat and element transport in abyssal hydrogen atmospheres. An international mission with an orbiter and a probe would allow for the direct measurements that we need in order to interpret with confidence the great wealth of data awaiting us with the more distant exoplanets. 

How to cite: Guillot, T.: Fluid Planets: from Theory to Observations and Beyond, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-8554, https://doi.org/10.5194/egusphere-egu23-8554, 2023.

PS1 – Multi-disciplinary applications to planetary and solar system science studies: spacecraft mission development and testing, planetary instrument testing, laboratory experiments and ground-truthing mission data with terrestrial analogues

The contemporary surface of Mars is shaped by wind driven sand transport, yet our knowledge of these processes is limited. Sand ripples are small bedform features commonly found superimposing dunes on the surface of Earth and Mars, perpendicular to the local wind direction. The mechanism behind the formation of Mars’ ripples is currently highly debated: either they are formed by saltation like Earth’s aeolian impact ripples, or they are formed by hydrodynamic instability such as subaqueous ripples. Investigating ripple pattern dynamics across the surface of Mars would improve our knowledge of local wind regimes and sand transport conditions, such as whether the dune shape and size affect wind flow, thus ripple patterns.

To enable efficient surveying of large areas of the surface of Mars, an automated mapping method has been developed to identify and categorise different classes of ripple patterns. For this project, ripple patterns found on barchan dunes across 40 HiRISE sites in the north polar region of Mars have been classified and segmented. The same mapping method will be applied to Earth’s aeolian impact ripples and subaqueous ripples to compare their morphology and dynamics with those on Mars. By doing so, we hope to determine the mechanism behind the formation of Martian ripples and more broadly enhance our understanding of sand transport conditions on the red planet.

How to cite: Delobel, L., Baas, A., and Moffat, D.: Analysis of Dune Ripple Patterns on the Surface of Earth and Mars to determine Local Sand Transport Conditions: A Machine Learning application., EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-392, https://doi.org/10.5194/egusphere-egu23-392, 2023.

The Taurus-Littrow Valley, location of the Apollo 17 landing site, hosts recent, late-Copernican geomorphological landforms and tectonic structures, namely the Light Mantle avalanche deposit and the Lee-Lincoln lobate scarp. The Light Mantle deposit represents a unique case of a hypermobile avalanche on the Moon (El-Baz 1972; Schmitt et al. 2017). The Lee-Lincoln lobate scarp is the surface expression of a recent thrust fault (Watters et al. 2010), which is considered to be the source of strong seismic shaking throughout Taurus-Littrow Valley (van der Bogert et al. 2012, 2019), and potentially still active (Watters et al. 2019).

The Light Mantle represents the only extraterrestrial landslide for which an absolute age is provided (70-110 Ma), thanks to the Apollo 17 returned samples (e.g., Schmitt et al. 2017). Therefore, the Light Mantle deposit can be used as a geomorphological marker and time constraint for surface changes that occurred since its emplacement. By applying the principle of superposition, surface changes superposed on the Light Mantle deposit, and on the slope from which it was generated (the NE-facing slope of the South Massif), must post-date the landslide event. For example, small scale grabens (10-20 m wide) associated with the Lee-Lincoln lobate scarp are found superposed on the Light Mantle unit (Watters et al. 2010). These troughs likely formed less than 50 Ma and are thought to be generated by the flexural bending of the hanging wall (Watters et al. 2010, 2012). Similarly, boulder tracks, whose survival time is estimated to range up to 35 Ma (e.g., Arvidson et al. 1976; Kumar et al. 2019), are found on the NE-facing slope of the South Massif, therefore evidence that boulder falls have occurred after the Light Mantle landslide event.

Here, we extend the body of evidence of surface changes that have affected the South Massif since the emplacement of the Light Mantle deposit. We map boulder tracks, areas of disturbed regolith, linear slope structures, and other structures associated with the summit of the South Massif. We identified features (i.e., slope structures oblique to contours, the Nansen Moat and the trough at the NE-base of the Sout Massif) directly related to back-thrust faults associated with the Lee-Lincoln thrust fault, which are re-activating the buried fault that bounds Taurus-Littrow Valley; we identified other features (i.e., crestal graben-like structures, slope structures parallel to contours) that derived from gravitational adjustment following basal slope support removal due to back-thrust faulting. Moreover, the overlapping relationships between the boulder tracks and regolith disturbance suggests that continuous slope deformation has been affecting the NE-facing slope. We attribute the efficiency of the process to repeated ground-shaking perturbation, which maintains the slope in a perpetually unstable state.

We conclude that the NE-facing slope of the South Massif has been recently and continuously affected by slope deformation processes. We suggest that the efficiency of these processes is the product of lasting, and perhaps ongoing, effects of activity of the Lee-Lincoln thrust fault, coupled with the influence of the subsurface geometry of the valley inherited from the impact basin formation.

How to cite: Magnarini, G., Grindrod, P., and Mitchell, T.: Slope Deformation Associated with Recent Tectonism and the Lasting Effect of Local Subsurface Geometry in the Taurus-Littrow Valley, Apollo 17 Landing Site., EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-1320, https://doi.org/10.5194/egusphere-egu23-1320, 2023.

EGU23-1437 | ECS | Posters on site | GM10.1

Investigating Crater Inlet Valley Formation: Field Study at Lonar Crater, India 

Emily Bamber, Timothy Goudge, Gaia Stucky de Quay, and Saranya Chandran

On planetary bodies, impact craters and fluvial activity interact, and valley incision competes with the topographic, lithologic and structural disruption caused by impacts that frequently occurred in the geologic past. Yet, many terrestrial and martian impact craters were breached by inlet valleys, which supplied (or still supply on Earth) crater interiors with water. Radial and concentric drainage patterns are also observed around craters, suggesting impact-induced structure fundamentally influences incision in these areas.

To gain a greater understanding of fluvial erosion in crater-dominated terrains, and inlet valley formation across crater rims, we will investigate the incision history of the Dhar valley inlet at Lonar Crater, Maharashtra, India. Lonar crater is the best-preserved impact crater in basalt, which formed within the last 100 ka when a bolide impacted the Deccan Traps basalts. At 1.8 km diameter and 135 m deep, it is a simple crater. A small, 5.5 m deep lake resides in the crater interior and is fed by the Dhar inlet to the north east, and groundwater springs in the crater walls. We would use cosmogenic radionuclide dating to investigate the onset and timescales of fluvial erosion that formed the inlet valley, with comparison to the surrounding non-cratered terrains. We plan to measure the accumulation of cosmogenic 3He in pyroxene and olivine to derive in situ exposure ages at different levels in the valley, and also to derive basin-averaged denudation rates from fluvial sediments. Vesicle-fill quartz is also present, so measurement of cosmogenic 10Be is a possible complement to 3He measurements.

We also plan to complete detailed mapping of the Dhar valley inlet and examine hypotheses relating to Dhar valley inlet formation. Previous authors have posited that the Dhar valley inlet formed as spring activity promoted drainage head erosion across the steep crater rim and/or that gullying concentrated in the north east of the crater due to water supply from higher elevation regions in that direction. We will also investigate whether a prominent fracture in the north east, and sub-vertical cooling fractures that trend NE-SW (an original basaltic flow feature), may have influenced the Dhar valley inlet formation.

Increased constraints on crater inlet valley incision mechanisms, controls, and rates, will help extrapolate our understanding of fluvial erosion to crater-dominated terrains, including key specific sites such as Jezero crater on Mars, and in generalized numerical simulations of cratered landscapes. This work will ultimately help place constraints on the extent, absolute timing, environments and mechanisms required to develop fluvial valleys around and into impact craters.

Field work is expected to be completed in early Spring 2023 and at EGU 2023 we will present preliminary findings from the field and detail our next steps moving forward. This work is possible thanks to funding from the Eugene and Carolyn Shoemaker Impact Crater Research Fund and graduate field work funding from the Jackson School of Geosciences. 

How to cite: Bamber, E., Goudge, T., Stucky de Quay, G., and Chandran, S.: Investigating Crater Inlet Valley Formation: Field Study at Lonar Crater, India, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-1437, https://doi.org/10.5194/egusphere-egu23-1437, 2023.

EGU23-2626 | ECS | Posters on site | GM10.1

CO2-driven granular flows as erosional forces on present-day Mars 

Lonneke Roelofs, Jonathan Merrison, Susan Conway, and Tjallng de Haas

Martian gullies are alcove-channel-fan systems which have been hypothesized to be formed by the action of liquid water and brines, the effects of sublimating CO2 ice or a combination of these processes. Recent activity and new flow deposits in these systems have shifted the leading hypothesis from water-based flows to CO2-driven flows. This shift in thinking is supported by the low availability of atmospheric water under present Martian conditions and the observation that gully activity occurs at times when CO2 ice is present. We recently performed novel experiments that have shown that this hypothesis holds; sediment can be mobilized and fluidized by sublimating CO2 ice under Martian atmospheric pressure. However, if these flows are able to erode the underlying surface and can explain the formation of Martian gully systems over the long term remains unknown. Therefore, we present an additional series of experiments that test the capacity of CO2-driven granular flows under Martian atmospheric conditions to erode sediment. These experiments were conducted in a 4 m long flume in the Aarhus Mars Simulation Wind Tunnel. Our experiments show that CO2-driven granular flows can erode loose sediment under a range of different slopes and CO2-ice fractions. The results also show that incorporation of warmer sediment increases fluidization of the mixture, reflected by an increase in gas pore pressure in the flow. These results thus prove that morphological evolution in the gully systems on Mars can be explained by CO2-driven granular flows.

How to cite: Roelofs, L., Merrison, J., Conway, S., and de Haas, T.: CO2-driven granular flows as erosional forces on present-day Mars, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-2626, https://doi.org/10.5194/egusphere-egu23-2626, 2023.

EGU23-2810 | ECS | Orals | GM10.1

Modelling River-Dune Interactions on Ancient Mars

Rickbir Bahia, Eleni Bohacek, Lisanne Braat, Sarah Boazman, Elliot Sefton-Nash, Csilla Orgel, Colin Wilson, and Lucie Riu

EGU23-2831 | ECS | Orals | GM10.1

Modelling River - Dunes Interactions on Titan 

Eleni Vassilia Bohaceck, Rickbir Singh Bahia, Lisanne Braat, Sarah Boazman, Elliot Sefton-Nash, Csilla Orgel, Colin Wilson, and Lucie Riu

The surface of Titan displays evidence of fluvial and aeolian activity. Rainfall on Titan results in fluvial landforms (FLs), lakes, and seas. Unlike Earth, this rainfall is predominantly liquid methane. Titan’s surface conditions allow for liquid methane and ethane to be stable. Although the rainfall is primarily methane, this methane (liquid density ~424 kg/m3) can be photolyzed to form ethane (liquid density ~544 kg/ m3), resulting in lakes and rivers of ethane. Liquid ethane is more likely to be fed back into rivers and lakes by springs and play a formative role in the lower reaches of rivers. Changes in fluid density from the source (methane) to the terminus (ethane) of Titan’s rivers may affect the flow dynamics of the river. Methane fed rivers are likely episodically active since rainfall, which is concentrated in the poles, lasts 10-100 hours each Titan year (30 Earth years). Although precipitation is limited in the mid-latitudes, FLs have been observed in these regions.

Titan is also covered by vast regions of active dune fields, primarily within the equatorial latitudes. They are composed of hydrocarbon and nitrile sand-sized particles forming from photochemical reactions in Titan’s atmosphere. Although observations of Titan are limited, interactions between rivers and dunes have been observed. Limited data availability means modelling fluvial and aeolian processes is one of the best methods to understand active and previously active processes on Titan.

Here we report the initial study by the Working group on Aeolian-Fluvial Terrain Interactions (WAFTI), based at the European Space Agency, which examines the effects of these processes in synergy under Titan conditions, using a combination of modelling and geomorphological analysis. We hypothesise that these interactions could have implications for the distribution and planforms of Titan FLs.

To simulate the interactions between fluvial and aeolian processes on Titan, we developed the Titan Aeolian-Fluvial Interactions model. This is a landscape evolution model based on a coupled implementation of the Caesar-Lisflood fluvial model, and Discrete ECogeomorphic Aeolian Landscape model (DECAL) dunes model. The Caesar-Lisflood fluvial model routes water over a digital elevation model and calculates erosion and deposition from fluvial and slope processes and changes elevations accordingly. The DECAL model is based on the Werner slab model of dunes, which simulates dune field development through self-organization.

Several scenarios shall be modelled: (1) a continuous methane river, flowing in a straight channel with linear dunes migrating towards the channel parallel to its length; (2) a continuous methane river flowing towards a dune field with crest lines perpendicular to the direction of flow; (3) simulation scenario (1) but altered slope to represent the three different reaches (source, mid-reaches, and termination) of the channel and simulate for both methane and ethane flows by altering fluid density; (4) simulation scenario (1) with an episodically active river and continually active dunes.

The findings of these simulations may help understand the drainage patterns and distribution of FLs and methane/ethane across Titan.

How to cite: Bohaceck, E. V., Bahia, R. S., Braat, L., Boazman, S., Sefton-Nash, E., Orgel, C., Wilson, C., and Riu, L.: Modelling River - Dunes Interactions on Titan, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-2831, https://doi.org/10.5194/egusphere-egu23-2831, 2023.

EGU23-2928 | ECS | Orals | GM10.1

Quantifying the Channel Networks of Fan-Shaped Landforms on Mars 

Luke Gezovich, Piret Plink-Bjorklund, and Jack Henry

            River deltas and fluvial fans are both fan-shaped landforms that contain complex channel networks. Fan shaped landforms have also been identified on Mars at Jezero, Eberswalde, and Gale craters among many other locations. A principal distinction between these two landforms is that only deltas systematically form along the shorelines of a standing body of water. Fluvial fans may form along a body of water, but can also form hundreds of kilometers inland. It is thus crucial to be able to accurately distinguish between deltas and fluvial fans for the purposes of mapping paleo-shorelines on planetary bodies and understanding paleoclimates. In this work, we apply multiple quantitative methods on Martian fan-shaped landform channel networks to map channel networks to differentiate fluvial fans from river deltas on Mars. We quantify differences in channel bifurcation and divergence angles due to channel crossovers. We also measure changes in channel reach length between bifurcation and divergence nodes. Differences in channel networks occur because fluvial fans are built by channel bed aggradation and channel avulsion. River deltas are constructed by both mouth bar growth and consequent channel bifurcations, as well as infrequent avulsions. In river deltas on Earth, channel bifurcations form at an angle of approximately 72°. Channel lengths and widths in river deltas decrease downstream with increases in successive channel bifurcations. On the contrary, fluvial fan avulsions generate smaller divergence angles and down-fan channel narrowing is not necessarily linked to divergence nodes. This project applies Earth derived channel network mapping techniques to Martian fan-shaped landforms and demonstrates that this methodology is applicable on Mars. Preliminary analysis of the channel network of the Jezero crater landform suggests that it resembles a fluvial fan and not a delta. Conversely, preliminary analysis of the Eberswalde crater channel network suggests that the landform here does resemble an Earth river delta. Our results indicate that fan-shaped channel networks can and must be carefully assessed. This is especially true if the presence of deltas is used for the estimation of the location of paleo-shorelines on planetary bodies, as only deltas regularly form at shorelines. Alternatively, additional evidence is required to identify paleo-shorelines as fluvial fans may also form along shorelines. On Earth, fluvial fans are less sensitive to sea-level rise and coastal hazards than deltas and thus react differently from deltas due to changing sea levels.

How to cite: Gezovich, L., Plink-Bjorklund, P., and Henry, J.: Quantifying the Channel Networks of Fan-Shaped Landforms on Mars, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-2928, https://doi.org/10.5194/egusphere-egu23-2928, 2023.

EGU23-3373 | Orals | GM10.1

The effects of dust content on surface sediment transport by carbon dioxide ice sublimation on Mars 

Susan Conway, Calvin Beck, Clémence Herny, Camila Cesar, Hanna Sizemore, Matthew Sylvest, and Manish Patel

During the martian year the surface temperatures in winter dip below the condensation temperature of carbon dioxide and it freezes onto the surface. In the spring, it sublimates directly back into the atmosphere and observations reveal that this cycle of condensation-sublimation results in identifiable sediment transport on the martian surface. We use data from the Colour and Stereo Surface Imaging System (CaSSIS) on ESA's Exomars Trace Gas Orbiter to illustrate the range of landforms thought to be created by these sublimation processes. Previous experiments have revealed that condensation of CO2 ice into the regolith pore space and its subsequent sublimation can result in downslope sediment transport. they also showed that aeolian sand was less prone to sediment motion triggered by sublimation than martian regolith simulant and it was suggested the presence of dust could be responsible for this difference. As dust is an important component of the martian atmosphere and surface, in these experiments we explore the influence of dust content on the sediment transport processes and capacity for sediment transport.

Our experimental setup consists of a liquid nitrogen cooled copper sample holder ~30cm long by 20 cm wide within which the sediment is formed into a slope at 30° (max. depth 10 cm). This container is placed inside the Open University’s Mars Chamber which has has a length of 2 m and a diameter of 1 m. One experiment typically takes 2hrs, and the preparation takes 12-14hrs. First the chamber is evacuated and backfilled with CO2 gas twice to purge terrestrial gases including H2O. Once this is complete the sample holder is cooled with liquid nitrogen until all the sediment temperatures reach the condensation temperature of CO2. The experiment then starts and a heat lamp is used to force the CO2 sublimation.  The experiments are monitored by an array of cameras for photogrammetry, a high definition video camera to record the processes, pressure gauges to maintain/monitor the pressure and thermocouples to monitor the sediment and surface temperature.

In this series of experiments we vary the dust content in an aeolian sand matrix from 0 to 20% by weight by adding the clay fraction of the MSC simulant. We find no significant difference in the results between 0 and 5% dust content, then at higher values the transported volume and activity increases suddenly and the transported volume and activity remains stable at a higher level from 10% dust upwards. Our results reveal that a sediment transport threshold seems to exist between 5% and 10% dust content and therefore this factor must be considered when studying seasonally active surface processes on Mars.

How to cite: Conway, S., Beck, C., Herny, C., Cesar, C., Sizemore, H., Sylvest, M., and Patel, M.: The effects of dust content on surface sediment transport by carbon dioxide ice sublimation on Mars, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-3373, https://doi.org/10.5194/egusphere-egu23-3373, 2023.

EGU23-3863 | ECS | Orals | GM10.1

Sand properties investigation at Meridiani Planum, Mars 

Joanna Kozakiewicz, Maciej Kania, Dorota Salata, and Leszek Nowak

Granulometry, shape, and chemical composition analyses of the sediments studied by the Opportunity rover along its entire 45-km-long traverse have been used to classify sediments and provide information about their origin and depositional processes.

We have conducted granulometry and shape analyses of 179 sediment targets visible in MI images [1]. To facilitate the analyses, we have used the PADM algorithm - a semi-automatic tool for particle detection, measurement, and analysis [2]. This allowed identification of more than 70000 individual grains. For chemical composition analysis we used APXS data of 62 sediment targets [3]. The normative mineral composition was calculated from APXS according to the CIPW procedure to calculate the estimated density of the material and to classify in QAPF system.

The analyses show five deposit classes: i) dust with very fine sand enriched in sulphur, ii) fine basaltic sand, iii) coarse sand enriched in iron, found only on the plains, iv) gravel enriched in iron, also found on the plains, and iv) gravel with a typical for basalts amount of iron, found at the Endeavour crater rim. These classes occur in the following geomorphological settings: i) dust mixed with very fine sand is common on the leeward side of topographical obstacles, ii) fine sand is present in depressions, iii) coarse sand is related to coarse-grained ripples fields, iv) gravel occur as a lag deposit, especially in coarse-grained ripple troughs and at crater rims and outcrops.

The typical diameter of grains for the fine sand is 0.13 mm, and for the coarse sand - 1.20 mm. The best sorted coarse sands were found on the slopes and the crests of coarse-grained ripples. In most cases, the normative mineral composition of deposits fits in the basalt/andesite field of the QAPF classification. The coarse sand found in coarse-grained ripples was characterized by the highest content of iron and shows the most mafic composition in the QAPF diagram. This deviation from the basalt composition is related to iron-rich spherules (a frequent component of the gravel) than to a more mafic type of rock. On the other hand, the coarse sand grains found in ripple fields were characterized by lower roundness than the iron-rich spherules. Therefore, many of the transported by wind coarse sand grains had their origin in partial fragmentation of iron-rich spherules.

The work was funded by the Anthropocene Priority Research Area budget under the program "Excellence Initiative – Research University" at the Jagiellonian University.

[1] Herkenhoff, K. E. (2003) MER1 Microscopic Imager Science Calibrated Data Bundle. PDS Geosciences Node. DOI: 10.17189/1519006

[2] Kozakiewicz, J. (2018). Image Analysis Algorithm for Detection and Measurement of Martian Sand Grains. Earth Science Informatics, 11, 257-272. DOI: 10.1007/s12145-018-0333-y

[3] Gellert, R. (2009). MER APXS Derived Oxide Data Bundle. PDS Geosciences (GEO) Node. DOI: 10.17189/1518973

How to cite: Kozakiewicz, J., Kania, M., Salata, D., and Nowak, L.: Sand properties investigation at Meridiani Planum, Mars, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-3863, https://doi.org/10.5194/egusphere-egu23-3863, 2023.

EGU23-3981 | Orals | GM10.1

Exploring Planetary Geomorphology with NASA’s Solar System Treks 

Brian Day and Emily Law

NASA's Solar System Treks Project (SSTP) online portals provide web-based suites of interactive visualization and analysis tools to enable planetary scientists, mission planners, students, and the general public to access mapped data products from past and current missions for a growing number of planetary bodies. 


The Solar System Treks portals provide advanced data visualization and analysis capabilities for data returned from a vast number of instruments aboard many past and current missions to a growing number of planetary bodies throughout Solar System. Multiple map projections as well as interactive 3D views are available to optimize visualization of different landforms. A detailed set of analysis tools helps users find and interpret morphological features across diverse landscapes on the surfaces of planets, moons, and asteroids. In some cases, these tools make use of machine learning and artificial intelligence to help users locate, identify, and understand landforms drawn from very large datasets. Having an integrated suite of portals presenting geomorphology across a range of planetary bodies within the Solar System greatly facilitates studies of comparative planetology. The portals are currently being used for site selection and analysis by NASA and its international and commercial partners supporting upcoming missions. 
Today, 11 web portals in the program are available to the public. This list includes portals for the Moon; the planets Mercury, Venus, and Mars; the asteroids Bennu, Ryugu, Vesta, and Ceres; and the outer moons Titan and Europa. The Icy Moons Trek portal features seven of Saturn’s smaller icy moons. All of the portals are unified under a project home site with supporting content. These web-based portals are free resources and publicly available. 


This presentation for EGU will detail and share examples of the how the portals can be applied to research in planetary geomorphology.

How to cite: Day, B. and Law, E.: Exploring Planetary Geomorphology with NASA’s Solar System Treks, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-3981, https://doi.org/10.5194/egusphere-egu23-3981, 2023.

EGU23-4080 | ECS | Orals | GM10.1

Geomorphic study of caldera features on Mars with the help of Earth analogues 

Yin Yau Chu and Joseph R. Michalski

Geomorphological analogues provide a valuable perspective for understanding planetary volcanic structures, landforms, and processes. Arabia Terra, Mars contains numerous collapse structures that are somewhat controversially interpreted as calderas. This work aims to use planetary analogues to shed further light on possible martian caldera collapse and volcanic processes.

The project had a focus on a population of underrecognized ancient volcanic constructs that associated with explosive and effusive volcanism, termed “plains-style caldera complexes” (Michalski and Bleacher, 2013), that are present within the Arabia Terra and perhaps across the Noachian-Hesperian crust on Mars. These features are characterised by deep crustal collapse, presence of flow deposits, potential pyroclastic materials, and more importantly, without a pronounced central edifice. Notable examples of the plains-style caldera complexes includes: Eden Patera (33.5°N, 348.8°E), type-locality of the plains-style caldera complexes; Siloe Patera (35.3°N, 6.55°E), which presents two overlapping classic piston-type caldera collapse; and Hiddekel Cavus (29.4°N, 16.2°E), a narrow, cone-shaped depression with extremely high depth/diameter ratio. In this project, besides working on Martian satellite imagery and topographic data, terrestrial analogue study was also a useful tool when analysing caldera floor geomorphology at Eden Patera. 

The Hawaiian volcanoes have previously been used as analogues for certain volcanic processes on Mars (Mouginis-Mark et al., 2007; Hauber et al., 2009). Though the Hawaiian volcanoes formed through different volcanic styles than the plains style caldera complexes, they nonetheless provide insight into key processes. At Kīlauea volcano, Hawaiʻi, the caldera collapse and volcanic deposits were associated with Hawaiian-style effusive eruption of basaltic lava, accompanied by minor explosive eruptions (Stovall et al., 2011; Patrick et al., 2020). Kīlauea Iki and Halemaʻumaʻu, the pit craters of Kīlauea, were considered as potential terrestrial analogue for (1) the “black ledge” formation (chilled lava lake margin feature) and (2) isolated “islands” of pyroclastic materials on the caldera floor at the Eden Patera, and both features are important evidence supporting a volcanic story, as well as both effusive and explosive activities of the Eden Patera caldera complex.

Nonetheless, potential analogue for caldera collapse mechanism was once again identified at Kīlauea Halemaʻumaʻufor an unnamed cavus of possible volcanic origin within the mid-Noachian to Hesperian plain of Xanthe Terra, Mars (Tanaka et al., 2014). Both the Hawaiian pit crater and Martian cavus are deep depressions with steep scarps, overlying a region of extensive concentric faults and fractured crust, making Kīlauea a good candidate for future analysis as a terrestrial analogue for caldera features of the plains-style caldera complexes on Mars.

How to cite: Chu, Y. Y. and Michalski, J. R.: Geomorphic study of caldera features on Mars with the help of Earth analogues, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-4080, https://doi.org/10.5194/egusphere-egu23-4080, 2023.

EGU23-4549 | ECS | Posters on site | GM10.1

Evidence of late Mars geological activity on the floor of the Gusev and Jezero craters. Landing sites of NASA's Mars exploration missions. 

Ronny Steveen Anangonó Tutasig, Susana del Carmen Fernández Menéndez, Javier Fernández Calleja, Enrique Díez Alonso, and Javier De Cos Juez

The Gusev crater, landing site of the MER-A mission, and the Jezero crater, site of the Mars2020 mission, currently located near the Martian equator. They may have been two fluvial-lacustrine systems from the planet's wet past, Nevertheless, cortical fractures, ridges and basaltic flows are present in the bottom of both craters. These features are well preserved and not affected by large craters, which seems to indicate that could be young and contemporary forms. Mapping of both Gusev Crater and Jezero Crater has been carried out by remote sensing onboard the Mars Reconnaissance Orbiter (MRO), of particular interest for Gusev Crater is the Context Camera (CTX)-based high-detail mapping, which improves the resolution of previous studies, and the High-Resolution Imaging Experiment (HiRISE). These are complemented by data from the Thermal Emission Imaging System (THEMIS) and Mars Orbiter Laser Altimeter (MOLA), the Mars Global Surveyor (MGS) mission. CTX and HiRISE are visible images that provide information about the surface features of morphological units in detail. The MOLA data have made it possible to determine the stratigraphic position of the mapped units and to obtain information on the slopes and elevations of the units, as well as to estimate the fill of both craters. The combination and analysis of these data show possible evidence of geological activity on the surface of these craters in more recent periods of Mars' past (millions of years). Crater counts (crater frequency) have been used to determine a possible age for the ridges described in crater Gusev. These indications may be associated with volcanic activity and horizontal “strike-slip” movements affecting the ridges observed in Gusev crater, as well as crustal fracture and the presence of basaltic plains in Jezero crater.

How to cite: Anangonó Tutasig, R. S., Fernández Menéndez, S. C., Fernández Calleja, J., Díez Alonso, E., and De Cos Juez, J.: Evidence of late Mars geological activity on the floor of the Gusev and Jezero craters. Landing sites of NASA's Mars exploration missions., EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-4549, https://doi.org/10.5194/egusphere-egu23-4549, 2023.

EGU23-5338 | ECS | Orals | GM10.1 | Highlight

Methane on Mars: Correlation of geomorphological features with current methane emissions 

Elettra Mariani and Pascal Allemand

This research deals with the detailed study of some global-scale geomorphological structures on Mars to identify possible current or fossil methane emission points. For years, attempts have been made to understand the mechanism that led to the formation of methane on Mars and how it may have been stored to date in subsurface reservoirs. From the data recently received from satellites (Tracer Gas Orbiter on board of ExoMars, Planetary Fourier Spectrometer on Mars Express) and rovers (Mars Science Laboratory Curiosity in Gale crater) on Mars, it is possible to infer that the methane on Mars is gradually emitted into the atmosphere and most of the times is detected by these instruments. Thanks to these dataset of methane emissions during the years (since 2004 with the PFS first detections) it is possible to trace the possible points in which the upper limit concentration of methane are equal to or greater than 10 p.b.b.v. so as to select a few areas where to begin the geomorphological and mineralogical analyses for this research in order to create a global map of possible areas where current methane emissions from subsurface methane reservoirs may be recorded. For this study the focus will be on hectometric to kilometric mounds of volcanic or sedimentary origin (mud volcanoes and/or pingos like structures), chaotic terrains and fracture fields in sedimentary piles. The areas selected for this research are Coprates and Candor Chasma (Valles Marineris, Mars), Nili Fossae (Mars), Vernal crater and the surrounding of Arabia Terra (Mars) and Gale crater (Mars). All of these locations have key characteristics such as proximity to a boundary zone (Gale crater), the presence of a fracture system (Nili Fossae), presence of mud volcanoes or pingoes (Valles Marineris and Utopia Planitia): all possible incentives for the presence of methane emission spots. The aim of this project, as already mentioned, will therefore be to analyse these areas in detail, trying to understand whether they could be or have been methane emission points, with the help of the planetary analogues that can be found in Azerbaijan regarding mud volcanoes, in Canada for pingos or fracture systems in China.

How to cite: Mariani, E. and Allemand, P.: Methane on Mars: Correlation of geomorphological features with current methane emissions, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-5338, https://doi.org/10.5194/egusphere-egu23-5338, 2023.

EGU23-7284 | ECS | Posters on site | GM10.1

Characterization of Shalbatana Vallis landslides 

Matilda Soldano and Pascal Allemand

Shalbatana Vallis is a valley located in the Oxia Palus quadrangle, characterized by a simple system and a homogeneous coverage. Shalbatana vallis flows into the Chryse Planitia basin, alongside Ares Vallis, Kasei Valles, Simud Valles and Tiu Valles. The valley is affected in different points by landslides with various surfaces and elongations. Landslides on Mars are a topic already studied by other authors. However, the problem of the dynamic of such structures remains debated. The landslides of Shalbatana Vallis occurred in a homogeneous lithology and in a valley with a quite constant depth. We first present the ages of the landslide and discuss the age distribution. The, we present a geometrical analysis of the landslides (surface, elongation, volume, runout, etc….) and use these parameters to constrain some dynamical properties (possible velocity, possible loss of volatiles) and to discuss possible triggering mechanisms.

How to cite: Soldano, M. and Allemand, P.: Characterization of Shalbatana Vallis landslides, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-7284, https://doi.org/10.5194/egusphere-egu23-7284, 2023.

EGU23-7673 | ECS | Posters on site | GM10.1

Dynamic reorientation of tidally locked bodies 

Vojtěch Patočka, Martin Kihoulou, and Ondřej Čadek
Planets and moons reorient in space due to mass redistribution associated with various types of internal and external processes. While the equilibrium orientation of a tidally locked body is well understood, much less explored are the dynamics of the reorientation process. This is despite their importance for assessing whether enough time has passed for the equilibrium orientation to be reached, and for predicting the patterns of TPW-induced surface fractures (true polar wander, TPW, is used here for the motion of either the rotation or the tidal pole). Here we present a simple yet accurate method to compute the reorientation dynamics of a tidally locked body. The method is based on assuming that during the TPW the tidal and the rotation axes closely follow respectively the minor and the major axes of the total, time-evolving inertia tensor of the body.
 
Motivated by the presumed reorientation of Pluto, the use of our method is illustrated in several test examples. In particular, we analyze whether reorientation paths tend to be curved or straight when the load sign and the mass of the host body are varied. When tidal forcing is relatively small, the paths of negative anomalies (e.g. basins) towards the rotation pole are highly curved, while positive loads reach the sub- or anti-host point in a straightforward manner. Our results suggest that the Sputnik Planitia basin cannot be a negative anomaly at present day, and that the remnant figure of Pluto must have formed prior to the reorientation. 
 
The situation is different for the icy satellites of Jupiter and Saturn. When the mass of the host body is relatively large, positive loads first move toward the center of the trailing or leading hemisphere, and reach the sub- or anti-host point only later, in a subsequent stage of TPW. The reorientation dynamics may have important consequences for the present location of some of the prominent features on the surfaces of icy moons. The custom written code LIOUSHELL that was used to perform the simulations is freely available on GitHub. V.P. and M.K. acknowledge support by the Czech Science Foundation through project No. 22-20388S.

How to cite: Patočka, V., Kihoulou, M., and Čadek, O.: Dynamic reorientation of tidally locked bodies, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-7673, https://doi.org/10.5194/egusphere-egu23-7673, 2023.

EGU23-8505 | ECS | Posters on site | GM10.1

What role did Tharsis formation during the Noachian/Hesperian period (3.8 – 3.5 Ga) have on the erosional history of Mars? 

Hannah Sophia Davies, Sylvain Bouley, David Baratoux, and Jean Braun

On Earth, the characteristics of fluvial erosion depends on two main parameters: climate (rain fall) and tectonic history. Mars is a planet that experienced erosion driven by liquid water but its geodynamics are vastly different from Earth’s. Mars therefore represents a unique opportunity to understand how landscape evolution differs on a planet with a “stagnant lid” tectonic regime. The formation of Tharsis dome, a vast volcanic province, during the early history of Mars represented a major magmato-tectonic upheaval for the planet. Over several hundreds of million years, the Tharsis region experienced large scale magmatic intrusions, crustal deformation and effusive volcanism resulting in crustal growth, dynamic uplift and true polar wander (TPW) that accounts for the present location of the Tharsis dome at the equator. This event occurred during a time when Mars had an active water cycle, although the total mass and relative proportion of ice, liquid water and vapor is not well constrained. The uplift and subsequent true polar wander of Mars have affected drainage systems across the planet with many being abandoned or modified due to the variable uplift or subsidence as a lithospheric response to the regional upheaval in the Tharsis region (load on the elastic lithosphere) and TPW. Here we present results from numerical simulations performed using a stream power law algorithm on Mars during the Noachian/Hesperian growth of Tharsis to assess how the patterns of erosion rate are affected by the distribution of atmospheric moisture and flow routing in an attempt to reproduce the observed distribution of valley networks and their geometry. For this, we adapted and used the fully-implicit and O(n)-complexity FastScape algorithm to perform the simulation at the planetary scale. The aims of this work are to quantify the effect of Tharsis dome formation on fluvial systems during the Noachian and early Hesperian, and to establish a first-order erosion rate for this period. This study could help to constrain how much water was cycling on Mars at this time.

How to cite: Davies, H. S., Bouley, S., Baratoux, D., and Braun, J.: What role did Tharsis formation during the Noachian/Hesperian period (3.8 – 3.5 Ga) have on the erosional history of Mars?, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-8505, https://doi.org/10.5194/egusphere-egu23-8505, 2023.

EGU23-8552 | Orals | GM10.1

Mapping Vesta using a hybrid method for incorporating spectroscopic and morphologic data 

R Aileen Yingst, Scott C. Mest, W. Brent Garry, David Williams, Daniel Berman, and Tracy K. P. Gregg

Defining criteria for mapping material units on airless, rocky bodies is challenging. Where the primary geologic process for most of a body’s history is impact cratering, traditional morphology-based mapping approaches may fail, because differences in morphologic characteristics among the various cratered surfaces can be hard to discern, and surface morphology is muted by the regolith’s physical and mechanical properties. In constructing a global geologic map of Vesta at 1:300,000-scale using the Dawn Framing Camera (FC), DTM-derived slope and contour, and multispectral data, we have countered this problem by utilizing a hybrid method of mapping that first requires creating two maps independently. The first map depends on morphology and topography to define map units, while the second uses spectral data to define units. The unique results of each map are then combined into the hybrid map units. 

 

Multispectral data provide unique insight into stratigraphy (material brought up through cratering processes) that is easily lost when using an albedo mosaic as the basemap. However, solely using a “color” ratio mosaic as a basemap easily magnifies potentially misleading data, because spectroscopy in the shorter wavelengths (UV-VIS-near IR) can only sample the upper few µm of the surface, and very little unique material is required to affect the signal of a regolith. Contacts defined by multispectral data may not coincide with clear morphologic boundaries as a result, so caution must be used in how the two maps are merged and clear criteria should be established to define hybrid map units.

 

We found that the crucial exercise in ensuring unique data were retained when combining these two maps was to create a decision tree for determining which data would be primary in choosing where to draw unit boundaries. We divided the decision tree into the following if-then statements:

  • If saturated colors (meaning the color signal in color-ratio spectral data was strong and the color itself was easy to describe) matched unit boundaries derived from morphology, there was no conflict. For example, saturated colors on Vesta tend to be associated with fresher expressions or exposures of regolith, which are more likely found at the youngest, freshest craters/ejecta, easily demarcated morphologically.
  • If muted colors exist, where the morphology is relatively clear, the morphology is the primary guide for unit definition, as it retains the least altered record of geologic processes and the most reliable record of the nature of the rock bodies. Colors provide additional characteristics of such units, allowing for some interpretation of composition.
  • If saturated colors are not associated with morphologic boundaries, the color boundaries are interpreted to record the most recent (even if very thin) impact evidence. In such cases we have mapped the saturated color data as impact material. This preserves the underlying morphology/topography information while supporting stratigraphic interpretations based on excavated subsurface layers revealed by crater ejecta.
  • In the case of muted colors where the morphology is unclear, decisions must be made case-by-case, using all available data to make a reasonable determination of where to mark unit boundaries.

How to cite: Yingst, R. A., Mest, S. C., Garry, W. B., Williams, D., Berman, D., and Gregg, T. K. P.: Mapping Vesta using a hybrid method for incorporating spectroscopic and morphologic data, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-8552, https://doi.org/10.5194/egusphere-egu23-8552, 2023.

EGU23-8692 | Orals | GM10.1

How does sediment cycling work on Mars? Three investigations into the cycling of Martian aeolian sand 

Devon Burr, Joshua Finch, Anna Baker, Rachel Fry, Van Nhi Nguyen, and Tanisha Chinchkhede

Aeolian sand transport on Mars is active today and was likely so throughout its history. Widespread dune motion is theorized to comminute sand to sub-sand sizes, a process also implied by lab experiments. In view of this sand destruction, discovering the source(s) and origin(s) of Martian sand provides critical information for understanding Martian sediment cycling.

Local sand sources have been discovered and considered to be consistent with the long-standing hypothesis for Martian sand as volcaniclastic in origin. A local source of Martian sand has recently been inferred in the western Medusae Fossae Formation (wMFF). Given the pyroclastic origin of the vast MFF, the new discovery of sand generation from that deposit substantiates a volcaniclastic origin of Martian sand.

However, the wMFF is limited in extent and unlikely to constitute an origin for the globally distributed dune fields on Mars. Continued exploration for sand origins is needed to explain this widespread distribution.

We examined the five global geological units interpreted as volcaniclastic, which yielded limited evidence of sand sourcing outside the wMFF. In these five units, sand sourcing was detected in visible-wavelength data in the Hesperian and Amazonian transitional units that comprise the central and eastern MFF and in the Noachian units of Arabia Terra. Investigation to characterize sand production from these units is revealing a variety of sand source outcrops.

Tracing sand deposits back to their sources is another approach for determining sand origins, as was used in determining the source – and thereby the origin – of sand in and from the wMFF. Determining sources for the widespread sand on Mars requires determining sand survivability: how far could sand travel from their sources before being destroyed by comminution to sub sand sizes? Simulation of aeolian transport on Mars has shown different sand mineralogies comminuting at different rates, suggesting that the bulk mineralogy of a sediment may change with increased transport distance. Building on that previous experimental work, we are undertaking comminution of 14 different Mars-analog sands to more fully characterize the mineralogical and physical effects on sand of aeolian transport. The results will support using dune sand compositions and distances from possible source outcrops to test if these outcrops sourced the sand.

Thermal inertia is used to characterize Martian sand, e.g., to estimate grain sizes. Available dune field mapping facilitates investigation into dune sand thermal inertia values, thereby providing data, e.g., on sand particle sizes and induration states. As available mapping incorporates non-sand substrate, we are remapping dune fields to include only visible sand and using the distributions of thermal inertia values to assess if non-sand substrate is still included in our mapping. Having completed remapping of tropical dune fields, we are beginning analysis of their thermal inertia values. The results will reveal any trends relative to geography, underlying geologic unit, elevation, and other factors.

These three investigations – into the sources and origins, effects of transport, and thermal inertia values of Martian sand – will support improved understanding of Martian aeolian sand cycling, one of the most active geologic agents on Mars.

How to cite: Burr, D., Finch, J., Baker, A., Fry, R., Nguyen, V. N., and Chinchkhede, T.: How does sediment cycling work on Mars? Three investigations into the cycling of Martian aeolian sand, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-8692, https://doi.org/10.5194/egusphere-egu23-8692, 2023.

EGU23-9136 | Orals | GM10.1

Updating the Lunar Reference Frame 

Brent Archinal and International Astronomical Union Working Group on Cartographic Coordinates and Rotational Elements

Introduction: The WGCCRE has made recommendations regarding the lunar reference frame (LRF) [1]. Over the last 2 years both the Artemis III SDT report [2] and the LEAG-MAPSIT LCDP SAT report [3] have included recommendations for an updated lunar reference frame. Park et al. [4] have published new Solar System ephemeris results that include a new lunar laser ranging (LLR) solution and lunar orientation ephemerides. The latter includes the DE440 ephemeris in the Mean Earth/polar axis (ME) frame, which is compatible with their earlier DE421 ME frame recommended for use by the WGCCRE.

Given the recent activities and interest on the LRF, and the expected increase in lunar missions by the various nations, it is appropriate for the WGCCRE to consider updating the recommendations on a LRF. We are soliciting input on such a recommendation.

Issues to consider: The Moon is one of few bodies in the Solar System without a specific longitude defining feature. It may be timely to use an LLR solution to define the LRF, following long-standing IAU and WGCCRE recommendations [1, p. 7]. Currently, a particular such LLR solution is already the underlying basis for the DE421 ME frame. Such a solution and similar future improved solutions could instead serve to directly define the frame in the ME system, and in practice would match in a no-net rotation sense the existing recommended DE421 ME frame.

Separately, the lunar orientation model could now be specified by using the JPL DE440 ephemeris in the ME frame. The new JPL solutions use substantially more available data, and improved modeling compared to the previous (2008) DE421 solution. Differences from the previous model are less than 1 meter during the period 1900–2050. Differences in the underlying LLR solutions are < 1.5 meters. Such differences are not so significant as to be noticeable in the positioning of data products except at the highest current levels of accuracy. This update would nevertheless help to prepare for the best future accuracy by removing one source of error.

We will present the benefits of updating the LRF and weigh them against the burden of changing the established definition.

Request for input: The WGCCRE is requesting feedback from the lunar community on these issues. Is using (the current new JPL) LLR solution to define the LRF appropriate? Is using the DE440 ephemeris in the DE421 ME frame appropriate as a new lunar orientation model? Are there other LLR and lunar ephemeris solutions that could be considered for use in this process? Feedback to the lead author is welcome, preferably by the time of or at the EGU meeting. We hope to complete the next version of our main WGCCRE report this year and possibly include an update for a recommended LRF definition.

References: [1] Archinal et al. (2018) CMDA 130:22. [2] NASA (2020) NASA/SP-20205009602. [3] LEAG-MAPSIT Special Action Team (2021), see MAPSIT website. [4] Park et al. (2021) The JPL Planetary and Lunar Ephemerides DE440 and DE441, Astron. J. 161(3), 105.

How to cite: Archinal, B. and Working Group on Cartographic Coordinates and Rotational Elements, I. A. U.: Updating the Lunar Reference Frame, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-9136, 2023.

EGU23-10690 | ECS | Posters on site | GM10.1

Slope Profile of Slope Streaks Indicate an Energetic Triggering Mechanism 

Rachael Hoover, David Stillman, Katie Primm, Hannah Kaplan, Tim Michaels, and Lori Fenton

There are several active geologic processes on Mars today one of which is the formation of slope streaks. Slope streaks are a widespread and relatively common process that were first observed as dark fan-shaped features with lobed ends in Viking Orbiter images taken in 1977 (Morris, 1982; Ferguson and Lucchitta, 1984). Investigation of repeat images identified slope streaks as relatively low-albedo features that vary in width (up to 200 m wide) and length (up to a few kilometers long) (Sullivan et al., 2001). Although it was assumed that the slope streaks formed on steep slopes >20°, the slopes were not resolved due to the resolution limit of the data. Slope streaks have been found to form in high-albedo dusty regions on Mars, concentrated around the equator between 39°N and 28°S (Sullivan et al., 2001; Schorghofer and King, 2011; Heyer et al., 2019). Additionally, slope streaks have been observed to fade over decades and high-albedo slope streaks have also been observed (interpreted to be faded slope streaks) (Schorghofer et al., 2007). The formation of slope streaks has previously been observed to be inconsistent spatially and temporally (Schorghofer and King, 2011); however, more recent research has identified seasonal variations of formation, with the highest rates of formation occurring in the fall (near Ls 190) (Heyer et al., 2019). There are many proposed formation mechanisms for slope streaks that fall into either a dry or wet mechanism category. The dry mechanism involves a granular flow triggered by a disturbance mechanism (e.g. dust devil or meteorite impact), while a wet mechanism would indicate a debris flow triggered by a phase change of H2O (e.g. melting of ice to trigger groundwater discharge). Research presented here investigates the slope profiles of identified slope streaks to further understand and constrain the formation mechanism. We investigated 13 well-monitored slope streak sites. Using Arcmap we identified slope streaks within each site with a polyline. For each site we identified CTX stereopairs, processed each image using the Integrated Software for Imagers and Spectrometers (ISIS3), and then used Ames Stereo Pipeline (ASP) to create digital elevation models (DEM) for each site. In Arcmap using the DEMs and the polylines for each slope streak we extracted the slope profiles to determine the starting and stopping slope of each slope streak and then average slope of the entire slope streak. Results indicate that on average slope streaks starts at a slope of 24° and end on a slope of 16° with the ending slope decreasing with increasing flow distance. Also, the majority of slope streaks start on a slope <30°, which is near the dynamic angle of repose. The low start angle and the decreasing stop angle with flow distances indicates an energetic triggering mechanism may be necessary to create a slope streak. Recent research from Heyer et al. (2020) identified dust devil tracks that appear to have triggered slope streaks, supporting our results that are most consistent with a dry and energetic triggering mechanism.

How to cite: Hoover, R., Stillman, D., Primm, K., Kaplan, H., Michaels, T., and Fenton, L.: Slope Profile of Slope Streaks Indicate an Energetic Triggering Mechanism, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-10690, https://doi.org/10.5194/egusphere-egu23-10690, 2023.

EGU23-10961 | Orals | GM10.1 | Highlight

Exploring biosignatures and geomorphology of Mars with close-up images – preparatory activities for the ExoMars mission. 

Nikolaus J. Kuhn, Gabriela Ligeza, Tomaso Bontognali, Jean-Luc Josset, and Brigitte Kuhn

ExoMars is an astrobiology program led by the European Space Agency, which aims to launch a rover to Oxia Planum to search for signs of past life. Although the primary goal of the mission is focused on astrobiology, there are several secondary mission objectives, such as investigating the geomorphology, aeolian and volcanic processes to better understand the evolution and paleoclimate of Mars. CLUPI (a close-up imager) will be used to acquire high-resolution images of rocks, geological outcrops, and drill cores to provide the overview on the geology of Oxia Planum. Due to the limited amount of data that can be transmitted at once from Mars, only few CLUPI images will be available daily to the science team for assessing hypotheses and decide how to program the rover of the next cycle of activities. Thus, it is curial that each CLUPI image will contain a maximum of relevant information. For this reason, we are conducting preparatory tests and simulations to identify ideal CLUPI working conditions in view of the prime mission on Mars. In this work, we specifically explored the impact that different illumination conditions (i.e., direction of the illumination axis and intensity of direct light vs diffused light) may have on the detection of textures and sedimentary structures in close-up images. We showed that by acquiring images at different type of day, under specific lighting conditions, it is possible to enhance the probability of detecting various rock textures and geological samples, which can contribute to the diverse data collection and answer main question about the geomorphology of Oxia Planum.

How to cite: Kuhn, N. J., Ligeza, G., Bontognali, T., Josset, J.-L., and Kuhn, B.: Exploring biosignatures and geomorphology of Mars with close-up images – preparatory activities for the ExoMars mission., EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-10961, https://doi.org/10.5194/egusphere-egu23-10961, 2023.

EGU23-11911 | ECS | Posters on site | GM10.1

Landforms and chronologies in the southern branch of Kasei Valles, MARS 

Deniz Yazıcı, Cengiz Yıldırım, and Tolga Görüm

The second-largest valley on Mars is Kasei Valles. This research focuses on the landforms produced by surface processes in the southern branch of Kasei Valles’s midstream. By using cross-cutting relationships, and empirical crater dating of landforms, we constructed a morpho-stratigraphical chronology of the valles. Landforms such as deeply eroded canyons, colluvial fans, landslides, topographic barriers, terraces, and trim lines are typical landforms that have been formed by surface processes.

Our geomorphic mapping reveals that the valles were temporarily obstructed by two colluvial fans and a landslide, creating topographical obstacles to impound fluids (e.g lava, mudflow, water). The toe of the alluvial fans and the landslide were eroded by flights of terraces and trim lines, indicating a temporary, water-like liquid presence in the channel of the valles. The surface texture of the terrace surfaces indicates that the terrace staircases were probably created by a water-like fluid that stagnated and fluctuated for a while before the final evacuation.

The chronology of these important events indicates that colluvial fans were deposited in two temporal clusters. The first colluvial fan generation was formed in the Early Amazonian period (1.74-1.14 Ga), and the second colluvial fan generation was formed in the Late-Middle Amazonian period (307 Ma). The landslide is significantly younger and is estimated to have formed 122 Ma ago. The floor of the valles’s channel is covered by platy-textured material, which was formed 90 Ma ago as lavas or mudflows, which is the youngest studied geomorphologic feature. The age of the landslide and valles’s floor help us to constrain the timing of erosional processes responsible for the flights of terraces and trimlines, which stretch along approximately 60 km from up to downstream. Accordingly, these features should be formed between 122 Ma and 90 Ma. We believe that the genesis of these features (terraces and trimlines) is associated with a Newtonian fluid (such as water) that ponded behind the colluvial fan dams and the climatic conditions that allow this fluid to stagnate over brief periods of time enough to form terraces and trimlines. 

How to cite: Yazıcı, D., Yıldırım, C., and Görüm, T.: Landforms and chronologies in the southern branch of Kasei Valles, MARS, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-11911, https://doi.org/10.5194/egusphere-egu23-11911, 2023.

EGU23-12945 | Posters virtual | GM10.1

Preliminary results of Tolstoj quadrangle (H08) geological mapping 

Lorenza Giacomini, Laura Guzzetta, Valentina Galluzzi, Luigi Ferranti, and Pasquale Palumbo

Tolstoj quadrangle is located in the equatorial area of Mercury, between 22.5°N and 22.5°S of latitude and 144° and 216°E of latitude. In this work we present the preliminary results of a geological map (1:3M scale). The main basemap used for the mapping is the MDIS (Mercury Dual Imaging System) 166 m/pixel BDR (map-projected Basemap reduced Data Record) monochrome mosaic compiled using NAC (Narrow Angle Camera) and WAC (Wide Angle Camera) 750 nm-images. Moreover, to distinguish spectral characteristics and topography of the surface, MDIS global color mosaics (Denevi et al., 2016) and the MDIS global DEM (Becker et al., 2009), have been taken into account. Then, the quadrangle has been mapped using ArcGIS at an average scale of 1:400k for a final out-put of 1:3M. So far, most of the geological contacts and lineaments of Tolstoj quadrangle have been mapped. The preliminary geological map shows the Caloris basin-related features dominating the Tolstoj quadrangle. The southern half of the basin is located in the upper left corner of quadrangle and interior and exterior smooth plains of the Caloris basin are the most extended volcanic deposits emplaced in the area. Also structural framework is mainly linked with the basin with radial and concentric grabens located in its floor and wrinkle ridges widespread both on the interior and exterior Caloris smooth plains. Further, thrusts have been detected on the quadrangle. They are located outside the Caloris basin but they are absent within its floor. Besides smooth plains, products of effusive volcanism, features related to explosive volcanism are also frequently detected. Interestingly, several volcanic vents have been identified in the inner Caloris smooth plains, aligned with the rim of Caloris basin. They were surrounded by extended pyroclastic deposits appearing in bright yellow in MDIS enhanced global color mosaics. However, vents are not clustered only inside Caloris basin, but other crater floors are affected by this type of features. Finally, few hollow fields have been detected, mainly located within crater floors.

Once the mapping activity is accomplished, the geological map will be integrated into the global 1:3M geological map of Mercury (Galluzzi et al., 2021), which is being prepared in support to ESA/JAXA (European Space Agency, Japan Aerospace Agency) BepiColombo mission.

 

Acknowledgements:  We gratefully acknowledge funding from the Italian Space Agency (ASI) under ASI-INAF agreement 2017-47-H.0

 

References:

Becker K. J., et al. AGU, Fall Meeting, ab-stract#P21A-1189, 2009

Denevi et al.:LPS XLVII. Abstract#1264, 2016

Galluzzi V. et al.:. Planetary Geologic Mappers 2021, LPI #2610, 2021

How to cite: Giacomini, L., Guzzetta, L., Galluzzi, V., Ferranti, L., and Palumbo, P.: Preliminary results of Tolstoj quadrangle (H08) geological mapping, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-12945, https://doi.org/10.5194/egusphere-egu23-12945, 2023.

EGU23-13051 | Orals | GM10.1

Landform Evolution Modelling of Volcanic Landforms using Landlab: A case study of Olympus Mons 

Sharmistha Sonowal, Uma Narayan M, Adnan Ahmad, and Archana M Nair

 Landscape Evolution Models (LEM) play a vital role in illustrating the complex landscape
responses to various geomorphic processes. These models favour replicating various evolution
processes over an extensive range of temporal and spatial scales. LEMs are also suitable for
simulating the effect of volcanic activity on landscape features. Olympus Mons, the largest
shield volcano in our solar system, acts as the perfect landform for this analysis. Tharsis
Volcanic Landforms on Mars, such as Olympus Mons and Tharsis Montes, are considered
analogues of basaltic shield volcanoes on Earth. The shield volcanoes of Tharsis are compared
to terrestrial Hawaiian volcanoes and Deccan volcanism and are often interpreted as hotspot
plume volcanism. The stream power incision model (SPIM) is used in landscape evolution
models to simulate river incisions. In this study, we utilised LandLab software to perform
numerical evolution modelling on Olympus Mons. The initial topography of the research
region is established using a DEM, and the maximum elevation of Olympus Mons is 21241.0
metres. The erodibility (Ksp) value, based on the lithological and climatic conditions, is taken
as 1
𝑀𝑎– ¹ under Hawaiian conditions considering the basaltic type rock property of Olympus
mons. With a concavity index value of 0.5 and zero upliftment, the model is run for 100000
years to observe its evolution. Our results reveal a change in the maximum elevation of 21241.0
to 21179.68, i.e., 124 m, due to the process of erosion. The results give an idea about how the
original volcanic landform, like that of Hawaii, must have shaped into the present landform
due to various geomorphic factors.
 

How to cite: Sonowal, S., Narayan M, U., Ahmad, A., and Nair, A. M.: Landform Evolution Modelling of Volcanic Landforms using Landlab: A case study of Olympus Mons, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-13051, https://doi.org/10.5194/egusphere-egu23-13051, 2023.

EGU23-13656 | Posters on site | GM10.1

CTX in-flight calibration and data dissemination 

Sebastian H. G. Walter, Robert R. C. Munteanu, and Michael Aye

The Context Camera (CTX) on board NASA's Mars Reconnaissance Orbiter (MRO) has been in orbit since 2006 and has so far delivered more than 130,000 images. The images are one of the most popular data sets for planetary geologists because the data cover almost the entire planet and have good radiometric resolution, allowing very detailed interpretation of surface features. Since the beginning of the mission, the images have exhibited a darkening effect from the centre of the images towards the edges, creating visible seam lines when multiple images are stitched together. Due to the symmetric decrease in reflectance plots averaged over all lines, this problem is often referred to as "frowning" (see Figure 1 left). Since the standard calibration routines of the Integrated Software for Imagers and Spectrometers (ISIS) only include flatfield files for the first year of the mission, there are no quick and easy standard methods to correct for these artefacts. In this work, we provide an extended in-flight radiometric calibration and the resulting flatfield files that can be used directly in the ISIS environment (see correction example in Figure 1 right). The files are updated regularly and are permanently available in this repository: https://dx.doi.org/10.17169/refubium-37236 .

Figure 1: left: CTX image N05_064260_1638 with standard ISIS calibration applied (top) and curve plot of all averaged lines (bottom); right: after additional in-flight calibration the image (top) shows less darkening to the borders and the downward trent in the plot has been removed.

In addition, we are in the process of updating our "integrated Mars analysis and research system" (iMars) to include the full set of CTX images, which will be readily processed and made available for download in GIS-compatible formats. As with the previous system, users can select the footprints and visualise the data directly in the map view. Special tools for switching between images with multiple coverage provide an excellent infrastructure for analysing surface changes and seasonal or interannual variations.  We have made a complete overhaul of the graphical interface, which is accessible under https://maps.planet.fu-berlin.de/ctx . 

This work is supported by the German Space Agency (DLR Bonn), grant 50 OO 2204, on behalf of the German Federal Ministry for Economic Affairs and Energy. We thank the HPC Service of Freie Universität Berlin for computing time.

How to cite: Walter, S. H. G., Munteanu, R. R. C., and Aye, M.: CTX in-flight calibration and data dissemination, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-13656, https://doi.org/10.5194/egusphere-egu23-13656, 2023.

EGU23-14806 | Posters on site | GM10.1

Coregistration of CTX images to HRSC Global Datasets 

Michael Aye, Sebastian H.G. Walter, and Frank Postberg

 

The current approach for ortho-rectifying images taken by the Context Camera (CTX) on the Mars Reconnaissance Orbiter (MRO) uses MOLA data as a global reference ([1]), but this approach is imprecise, specifically at the equator, due to the large difference in spatial resolution between the two datasets (6 vs 463 m/pix).  Automatic point matching of image pixels to DTM pixels are not reliable, therefore usually the CTX pixels are matched to imagery datasets which are themselves controlled to MOLA, such as the THEMIS IR dataset ([2]).

The HRSC team is working on creating global mosaics of bundle-block-adjusted digital terrain models (DTMs) and corresponding image mosaics with better internal photogrammetric precision than the 50 m used as the grid size, and less deviation from MOLA profile heights, aimed to be finished by the end of 2023. 

This abstract presents our progress in using a new approach, by using HRSC DTMs as the global reference for CTX image rectification instead of MOLA, which involves using the HRSC ortho-image for co-registration of CTX images and applying brightness correction before combining all images of a quadrangle together to form a seamless mosaic which is then exported as a single image file. 

 

The workflow and processing is performed using modern pixel registration techniques, the USGS’ ISIS system, a database management system, and high-performance computing, and results in significantly less pixel offsets compared to the previous approach.

References[1] J. L. Dickson et al., LPSC 49, #2480. [2] S. J. Robbins et al., LPSC 52, #2066. 

Acknowledgements: This work is supported by the German Space Agency (DLR Bonn), grant 50OO2204, on behalf of the German Federal Ministry for Economic Affairs and Climate Action. We thank the HPC Service of FU for computing time.

How to cite: Aye, M., Walter, S. H. G., and Postberg, F.: Coregistration of CTX images to HRSC Global Datasets, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-14806, https://doi.org/10.5194/egusphere-egu23-14806, 2023.

EGU23-14816 | Orals | GM10.1

Estimating subglacial water discharges needed to form Amazonian-aged mid-latitude eskers on Mars 

Neil Arnold, Frances Butcher, Colman Gallagher, Matt Balme, and Susan Conway

Eskers are sinuous sedimentary ridges formed in meltwater-filled subglacial tunnels. They are widespread in formerly glaciated landscapes on Earth. A small but growing number of late Amazonian-aged (~110-330 Ma) candidate eskers have been identified in Mars’ mid-latitudes in association with extant buried glaciers. These eskers are thought to have formed during periods when mid-latitude glaciation on Mars was more extensive than at present, due to variations in planetary spin-axis obliquity. The basal melting required for esker formation seems likely to have required elevated local or regional geothermal heating.

A recent study using current terrestrial theories for subglacial water flow adapted for Mars suggests that, if water was present beneath Martian ice masses, lower gravity favours the formation of efficient, tunnel-based drainage, as opposed to water flow through a distributed system of small cavities linked by water-filled orifices which is favoured for terrestrial ice masses. Tunnel-based drainage systems are more efficient, leading to lower water pressures and gradients, and slower water velocity.  Our previous experiments with a Mars-adapted model of esker sedimentation also suggest that, once a subglacial tunnel has formed, sediment deposition occurs more readily on Mars than Earth, as the lower gravity, and consequent lower water pressure and velocity, allows more rapid deposition.

These factors suggest that if subglacial water and mobilised sediment are present beneath Martian ice masses, esker formation is more likely on Mars than Earth as subglacial tunnels would be more widespread, and sediment deposition within them more rapid. However, this leads to questions regarding the likely source(s) of esker-forming sediment, and the water volumes needed to erode it. Initial calculations with a Mars-adapted model for erosion by subglacial water suggest that for a particle size typical of Martian sandy regolith (150 mm), erosion requires water velocities > 0.1 ms-1. Calculated erosion rates vary from 5x10-10 ms-1 to 3.5x 10-7 ms-1 for water velocities between 0.1 ms-1 and 1 ms-1, and are higher than for equivalent terrestrial channels, largely because the critical shear stress needed to mobilise sediment is lower due to Mars’ gravity. This suggests that sediment will be readily mobilised beneath wet Martian ice masses, making the supply of water the critical limiting factor. Thus, this study will use an ice flow model to reconstruct a more extensive glacier over a candidate esker in the Phlegra Montes of Mars’ northern mid latitudes. Geothermal heat will be varied, along with other glaciological and climatic parameters, to investigate the possible extent of warm-based ice in the region, and to estimate the extent and volume of subglacial meltwater. The modelled meltwater will then be input into the Mars-adapted subglacial water erosion model to explore the impact of water availability and sediment characteristics on the possible extent of sediment erosion. Modelled sediment supply will then be compared with the sediment volume within the candidate esker, reconstructed from a 1 m/pixel digital elevation model, to help constrain the regional glaciological, sedimentological, climatological and geothermal conditions needed for esker formation.

How to cite: Arnold, N., Butcher, F., Gallagher, C., Balme, M., and Conway, S.: Estimating subglacial water discharges needed to form Amazonian-aged mid-latitude eskers on Mars, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-14816, https://doi.org/10.5194/egusphere-egu23-14816, 2023.

EGU23-15877 | ECS | Posters on site | GM10.1

Large Area Glacier-Like Forms on Mars: Insights from Impact Crater Morphologies and Crater Retention Ages 

Graham Driver, Mohamed Ramy El-Maarry, Bryn Hubbard, and Stephen Brough

Ice-rich landforms known as Viscos-Flow Features (VFFs) are common in Mars’ mid-latitudes. Glacier-Like Forms (GLFs) are a distinct sub-category of VFFs and appear morphologically similar to terrestrial valley glaciers or rock glaciers. GLFs are thought to be the result of the redistribution of water ice from the Martian poles during periods of high obliquity (>35o) and the Last Martian Glacial Maximum (LMGM), which ended ~5 Myr. Numerous distinct impact crater morphologies have been observed on these ice-rich terrains. Research has suggested that this variation results from interactions between landform lithologies and surface evolution through depositional and erosional processes. We investigated impact crater quantities and morphologies on 100 GLFs with large surface areas, with the aim of determining Crater Retention Ages (CRAs) for the landforms and exploring the relationships between crater morphology variation and relative surface ages.

Our results show GLF ages vary across Mars, with various surface retention ages and crater morphologies populations. There are populations of GLFs with young CRAs (<20 Ma), particularly in the southern hemisphere, suggesting recent glaciation could have been more favourable in the southern mid-latitudes. Our results suggest several scenarios for GLFs across Mars. (1) That some GLFs have the potential to be very young, having perhaps formed in the last few million years during the LMGM. (2) That some GLFs may have formed before the LMGM (>20Ma) but have high resurfacing rates, partially removing their impact records. (3) That some GLFs formed long before the LMGM and have medium to very low resurfacing rates. These GLFs have surfaces with greater quantities and morphological variation of craters. Consequently, they also appear to record more resurfacing events and have more comprehensive CRA ranges. The low resurfacing rates suggest that these GLFs have not been in favourable depositional environments for an extended period and are possibly in low erosional settings. The study hints that while high Martian obliquity periods can favour glaciation, material accumulation, and resurfacing events, this occurs within local geographical constraints and that not all periods of glaciation are favourable to all GLFs across Mars.

How to cite: Driver, G., El-Maarry, M. R., Hubbard, B., and Brough, S.: Large Area Glacier-Like Forms on Mars: Insights from Impact Crater Morphologies and Crater Retention Ages, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-15877, https://doi.org/10.5194/egusphere-egu23-15877, 2023.

EGU23-542 | ECS | Posters on site | ESSI1.3

Electron Temperature Inference from Fixed Bias Langmuir Probes Set-Ups in Ionospheric Conditions 

Florine Enengl, Sigvald Marholm, Sayan Adhikari, Richard Marchand, and Wojciech J. Miloch

In this work, we show the first achievement of inferring the electron temperature in ionospheric conditions from synthetic data using fixed-bias Langmuir probes operating in the electron saturation region. This was done using machine learning, as well as by altering the probe geometry. The electron temperature is inferred at the same rate as the currents are sampled by the probes. For inferring the electron temperature along with the electron density and the floating potential, a minimum number of three probes is required. Furthermore does one probe geometry need to be distinct from the other two, since otherwise the probe setup may be insensitive to temperature. This can be achieved by having either one shorter probe or a probe of a different geometry, e.g. two longer and a shorter cylindrical probe or two cylindrical probes and a spherical probe. We use synthetic plasma parameter data and calculate the synthetic collected probe currents to train a neural network (using TensorFlow) and verify the results with a test set as well as with data from the International Reference Ionosphere (IRI) model. A table with computed currents collected by a spherical probe by Laframboise was extended to calculate currents of the synthetic plasma parameters for high eta values (eta >25) to cover a large altitude range (100-500 km, within Earth's ionosphere). The extrapolated values were benchmarked with Particle-in-Cell simulations. Finally, we evaluate the robustness and errors of different probe setups that can be used to infer the electron temperature. As the inferred temperatures are compared to results from the International Reference Ionosphere model, we verify the validity of the inferred temperature in altitudes ranging from about 100-500 km. We show that electron temperature inference from different combinations of spherical and cylindrical probes - three cylindrical probes, three spherical probes, four cylindrical and a spherical probe - can be achieved. Even minor changes in the probe sizing enable the temperature inference and result in root mean square relative errors (RMSRE) between inferred and ground truth data of under 3%. With further optimizations, the RMSRE can even be decreased to under 1%. When limiting the temperature inference to 120-450 km altitude an RMSRE of under 0.7% is achieved for all probe setups. In future, the multi-needle Langmuir Probe (m-NLP) instrument dimensions can be adapted for higher temperature inference accuracy.

How to cite: Enengl, F., Marholm, S., Adhikari, S., Marchand, R., and Miloch, W. J.: Electron Temperature Inference from Fixed Bias Langmuir Probes Set-Ups in Ionospheric Conditions, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-542, https://doi.org/10.5194/egusphere-egu23-542, 2023.

EGU23-850 | Posters on site | ESSI1.3

Unsupervised learning of active-region nesting on the Sun 

Emre Isik, Nurdan Karapinar, and Selim Göktug Cankurtaran

Active-region emergence on the Sun shows a degree of clumpiness in both space and time. At a given time, multiple active regions can be seen in what is called active-region- or sunspot-group nests. This tendency also increases the potential to produce large flares and associated CMEs. In the literature, the nesting tendency of active regions is reported in the range of 30-50 per cent, but no statistically robust and ML-based approaches exist so far. Quantifying the nesting degree along an activity cycle and determining its spatial and temporal scales are important to investigate the processes that cause this phenomenon. 

In this study, we estimate the latitudinal and longitudinal extents of active region nesting using both continuum and magnetogram data, using SDO/HMI synoptic magnetograms and Kislovodsk Mountain Astronomical Station (KMAS) sunspot group data. We carry out kernel density estimation (Fig. 1) and unsupervised ML techniques (e.g., DBSCAN and Gaussian mixtures) in spatial and spatio-temporal domains. Our study reveals trends in the emergence characteristics of sunspot groups on the Sun.


Figure 1: Kernel density estimation with a Gaussian kernel on the time-longitude plane. The dot size indicates sunspot group areas in MSH. 

How to cite: Isik, E., Karapinar, N., and Cankurtaran, S. G.: Unsupervised learning of active-region nesting on the Sun, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-850, https://doi.org/10.5194/egusphere-egu23-850, 2023.

EGU23-2719 | Posters on site | ESSI1.3

Different types of PCA-NN model for TEC with space weather parameters as predictors: advantages and disadvantages of different NN algorithms 

Anna Morozova, Ricardo Gafeira, Teresa Barata, and Tatiana Barlyaeva

A PCA-NN model for the total electron content (TEC) for the midlatitudinal region (Iberian Peninsula) presented here uses the principal component analysis (PCA) to decompose TEC variations into different modes and to reconstruct/forecast amplitudes of these modes using neural networks (NN) with different sets of space weather parameters as predictors.

Feedforward, convolutional and recurrent NN algorithms are tested with different sets of predictors. The performance of the models is tested on 3.5 years of observational data obtained at the declined phase of the 24th solar cycle, which allows us to estimate the models’ performance in relation to the solar activity level. The advantages and disadvantages of different NN algorithms are discussed.

How to cite: Morozova, A., Gafeira, R., Barata, T., and Barlyaeva, T.: Different types of PCA-NN model for TEC with space weather parameters as predictors: advantages and disadvantages of different NN algorithms, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-2719, https://doi.org/10.5194/egusphere-egu23-2719, 2023.

EGU23-2756 | ECS | Orals | ESSI1.3

SuNeRF: AI enables 3D reconstruction of the solar EUV corona 

Robert Jarolim, Benoit Tremblay, Andres Munoz-Jaramillo, Kyriaki-Margarita Bintsi, Anna Jungbluth, Miraflor Santos, James Paul Mason, Sairam Sundaresan, Cooper Downs, Ronald Caplan, and Angelos Vourlidas

To understand the solar evolution and effects of solar eruptive events, the Sun is permanently observed by multiple satellite missions. The optically-thin emission of the solar plasma and the limited number of viewpoints make it challenging to reconstruct the geometry and structure of the solar atmosphere; however, this information is the missing link to understand the Sun as it is: a three-dimensional, evolving star. We present a method that enables a complete 3D representation of the uppermost solar layer observed in extreme ultraviolet (EUV) light. We use a deep learning approach for 3D scene representation that accounts for radiative transfer, to map the entire solar atmosphere from three simultaneous observations. We demonstrate that our approach provides unprecedented reconstructions of the solar poles, and directly enables height estimates of coronal structures, solar flux ropes, coronal hole profiles, and coronal mass ejections. We validate the approach using model-generated synthetic EUV images, finding that our method accurately captures the 3D geometry even from a limited number of viewpoints. We quantify uncertainties of our model using an ensemble approach that allows us to estimate the model performance in absence of a ground-truth. Our method enables a novel view of our closest star, and is a breakthrough technology for the efficient use of multi-instrument datasets, which paves the way for future cluster missions.

How to cite: Jarolim, R., Tremblay, B., Munoz-Jaramillo, A., Bintsi, K.-M., Jungbluth, A., Santos, M., Mason, J. P., Sundaresan, S., Downs, C., Caplan, R., and Vourlidas, A.: SuNeRF: AI enables 3D reconstruction of the solar EUV corona, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-2756, https://doi.org/10.5194/egusphere-egu23-2756, 2023.

EGU23-2897 | Orals | ESSI1.3

Automatic Classification of THEMIS All-Sky Images via Self-Supervised Semi-Supervised Learning 

Jeremiah Johnson, Dogacan Ozturk, Hyunju Connor, Donald Hampton, Matthew Blandin, and Amy Keesee

Dynamic interactions between the solar wind and the magnetosphere give rise to dramatic auroral forms that have been instrumental in the ground-based study of magnetospheric dynamics. The general mechanism of aurora types and their large-scale patterns are well-known, but the morphology of small- to meso-scale auroral forms observed in all-sky imagers and their relation to magnetospheric dynamics  and the coupling of the magnetosphere to the upper atmosphere remain in question. Machine learning has the potential to provide answers to these questions, but most existing auroral image data lack the ground-truth labels required for supervised learning and conventional statistical analyses. To mitigate this issue, we propose a novel self-supervised semi-supervised algorithm to automatically label the THEMIS all-sky image database. Specifically, we adapt the self-supervised Simple framework for Contrastive Learning of Representations (SimCLR) algorithm to learn latent representations of THEMIS all-sky images. These representations are finetuned using a small set of manually labeled data from the Oslo Aurora THEMIS (OATH) dataset, after which semi-supervised classification is used to train a classifier, beginning by training on the manually labeled OATH dataset and gradually incorporating the classifier’s most confident predictions on unlabeled data into the training dataset as ground-truth. We demonstrate that (a) classifiers fit to the learned representations of the manually labeled images achieve state–of–the–art performance, improving the classification accuracy by almost 10% over the current benchmark on labeled data; and (b) our model’s learned representations naturally cluster into more clusters than manually assigned categories, suggesting that existing categorizations are coarse and may obscure important connections between auroral types and their drivers. Finally, we introduce AuroraClick, a citizen science project with the goal of manually annotating a large representative sample of THEMIS all-sky images for the validation of our current models and the training of future models.  

How to cite: Johnson, J., Ozturk, D., Connor, H., Hampton, D., Blandin, M., and Keesee, A.: Automatic Classification of THEMIS All-Sky Images via Self-Supervised Semi-Supervised Learning, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-2897, https://doi.org/10.5194/egusphere-egu23-2897, 2023.

EGU23-3379 | ECS | Posters on site | ESSI1.3

Estimation and Prediction of Solar Wind Propagation from L1 Point to Earth’s Bow Shock 

Samira Tasnim, Ying Zou, Claudia Borries, Carsten Baumann, Brian Walsh, Krishna Khanal, Connor O'Brien, and Huaming Zhang

Having precise knowledge of the near-Earth solar wind (SW) and the embedded interplanetary magnetic field (IMF) is of critical importance to space weather operation due to the usage of SW and IMF in almost all magnetospheric and ionospheric models. The most widely used data source, OMNI, propagates SW properties from Lagrangian point L1 to the Earth’s bow shock by estimating the propagation time of the SW. However, the time difference between OMNI timeshifted IMF and the best match-up of IMF can reach ˜15 min. Firstly, we aim to develop an improved statistical algorithm to contribute to the SW propagation delay problem of space weather prediction. The algorithm focuses on matching SW features around the L1 point and upstream of the bow shock by computing the variance, cross-correlation coefficient, the plateau-shaped magnitude index, and the non-dimensional measure of average error index between the measurements at the two locations. The obtained propagation times are then compared to OMNI. Factors that limit the OMNI accuracy are also examined. Secondly, the automatic algorithm allows us to generate large sets of input and target variables using multiple spacecraft pairs at L1 and near-Earth locations to train, validate, and test machine learning models to specify and forecast near-Earth SW conditions. Finally, we offer a machine learning (ML) approach to specify and predict the propagation time from L1 monitors to a given location upstream or at the bow shock and forecast near-Earth SW conditions with the gradient boosting and random forest prediction models in the form of an ensemble of decision trees.

How to cite: Tasnim, S., Zou, Y., Borries, C., Baumann, C., Walsh, B., Khanal, K., O'Brien, C., and Zhang, H.: Estimation and Prediction of Solar Wind Propagation from L1 Point to Earth’s Bow Shock, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-3379, https://doi.org/10.5194/egusphere-egu23-3379, 2023.

EGU23-4069 | ECS | Posters on site | ESSI1.3

Plasma-Sheet Bubble Identification Using Muitivariate Time Series Classification 

Feng Xuedong and Yang Jian

Abstract: Plasma-sheet bubbles play a major role in the process of magnetotail particle injections. They are defined as fast flows with reduced plasma density or pressure accompanied by magnetic field dipolarization. Typically, we can detect these bubbles from in-situ observations, but subjective uncertainty needs human verification. In this study, we combine three different methods including MINImally RandOm Convolutional KErnel Transform (MINIROCKET), 1D and 2D convolution neural network (CNN) to identify bubbles. The imbalanced training dataset consists of bubble and non-bubble events with a ratio of 1:40 from year 2007 to 2020. The results indicate that the accuracy of the all three models is around 99%, and the precision and recall rates of all three models are above 80% in both the validation and test datasets. The three methods are combined with the intersection set as the minimum set of predictions and the union set as the maximum set. The methods greatly reduce the number of false positives. To identify bubbles in the observations of year 2021, our neural network model is found to be comparably good to the traditional criterial and manual inspections. Using joint machine learning forecasting methods, we can easily and automatically identify bubbles without a priori knowledge like a domain expert.

Keywords: plasma-sheet bubble, multivariate time series classification, sample imbalanced, image identification

How to cite: Xuedong, F. and Jian, Y.: Plasma-Sheet Bubble Identification Using Muitivariate Time Series Classification, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-4069, https://doi.org/10.5194/egusphere-egu23-4069, 2023.

EGU23-5254 | Posters on site | ESSI1.3

AI Assisted Data Selection of Laser Altimeter Observations 

Oliver Stenzel, Lukas Maes, and Martin Hilchenbach

Laser altimeters create large amounts of data that often have to be preprocessed and checked before further use. The BepiColombo mission to Mercury is set to arrive in December 2025 and observations with the BepiColombo Laser Altimeter (BELA, (Benkhoff et al., 2010; Thomas et al., 2021)) will start during the following spring. These measurements are planned to be used to derive information about the tides of Mercury (Thor et al., 2020). Careful assessment, selection, and filtering on the raw data is needed to extract the small tidal signal. Until the BELA data becomes available artificial data and records from other missions have to be used to study the data selection strategy. We present our work on MESSENGER Laser Altimeter (MLA, (Cavanaugh et al., 2007)) using a convolutional neural network to sort observations on an orbit by orbit basis into different classes. The already existing neural network (Stenzel and Hilchenbach, 2021; Stenzel, Thor and Hilchenbach, 2021) is tuned and a new test data set is created.

 

Benkhoff, J. et al. (2010) ‘BepiColombo—Comprehensive exploration of Mercury: Mission overview and science goals’, Planetary and Space Science, 58(1), pp. 2–20. Available at: https://doi.org/10.1016/j.pss.2009.09.020.

Cavanaugh, J.F. et al. (2007) ‘The Mercury Laser Altimeter Instrument for the MESSENGER Mission’, Space Science Reviews, 131(1), pp. 451–479. Available at: https://doi.org/10.1007/s11214-007-9273-4.

Stenzel, O. and Hilchenbach, M. (2021) ‘Towards machine learning assisted error identification in orbital laser altimetry for tides derivation’, pp. EPSC2021-688. Available at: https://doi.org/10.5194/espc2021-688.

Stenzel, O., Thor, R. and Hilchenbach, M. (2021) ‘Error identification in orbital laser altimeter data by machine learning’, pp. EGU21-14749. Available at: https://doi.org/10.5194/egusphere-egu21-14749.

Thomas, N. et al. (2021) ‘The BepiColombo Laser Altimeter’, Space Science Reviews, 217(1), p. 25. Available at: https://doi.org/10.1007/s11214-021-00794-y.

Thor, R.N. et al. (2020) ‘Prospects for measuring Mercury’s tidal Love number h2 with the BepiColombo Laser Altimeter’, Astronomy & Astrophysics, 633, p. A85. Available at: https://doi.org/10.1051/0004-6361/201936517.

 

How to cite: Stenzel, O., Maes, L., and Hilchenbach, M.: AI Assisted Data Selection of Laser Altimeter Observations, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-5254, https://doi.org/10.5194/egusphere-egu23-5254, 2023.

EGU23-6968 | ECS | Posters on site | ESSI1.3

Forecasting solar wind speed by machine learning based on coronal hole characteristics 

Daniel Collin, Stefano Bianco, Guillermo Gallego, and Yuri Shprits

One of the main sources of solar wind disturbances are coronal holes which can be identified in extreme ultra-violet (EUV) images of the Sun. Previous research has shown the connection between coronal holes and an increase of the solar wind speed at Earth. The time lag between the appearance of coronal holes on the visible side of the Sun and its effects on Earth is 2-5 days. In this study, a machine learning model predicting the solar wind speed originating from coronal holes is proposed. It is based on the analysis of solar EUV images. A segmentation algorithm is applied to the images in order to identify coronal holes and derive their characteristics (e.g. area, location). We also present a new method to calculate the geoeffective coronal hole area: Instead of specifying in advance a sector of the solar surface in which the area is measured and a lag time between area measurement and the arrival of the solar wind, the specification of this sector and the corresponding delay are formulated as a mathematical optimization problem and included in the machine learning model. This approach facilitates an improvement of the prediction accuracy and also prolongs the prediction horizon, as the solar wind speed can be predicted up to approximately 5 days in advance of the disturbance. Several machine learning model architectures are explored. We also study how the time evolution can be included in the model.

How to cite: Collin, D., Bianco, S., Gallego, G., and Shprits, Y.: Forecasting solar wind speed by machine learning based on coronal hole characteristics, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-6968, https://doi.org/10.5194/egusphere-egu23-6968, 2023.

EGU23-7529 | ECS | Posters on site | ESSI1.3

Landform detection on Mars using image segmentation with a u-net convolutional neural network architecture 

Florian Auer-Welsbach, Andreas Windisch, and Giacomo Nodjoumi

The detection and classification of landforms on planetary surfaces is a time-consuming task which deeply relies on expert knowledge. Such a process can be partially automated and optimized in a resource-efficient way using image processing algorithms. By classifying the surface into different landforms, such as volcanic craters, asteroid impacts, dunes, and more, several analyses can be performed, for instance the widely used crater counting age estimation method. In addition, by conducting these analyses, information about the characteristics and properties of a planet can be revealed. One of the major challenges for the implementation of these algorithms is to provide a generalized model. In many cases the generalization error tends to be very large and therefore a satisfactory accuracy on the test data set cannot be accomplished. This prevents reliable evaluation of new unseen data. In this work, a multi-class image segmentation algorithm is presented, which is based on a U-net convolutional neural network architecture. U-nets classify each pixel of a given input image and can thus produce segmentation masks for various landforms. Given that enough labeled data is available, such a classifier can replace manual detection and classification, thereby saving resources by providing a fast method for landform detection.

How to cite: Auer-Welsbach, F., Windisch, A., and Nodjoumi, G.: Landform detection on Mars using image segmentation with a u-net convolutional neural network architecture, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-7529, https://doi.org/10.5194/egusphere-egu23-7529, 2023.

EGU23-7761 | ECS | Posters virtual | ESSI1.3

Comparison study on the deep-learning-based detection of Mars craters 

Hind AlRiyami, Claus Gebhardt, and Christopher Lee

Deep-learning methods are of interest for the analysis of imagery and digital elevation models from Mars orbiting satellites. They detect various atmosphere and surface characteristics. For instance, these include dust storms and craters [1,2]. We approach this topic by using the deep-learning-based crater detection algorithm DeepMars2 [3,4]. The algorithm is applied to two digital elevation models (DEMs) of the Mars surface. The DEMs are based on the satellite instruments MOLA/MGS (Mars Orbiter Laser Altimeter/Mars Global Surveyor) and HRSC/MEX (High Resolution Stereo Camera/Mars Express) and have different resolution. Crater detection statistics are compared between both DEMs.

[1] Alshehhi, R., Gebhardt, C. Detection of Martian dust storms using mask regional convolutional neural networks. Prog Earth Planet Sci 9, 4 (2022). https://doi.org/10.1186/s40645-021-00464-1

[2] R. Alshehhi and C. Gebhardt, "Automated Geological Landmarks Detection on Mars Using Deep Domain Adaptation From Lunar High-Resolution Satellite Images," in IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing, vol. 15, pp. 2274-2283, 2022, doi: 10.1109/JSTARS.2022.3156371.

[3] Lee, C. (2019). Automated crater detection on Mars using deep learning. Planetary and Space Science, 170, 16-28. https://doi.org/10.1016/j.pss.2019.03.008

[4] Lee, C. & Hogan, J. (2021). Automated crater detection with human level performance. Computers & Geosciences, 147, 104645. https://doi.org/10.1016/j.cageo.2020.104645

How to cite: AlRiyami, H., Gebhardt, C., and Lee, C.: Comparison study on the deep-learning-based detection of Mars craters, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-7761, https://doi.org/10.5194/egusphere-egu23-7761, 2023.

EGU23-7941 | ECS | Orals | ESSI1.3

Machine learning ensemble models for solar wind speed prediction 

Federico Sabbatini and Catia Grimani

Machine learning models trained to reproduce space mission observations are precious resources to fill gaps of missing data in measurement time series or to perform data forecasting within a reasonable uncertainty degree. The latter option is of particular importance for future space missions that will not host instrumentation dedicated to interplanetary medium parameter monitoring. The future LISA mission for low-frequency gravitational wave detection, for instance, will benefit of particle detectors to measure the galactic cosmic-ray integral flux variations and magnetometers that will allow to monitor the passage of large scale magnetic structures through the three LISA spacecraft as part of a diagnostics subsystem. Unfortunately, no instruments dedicated to solar wind speed measurements will be present on board the spacecraft constellation. Moreover, LISA, scheduled to launch in 2035, will trail Earth on the ecliptic at 50 million km distance, far from the orbits of other space missions dedicated to the interplanetary medium monitoring.

Based on precious lessons learned with LISA Pathfinder, the ESA LISA precursor mission, about the correlation between galactic cosmic-ray flux short-term variations and solar wind speed increases, we built a machine learning ensemble model able to reconstruct the solar wind trend only on the basis of contemporaneous and preceding observations of galactic cosmic-ray flux variations. Details about the model creation and performance will be presented, together with a description of the underlying data set, weak predictors and training phase. Advantages and limitations will be discussed, showing that the model performance may be enhanced by providing interplanetary magnetic field intensity observations as additional input data, with the goal of providing the LISA mission with an effective solar wind speed predictive tool.

How to cite: Sabbatini, F. and Grimani, C.: Machine learning ensemble models for solar wind speed prediction, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-7941, https://doi.org/10.5194/egusphere-egu23-7941, 2023.

EGU23-8430 | Orals | ESSI1.3

Modelling Jupiter's global and regional magnetic fields using physics-informed neural networks 

Longwei Chen, Phil Livermore, Leyuan Wu, Sjoerd de Ridder, and Chong Zhang

As is known, neural networks can universally approximate any complex functions. This ground truth naturally makes it a suitable candidate for solution representation of complex partial differential equation (PDE) governed. For planetary magnetic field modelling problem, spherical harmonic functions are most used as standard modelling method. Spherical harmonic method requires globally nearly uniformly distributed observations. Meanwhile this method has quite limited ability for conducting regional field modelling. Instead, neural networks have great potential to deal with global or regional modelling problems. In this work, we thoroughly investigate the representative ability of neural networks for magnetic field modelling problem at global and regional scale, and concentrate on a specific neural network, that is physics-informed neural networks (PINNs) for implementation. PINNs makes it easier to incorporate different kinds of informed physics within a uniform optimization framework. Through synthetic model tests and partial mathematical proof, we showcase the importance of employing natural boundary condition, Laplace equation constraint and Poisson equation constraint at suitable collocation points for a reasonable and accurate magnetic field representation and introduce the detailed scheme for implementation. Finally, we use newly released Juno mission measurements, and present a global PINNs model for Jupiter's magnetic field, and a regional PINNs model for Great Blue Spot (GBS) region. Comparison with spherical harmonic model has been conducted to evaluate the correctness and flexibility of PINNs models.

How to cite: Chen, L., Livermore, P., Wu, L., de Ridder, S., and Zhang, C.: Modelling Jupiter's global and regional magnetic fields using physics-informed neural networks, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-8430, https://doi.org/10.5194/egusphere-egu23-8430, 2023.

To accurately predict potential future impacts with the Earth, it is crucial to continuously examine the area around it for Near Earth Objects (NEOs) and particularly Near Earth Asteroids (NEAs). Large data sets of astronomical images must be analyzed in order to accomplish this task. NEARBY [1] offers such a processing and analysis platform based on Cloud computing. Despite the fact that this method is automated, the results are validated by human observers after potential asteroids have been identified from the raw data. It is crucial that the amount of candidate objects does not outweigh the available human resources. We believe we can maximize the advantages of having access to enormous amounts of data in the field of astronomy by combining artificial intelligence with the use of high-performance distributed processing infrastructures like Cloud-based solutions. This research is carried out as part of the CERES project which aims to design and put into practice a software solution that can classify objects found in astronomical images. The objective is to identify and recognize asteroids. We use machine learning techniques to develop an asteroid classification model in order to achieve this goal. It is essential to reduce the number of false negative findings. The major objective of the current paper is to assess how well deep CNNs perform when it comes to categorizing astronomical objects, particularly asteroids. We will compare the outcomes of several of the most well-known deep convolutional neural networks (CNNs), including InceptionV3, Xception, InceptionResNetV2, and ResNet152V2. These cutting-edge classification CNNs are used to investigate the best approach to this specific classification challenge, either through full-training or through fine-tuning.

Acknowledgment: This work was partially supported by a grant of the Romanian Ministry of Education and Research, CCCDI - UEFISCDI, project number PN-III-P2-2.1-PED-2019-0796, within PNCDI III. This research was partially supported by the project 38 PFE in the frame of the programme PDI-PFE-CDI 2021.

References:

1. Bacu, V., Sabou, A., Stefanut, T., Gorgan, D., Vaduvescu, O., NEARBY platform for detecting asteroids in astronomical images using cloud-based containerized applications, 2018 IEEE 14th International Conference on Intelligent Computer Communication and Processing (ICCP), pp. 371-376

How to cite: Bacu, V.: Software solution for detecting asteroids using machine learning techniques, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-8676, https://doi.org/10.5194/egusphere-egu23-8676, 2023.

To monitor the results of our instrument on a daily basis, we create a series of daily plots that are generated in an automated fashion.  In our case, we are creating two plot types for four spacecraft for five different species.  Unfortunately, due to circumstances beyond our control (primarily network and system issues), plots were failing and if not monitored daily, they were unavailable when finally needed.  

To solve this problem, we investigated using Computer Vision (OpenCV) to validate our generation of daily plots.  It was surprisingly easy and more advantageous than trying to either monitor it daily or more simplistic methods.  By using the cloud, we were able to improve throughput as well.  Future work would be to use Computer Vision to analyze the data within the plots for actual scientific study.

How to cite: Mukherjee, J.: Using Artificial Intelligence/Computer Vision for Automated Plot Validation, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-8946, https://doi.org/10.5194/egusphere-egu23-8946, 2023.

EGU23-10654 | ECS | Orals | ESSI1.3

Predicting the 1 AU Arrival Time of Coronal Mass Ejections Based on Convolutional Neural Network 

Yi Yang, Fang Shen, Yucong Li, and Rongpei Lin

Coronal mass ejections (CMEs) are one of the most violent solar eruptions, which can burst out large amounts of magnetized plasma with speeds up to thousands of kilometers per second. When it reaches the Earth, a CME can cause geomagnetic storm, affecting aviation safety, satellite operations, communications systems and power facilities. Therefore, fast and accurate prediction of CME arrival time is crucial for avoiding severe damaging effects and reducing economic losses. The initial morphology and kinematics of a CME in the corona can be observed by the coronagraphs equipped on the Solar and Heliospheric Observatory (SOHO), so that the coronagraphs should be useful to predict the CME arrival times. In this study, convolutional neural network (CNN) is used to obtain the features of SOHO/LASCO coronagraph pictures related to the CME transit time, and establish a model capable of predicting the CME arrival time. The influence of different hyperparameters of CNN on the prediction results is studied. Further, we add a physical information constraint of the initial velocities of CME to the basic CNN outputs, and found that smaller prediction errors can be obtained. 

How to cite: Yang, Y., Shen, F., Li, Y., and Lin, R.: Predicting the 1 AU Arrival Time of Coronal Mass Ejections Based on Convolutional Neural Network, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-10654, https://doi.org/10.5194/egusphere-egu23-10654, 2023.

Solar eruptive events are complex phenomena, which most often include solar flares, filament eruptions, coronal mass ejections (CMEs), and CME-driven shock waves. CME-driven shocks in the corona and interplanetary space are considered to be the main producer of solar energetic particles (SEPs). A number of fundamental questions remain about how SEPs are produced. Current understanding points to CME-driven shocks and compressions in the solar corona.

A CME kinematics shows three phases - an initial rising phase (weakly accelerated motion), an impulsive phase and a residual propagation phase with constant or decreasing speed.

Despite significant amount of data available from ground-based (COSMO K-Cor, LOFAR) and remote instruments onboard of heliospheric space missions (SDO AIA, SOHO), processing of the data still requires noticeable effort. Most algorithms currently used in solar feature detection and tracking are known for their limited applicability and complexity of their processing chains, while usage of data-driven approaches for tracking of CME-related phenomena is currently limited due to insufficiency of training sets.

Recently (Stepanyuk et.al, J. Space Weather Space Clim. Vol 12, 20(2022)), we have demonstrated the method and the software(https://gitlab.com/iahelio/mosaiics/wavetrack) for smart characterization and tracking of solar eruptive features based on the a-trous wavelet decomposition technique, intensity rankings and a set of filtering techniques. In this work we use Wavetrack to generate training sets for data-driven feature extraction and characterization. We utilize U-Net, a fully convolutional network which training strategy relies on the strong use of data augmentation to use the available annotated samples more efficiently. U-NET can be trained end-to-end from a very limited set of images, while feature engineering allows to improve this approach even further by expanding available training sets.

Here we present pre-trained models and demonstrate data-driven characterization and tracking of solar eruptive features on a set of CME-events.

How to cite: Stepanyuk, O. and Kozarev, K.: Advanced Multi-Instrument and Multi-Wavelength Image Processing and Feature Tracking for Remote CME Characterization with Convolutional Neural Network, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-10705, https://doi.org/10.5194/egusphere-egu23-10705, 2023.

EGU23-11898 | ECS | Orals | ESSI1.3

Composition Analysis of an Apatite Crystal using a Space-Prototype Mass Spectrometric Instrument and Machine Learning for Unsupervised Mineralogical Phase Detection 

Salome Gruchola, Marek Tulej, Peter Keresztes Schmidt, Rustam Lukmanov, Andreas Riedo, and Peter Wurz

We present the analysis of a 2.06 Ga apatite crystal obtained from an ultramafic phoscorite rock from the Phalaborwa Complex (Limpopo Province, South Africa) [1]. A space-prototype laser ablation ionisation mass spectrometer (LIMS) [2,3] was used to study the chemical composition of the sample. Mass spectra were recorded from a sample area of 0.6x0.6 mm2, with a spatial resolution of 30 μm and sub-micrometre depth resolution.

Apatite is a calcium phosphate mineral expressed by the chemical stoichiometric formula [Ca5(PO4)3(F, Cl, OH)]. The halogen site, occupied by F, Cl, and OH, corresponds to an isomorpous series with fluor-, chlor- and hydroxyl-apatite end members, respectively. Apatite, being an accessory mineral in igneous and other rocks, commonly contains a range of other elements that do not fit well into the major rock forming minerals, such as rare earth elements (REE). These are suitable targets for investigating physical and chemical conditions in igneous rocks and the volatile evolution of magmas.

The analysis of the spectra recorded with our LIMS system for the abundances of the elements of interest at each location were performed in two steps. First, the abundances of each element across the sampled area were compiled in element maps. And second, an unsupervised machine learning algorithm based on clustering and network analysis was applied to the data set of analysed mass spectra to separate it into groups of distinct chemical composition. Subsequently, a more detailed analysis was conducted on each of the recovered groups to assign the corresponding mineral. In addition to the group of spectra belonging to apatite, which was assigned to fluorapatite, other minerals were identified, amongst others olivine. This method yields an unsupervised approach to identify different mineralogical entities present within a sample. This network analysis method was previously applied to a 1.88 Ga Gunflint sample (Ontario, Canada) to separate spectra recorded from the host (chert) from spectra containing signatures of organic matter from fossilized microbes [4].

Given that the data were recorded using a miniature mass spectrometer designed for space flight, this analysis demonstrates the analytical capabilities of our LIMS system that could be achieved in-situ on other planetary bodies in our Solar System, for example on the Moon or on Mars. The current performance of this miniature LIMS instrument to study the chemical composition of apatite is sufficiently high to measure volatiles (H, F, Cl) and nearly all relevant mineral and partially trace elements (Na, C, Mg, Si, S, K, Mn, Fe, Sr, Ba), including REE (La, Ce, Pr, Sm) which allows for a systematic quantitative analysis of their distribution.

[1] Tulej, M. et al., 2022, https://doi.org/10.3390/universe8080410.

[2] Riedo, A. et al., 2012, https://doi.org/10.1002/jms.3104.

[3] Tulej, M. et al., 2021, https://doi.org/10.3390/app11062562.

[4] Lukmanov, R.A. et al., 2022, https://doi.org/10.3389/frspt.2022.718943

How to cite: Gruchola, S., Tulej, M., Keresztes Schmidt, P., Lukmanov, R., Riedo, A., and Wurz, P.: Composition Analysis of an Apatite Crystal using a Space-Prototype Mass Spectrometric Instrument and Machine Learning for Unsupervised Mineralogical Phase Detection, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-11898, https://doi.org/10.5194/egusphere-egu23-11898, 2023.

The origin of cold materials identified by different criteria is unclear. They are highly suspected to be the erupted prominence. However, some cold materials defined by charge depletion exist in both solar wind and ICMEs. Recently, solar observations show failed prominence eruption in CMEs that it did not propagate into the interplanetary space. Besides, the related prominence eruptions of the earth-directed ICMEs at 1 au are difficult to identify before the launch of STEREO mission. This work uses Random Forest (RF) that is an interpretable classifier of supervised machine learning to study the distinct signatures of prominence cold materials (PCs) compared to quiet solar wind (SW) and ICMEs. 12 parameters measured by ACE at 1 au are used in this study, which are proton moments, magnetic field component Bz, He/H, He/O, Fe/O, mean charge of oxygen and carbon, C6+/C5, C6+/C4+, and O7+/O6+. According to the returned weights from RF classifier and the training accuracy from one black box classifier, the most important in situ signatures of PCs are obtained. Next, the trained RF classifier is used to check the category of the origin-unknown cold materials in ICMEs. The results show that most of the cold materials are from prominence, but 2 of them are possibly from quiet solar wind. The most distinct signatures of PCs are lower charges of C and O, proton temperature, and He/O. This work provides quantitative evidence for the charges of C and O being most effective solid criteria. Considering the obvious overlaps on key parameters between SW, ICMEs, and PCs, multi-parameter classifier of machine learning show an advantage in separating them than solid criteria.

How to cite: Meng, S., Yao, S., and Cheng, Z.: Key Signatures of Prominence Materials and Category of Unknown-origin Cold Materials identified by Machine Learning Classifier, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-12354, https://doi.org/10.5194/egusphere-egu23-12354, 2023.

EGU23-14927 | ECS | Orals | ESSI1.3

Automatically Calculating Depths of Martian and Lunar Pits with Satellite Imagery 

Daniel Le Corre, Nigel Mason, Jeronimo Bernard-Salas, Nick Cox, and David Mary

Pits, or pit craters, are roughly circular depressions found in planetary surfaces which are generally formed through gravitational collapse. Pits will be primary targets for future space exploration and habitability for their presence on most rocky Solar System surfaces and their potential to be entrances to sub-surface cavities. This is particularly true on the Moon and Mars where future astronauts will also be exposed to high radiation dosages whilst on the surface. However, since pits are rarely found to have corresponding high-resolution elevation data, tools are required for approximating their depths in order to find those which are the ideal candidates for exploration and habitation.

We develop a tool that automatically calculates a pit’s apparent depth – the depth at the edge of its shadow - by measuring the shadow’s width as it appears in satellite imagery. The tool can produce a profile of the apparent depth along the entire length of the shadow, using just one cropped single- or multi-band image of a pit. Thus, allowing for the search for possible cave entrances to continue where altimetry or stereo image data is not available. Shadows are automatically extracted using k-means clustering with silhouette analysis for automatic cluster validation. We will present the results of testing the shadow extraction upon shadow-labelled Mars Reconnaissance Orbiter HiRISE imagery of Martian pits, as well as the findings of applying the tool to HiRISE images of Atypical Pit Craters (APCs) from the Mars Global Cave Candidate Catalog (MGC3) [1]. We will also present preliminary results of applying our tool to Lunar Reconnaissance Orbiter Narrow Angle Camera data taken of Lunar pits catalogued in the Lunar Pit Atlas [2].

[1] – Cushing et al. (2015). Atypical pit craters on Mars: New insights from THEMIS, CTX, and HiRISE observations, Journal of Geophysical Research: Planets, 120, 1023–1043

[2] – Wagner & Robinson (2021). Occurrence and Origin of Lunar Pits: Observations from a New Catalog, in 52nd Lunar and Planetary Science Conference, Lunar and Planetary Science Conference, p. 2530

How to cite: Le Corre, D., Mason, N., Bernard-Salas, J., Cox, N., and Mary, D.: Automatically Calculating Depths of Martian and Lunar Pits with Satellite Imagery, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-14927, https://doi.org/10.5194/egusphere-egu23-14927, 2023.

EGU23-15160 | ECS | Orals | ESSI1.3

Detecting the magnetopause of Mercury by neural network — using MESSENGER data to train for BepiColombo. 

Lukas Maes, Markus Fraenz, and Daniel Heyner

The BepiColombo mission will arrive at Mercury in 2025. It consists of two spacecraft, which both have a magnetometer on board. One of the science objectives of these instruments is to study the structure of Mercury’s magnetosphere and its dynamical interaction with the solar wind. To study this statistically, a large dataset of observations of the magnetopause (the magnetosphere’s outer boundary) is needed. However, identifying such magnetopause crossings in magnetic field data requires visual inspection by humans with expert knowledge and as such is a very time consuming process. We therefore design an algorithm to automatically detect the Hermean magnetopause in magnetometer time series data, making use of a convolutional neural network.

Since no BepiColombo data (in orbit) is available yet, we train the network on MESSENGER magnetometer data. However, we formulate the problem and design the architecture of the network in such a way that the algorithm should be easily transferable to BepiColombo magnetometer data, avoiding the possible impact of any instrumental particularities or orbital biases.

The goal is to have a neural network which is directly applicable to BepiColombo magnetometer data, as soon as the observations start and without any further training, thereby eliminating the necessity of manually creating a new dataset of BepiColombo magnetopause crossings.

How to cite: Maes, L., Fraenz, M., and Heyner, D.: Detecting the magnetopause of Mercury by neural network — using MESSENGER data to train for BepiColombo., EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-15160, https://doi.org/10.5194/egusphere-egu23-15160, 2023.

EGU23-16941 | ECS | Orals | ESSI1.3

Mars Perseverance Panoramic Image for Self-Determination Mission Algorithm 

Okta Bramantio Swida, Bernard Foing, and Constantijn Vleugels

Aiming to unravel the astrobiology of Mars, the Perseverance mission came with a lot of unknowns. With the surface level knowledge that we have already known, The High Resolution Imaging Science Experiment (HiRISE) can already determine the observation or experimental sites through the images generated from the orbiter. Although the resolution is high, with the power of a 1-meter-size object determinator, we can always expect so much more from the ground-level observation.

 

The Mars Perseverance rover is equipped with a pair of Mastcam-Z set cameras that are equipped in a manner to simulate the human eye for depth determination in image processing. The instruments can process stereo colour images of the ground level. These images can be used to make detailed maps of the Mars surface scenery at ground level with high precision.

 

Building and analyzing these images can take days to process on Earth manually. But if we utilise machine learning tools and onsite computation, it might save a lot of time for the mission. The current model used in the Mars Perseverance is the AutoNav Mark 4 with a lot of tasks, including spacecraft positioning, in-flight orbit determination, target tracking, and ephemeris calculations. All those might be computationally expensive to process. Therefore, the aim of this research is to develop a simple algorithm to do object and slope determinations to feed into an autonomous path determination process. The data fed into the algorithm are panoramic images captured by the MastCam-Z mounted on Mars Perseverance.

How to cite: Swida, O. B., Foing, B., and Vleugels, C.: Mars Perseverance Panoramic Image for Self-Determination Mission Algorithm, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-16941, https://doi.org/10.5194/egusphere-egu23-16941, 2023.

EGU23-320 | ECS | Orals | GI3.1 | Highlight

A comparison of Perseverance rover and HiRISE data: siteinterpretations in Jezero Crater 

Constantijn Vleugels, Bernard Foing, and Okta Swida

Large parts of the Martian surface have been imaged with orbiters. The High Resolution Imaging Science Experiment (HiRISE) can be used to build Digital Terrain Models (DTMs) of Mars with high horizontal and vertical resolution – distinguishing metre-size objects with a vertical error of tens of centimetres – and interpret the geologic history of a site. These maps may aid in rover landing site selection and finding science targets for these missions. However, rover-based imaging ultimately brings the most detailed view of a site and provides ‘ground-truth’ data to orbital observations on much smaller scales. Studying the differences between geologic interpretations from larger scale orbital observations and smaller scale rover images helps understand the limits of orbital maps and the added value of rover observations. We compare remote sensing data from orbit with rover panoramic camera data. The validity of geologic interpretations derived from orbital image data (such as HiRISE) in Jezero Crater is examined with ground-based, publicly available data from Mastcam-Z on the Mars 2020 Perseverance rover. Mastcam-Z can provide stereo colour images of the scene around the rover. 

The rover is currently in its Delta Campaign after landing at the Octavia E. Butler site and its subsequent trip to the Séítah formation, indicated in the figure below which shows Perseverance’s traverse near the western delta of Jezero crater (the basemap is a HiRISE DTM overlaid on a Context Camera mosaic produced by The Murray Lab).  Along the way, it has imaged the Séítah and Máaz formations and outcrops of the western delta formation. These units are expected to be volcanic (Séítah and Máaz) and deltaic (western delta) deposits. We can use the Mastcam-Z images made along the traverse to test what geologic interpretations we can reliably infer from orbital data.

How to cite: Vleugels, C., Foing, B., and Swida, O.: A comparison of Perseverance rover and HiRISE data: siteinterpretations in Jezero Crater, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-320, https://doi.org/10.5194/egusphere-egu23-320, 2023.

EGU23-1679 | ECS | Posters virtual | GI3.1

Improving the Accessibility of Borehole Geophysics: A Cost-Efficient, Highly Modifiable Borehole Tilt Sensor 

Ian Lee, Robert Hawley, David Collins, and Joshua Elliott

We present a cost-efficient borehole tilt sensor that was developed by our group at Dartmouth College to study ice deformation on Jarvis Glacier in Alaska. We first detail the entire sensor development, deployment, and data collection process, along with showcasing successful use cases of our sensors on Jarvis and other glaciers both by our and other geophysical research groups. For our Jarvis work, we installed our tilt sensor system in two boreholes drilled close to the lateral shear margin of Jarvis Glacier and successfully collected over 16 months of uninterrupted borehole deformation data in a harsh polythermal glacial environment. The data included gravity and magnetic measurements that tracked the orientation of the sensors in the borehole as ice flows, and we used the resultant kinematic measurements to compute borehole deformation that provided insights into the ice flow dynamics on polythermal glaciers. Our tilt sensors can house many types of sensors to accommodate different scientific needs (e.g., temperature, pressure, electrical conductivity), and can be adapted for the different glacial thermal regimes and conditions like Athabasca Glacier in Canada, which is a temperate glacier in contrast to Jarvis’ polythermal regime. There remains a high knowledge and financial barrier to entry for borehole geophysics research for both development and procurement of a tilt sensor system, and our goal is to lower this barrier by supporting production efforts of our tilt sensor system for both research and educational needs. With our established sensor development plan and demonstrated success in the field, our group has collaborated with Polar Research Equipment (PRE), a Dartmouth alumni-founded company specializing in the development of polar research tools, to serve as a commercial resource to help support polar researchers during the development and/or production of an effective and cost-efficient (~80% cheaper than commercial versions) tilt sensor and its associated systems.

How to cite: Lee, I., Hawley, R., Collins, D., and Elliott, J.: Improving the Accessibility of Borehole Geophysics: A Cost-Efficient, Highly Modifiable Borehole Tilt Sensor, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-1679, https://doi.org/10.5194/egusphere-egu23-1679, 2023.

EGU23-2676 | Orals | GI3.1

MaQuIs - Mars Quantum Gravity Mission 

Lisa Woerner, Bart Root, Philippe Bouyer, Claus Braxmaier, Dominic Dirkx, Joao Encarnacao, Ernst Hauber, Hauke Hussmann, Ozgur Karatekin, Alexander Koch, Lee Kumanchik, Federica Migliaccio, Mirko Reguzzoni, Birgit Ritter, Manuel Schilling, Christian Schubert, Cedric Thieulot, Wolf von Klitzing, and Olivier Witasse

With MaQuIs we propose a mission to investigate the gravitational field of Mars. Observing the gravitational field over time yields information about the planets tectonic lithoshphere, mass distribution, and composition. Consequently, this mission allows to study static and dynamic processes on and under the surface of Mars, including phenomena such as melting cycles and tectonic activity.

MaQuIs will deploy quantum mechanical means to measure Mars gravitational field with the highest precision yet. In addition, the nature of the proposed instrumentation achieves high sensitivities without needing more complex satellite constellations. As such, MaQuIs follows successful missions for the Earth and Moon, extending the technology to Mars.

In this presentation we will outline the expected scientific merit and explain the underlying technology and planned configuration of the mission.  

How to cite: Woerner, L., Root, B., Bouyer, P., Braxmaier, C., Dirkx, D., Encarnacao, J., Hauber, E., Hussmann, H., Karatekin, O., Koch, A., Kumanchik, L., Migliaccio, F., Reguzzoni, M., Ritter, B., Schilling, M., Schubert, C., Thieulot, C., von Klitzing, W., and Witasse, O.: MaQuIs - Mars Quantum Gravity Mission, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-2676, https://doi.org/10.5194/egusphere-egu23-2676, 2023.

EGU23-2838 | ECS | Orals | GI3.1

Development of a 3D-printed ion-electron plasma spectrometer with an hemispheric field of view for microsats and planetary missions 

Gwendal Hénaff, Matthieu Berthomier, Leblanc Frédéric, Techer Jean-Denis, Degret Gabriel, and Pledel Sylvain

One of the challenges in space instrumentation is to measure the energy and 3D angular distribution of charged particles within the limited resources available on planetary missions. Current electrostatic energy analyzers allow the measurement of the energy and angular distribution of charged particles around a 2D viewing plane.

Since most planetary probes are three-axis stabilized, electrostatic scanning deflectors are needed to provide the 3D distribution of charged particles using a minimum of two sensors. However, deflections up to +/- 90° cannot be achieved at high energy (above 10-15 keV) while higher energy accelerated particles play a key role in the dynamics of planetary magnetospheres. In addition, electrons and positive ions have to be measured with dedicated sensors which increases the complexity of plasma payloads and of their accommodation on planetary platforms.

We introduce a novel instrument design, that would allow measurement of the energy spectrum and 3D angular distribution of charged particles on three-axis stabilized platforms without using scanning deflectors. The design is possible using new electrostatic geometries and the capability of additive manufacturing technology. An innovative and compact ion/electron detection system is used to simultaneously observe both type of particles with a single sensor.

 We show that we reach the performance of current reference designs while having a true 3D field of view and significantly reducing the payload needs. With a mass budget of 2 kg, our combined electron/ion instrument fits the requirements to fly aboard small satellites. It would significantly reduce the size and cost of the platform and may open new perspectives for planetary exploration by a fleet of micro/nano-satellites.

How to cite: Hénaff, G., Berthomier, M., Frédéric, L., Jean-Denis, T., Gabriel, D., and Sylvain, P.: Development of a 3D-printed ion-electron plasma spectrometer with an hemispheric field of view for microsats and planetary missions, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-2838, https://doi.org/10.5194/egusphere-egu23-2838, 2023.

NASA’s Earth Surface Mineral Dust Source Investigation (EMIT) imaging spectrometer was launched to the International Space Station (ISS) on the 14th of July 2022.  EMIT measures the spectral range from 380 to 2500 nm with 285 contiguous spectral channels with 60 m spatial sampling and an 80 km swath.  The EMIT imaging spectrometer is optically fast at F/1.8 to deliver high signal-to-noise ratio observations.  Novel methods are used for on-orbit calibration, dark signal measurement, and geolocation.  The EMIT measurement characteristics and processing results through calibration, atmospheric corrections, and surface mineralogy retrievals are reported.  The EMIT science team will use these new comprehensive observations of surface mineralogy across the Earth’s arid land dust source regions to update the initial conditions of Earth System Models to understand and reduce uncertainties in mineral dust radiative forcing at the regional and global scale now and in the future.  EMIT’s measurements, products, and results with be available to other investigators for the broad set of science and applications they enable through the NASA Land Processes Data Active Archive Center.  The connection between EMIT, Carbon Plume Mapper, the Mapping Imaging Spectrometer for Europa, and the High-resolution Volatiles and Minerals Moon Mapper on Lunar Trailblazer is also described.

How to cite: Green, R.: Imaging Spectroscopy Observations from NASA’s Earth Surface Mineral Dust Source Investigation launched in 2022 and Connections to Imaging Spectrometers for Greenhouse Gas Measurement, Europa, the Moon, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-4510, https://doi.org/10.5194/egusphere-egu23-4510, 2023.

EGU23-7046 | ECS | Orals | GI3.1

Evolution of the oxygen escape from Earth over geological time scales 

Maria Luisa Alonso Tagle, Romain Maggiolo, Herbert Gunell, Johan De Keyser, Gael Cessateur, Giovanni Lapenta, Viviane Pierrard, and Ann Carine Vandaele

Atmospheric erosion plays a significant role in the long-term evolution of planetary atmospheres, and therefore on the development and sustainability of habitable conditions. Atmospheric escape varies over time, due to changes in planetary conditions and the evolution of the Sun. In the case of a magnetized planet like Earth, the dominant scavenging mechanisms are polar wind and polar cusp escape. Both processes are sensitive to the ion supply from the atmosphere, which depends on the solar EUV radiation and the composition of the neutral atmosphere. Moreover, they are modulated by the coupling between the solar wind and the ionosphere, which depends on the solar wind dynamic pressure and the planetary magnetic moment.

We developed a semi-empirical model of atmospheric loss to extrapolate from current measurements of oxygen escape from Earth to past conditions. This model takes into account the variations of the solar EUV/UV flux, the solar wind dynamic pressure, and the Earth’s magnetic moment. In this study, we identify the main factors and processes that control oxygen escape from Earth, considering present-day atmospheric conditions. We constrain the variation of the oxygen loss rate over time and estimate the total oxygen loss during the last ~2 billion years.

How to cite: Alonso Tagle, M. L., Maggiolo, R., Gunell, H., De Keyser, J., Cessateur, G., Lapenta, G., Pierrard, V., and Vandaele, A. C.: Evolution of the oxygen escape from Earth over geological time scales, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-7046, https://doi.org/10.5194/egusphere-egu23-7046, 2023.

EGU23-7363 | Posters on site | GI3.1

On modeling of silicon detector for space applications using Geant4 

Mikhail Rashev

Silicon detectors are widely used for analyses of particles/radiation in space. They show a good response for a wide spectrum of different particles. Via construction of an appropriate shielding, one can select and analyze only a single sort of particles/their energy and suppress detection of particles of all other kinds. It is difficult to find a good solution for shielding only experimentally. A modeling software such as Geant4 allows us to find a solution for the shielding. This software calculates interaction of particles with shielding or detector and the resulting energy deposition.

The current work is based on modeling of aluminum shielding of the RAPID/IES instrument on board of four Cluster spacecrafts. Since 2000 Cluster mission encounters the Earth's radiation belts and measures energetic electrons among other particles, waves and electromagnetic fields. Accurate modeling using Geant4 allows us to filter unwanted particles out of the result and possibly remove some artifacts in space.

The Geant4 code calculates an attenuation of radiation. Preliminary this software does not calculate electrical signal. There is, however, a possibility to extend the code and add other functionalities. We are exploring possibilities to include signal processing in the Geant4 code for the detector, analog and digital processing units.

How to cite: Rashev, M.: On modeling of silicon detector for space applications using Geant4, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-7363, https://doi.org/10.5194/egusphere-egu23-7363, 2023.

EGU23-7966 | ECS | Posters on site | GI3.1

Faraday cup instruments for solar wind and interplanetary dust monitoring 

Oleksii Kononov, Jiří Pavlů, Tereza Ďurovcová, Jana Šafránková, Zdeněk Němeček, and Lubomír Přech

Importance of solar wind monitoring for space weather applications increases with expansion of power networks and oils or gas pipelines to larger geomagnetic latitudes and development of new communication networks. Instruments based on Faraday cups are an ideal solution for these purposes because they are robust and their light weight and low power consumption facilitate their applications for a small spacecraft. Another important feature of Faraday cups is their capability of detection of impacts of interplanetary dust. Such instruments are currently a part of two planned ESA missions that will be briefly introduced. In the core of contribution, we describe the preliminary instrument design and concentrate on most important technical aspects of their development including a computer modeling of the most important parts of detectors. Among others, we present the effects of the grid geometry on the detector capability to determine the plasma velocity vector and temperature and search for optimum detector configuration for small spacecraft missions. We also discuss the data strategy allowing maximum scientific income with limited spacecraft telemetry.

How to cite: Kononov, O., Pavlů, J., Ďurovcová, T., Šafránková, J., Němeček, Z., and Přech, L.: Faraday cup instruments for solar wind and interplanetary dust monitoring, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-7966, https://doi.org/10.5194/egusphere-egu23-7966, 2023.

EGU23-8161 | ECS | Posters on site | GI3.1

Formulation of spectral indexes from M3 cubes for lunar mineral exploration using python 

Javier Eduardo Suarez Valencia, Angelo Pio Rosi, and Giacomo Nodjourmi

Introduction

The scientific exploration of planetary bodies is enhanced using spectral indexes, and specific band combinations/operations that allow the interpretation of the compositional properties of planetary surfaces. The best hyperspectral sensor for the study of the Moon is M3 onboard Chandrayan-1 (Pieters et al., 2008), it has 86 channels, and covers the range between 450 to 3000 nm, a region that shows the main properties of the rock-forming minerals of the Moon. Although the data of M3 has been widely used with different techniques, there is no unified set of spectral indexes for this instrument, and the ones defined are usually produced in proprietary software. In this work, we compiled spectral indexes from several sources and recreated them in python.

Methods

We compiled spectral indexes from the literature, namely the ones defined by Zambon et al. (2020), Bretzfelder et al. (2020), and Horgan et al. (2014). Before applying the indexes, an M3 cube was processed in ISIS3 (Laura et al., 2022) and filtered in python to reduce the noise. Subsequently, the spectral indexes were replicated according to the procedures described by the authors and compared with the original results. Most of the process was done with common scientific libraries such as rioxarray (Guillies, 2013), OpenCV (Bradski, 2000), specutils (Earl et al., 2022), and NumPy (Harris et al., 2020).

Results

We were able to reproduce fourteen indexes with high fidelity. All of them are formulated to highlight the spectral features around the absorptions in 1000 nm and 2000 nm, which are the location with the major expressions from olivine and pyroxenes. Comparing our results with the ones in the literature, we found that the color ramps are similar in both results and that the surface features showcased in both cases are consistent with each other and their known compositions.

Discussion and conclusions

Small differences between the original indexes and the ones recreated here are expected, due to variations in the internal methods across libraries, the different ways of preprocessing and filtering, and the quality of the original cubes. Further comparison and validation of the procedures is planned.

Nevertheless, we believe that the results are consistent enough to be used as scientific inputs, thus providing an open-source alternative for the analysis of spectral indexes of the surface of the Moon. This work is in progress, and the code is going to be available via EuroPlanet GitHub organization (https://github.com/europlanet-gmap), as well as in the Space Browser of the EXPLORE platform (https://explore-platform.eu/space-browser).

Acknowledgments

This project has received funding from the European Union’s Horizon 2020 research and innovation program under grant agreement No 101004214.

References

Bradski, G. (2000). The OpenCV Library.

Bretzfelder et al., (2020). Identification of Potential Mantle Rocks Around the Lunar Imbrium Basin.

Earl et al., (2022). astropy/specutils: V1.9.1 

Gillies, S. & others. (2013). Rasterio: Geospatial raster I/O for Python programmers. 

Harris et al., (2020). Array programming with NumPy.

Horgan et al., (2014). Near-infrared spectra of ferrous mineral mixtures and methods for their identification in planetary surface spectra.

Laura et al., (2022). Integrated Software for Imagers and Spectrometers 

Zambon et al., (2020). Spectral Index and RGB maps.

How to cite: Suarez Valencia, J. E., Pio Rosi, A., and Nodjourmi, G.: Formulation of spectral indexes from M3 cubes for lunar mineral exploration using python, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-8161, https://doi.org/10.5194/egusphere-egu23-8161, 2023.

EGU23-8918 | ECS | Posters on site | GI3.1

Strofio: A Status Update 

Jared Schroeder, Stefano Livi, and Frederic Allegrini

Strofio is a neutral mass spectrometer designed to measure the chemical composition of Mercury’s exosphere. Neutral species enter the instrument through one of two inlets before they are ionized via electron impact. The product ions are then guided by dozens of individually programmed electrodes toward the detector. A rotating electric field determines the time-of-flight (TOF) of each particle before they collide with a microchannel plate (MCP). Upon launch, one of the system’s electrodes (D5) suffered an anomaly that disrupted communications between the commanded value and the value reported in telemetry. This particular electrode is responsible for steering the particles into the MCP. Laboratory tests with the engineering model confirm mission requirements are satisfied regardless of the electrode state with the caveat being a reduced first-order mass range; however, second-order manipulation can extend the mass range to pre-anomaly standards. I will present the latest advances we have made in optimizing the instrument in its current state.

How to cite: Schroeder, J., Livi, S., and Allegrini, F.: Strofio: A Status Update, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-8918, https://doi.org/10.5194/egusphere-egu23-8918, 2023.

EGU23-9318 | ECS | Orals | GI3.1

Training the future Space Entrepreneurs and Astronauts: the experience of the EuroSpaceHub Academy with the Analog Missions for validation of planetary instruments, protocols and techniques 

Serena Crotti, Jara Pascual, Bernard Foing, Agata Kołodziejczyk, Brent Reymen, Ioana Roxana Perrier, Henk Rogers, Sofia Pavanello, Celia Avila Rauch, Gabriel De La Torre, and Armin Wedler

EuroSpaceHub is a project funded by the EIT HEI initiative, led by EIT Manufacturing and Raw Materials. The main goal of the project is fostering collaborative innovation and entrepreneurship in the Space-Tech ecosystem. EuroSpaceHub includes several initiatives; among them is the EuroSpaceHub Academy: an educational programme to train young students, researchers and professionals as Analog Astronauts and Space entrepreneurs.

Thanks to the experience of one of the founding partners of EuroSpaceHub - Lunex EuroMoonMars - students have the opportunity to participate as analog astronauts in various campaigns, which makes them learn with a hands-on approach. Analog missions are both important for carrying out investigations with a view to future Space exploration  and for developing technical scientific knowledge in students. EuroMoonMars has been involved in the organization of these campaigns since 2009, starting at the MDRS (Utah). Other missions were organized at the HISEAS base on the Mauna Loa (Hawaii), in Iceland (CHILL-ICE), in Etna/Vulcano Italy, Atacama Desert (Chile), at the AATC in Poland, ESTEC Netherlands, Eifel Germany and others [1-10]. During analog simulations, students learn to control on-board instruments and to structure their own experiments, collecting data and processing the results efficiently. EuroSpaceHub and Lunex support not only student participation in these missions and their organisation, but also a set of specific trainings under the umbrella of the ESH Academy, complementary to the missions. During the missions, PhD and Master's students can take advantage of special settings and equipment to conduct their investigations, which range from Space and planetary science, instruments, protocols, data analysis,
(biology, psychology, physiology and engineering, to name but a few).

EuroSpaceHub and Lunex are also developing an innovative habitat for analog missions and outreach, ExoSpaceHab Express. Its easy transportation, which is conceived on wheels, makes it a unique contribution in the landscape of existing habitats. Thanks to ExoSpaceHab-X, an increasing number of students will have access to the missions and dedicated training. Also, more and more data will be collected to investigate crews’ reactions in confinement, mission protocols, planning and operations. 

References: [1] Foing, B. et al (2022) LPSC 53, 2042 [2] Foing B. et al (2021) LPSC52, 2502 [3] Musilova M. et al (2020) LPSC51, 2893 [4] Perrier I.R. et al (2021) LPSC52, 2562 [5] Crotti, S. et al (2022) EGU22, 5974 [6] Foing, B. et al (2021) LPSC52, 2502 [7] Heemskerk, M. et al (2021) LPSC52, 2762 [8] Foing, B. et al (Editors, 2011) Astrobiology field Research in Moon/Mars Analogue Environments, Special Issue IJA, 10, vol. 3. 137-305; [9] Foing B. et al. (2011) Field astrobiology research at Moon-Mars analogue site: Instruments and methods, IJA 2011, 10 (3), 141 [10] Foing, B. H. et al, (2017) LPICo2041, 5073 

Acknowledgments: We thank EuroSpaceHub Consortium, collaborators, EIT HEI initiative, EIT Manufacturing and Raw Materials, VilniusTech, Collabwith, International Space University, Universidad Complutense de Madrid, Igor Sikorsky Kyiv Polytechnic Institute, Lunex Foundation and EuroMoonMars. We thank Adriano Autino and Space Renaissance International, all EMMPOL participants and the staff of AATC.

How to cite: Crotti, S., Pascual, J., Foing, B., Kołodziejczyk, A., Reymen, B., Perrier, I. R., Rogers, H., Pavanello, S., Rauch, C. A., De La Torre, G., and Wedler, A.: Training the future Space Entrepreneurs and Astronauts: the experience of the EuroSpaceHub Academy with the Analog Missions for validation of planetary instruments, protocols and techniques, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-9318, https://doi.org/10.5194/egusphere-egu23-9318, 2023.

EGU23-9912 | Orals | GI3.1

The Magnetometer on the Psyche mission 

Jose M. G. Merayo, Benjamin P. Weiss, Jodie Ream, Rona Oran, Peter Brauer, Corey J. Cochrane, Kyle D. Cloutier, Lindy Elkins-Tanton, John Leif Jørgensen, Clara Maurel, Ryan S. Park, Carol A. Polanskey, Maria De Soria-Santacruz Pich, Carol A. Raymond, Christopher Russell, Daniel Wenkert, Mark A. Wieczorek, Maria T. Zuber, and Kyle Webster

The asteroid (16) Psyche is the target of the NASA Psyche mission, where the magnetometer is one of the three science instruments on board. Its purpose is to prove whether the asteroid formed from the core of a differentiated planetesimal. The magnetometer will measure the magnetic field at different distances from the asteroid in order to detect any remanent magnetization, where a magnetic moment larger than 2×10^14 Am2 could imply that the body once generated a core dynamo, and therefore formed as an igneous differentiation.

The Psyche spacecraft carries two three-axis fluxgate magnetometers mounted on a fixed boom at 2.15m and 1.45m, respectively, which provide redundancy and gradiometer capabilities to compensate for spacecraft-generated magnetic fields. The magnetometers will be powered on early in the initial checkout phase and remain on throughout cruise and orbital operations and producing 50 vectors per second. The in-flight temperature of the magnetometers is expected to span a large range, therefore an extensive calibration program has been carried out in order to characterize the instruments and prove the performance pre-flight.

How to cite: Merayo, J. M. G., Weiss, B. P., Ream, J., Oran, R., Brauer, P., Cochrane, C. J., Cloutier, K. D., Elkins-Tanton, L., Jørgensen, J. L., Maurel, C., Park, R. S., Polanskey, C. A., Pich, M. D. S.-S., Raymond, C. A., Russell, C., Wenkert, D., Wieczorek, M. A., Zuber, M. T., and Webster, K.: The Magnetometer on the Psyche mission, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-9912, https://doi.org/10.5194/egusphere-egu23-9912, 2023.

EGU23-10104 | Orals | GI3.1

Sense-checking the calibration of the Cluster FGM magnetometer spin-axis offsets using mirror mode waves in the magnetosheath 

Leah-Nani Alconcel, Timothy Oddy, Patrick Brown, and Chris Carr

The calibrated data from the Cluster fluxgate magnetometer instruments (FGMs) aboard the four Cluster spacecraft are accessible through the European Space Agency (ESA) Cluster Science Archive (CSA). The FGM team at Imperial College – the PI institute that built and supports operation of the magnetometers – has regularly provided validated data to the CSA since its inception. The calibration and validation pipeline is well established and provides measurements at the highest instrument resolution within an uncertainty as low as 0.1 nT. New methods for magnetic field calibration have been proposed in the many years since Cluster’s commissioning. One of these uses mirror mode waves in the Earth’s magnetosheath to determine the spin-axis offsets of an in-flight magnetometer instrument. The FGM team applied this method to the Cluster instrument data during periods when the spacecraft spend a substantive proportion of their orbits in the magnetosheath, typically May-June and October-November. The offsets determined by this method were compared to those determined by the method already integrated into the pipeline. Good agreement was found between the two methods.

Due to the limitations in resource, the substantial effort that would be required to change calibration methods and re-deliver over 20 years of FGM data, and the potential impact on literature already published, the team would not recommend retroactive integration of the new method into the pipeline. However, the study provides a useful sense check of the pipeline and the data already delivered, as well as the remaining data to be delivered through to the end of the Cluster mission.

How to cite: Alconcel, L.-N., Oddy, T., Brown, P., and Carr, C.: Sense-checking the calibration of the Cluster FGM magnetometer spin-axis offsets using mirror mode waves in the magnetosheath, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-10104, https://doi.org/10.5194/egusphere-egu23-10104, 2023.

EGU23-10788 | Orals | GI3.1 | Highlight

Botany on The Moon 

Heather Smith

We propose a suite of instruments, Botany on The Moon, designed to investigate the feasibility of plant growth on the Moon. Botany is composed of two single-species plant growth modules (Arabidopsis, & radish) plus two environmental monitoring instruments that record (1) direct and scattered sunlight in the photosynthetically active radiation or wavelengths (termed PAR), and (2) level of cosmic radiation and induced lunar neutrons. Together these four investigations contribute to our understanding of how plants can be grown on the Moon.

The core perspective in Botany is that physical experiments are needed to understand plant growth on the Moon. Little is known about plant behavior in reduced (fractional) gravity environments (less than the nominal 1g that occurs on Earth). How biology responds to partial gravity (in combination with radiation effects) remains unexplored.

Botany’s primary science goals can be achieved during the sunlit timeframe of a Lunar Day. However, significantly more data and knowledge is gained by extending the growth duration window to approximately 45 Earth days. Hence, Botany is proposing to take advantage of the CLPS provided Survive-the-Night service.  If the CLPS provider is able to provide power for Botany to survive the night, our secondary science goal to determine the feasibility of transitioning the plants from a normal growth phase (at 22oC during the sunlit time) to a slow growth phase (at 5oC during the nighttime), returning to normal growth phase (at 22oC during the second sunlit time) can be achieved. However, all of Botany’s primary science goals can be achieved during the lunar sunlit timeframe, albeit with the loss of data due to the shorter growth duration. The Botany instrument suite including the LPX plant chambers are designed for a 45 Earth-day mission on the Lunar surface, including surviving the 354 hours of the Lunar night. The Botany on The Moon proposed project has a payload mass of ~ 12kg and estimated cost of ~ $11.5 Million U.S. dollars.

The 20-person Botany payload team is led by a mid-career women scientist and involves a gender diverse science and engineering team at various stages in their career from 10 institutions located within three countries. The Botany team includes NASA ARC, KIPR (a long-term NASA ARC contract organization), SDL, UNC-G (a minority serving institution (MSI)), a Canadian instrument provided by McMaster University, and a science team from various institutions. Our team combines complimentary skills, mission management experience, and expertise in plant science.

How to cite: Smith, H.: Botany on The Moon, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-10788, https://doi.org/10.5194/egusphere-egu23-10788, 2023.

The HyTI (Hyperspectral Thermal Imager) mission, funded by NASA’s Earth Science Technology Office InVEST (In-Space Validation of Earth Science Technologies) program, will demonstrate how high spectral and spatial long-wave infrared image data can be acquired from a 6U CubeSat platform. The mission will use a spatially modulated interferometric imaging technique to produce spectro-radiometrically calibrated image cubes, with 25 channels between 8-10.7 microns, at 13 cm-1 resolution), at a ground sample distance of ~60 m. The HyTI performance model indicates narrow band NEDTs of <0.3 K. The small form factor of HyTI is made possible via the use of a no-moving-parts Fabry-Perot interferometer, and JPL’s cryogenically-cooled HOT-BIRD FPA technology. Launch is scheduled for June 2023. The value of HyTI to Earth scientists will be demonstrated via on-board processing of the raw instrument data to generate L1 and L2 products, with a focus on rapid delivery of data regarding volcanic degassing, and land surface temperature. This presentation will describe the mission and the technology, including the interferometric imaging approach, and how the Cube Sat will support instrument operations and data processing.

How to cite: Wright, R. and the HyTI Team: The HyTI Mission: High Spatial and Spectral Sesolution Imaging from a 6U Cube Satellite, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-10917, https://doi.org/10.5194/egusphere-egu23-10917, 2023.

EGU23-11555 | Posters on site | GI3.1

BepiColombo: Operations and Data Analysis through the Quick-Look Analysis (QLA) tool 

Thomas Cornet, Alan Macfarlane, Elena Racero, Sebastien Besse, and Santa Martinez

The ESA-JAXA BepiColombo mission is currently en route to Mercury since October 2018. It consists of the ESA Mercury Planetary Orbiter (MPO) and the JAXA Mercury Magnetospheric Orbiter (MMO) spacecraft which, along with the Mercury Transfer Module (MTM), are stacked all together during the seven years’ cruise phase. This long cruise phase is interspersed by nine planetary flybys used to reach Mercury’s orbit capture. In this configuration, most of the MPO instruments located on the nadir side are obstructed by the MTM and cannot observe. Nevertheless, a subset of “side-looking” instruments can be operated in the stacked-spacecraft configuration during the cruise and gather scientific data. These instruments, mostly dedicated to the study of the Hermean environment (magnetic field, solar wind, exosphere), are operated during the planetary flybys as well as for several cruise science observations. Such events are used to test the BepiColombo Science Ground Segment (SGS) operating systems and processes. The SGS develops the Quick-Look Analysis (QLA) tool that will support the rapid analysis of the instruments’ operational and scientific data acquired during the mission science phase observations, starting in 2026. At present, the tool is used to support cruise and flybys operations, in addition to fostering science collaborations between the BepiColombo instrument teams through its data sharing capabilities. We will present the current status and functionalities.

How to cite: Cornet, T., Macfarlane, A., Racero, E., Besse, S., and Martinez, S.: BepiColombo: Operations and Data Analysis through the Quick-Look Analysis (QLA) tool, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-11555, https://doi.org/10.5194/egusphere-egu23-11555, 2023.

In response to the problem that ground-based optical monitoring systems cannot monitor near-Earth asteroids which are too close to the Sun on the celestial sphere, we raise a method that tracks and determines the orbit of asteroids by Distant Retrograde Orbit (DRO) platforms with optical monitoring. Through data filtering by visibility analysis and the initial orbit information of the asteroids provided by Jet Propulsion Laboratory (JPL), the asteroids' orbits are determined and compared with the reference orbit. Simulation results show that with a measurement accuracy of two arcseconds and an arc length of three years, the orbit determination accuracy of the DRO platform for near-Earth asteroids can reach tens of kilometers, especially the asteroids with Atira orbits to an accuracy of fewer than ten kilometers. In conclusion, the near-Earth asteroids monitoring systems based on DRO platforms are capable to provide sufficient monitoring effectiveness which enables precise tracking of the target asteroids and forecast of their positions.

How to cite: Yezhi, S.: Near-Earth asteroids orbit determination by DRO space-based optical observations, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-13233, https://doi.org/10.5194/egusphere-egu23-13233, 2023.

EGU23-13996 | ECS | Posters on site | GI3.1

Simulation Study for Precise Orbit Determination of a Callisto Orbiter and Geodetic Parameter Recovery 

William Desprats, Daniel Arnold, Stefano Bertone, Michel Blanc, Adrian Jäggi, Lei Li, Mingtao Li, and Olivier Witasse

Callisto, the outermost of the four Galilean satellites, is identified as a key body to answer present questions about the origin and the formation of the Jovian system. Callisto appears to be the least differentiated and the geologically least evolved of the Galilean satellites, and therefore the one best reflecting the early ages of the Jovian system.

While the ESA JUICE mission plans several flybys of Callisto, an orbiter would allow it to measure geodetic parameters to much higher resolution, as it was suggested by several recent mission proposals,e.g., the Tianwen-4 (China National Space Administration) and MAGIC (Magnetics, Altimetry, Gravity, and Imaging of Callisto) proposals. Recovering parameters such as those describing Callisto’s gravity field, its tidal Love numbers, and its orientation in space would help to significantly constrain Callisto’s interior structure models, including the characterization of a potential subsurface ocean.

We perform a closed-loop simulation of spacecraft tracking, altimetry, and accelerometer data of a high inclination, low altitude orbiter, which we then use for the recovery of its precise orbit and of Callisto’s geodetic parameters. We compare our sensitivity and uncertainty results to previous covariance analyses. We estimate geodetic parameters, such as gravity field, rotation, and orientation parameters and the k2 tidal Love number, based on radio tracking (2-way Doppler) residuals. We consider several ways to mitigate the mismodeling of non-gravitational accelerations, such as using empirical accelerations and pseudo stochastic pulses, and we evaluate the benefits of an on-board accelerometer.

We also investigate the added value of laser altimeter measurements to enable the use of altimetry crossovers to improve orbit determination and gravity-related geodetic parameters, but also to estimate the recovery of surface tidal variations (via the h2 Love number). For our closed-loop analyses, we use both a development version of the Bernese GNSS Software and the open-source pyXover software.

How to cite: Desprats, W., Arnold, D., Bertone, S., Blanc, M., Jäggi, A., Li, L., Li, M., and Witasse, O.: Simulation Study for Precise Orbit Determination of a Callisto Orbiter and Geodetic Parameter Recovery, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-13996, https://doi.org/10.5194/egusphere-egu23-13996, 2023.

EGU23-14692 | Orals | GI3.1

Project DragLiner: Harnessing plasma Coulomb drag for satellite deorbiting to keep orbits clean 

Maria Genzer, Pekka Janhunen, Harri Haukka, Antti Kestilä, Maria Hieta, Pyry Peitso, Perttu Yli-Opas, Hannah Ploskonka, Petri Toivanen, Janne Sievinen, Marco Marques, David Macieira, Ahmed El Moumen, Farzaneh Gholami, Miguel Olivares-Mendez, Baris Can Yalcin, and Carol Martinez Luna

When a high-voltage charged tether is put into streaming space plasma, the tether’s electric field disturbs the flow of plasma ions and thereby taps momentum from the plasma flow [1-4]. The effect is called electrostatic Coulomb drag. One application is the electric solar wind sail which uses the solar wind to generate interplanetary propulsion [1, 2]. Another application is the Plasma Brake [3, 4] which uses the ionospheric ram flow to generate Coulomb drag that slowly de-orbits the satellite. Both positive and negative tether polarities work. The plasma physics is different, but the net effect is a transfer of momentum in both cases. The reasons are somewhat complicated, but there is good motivation to select positive polarity in the solar wind case and negative polarity in the ionospheric Plasma Brake case. Measurement of Coulomb drag in Low Earth Orbit and testing deployment of tether is to be carried out by ESTCube-2 cubesat [5] which is scheduled for launch in spring 2023, and forthcoming Foresail cubesat scheduled for launch later in 2023-2024.

Project DragLiner is ongoing and funded by ESA to define requirements and a preliminary design of a passive Coulomb Drag based deorbit system capable of bringing down LEO spacecrafts in an order of magnitude shorter time than the current regulations of re-enter time for the spacecraft (25 years). Other main requirements for the deorbiting system are low mass and independence from the spacecraft resources. The project will also create a TRL 4 prototype of a Plasma Brake module that can be used to deorbit a few hundred kilogram satellite or launcher upper stage from Low Earth Orbit. The module deploys ~5 km long tether that is made of four 25-50 micrometre diameter conductive wires. In addition to aluminium wires used previously in Cubesat projects we will also evaluate more advanced carbon fibre composite wires. The redundant multi-wire tether structure is used so that the tether does not break even when micrometeoroids cut some of its wires. The tether is deployed from a storage reel. The tether is kept at -1 kV voltage by an onboard high-voltage source. A ~100 m long metal-coated tape tether is used as an electron-gathering surface that closes the current loop. Alternatively, conducting parts of the debris satellite could be used for electron gathering. The power consumption is a few watts. 

Project Dragliner uses basic Space Plasma Physics to solve a practical and important problem of keeping satellite orbits clean for future generations and preventing a catastrophic Kessler syndrome scenario.

[1] Janhunen, P., Electric sail for spacecraft propulsion, J. Prop. Power, 20, 763-764, 2004.

[2] Janhunen, P. and A. Sandroos, Simulation study of solar wind push on a charged wire: basis of solar wind electric sail propulsion, Ann. Geophys., 25, 755-767, 2007.

[3] Janhunen, P., Electrostatic plasma brake for deorbiting a satellite, J. Prop. Power, 26, 370-372, 2010.

[4] Janhunen, P., Simulation study of the plasma-brake effect, Ann. Geophys., 32, 1207-1216, 2014.

[5] Iakubivskyi, I., et al., Coulomb drag propulsion experiment of ESTCube-2 and FORESAIL-1, Acta Astronautica, 177, 771-783, 2020.

How to cite: Genzer, M., Janhunen, P., Haukka, H., Kestilä, A., Hieta, M., Peitso, P., Yli-Opas, P., Ploskonka, H., Toivanen, P., Sievinen, J., Marques, M., Macieira, D., El Moumen, A., Gholami, F., Olivares-Mendez, M., Yalcin, B. C., and Martinez Luna, C.: Project DragLiner: Harnessing plasma Coulomb drag for satellite deorbiting to keep orbits clean, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-14692, https://doi.org/10.5194/egusphere-egu23-14692, 2023.

EGU23-14760 | ECS | Posters on site | GI3.1

A novel user-friendly Jupyter-based tool for analysing orbital subsurface sounding radar data. 

Giacomo Nodjoumi, Sebastian Emanuel Lauro, and Angelo Pio Rossi

Orbital radars, such as the SHAllow RADar (SHARAD) [1] or the Mars Advanced Radar for Subsurface and Ionosphere Sounding (MARSIS) [2] instruments on board Mars Reconnaissance Orbiter (MRO) and Mars Express (MEX) respectively, provide valuable data about the Martian subsurface [3,4].

Common analysis methodologies comprise a direct comparison between the radargram (RDR) and the corresponding Surface Clutter Simulation (SCS) to visually spot any subsurface reflector. The surface time delays converted in the space domain are then compared with the corresponding topographic profile to check if any discrepancy occurred. and thus be mistaken for subsurface reflections. Once confirmed that the subsurface reflector is valid, the proper picking can be performed by looking at the radargram and both the radargram and the simulation power intensities. Finally, it is possible to estimate the real dielectric constant ε', which is the real component of the complex permittivity ε' - iε'' using Equation Eq1 [3]:

where Δt is the two-way travel time between the surface and the subsurface reflector, c is the speed of light in a vacuum and h is the reflector’s depth. Assuming different values for ε' and inverting Eq1, is possible to estimate the depth, thus the thickness of the reflector’s unit. In this work, we present the first pre-release of a user-friendly interface, with which is possible to easily perform the above analysis while granting robustness and reproducibility. Besides, it is possible to implement further custom processing functions to increase the accuracy of the results and/or expand the tool capabilities. We started the development using SHARAD US RDR and SCS, while MARSIS compatibility is under implementation. We provided also additional Jupyter notebooks for data download. This tool is based on the Jupyter lab environment and open-source python packages served as a docker container.

Open Research: The tool presented here is available on GitHub [5]

Funding: This project has received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreements No 101004214 and No 871149.

References:

[1] Seu, R., et al., SHARAD Sounding Radar on the Mars Reconnaissance Orbiter., doi:10.1029/2006JE002745.

[2] Jordan, R., et al., The Mars Express MARSIS Sounder Instrument. doi:10.1016/j.pss.2009.09.016.

[3] Shoemaker, E.S., et al., New Insights Into Subsurface Stratigraphy Northwest of Ascraeus Mons, Mars, Using the SHARAD and MARSIS Radar Sounders. doi:10.1029/2022JE007210.

[4] Lauro, S.E., et al., Using MARSIS Signal Attenuation to Assess the Presence of South Polar Layered Deposit Subglacial Brines. doi:10.1038/s41467-022-33389-4.

[5] Nodjoumi, G. MORDOR - Mars Orbital Radar Data Open-Reader 2023.

How to cite: Nodjoumi, G., Lauro, S. E., and Rossi, A. P.: A novel user-friendly Jupyter-based tool for analysing orbital subsurface sounding radar data., EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-14760, https://doi.org/10.5194/egusphere-egu23-14760, 2023.

EGU23-14810 | ECS | Orals | GI3.1

Statistics of Alfvénic structures in the Solar Wind and their impact on Magnetometer Calibration 

Johannes Z. D. Mieth, Ferdinand Plaschke, Uli Auster, David Fischer, Daniel Heyner, and Werner Magnes

Exploiting the Alfvénic structures of the solar wind is an established method for calibrating spaceborne magnetometers. However, not every statistical property of Alfvén waves follows a uniform distribution, so calibration accuracy in certain sensor directions may be significantly affected by the choice of the data set used. This work examines the statistical properties of Alfvénic disturbances and other structures of the solar wind in a wide range of spatial and temporal scales using data from the current BepiColombo mission, now in the inner solar system, the lunar and Earth-bound satellites of the THEMIS and ARTEMIS missions, and the Earth-bound MMS mission. The influence of the data selection on calibration is characterized and quantified. We benefit from the fact that the magnetometers of the above-mentioned missions have been partially calibrated by independent methods, using the spacecraft spin or alternative observations of the total magnetic field.

How to cite: Mieth, J. Z. D., Plaschke, F., Auster, U., Fischer, D., Heyner, D., and Magnes, W.: Statistics of Alfvénic structures in the Solar Wind and their impact on Magnetometer Calibration, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-14810, https://doi.org/10.5194/egusphere-egu23-14810, 2023.

EGU23-15409 | ECS | Orals | GI3.1

Callio SpaceLab – Sustainable living, sustaining life 

Jari Joutsenvaara, Antti Tenetz, Julia Puputti, and Ossi Kotavaara

Callio SpaceLab is an initiative for international space testing, R&D for future human space exploration. SpaceLab's extremely confined environment of the mine and surroundings provide testbeds to simulate human space exploration, analogue astronaut training and experiences for space research and systems in extreme environments on Earth.

Many steps need to be taken here on Earth to put a (hu)man on the Moon and later on Mars. The Earth-based simulation environments are called Terrestrial analogue sites or space analogues. Some analogues are more general, but some have characteristics similar to the extra-terrestrial conditions: e.g., Venus has an analogue environment at Mt. Etna (1), Italy, Mars at Atacama desert (2), Chile and Moon (3), Mauna Kea, Hawai, USA.

Space analogues research covers many topics ranging from testing of habitats and other constructions, fieldwork, in-situ resource utilisation and vehicles; some concentrate on low gravity  (simulated, e.g., in pools) and confinement from the existing world in enclosed environments.

Callio SpaceLab is a concept being developed at the Pyhäsalmi mine, Finland. It is one of Europe’s deepest  (1.4 km) base metal mines. The underground mining ended in 8/2022, but that is just the beginning. The Pyhäjärven Callio is developing the site for a second life, including underground pumped-hydro energy storage, a solar park, FUTUREMINE testing environment for autonomous mining equipment, and more (4,5). Research activities are coordinated by the University of Oulu´s Kerttu Saalasti Institute.

In order to survive on the extraterrestrial landscapes Moon and Mars, one needs to bring enough protection to sustain life and activities. Mine is a suitable terrestrial analogue test environment for confinement studies, biology, astrobiology, in-situ resource utilisation, scientific drilling, rover testing (inclines up to1:7), communications systems testing, space design-, art- and culture projects, etc. (6). The mine has extensive connectivity. Deep space communications can be simulated for different missions, from spaceflights to extraterrestrial bases and activities both on surfaces and in the depth of space objects and celestial bodies.

The site´s hosting rock is a massive volcanogenic sulfide (VMS) deposit formed 1.9 Ga (7). Exploration drilling has found saline water pockets dated at least 30 Ma old. The water samples have shown traces of bacteria common to deep subsurface environments (8).

 

References

  • Gabriel V.,  et al. Mineralogy and Spectroscopy of Mount Etna Lava Flows as an Analogue to Venus. https://ui.adsabs.harvard.edu/abs/2022LPICo2678.2255E
  • Azua-Bustos A.,  et al. The Atacama Desert in Northern Chile as an Analog Model of Mars. 2022. https://doi.org/10.3389/fspas.2021.810426
  • Inge IL ten K.,  et al. Mauna Kea, Hawaii, as an Analog Site for Future Planetary Resource Exploration: Results from the 2010 ILSO-ISRU Field-Testing Campaign. Journal of Aerospace Engineering. https://doi:10.1061/(ASCE)AS.1943-5525.0000200
  • Callio - Mine for Business. 2023. https://callio.info
  • Joutsenvaara J.,  et al. Callio Lab - the deep underground research centre in Finland, Europe. 2021.  https://doi.org/10.1088/1742-6596/2156/1/012166
  • Tenetz A., More than Planet - Deep residency and workshop, creative Eu-project - 2022-2025. http://www.photonorth.fi/fi/projektit/more-than-planet/
  • Imaña M,  et al., 3D modeling for VMS exploration in the Pyhäsalmi district, Central Finland in. In: Proceedings of the 12th Biennial SGA Meeting. 2013. p. 12–5.
  • Miettinen H, et al., Microbiome composition and geochemical characteristics of deep subsurface high-pressure environment, Pyhasalmi mine Finland. https://doi.org/10.3389%2Ffmicb.2015.01203

How to cite: Joutsenvaara, J., Tenetz, A., Puputti, J., and Kotavaara, O.: Callio SpaceLab – Sustainable living, sustaining life, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-15409, https://doi.org/10.5194/egusphere-egu23-15409, 2023.

EGU23-2843 | ECS | PICO | ESSI1.1

Geography-Aware Masked Autoencoders for Change Detection in Remote Sensing 

Lukas Kondmann, Caglar Senaras, Yuki M. Asano, Akhil Singh Rana, Annett Wania, and Xiao Xiang Zhu

Increasing coverage of commercial and public satellites allows us to monitor the pulse of the Earth in ever-shorter frequency (Zhu et al., 2017). Together with the rise of deep learning in artificial intelligence (AI) (LeCun et al., 2015), the field of AI for Earth Observation (AI4EO) is growing rapidly. However, many supervised deep learning techniques are data-hungry, which means that annotated data in large quantities are necessary to help these algorithms reach their full potential. In many Earth Observation applications such as change detection, this is often infeasible because high-quality annotations require manual labeling which is time-consuming and costly.  

Self-supervised learning (SSL) can help tackle the issue of limited label availability in AI4EO. In SSL, an algorithm is pretrained with tasks that only require the input data without annotation. Notably, Masked Autoencoders (MAE) have shown promising performances recently where a Vision Transformer learns to reconstruct a full image with only 25% of it as input. We hypothesize that the success of MAEs also extends to satellite imagery and evaluate this with a change detection downstream task. In addition, we provide a multitemporal DINO baseline which is another widely successful SSL method. Further, we test a second version of MAEs, which we call GeoMAE. GeoMAE incorporates the location and date of the satellite image as auxiliary information in self-supervised pretraining. The coordinates and date information are passed as additional tokens to the MAE model similar to the positional encoding. 
The pretraining dataset used is the RapidAI4EO corpus which contains multi-temporal Planet Fusion imagery for a variety of locations across Europe. The dataset for the downstream task also uses Planet Fusion in pairs as input data. These are provided on a 600m * 600m patch level three months apart together with a classification if the respective patch has changed in this period. Self-supervised pretraining is done for up to 150 epochs where we take the model with the best validation performance on the downstream task as a starting point for the test set. 

We find that the regular MAE model scores the best on the test set with an accuracy of 81.54% followed by DINO with 80.63% and GeoMAE with 80.02%. Pretraining MAE with ImageNet data instead of satellite images results in a notable performance loss down to 71.36%. Overall, our current pretraining experiments can not yet confirm our hypothesis that GeoMAE is advantageous compared to regular MAE. However, in similar spirit, Cong et al. (2022) recently introduced SatMAE which outlines that for other remote sensing applications, the combination of auxiliary information and novel masking strategies is a key factor. Therefore, it seems that a combination of location and time inputs together with adapted masking may also hold the most potential for change detection. There is ample potential for future research in geo-specific applications of MAEs and we provide a starting point for this with our experimental results for change detection. 

How to cite: Kondmann, L., Senaras, C., Asano, Y. M., Rana, A. S., Wania, A., and Zhu, X. X.: Geography-Aware Masked Autoencoders for Change Detection in Remote Sensing, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-2843, https://doi.org/10.5194/egusphere-egu23-2843, 2023.

EGU23-3267 | ECS | PICO | ESSI1.1

Decomposition learning based on spatial heterogeneity: A case study of COVID-19 infection forecasting in Germany 

Ximeng Cheng, Jost Arndt, Emilia Marquez, and Jackie Ma

New models are emerging from Artificial Intelligence (AI) and its sub-fields, in particular, Machine Learning and Deep Learning that are being applied in different application areas including geography (e.g., land cover identification and traffic volume forecasting based on spatial data). Different from well-known datasets often used to develop AI models (e.g., ImageNet for image classification), spatial data has an intrinsic feature, i.e., spatial heterogeneity, which leads to varying relationships across different regions between the independent (i.e., the model input X) and dependent variables (i.e., the model output Y). This makes it difficult to conduct large-scale studies with a single robust AI model. In this study, we draw on the idea of modular learning, i.e., to decompose large-scale tasks into sub-tasks for specific sub-regions and use multiple AI models to achieve these sub-tasks. The decomposition is based on the spatial characteristics to ensure that the relationship between independent and dependent variables is similar in each sub-region. We explore this approach for forecasting COVID-19 cases in Germany using spatiotemporal data (e.g., weather data and human mobility data) as an example and compare the prediction tasks with a single model to the proposed decomposition learning procedure in terms of accuracy and efficiency. This study is part of the project DAKI-FWS which is funded by the Federal Ministry of Economic Affairs and Climate Action in Germany to develop an early warning system to stabilize the German economy.

How to cite: Cheng, X., Arndt, J., Marquez, E., and Ma, J.: Decomposition learning based on spatial heterogeneity: A case study of COVID-19 infection forecasting in Germany, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-3267, https://doi.org/10.5194/egusphere-egu23-3267, 2023.

EGU23-4929 | PICO | ESSI1.1

Using AI and ML to support marine science research 

Ilaria Fava, Peter Thijsse, Gergely Sipos, and Dick Schaap

The iMagine project is devoted to developing and delivering imaging data and services for aquatic science. Started in September 2022, the project will provide a portfolio of image data collections, high-performance image analysis tools empowered with Artificial Intelligence, and best practice documents for scientific image analysis. These services and documentation will enable better and more efficient processing and analysis of imaging data in marine and freshwater research, accelerating our scientific insights about processes and measures relevant to healthy oceans, seas, and coastal and inland waters. By building on the European Open Science Cloud compute platform, iMagine delivers a generic framework for AI model development, training, and deployment, which researchers can adopt for refining their AI-based applications for water pollution mitigation, biodiversity and ecosystem studies, climate change analysis and beach monitoring, but also for developing and optimising other AI-based applications in this field. The iMagine AI development and testing framework offers neural networks, parallel post-processing of extensive data, and analysis of massive online data streams in distributed environments. The synergies among the eight aquatic use cases in the project will lead to common solutions in data management, quality control, performance, integration, provenance, and FAIRness and contribute to harmonisation across RIs. The resulting iMagine AI development and testing platform and the iMagine use case applications will provide another component to the European marine data management landscape, valid for the Digital Twin of the Ocean, EMODnet, Copernicus, and international initiatives. 

How to cite: Fava, I., Thijsse, P., Sipos, G., and Schaap, D.: Using AI and ML to support marine science research, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-4929, https://doi.org/10.5194/egusphere-egu23-4929, 2023.

EGU23-6818 | ECS | PICO | ESSI1.1

Eddy identification from along-track altimeter data with multi-modal deep learning 

Adili Abulaitijiang, Eike Bolmer, Ribana Roscher, Jürgen Kusche, and Luciana Fenoglio-Marc

Eddies are circular rotating water masses, which are usually generated near the large ocean currents, e.g., Gulf Stream. Monitoring eddies and gaining knowledge on eddy statistics over a large region are important for fishery, marine biology studies, and testing ocean models.

At mesoscale, eddies are observed in radar altimetry, and methods have been developed to identify, track and classify them in gridded maps of sea surface height derived from multi-mission data sets. However, this procedure has drawbacks since much information is lost in the gridded maps. Inevitably, the spatial and temporal resolution of the original altimetry data degrades during the gridding process. On the other hand, the task of identifying eddies has been a post-analysis process on the gridded dataset, which is, by far, not meaningful for near-real time applications or forecasts. In the EDDY project at the University of Bonn, we aim to develop methods for identifying eddies directly from along track altimetry data via a machine (deep) learning approach.

Since eddy signatures (eddy boundary and highs and lows on sea level anomaly, SLA) are not possible to extract directly from along track altimetry data, the gridded altimetry maps from AVISO are used to detect eddies. These will serve as the reference data for Machine Learning. The eddy detection on 2D grid maps is produced by open-source geometry-based approach (e.g., py-eddy-tracker, Mason et al., 2014) with additional constraints like Okubo-Weiss parameter. Later, Sea Surface Temperature (SST) maps of the same region and date (also available from AVISO) are used for manually cleaning the reference data. Noting that altimetry grid maps and SST maps have different temporal and spatial resolution, we also use the high resolution (~6 km) ocean modeling simulation dataset (e.g., FESOM, Finite Element Sea ice Ocean Model). In this case, the FESOM dataset provides a coherent, high-resolution SLA and SST, salinity maps for the study area and is a potential test basis to develop the deep learning network.

The single modal training via a Conventional Neural Network (CNN) for the 2D altimetry grid maps produced excellent dice score of 86%, meaning the network almost detects all eddies in the Gulf Stream, which are consistent with reference data. For the multi-modal training, two different training networks are developed for 1D along-track altimetry data and 2D grid maps from SLA and SST, respectively, and then they are combined to give the final classification output. A transformer model is deemed to be efficient for encoding the spatiotemporal information from 1D along track altimetry data, while CNN is sufficient for 2D grid maps from multi-sensors.

In this presentation, we show the eddy classification results from the multi-modal deep learning approach based on along track and gridded multi-source datasets for the Gulf stream area for the period between 2017 and 2019. Results show that multi-modal deep learning improve the classification by more than 20% compared to transformer model training on along-track data alone.

How to cite: Abulaitijiang, A., Bolmer, E., Roscher, R., Kusche, J., and Fenoglio-Marc, L.: Eddy identification from along-track altimeter data with multi-modal deep learning, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-6818, https://doi.org/10.5194/egusphere-egu23-6818, 2023.

EGU23-8479 | ECS | PICO | ESSI1.1

Model evaluation strategy impacts the interpretation and performance of machine learning models 

Lily-belle Sweet, Christoph Müller, Mohit Anand, and Jakob Zscheischler

Machine learning models are able to capture highly complex, nonlinear relationships, and have been used in recent years to accurately predict crop yields at regional and national scales. This success suggests that the use of ‘interpretable’ or ‘explainable’ machine learning (XAI) methods may facilitate improved scientific understanding of the compounding interactions between climate, crop physiology and yields. However, studies have identified implausible, contradicting or ambiguous results from the use of these methods. At the same time, researchers in fields such as ecology and remote sensing have called attention to issues with robust model evaluation on spatiotemporal datasets. This suggests that XAI methods may produce misleading results when applied to spatiotemporal datasets, but the impact of model evaluation strategy on the results of such methods has not yet been examined.

In this study, machine learning models are trained to predict simulated crop yield, and the impact of model evaluation strategy on the interpretation and performance of the resulting models is assessed. Using data from a process-based crop model allows us to then comment on the plausibility of the explanations provided by common XAI methods. Our results show that the choice of evaluation strategy has an impact on (i) the interpretations of the model using common XAI methods such as permutation feature importance and (ii) the resulting model skill on unseen years and regions. We find that use of a novel cross-validation strategy based on clustering in feature-space results in the most plausible interpretations. Additionally, we find that the use of this strategy during hyperparameter tuning and feature selection results in improved model performance on unseen years and regions. Our results provide a first step towards the establishment of best practices for model evaluation strategy in similar future studies.

How to cite: Sweet, L., Müller, C., Anand, M., and Zscheischler, J.: Model evaluation strategy impacts the interpretation and performance of machine learning models, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-8479, https://doi.org/10.5194/egusphere-egu23-8479, 2023.

EGU23-9437 | PICO | ESSI1.1

On Unsupervised Learning from Environmental Data 

Mikhail Kanevski

Predictive learning from data usually is formulated as a problem of finding the best connection between input and output spaces by optimizing well-defined cost or risk functions.

In geo-environmental studies input space is usually constructed from the geographical coordinates and features generated from different sources of available information (feature engineering), by applying expert knowledge, using deep learning technologies and taking into account the objectives of the study. Often, it is not known in advance if the input space is complete or contains redundant features. Therefore, unsupervised learning (UL) is essential in environmental data analysis, modelling, prediction and visualization. UL also helps better understand the data and phenomena they describe as well as in interpreting/communicating modelling strategies and the results in the decision-making process.

The main objective of the present investigation is to review some important topics in unsupervised learning from environmental data: 1) quantitative description of the input space (“monitoring network”) structure using global and local topological and fractal measures, 2) dimensionality reduction, 3) unsupervised feature selection and clustering by applying a variety of machine learning algorithms (kernel-based, ensemble learning, self-organizing maps) and visualization tools.

Major attention is paid to the simulated and real spatial data (pollution, permafrost, geomorphological and wind fields data).  Considered case studies have different input space dimensionality/topology and number of measurements. It is confirmed that UL should be considered an integral part of a generic methodology of environmental data analysis. Comprehensive comparisons and discussions of the results conclude the research.

 

 

How to cite: Kanevski, M.: On Unsupervised Learning from Environmental Data, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-9437, https://doi.org/10.5194/egusphere-egu23-9437, 2023.

EGU23-11601 | PICO | ESSI1.1

Clustering Geodata Cubes (CGC) and Its Application to Phenological Datasets 

Francesco Nattino, Ou Ku, Meiert W. Grootes, Emma Izquierdo-Verdiguier, Serkan Girgin, and Raúl Zurita-Milla

Unsupervised classification techniques are becoming essential to extract information from the wealth of data that Earth observation satellites and other sensors currently provide. These datasets are inherently complex to analyze due to the extent across multiple dimensions - spatial, temporal, and often spectral or band dimension – their size, and the high resolution of current sensors. Traditional one-dimensional cluster analysis approaches, which are designed to find groups of similar elements in datasets such as rasters or time series, may come short of identifying patterns in these higher-dimensional datasets, often referred to as data cubes. In this context, we present our Clustering Geodata Cubes (CGC) software, an open-source Python package that implements a set of co- and tri-clustering algorithms to simultaneously group elements across two and three dimensions, respectively. The package includes different implementations to most efficiently tackle datasets that fit into the memory of a single machine as well as very large datasets that require cluster computing. A refining strategy to facilitate data pattern identification is also provided. We apply CGC to investigate gridded datasets representing the predicted day of the year when spring onset events (first leaf, first bloom) occur according to a well-established phenological model. Specifically, we consider spring indices computed at high spatial resolution (1 km) and continental scale (conterminous United States) for the last 40+ years and extract the main spatiotemporal patterns present in the data via CGC co-clustering functionality.  

How to cite: Nattino, F., Ku, O., Grootes, M. W., Izquierdo-Verdiguier, E., Girgin, S., and Zurita-Milla, R.: Clustering Geodata Cubes (CGC) and Its Application to Phenological Datasets, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-11601, https://doi.org/10.5194/egusphere-egu23-11601, 2023.

EGU23-12773 | PICO | ESSI1.1

Industrial Atmospheric Pollution Estimation Using Gaussian Process Regression 

Anton Sokolov, Hervé Delbarre, Daniil Boldyriev, Tetiana Bulana, Bohdan Molodets, and Dmytro Grabovets

Industrial pollution remains a major challenge in spite of recent technological developments and purification procedures. To effectively monitor atmosphere contamination, data from air quality networks should be coupled with advanced spatiotemporal statistical methods.

Our previous studies showed that standard interpolation techniques (like inverse distance weighting, linear or spline interpolation, kernel-based Gaussian Process Regression, GPR) are quite limited for the simulation of a smoke-like narrow-directed industrial pollution in the vicinity of the source (a few tenths of kilometers). In this work, we try to apply GPR, based on statistically estimated covariances. These covariances are calculated using СALPUFF atmospheric pollution dispersion model for a one-year simulation in the Kryvyi Rih region. The application of GPR permits taking into account high correlations between pollution values in neighboring points revealed by modeling. The result of the GPR covariance-based technique is compared with other interpolation techniques. It can be used then in the estimation and optimization of air quality networks.

How to cite: Sokolov, A., Delbarre, H., Boldyriev, D., Bulana, T., Molodets, B., and Grabovets, D.: Industrial Atmospheric Pollution Estimation Using Gaussian Process Regression, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-12773, https://doi.org/10.5194/egusphere-egu23-12773, 2023.

EGU23-12933 | ECS | PICO | ESSI1.1

Estimating vegetation carbon stock components by linking ground databases with Earth observations 

Daniel Kinalczyk, Christine Wessollek, and Matthias Forkel

Land ecosystems dampen the increase of atmospheric CO2 by storing carbon in soils and vegetation. In order to estimate how long carbon stays in land ecosystems, a detailed knowledge about the distribution of carbon in different vegetation components is needed. Current Earth observation products provide estimates about total above-ground biomass but do not further separate between carbon stored in trees, understory vegetation, shrubs, grass, litter or woody debris. Here we present an approach in which we link several Earth observation products with a ground-based database to estimate biomass in various vegetation components. Therefore, we use information about the statistical distribution of biomass components provided by the North American Wildland Fuels Database (NAWFD), which are however not available as geocoded data. We use ESA CCI AGB version 3 data from 2010 as a proxy in order to link the NAWFD data to the spatial information from Earth observation products. The biomass and corresponding uncertainty from the ESA CCI AGB and a map of vegetation types are used to select the likely distribution of vegetation biomass components from the set of in-situ measurements of tree biomass. We then apply Isolation Forest outlier detection and bootstrapping for a robust comparison of both datasets and for uncertainty estimation. We use Random Forest and Gaussian Process regression to predict the biomass of trees, shrubs, snags, herbaceous vegetation, coarse and fine woody debris, duff and litter from ESA CCI AGB and land cover, GEDI canopy height, Sentinel-3 LAI and bioclimatic data. The regression models reach high predictive power and allow to also extrapolate to other regions. Our derived estimates of vegetation carbon stock components provide a more detailed view on the land carbon storage and contribute to an improved estimate of potential carbon emissions from respiration, disturbances and fires.

How to cite: Kinalczyk, D., Wessollek, C., and Forkel, M.: Estimating vegetation carbon stock components by linking ground databases with Earth observations, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-12933, https://doi.org/10.5194/egusphere-egu23-12933, 2023.

EGU23-13196 | ECS | PICO | ESSI1.1

From Super-Resolution to Downscaling - An Image-Inpainting Deep Neural Network for High Resolution Weather and Climate Models 

Maximilian Witte, Danai Filippou, Étienne Plésiat, Johannes Meuer, Hannes Thiemann, David Hall, Thomas Ludwig, and Christopher Kadow

High resolution in weather and climate was always a common and ongoing goal of the community. In this regards, machine learning techniques accompanied numerical and statistical methods in recent years. Here we demonstrate that artificial intelligence can skilfully downscale low resolution climate model data when combined with numerical climate model data. We show that recently developed image inpainting technique perform accurate super-resolution via transfer learning using the HighResMIP of CMIP6 (Coupled Model Intercomparison Project Phase 6) experiments. Its huge data base offers a unique training opportunity for machine learning approaches. The transfer learning purpose allows also to downscale other CMIP6 experiments and models, as well as observational data like HadCRUT5. Combined with the technology of Kadow et al. 2020 of infilling missing climate data, we gain a neural network which reconstructs and downscales the important observational data set (IPCC AR6) at the same time. We further investigate the application of our method to downscale quantities predicted from a numerical ocean model (ICON-O) to improve computation times. In this process we focus on the ability of the model to predict eddies from low-resolution data.

An extension to:

Kadow, C., Hall, D.M. & Ulbrich, U. Artificial intelligence reconstructs missing climate information. Nature Geoscience 13, 408–413 (2020). https://doi.org/10.1038/s41561-020-0582-5

How to cite: Witte, M., Filippou, D., Plésiat, É., Meuer, J., Thiemann, H., Hall, D., Ludwig, T., and Kadow, C.: From Super-Resolution to Downscaling - An Image-Inpainting Deep Neural Network for High Resolution Weather and Climate Models, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-13196, https://doi.org/10.5194/egusphere-egu23-13196, 2023.

EGU23-14716 | ECS | PICO | ESSI1.1

Spatial-temporal transferability assessment of remote sensing data models for mapping agricultural land use 

Jayan Wijesingha, Ilze Dzene, and Michael Wachendorf

To assess the impact of anthropogenic and natural causes on land use and land use cover change, mapping of spatial and temporal changes is increasingly applied. Due to the availability of satellite image archives, remote sensing (RS) data-based machine learning models are in particular suitable for mapping and analysing land use and land cover changes. Most often, models trained with current RS data are employed to estimate past land cover and land use using available RS data with the assumption that the trained model predicts past data values similar to the accuracy of present data. However, machine learning models trained on RS data from particular locations and times may not be well transferred to new locations and time datasets due to various reasons. This study aims to assess the spatial-temporal transferability of the RS data models in the context of agricultural land use mapping. The study was designed to map agricultural land use (5 classes: maize, grasslands, summer crops, winter crops, and mixed crops) in two regions in Germany (North Hesse and Weser Ems) between the years 2010 and 2018 using Landsat archive data (i.e., Landsat 5, 7, and 8). Three model transferability scenarios were evaluated, a) temporal - S1, b) spatial - S2 and c) spatial-temporal - S3. Two machine learning models (random forest - RF and Convolution Neural Network - CNN) were trained. For each transferability scenario, class-level F1 and macro F1 values were compared between the reference and targeted transferability systems. Moreover, to explain the results of transferability scenarios, transferability results were further explored using dissimilarity index and area of applicability (AOA) concepts. The average macro F1 value of the trained model for the reference scenario (no transferability) was 0.75. For assessed transferability scenarios, the average macro F1 values were 0.70, 0.65 and 0.60, for S1, S2, and S3 respectively. It shows that, when predicting data from different spatial-temporal contexts, the model performance is decreasing. In contrast, the average proportion of the data inside the AOA did not show a clear pattern for different scenarios. In the context of RS data-related model building, spatial-temporal transferability is essential because of the limited availability of the labelled data. Thus, the results from this case study provide an understanding of how model performance changes when the model is transferred to new settings with data from different temporal and spatial domains.

How to cite: Wijesingha, J., Dzene, I., and Wachendorf, M.: Spatial-temporal transferability assessment of remote sensing data models for mapping agricultural land use, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-14716, https://doi.org/10.5194/egusphere-egu23-14716, 2023.

EGU23-16096 | ECS | PICO | ESSI1.1

Limitations of machine learning in a spatial context 

Jens Heinke, Christoph Müller, and Dieter Gerten

Machine learning algorithms have become popular tools for the analysis of spatial data. However, a number of studies have demonstrated that the application of machine learning algorithms in a spatial context has limitations. New geographic locations may lie outside of the data range for which the model was trained, and estimates of model performance may be too optimistic, when spatial autocorrelation of geographic data is not properly accounted for in cross-validation. We here use artificially created spatial data fields to conduct a series of experiments to further investigate the potential pitfalls of random forest regression applied to spatial data. We provide new insights on previously reported limitations and identify further limitations. We demonstrate that the same mechanism that leads to overoptimistic estimates of model performance (when based on ordinary random k-fold cross-validation) can also lead to a deterioration of model performance. When covariates contain sufficient information to deduce spatial coordinates, the model can reproduce any spatial pattern in the training data even if it is entirely or partly unrelated to the covariates. The presence of spatially correlated residuals in the training data changes how the model utilizes the information of the covariates and impedes the identification of the actual relationship between covariates and response. This reduces model performance when the model is applied to data with a different spatial structure. Under such conditions, machine learning methods that are sufficiently flexible to fit to autocorrelated residuals (such as random forest) may not be an optimal choice. Better models may be obtained using less flexible but more transparent approaches such as generalized linear models or additive models.

How to cite: Heinke, J., Müller, C., and Gerten, D.: Limitations of machine learning in a spatial context, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-16096, https://doi.org/10.5194/egusphere-egu23-16096, 2023.

EGU23-16768 | PICO | ESSI1.1

Knowledge Representation of Levee Systems - an Environmental Justice Perspective 

Armita Davarpanah, Anthony.l Nguy Robertson, Monica Lipscomb, Jacob.w. McCord, and Amy Morris

Levee systems are designed to reduce the risk of water-related natural hazards (e.g., flooding) in areas behind levees. Most levees in the U.S. are designed to protect people and facilities against the impacts of the 100-year floods. However, the current climate change is increasing the probability of the occurrence of 500-year flood events that in turn increases the likelihood of economic loss, environmental damage, and fatality that disproportionately impacts communities of color and low-income groups facing socio-economic inequities in leveed areas. The increased frequency and intensity of flooding is putting extra pressure on emergency responders that often require diverse, multi-dimensional data originating from different sources to make sound decisions. Currently, the integration of these heterogeneous data acquired by diverse sensors and emergency agencies about environmental, hydrological, and demographic indicators requires costly and complex programming and analysis that hinder rapid disaster management efforts. Our domain ‘Levee System Ontology (LSO)’ resolves the data integration and software interoperability issues by semantically modeling the static aspects, dynamic processes, and information content of the levee systems by extending the well-structured, top-level Basic Formal Ontology (BFO) and mid-level Common Core Ontologies (CCO). LSO’s class and property names follow the terminology of the National Levee Database (NLD), allowing data scientists using NLD data to constrain their classifications based on the knowledge represented in LSO. In addition to modeling the information related to the characteristics and status of the structural components of the levee system, LSO represents the residual risk in leveed areas, economic and environmental losses, and damage to facilities in case of breaching and/or overtopping of levees. LSO enables reasoning to infer components and places along levees and floodwalls where the system requires inspection, maintenance, and repair based on the status of system components. The ontology also represents the impact of flood management activities on different groups of people from an environmental justice perspective, based on the principles of DEI (diversity, equity, inclusion) as defined by the U.N. Sustainable Development Goals.

How to cite: Davarpanah, A., Nguy Robertson, A. L., Lipscomb, M., McCord, J. w., and Morris, A.: Knowledge Representation of Levee Systems - an Environmental Justice Perspective, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-16768, https://doi.org/10.5194/egusphere-egu23-16768, 2023.

EGU23-1981 | ECS | Posters on site | GI3.3

Total stratospheric bromine inferred from balloon-borne solar occultation bromine oxide (BrO) measurements using the new TotalBrO instrument 

Karolin Voss, Philip Holzbeck, Ralph Kleinschek, Michael Höpfner, Gerald Wetzel, Björn-Martin Sinnhuber, Klaus Pfeilsticker, and André Butz

Halogenated organic and inorganic compounds, in particular those containing chlorine, bromine and iodine are known to contribute to the global ozone depletion as well as directly and indirectly to climate forcing. As a result of the Montreal Protocol (1987), the chlorine and bromine loadings of the stratosphere are closely monitored, while the role of iodinated compounds to the stratospheric ozone photochemistry is still uncertain.

To address the questions concerning bromine and iodine compounds, a compact solar occultation instrument (TotalBrO) has been specifically designed to measure BrO, IO (iodine oxide) and other UV/Vis absorbing gases by means of Differential Optical Absorption Spectroscopy (DOAS) from aboard a stratospheric balloon. The instrument (power consumption < 100 W) comprises of an active camera-based solar tracker (LxWxH ~ 0.40 m x 0.40 m x 0.50 m, weight ~ 12 kg) and a spectrometer unit (LxWxH ~ 0.45 m x 0.40 m x 0.40 m, weight ~ 25 kg). The spectrometer unit houses two grating spectrometers which operate in vacuum and under temperature stabilization by an ice-water bath.

We discuss the performance of the TotalBrO instrument during the first two deployments on stratospheric balloons launched from Kiruna in August, 2021 and from Timmins in August, 2022 within the HEMERA program. Once the balloon gondola was azimuthally stabilized the solar tracker was able to follow the sun with a 1σ precision lower than 0.02° up to solar zenith angles (SZAs) of 95°. The spectral retrieval (of 46 spectra acquired at SZA between 84° and 90°) allowed us to infer the BrO mixing ratio above 32 km altitude. The total bromine in the middle stratosphere is inferred by accounting for the BrO/Bry partitioning derived from a photochemical model.

How to cite: Voss, K., Holzbeck, P., Kleinschek, R., Höpfner, M., Wetzel, G., Sinnhuber, B.-M., Pfeilsticker, K., and Butz, A.: Total stratospheric bromine inferred from balloon-borne solar occultation bromine oxide (BrO) measurements using the new TotalBrO instrument, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-1981, https://doi.org/10.5194/egusphere-egu23-1981, 2023.

EGU23-2923 | ECS | Posters on site | GI3.3

Total organic carbon measurements reveal large discrepancies in reported petrochemical emissions 

Megan He, Jenna Ditto, Lexie Gardner, Jo Machesky, Tori Hass-Mitchell, Christina Chen, Peeyush Khare, Bugra Sahin, John Fortner, Katherine Hayden, Jeremy Wentzell, Richard Mittermeier, Amy Leithead, Patrick Lee, Andrea Darlington, Junhua Zhang, Samar Moussa, Shao-Meng Li, John Liggio, and Drew Gentner

Oil sands are a prominent unconventional source of petroleum. Total organic carbon measurements via an aircraft campaign (Spring-Summer 2018) revealed emissions above Canadian oil sands exceeding reported values by 1900-6300%. The “missing” compounds were predominantly intermediate- and semi-volatile organic compounds, which are prolific precursors to secondary organic aerosol formation. 

Here we use a novel combination of aircraft-based measurements (including total carbon emissions measurements) and offline analytical instrumentation to characterize the mixtures of organic carbon and their volatility distributions above oil sands facilities. These airborne, real-time observations are supplemented by laboratory experiments identifying substantial, unintended emissions from waste management practices, emphasizing the importance of accurate facility-wide emissions monitoring and total carbon measurements to detect potentially vast missing emissions across sources.

Detailed chemical speciation confirms these observations near both surface mining and in-situ facilities were oil sands-derived, with facility-wide emissions around 1% of extracted petroleum—a comparable loss rate to natural gas extraction. Total emissions, spanning extraction through waste processing, were equivalent to total Canadian anthropogenic emissions from all sources. These results demonstrate that the full air quality and environmental impacts of oil sands operations cannot be captured without complete coverage of a wider volatility range of emissions.

How to cite: He, M., Ditto, J., Gardner, L., Machesky, J., Hass-Mitchell, T., Chen, C., Khare, P., Sahin, B., Fortner, J., Hayden, K., Wentzell, J., Mittermeier, R., Leithead, A., Lee, P., Darlington, A., Zhang, J., Moussa, S., Li, S.-M., Liggio, J., and Gentner, D.: Total organic carbon measurements reveal large discrepancies in reported petrochemical emissions, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-2923, https://doi.org/10.5194/egusphere-egu23-2923, 2023.

EGU23-3473 | Posters on site | GI3.3 | Highlight

The FAAM large atmospheric research aircraft: a brief history and future upgrades 

James Lee

The UK’s large atmospheric research aircraft is a converted BAe 146 operated by the Facility for Airborne Atmospheric Measurements (FAAM). With a range of 2000 nautical miles, the FAAM aircraft is capable of operating all over the world and it has taken part in science campaigns in over 30 different countries since 2004. The aircraft can fly as low as 50 feet over the sea and sustain flight at 100 feet high. The service ceiling is nearly 11 km high. Typically, flights will last anywhere between one and six hours, and we will carry up to 18 scientists onboard, who guide the mission and support the operation of up to 4 tonnes of scientific equipment. Currently, the aircraft is undergoing a £49 million mid-life upgrade (MLU) program, which will extend its lifetime to at least 2040. The three overarching objectives of the MLU are to:

Safeguard the UK’s research capability – allowing the facility to meet the needs of the research community, enhance the range of services available, and respond to environmental emergencies.

Provide frontier science capability – meeting new and existing research needs and supporting ground-breaking science discoveries, with a flexible and world-class airborne laboratory.

Reduce environmental impact – maintaining and improving the performance of the facility, and minimising emissions and resource use from aircraft operation.

Presented here will be a brief history of the aircraft operations, including example science outcomes from all flights all over the world. In addition, detail of the ongoing upgrades, in particular the new and cutting-edge measurement capability for gases, aerosols, clouds, radiation and meteorology. Also presented will be the expected reductions in environmental impact of the aircraft and how these will be monitored.

How to cite: Lee, J.: The FAAM large atmospheric research aircraft: a brief history and future upgrades, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-3473, https://doi.org/10.5194/egusphere-egu23-3473, 2023.

EGU23-6620 | ECS | Posters on site | GI3.3

Airborne observations over the North Atlantic Ocean reveal the first gas-phase measurements of urea in the atmosphere 

Emily Matthews, Thomas Bannan, M. Anwar Khan, Dudley Shallcross, Harald Stark, Eleanor Browne, Alexander Archibald, Stéphane Bauguitte, Chris Reed, Navaneeth Thamban, Huihui Wu, James Lee, Lucy Carpenter, Ming-xi Yang, Thomas Bell, Grant Allen, Carl Percival, Gordon McFiggans, Martin Gallagher, and Hugh Coe

Despite the reduced nitrogen (N) cycle being central to global biogeochemistry, there are large uncertainties surrounding its sources and rate of cycling. Here, we present the first observations of gas-phase urea (CO(NH₂)₂) in the atmosphere from airborne high-resolution mass spectrometer measurements over the North Atlantic Ocean. We show that urea is ubiquitous in the marine lower troposphere during the Summer, Autumn and Winter flights but was found to be below the limit of detection during the Spring flights. The observations suggest the ocean is the primary emission source but further studies are required to understand the processes responsible for the air-sea exchange of urea. Urea is also frequently observed aloft due to long-range transport of biomass-burning plumes. These observations alongside global model simulations point to urea being an important, and as yet unaccounted for, component of reduced-N to the remote marine environment.  Since we show it readily partitions between gas and particle phases, airborne transfer of urea between nutrient rich and poor parts of the ocean can occur readily and could impact ecosystems and oceanic uptake of CO2, with potentially important atmospheric implications.  

How to cite: Matthews, E., Bannan, T., Khan, M. A., Shallcross, D., Stark, H., Browne, E., Archibald, A., Bauguitte, S., Reed, C., Thamban, N., Wu, H., Lee, J., Carpenter, L., Yang, M., Bell, T., Allen, G., Percival, C., McFiggans, G., Gallagher, M., and Coe, H.: Airborne observations over the North Atlantic Ocean reveal the first gas-phase measurements of urea in the atmosphere, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-6620, https://doi.org/10.5194/egusphere-egu23-6620, 2023.

EGU23-7804 | Posters virtual | GI3.3

In-situ trace-gas measurements from the ground to the stratosphere by an OF-CEAS balloon-borne instrument 

Valery Catoire, Chaoyang Xue, Gisèle Krysztofiak, Patrick Jacquet, Michel Chartier, and Claude Robert

Monitoring climate change and stratospheric ozone budget requires accurate knowledge of the abundances of greenhouse gases and ozone depleting substances from the lower troposphere to the stratosphere. An infrared laser absorption spectrometer called SPECIES (acronym for SPECtromètre Infrarouge à lasErs in Situ) has been developed for balloon-borne trace gases measurements.

The complete instrument has been validated on the occasion of a flight in August 2021 in the polar region (Kiruna, Sweden) within the frame of the “KLIMAT 2021” campaign managed by CNES for the “MAGIC” project using concomitant balloon and aircraft flights. Results of this flight concerning CH4 and CO2 will be presented.

How to cite: Catoire, V., Xue, C., Krysztofiak, G., Jacquet, P., Chartier, M., and Robert, C.: In-situ trace-gas measurements from the ground to the stratosphere by an OF-CEAS balloon-borne instrument, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-7804, https://doi.org/10.5194/egusphere-egu23-7804, 2023.

EGU23-7986 | ECS | Posters on site | GI3.3

Ship emissions and apparent sulphur fuel content measured of board of a large research aircraft in international waters and Sulphur Emission Control Area 

Dominika Pasternak, James Lee, Beth Nelson, Magdalini Alexiadou, Loren Temple, Stéphane Bauguitte, Steph Batten, James Hopkins, Stephen Andrews, Emily Mathews, Thomas Bannan, Huihui Wu, Navaneeth Thamban, Nicholas Marsden, Ming-Xi Yang, Thomas Bell, Hugh Coe, and Keith Bower

Since 1st January 2020 the legal sulphur content of shipping fuel was decreased – from 3.5% to 0.5% by mass outside of the Sulphur Emission Control Areas (SECAs) to improve coastal air quality. A possible downside of this change was acceleration of climate change since sulphur is believed to be a negative climate forcer and sipping is one of its main sources. Further question was the level of compliance to the new rules, especially in the open waters. Another climate related aspect of shipping is recent growth in the liquified natural gas (LNG) tanker fleets. LNG is considered the greenest of the fossil fuels, however there are few empirical studies of methane emissions from marine LNG transport.

The Atmospheric Composition and Radiative forcing changes due to UN International Ship Emissions regulations (ACRUISE) project aims to address the above considerations. During three field campaigns the FAAM Airborne Laboratories’ large research aircraft was deployed to target ships in coastal shipping lanes and open waters. First measurements were performed in July 2019 (before regulation change) in shipping lanes along the Portuguese coast, the English Channel SECA and the Celtic Sea. Further two campaigns were delayed by the COVID-19 pandemic until September 2021 and April 2022, targeting ships in the Bay of Biscay, the English Channel SECA and the Celtic Sea. Throughout the project, nearly 300 ships were measured during 30 research flights, varying from plume aging and cloud interaction studies, through collecting bulk statistics in busy shipping lanes to comparing emissions in and out of SECA. This work focuses on the gaseous species measurements (SO2, CO2, CH4 and VOCs from whole air samples). They are used to study changes in apparent sulphur fuel content of the ships observed throughout ACRUISE, plume composition and methane emissions from LNG tankers.

How to cite: Pasternak, D., Lee, J., Nelson, B., Alexiadou, M., Temple, L., Bauguitte, S., Batten, S., Hopkins, J., Andrews, S., Mathews, E., Bannan, T., Wu, H., Thamban, N., Marsden, N., Yang, M.-X., Bell, T., Coe, H., and Bower, K.: Ship emissions and apparent sulphur fuel content measured of board of a large research aircraft in international waters and Sulphur Emission Control Area, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-7986, https://doi.org/10.5194/egusphere-egu23-7986, 2023.

EGU23-8329 | ECS | Posters on site | GI3.3 | Highlight

Airborne remote sensing research infrastructure for strengthening science, international collaboration and capacity building in the Arctic 

Shridhar Jawak, Agnar Sivertsen, William D. Harcourt, Rudolf Denkmann, Ilkka Matero, Øystein Godøy, and Heikki Lihavainen

Svalbard Integrated Arctic Earth Observing System (SIOS) is an international collaboration of 28 scientific institutions from 10 countries to build a collaborative research infrastructure that will enable better estimates of future environmental and climate changes in the Arctic. SIOS' mission is to develop an efficient observing system in Svalbard, share technology and data using FAIR principles, fill knowledge gaps in Earth system science and reduce the environmental footprint of science in the Arctic. This study presents SIOS' efforts to strengthen science, international collaboration and capacity building in the high Arctic archipelago of Svalbard through its airborne research infrastructure. SIOS supports the coordinated usage of its airborne remote sensing resources such as the Dornier aircraft and uncrewed aerial vehicles (UAVs) for improved research activities in Svalbard, complementing in situ and space-borne measurements and reducing the environmental footprint of research in Svalbard. Since 2019, SIOS in collaboration with its member institution Norwegian Research Centre (NORCE) installed, tested, and operationalised optical imaging sensors in the Lufttransport Dornier (DO228) passenger aircraft stationed in Longyearbyen under the SIOS-InfraNor project making it compatible with research use in Svalbard. Two optical sensors are installed onboard the Dornier aircraft; (1) the PhaseOne IXU-150 RGB camera and (2) the HySpex VNIR-1800 hyperspectral sensor. The aircraft with these cameras is configured to acquire aerial RGB imagery and hyperspectral remote sensing data in addition to its regular logistics and transport operation in Svalbard. Since 2020, SIOS has supported and coordinated around 50 flight hours to acquire airborne data using the Dornier aircraft and UAVs in Svalbard supporting around 20 scientific projects. The use of airborne imaging sensors in these projects enabled a variety of applications within glaciology, biology, hydrology, and other fields of Earth system science: Mapping glacier crevasses, generating DEMs for glaciological applications, mapping and characterising earth (e.g., minerals, vegetation), ice (e.g., sea ice, icebergs, glaciers and snow cover) and ocean surface features (e.g., colour, chlorophyll). The use of passenger aircraft warrants the following benefits: (1) regular logistics and research activities are optimally coordinated to reduce flight hours in carrying scientific observations, (2) project proposals for the usage of aircraft-based measurements facilitate international collaboration, (3) measurements conducted during 2020-21 are useful in filling the gaps in field based observations occurred due to the Covid-19 pandemic, (4) airborne data are used to train polar scientists as a part of the annual SIOS training course and upcoming data usability contest, (5) data is also useful for Arctic field safety as it can be used to make products such as high-resolution maps of crevassed areas on glaciers. In short, SIOS airborne remote sensing activities represent optimized use of infrastructure, promote capacity building, Arctic safety and facilitate international cooperation.

How to cite: Jawak, S., Sivertsen, A., Harcourt, W. D., Denkmann, R., Matero, I., Godøy, Ø., and Lihavainen, H.: Airborne remote sensing research infrastructure for strengthening science, international collaboration and capacity building in the Arctic, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-8329, https://doi.org/10.5194/egusphere-egu23-8329, 2023.

EGU23-11813 | Posters on site | GI3.3

First evaluation of a 6-months Meteodrone campaign 

Maxime Hervo, Julie Pasquier, Lukas Hammerschmidt, Tanja Weusthoff, Martin Fengler, and Alexander Haefele

 From December 2021 to May 2022, MeteoSwiss conducted a proof of concept with Meteomatics to demonstrate the capability of drones to provide data of sufficient quality and reliability on a routine operational basis. Meteodrones MM-670 were operated automatically 8 times per night at Payerne, Switzerland. 864 meteorological profiles were measured and compared to co-localized measurements including radiosoundings and remote-sensing instruments. To our knowledge, it is the first time that Meteodrone measurements are evaluated in such an intensive campaign.

The availability of the Meteodrone measurements over the whole campaign was 75.7% with 82.2% of the flights reaching the nominal altitude of 2000m above sea level. Using the radiosondes as a reference, the quality of the Meteodrone measurements can be quantified according to WMO requirements (WMO OSCAR , 2022). Applying this method, the temperature measured by the Meteodrone can be considered as a “breakthrough”, meaning that they are a significant improvement if they are used for high resolution Numerical Weather Prediction. The Meteodrone’s humidity and wind profiles are classified as “useful” for high-resolution numerical weather predictions, suggesting they can be used for assimilation in numerical models. The quality is similar compared to the temperature measured by a microwave radiometer and the humidity measured by a Raman Lidar. However, the wind measured by a Doppler Lidar was more accurate than the estimation of the Meteodrone.

This campaign opens the door for operational usage of automatic drones for meteorological applications.

How to cite: Hervo, M., Pasquier, J., Hammerschmidt, L., Weusthoff, T., Fengler, M., and Haefele, A.: First evaluation of a 6-months Meteodrone campaign, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-11813, https://doi.org/10.5194/egusphere-egu23-11813, 2023.

EGU23-13766 | ECS | Posters on site | GI3.3

How inlet tubing material affects the response time of water vapor concentration measurements 

Markus Miltner, Tim Stoltmann, and Erik Kerstel

Measurements involving water in the vapor phase have to deal with the stickiness of the H2O molecule: The associated adsorption and desorption processes can increase the response time of these measurements significantly. To achieve short response times in scientific instrument design, hydrophobic surface materials are used to reduce surface interactions in the tubing that guides the sample towards the analyzer. The study presented here focuses on the effects of the tubing material choice, length, humidity level, gas flow rate, and temperature on the observed response time. We use an Optical Feedback Cavity Enhanced Absorption Spectrometer (OFCEAS) designed for stable water isotope measurements at low water concentration (< 1000 ppm), which we connect to two bottles containing humidified synthetic air of different water concentration using 6.6-m tubing of different materials and surface treatments. Other parameters that are varied are the flow rate and the temperature of the tubing. With proper selection of tubing material and surface treatment, the contribution from the tubing to the overall response time for low water concentration isotopic measurements can be sufficiently suppressed for it to be neglected.

How to cite: Miltner, M., Stoltmann, T., and Kerstel, E.: How inlet tubing material affects the response time of water vapor concentration measurements, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-13766, https://doi.org/10.5194/egusphere-egu23-13766, 2023.

EGU23-14164 | ECS | Posters virtual | GI3.3

Multi-angular airborne thermal observations: A new hyperspectral setup for simulating thermal radiation and emissivity directionality at the satellite scale 

Mary Langsdale, Callum Middleton, Martin Wooster, Mark Grosvenor, and Dirk Schuettemeyer

Land Surface Temperature (LST) is a key parameter to the understanding and modelling of many Earth system processes. Viewing and illumination geometry are known to have significant impacts on remotely sensed retrieval of LST, particularly for heterogeneous regions with mixed components. However, it is difficult to accurately quantify these impacts, in part due to the challenges of retrieving high-quality data for the different components in a scene at a variety of different viewing and illumination geometries over a time period where the real surface temperature and sun-sensor geometries are invariant. Previous field studies have attempted this through observations with aircraft-mounted single-band thermal cameras to further understanding of real-world conditions, but these sensors have limited accuracies and cannot be used to consider the angular variability of emissivity or to simulate multi-band satellite observations.

To redress this, the National Centre for Earth Observation’s Airborne Earth Observatory (NAEO) have developed and manufactured a modified mount for their state-of-the-art commercial pushbroom longwave hyperspectral airborne sensor, the Specim AisaOWL (102 narrowband channels across the 7.6 – 12.6 µm region). When mounted in standard mode, the field-of-view of the OWL sensor is 24° (± 12°), however the modified mount enables off-nadir measurements up to 48°. This has the potential to evaluate both thermal radiation and spectral emissivity directionality up to and beyond the view angles of most thermal satellite sensors. With LST now classified as an Essential Climate Variable, this work is particularly relevant as it will help to improve the accuracy of retrievals from current and future satellites (e.g. LSTM, SBG, TRISHNA).

In this presentation, we first present an overview of the design modifications that enable these high-angle observations and preliminary results from test flights before detailing how this setup will be used in an upcoming joint ESA-NASA campaign dedicated to quantifying and simulating thermal radiation directionality over agricultural regions at the satellite scale.

How to cite: Langsdale, M., Middleton, C., Wooster, M., Grosvenor, M., and Schuettemeyer, D.: Multi-angular airborne thermal observations: A new hyperspectral setup for simulating thermal radiation and emissivity directionality at the satellite scale, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-14164, https://doi.org/10.5194/egusphere-egu23-14164, 2023.

EGU23-14187 | ECS | Posters on site | GI3.3

Aircraft observations of NH3 from agricultural sources 

Lara Noppen, Lieven Clarisse, Frederik Tack, Thomas Ruhtz, Alexis Merlaud, Martin Van Damme, Michel Van Roozendael, Dirk Schuettemeyer, and Pierre Coheur

Ammonia (NH3) is mainly emitted in the atmosphere by anthropogenic activities, especially by agriculture. Excess emissions greatly disturb ecosystems, biodiversity, and air quality. Despite our awareness of these deleterious consequences, NH3 concentrations are increasing in most industrialized countries. This underlines the need for more stringent regulations and good knowledge of the species gained through effective monitoring.

Since a decade, NH3 is monitored from space, daily and globally, with thermal infrared sounders. However, their coarse spatial resolution (above 10 km) renders accurate quantification of NH3 sources particularly challenging. Indeed, only the largest and most isolated NH3 point sources have been identified and quantified from current observations and often only by exploiting long-term averages. To address the urgent need for better constraining NH3 emissions, a new satellite, called Nitrosat, has been proposed in response to the 11th ESA’s Earth Explorer call. The mission aims at mapping simultaneously NO2 and NH3 at a spatial resolution of 500 m at a global scale. With the support of ESA, almost 30 aircraft demonstration flights took place in Europe between 2020 and 2022. These flights mapped gapless areas of at least 10 by 20 km containing various sources of NO2 and NH3 using two instruments: the SWING instrument targeting NO2 in the UV-VIS and Hyper-Cam LW measuring infrared spectra to observe NH3.

Here we present NH3 observations from campaigns performed in Italy in spring 2022. The Po Valley was the main target, as it is the largest (agricultural) hotspot of NH3 in Europe.  Despite the presence of large background concentrations in the Po Valley, we show that the infrared measurements are able to expose a multitude of local agricultural hotspots such as cattle farms. A particularly successful campaign covering the region from Vetto to Colorno demonstrates measurement sensitivity to the gradual increase of NH3 background concentrations outside and inside the Po Valley. We also discuss flights carried out further south in Italy targeting other emissions of NH3, such as those from a soda ash plant, and the emissions from a fertilizer release experiment that was organized in collaboration with a farmer. We present the measurements both at their native horizontal resolution of 4 m and downsampled at the 500 m resolution of Nitrosat.

How to cite: Noppen, L., Clarisse, L., Tack, F., Ruhtz, T., Merlaud, A., Van Damme, M., Van Roozendael, M., Schuettemeyer, D., and Coheur, P.: Aircraft observations of NH3 from agricultural sources, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-14187, https://doi.org/10.5194/egusphere-egu23-14187, 2023.

EGU23-15334 | ECS | Posters on site | GI3.3

Global measurements of cloud properties using commercial aircraft 

Gary Lloyd and Martin Gallagher

In-Service Aircraft for a Global Observing System (IAGOS) is a European research infrastructure that uses the infrastructure of commercial aviation to make in-situ measurements of the atmosphere. We present data from the cloud sensing instrument installed on these aircraft between 2011 and 2021. This includes 1000s of flights across the globe that detect the concentration of cloud particles over the range 5-75 um and this provides information about seasonal variation in cloud frequency across different parts of the globe. From these measurements we are able to estimate properties such as Liquid/Ice Water Content (LWC/IWC), The Effective Diameter (ED) and Mean Volume Diameter (MVD).

How to cite: Lloyd, G. and Gallagher, M.: Global measurements of cloud properties using commercial aircraft, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-15334, https://doi.org/10.5194/egusphere-egu23-15334, 2023.

EGU23-17533 | ECS | Posters on site | GI3.3

Synergy of active and passive airborne observations for the evaluation of the radiative impacts of aerosols. Application to the AEROCLO-SA field campaign in Namibia 

Mégane Ventura, Fabien Waquet, Gerard Brobgniez, Frederic Parol, Marc Mallet, Nicolas Ferlay, Oleg Dubovic, Philippe Goloub, Cyrille Flamant, and Paola Formenti

Aerosols have important effects on both local and global climate, as well as on clouds and precipitations. We present here some original results of the AErosol RadiatiOn and CLOud in Southern Africa (AEROCLO-sA) field campaign led in Namibia in August and September 2017. This region shows a strong response to climate change and is associated with large uncertainties in climate models. Large amounts of biomass burning aerosols emitted by vegetation fires in Central Africa are transported far over the Namibian deserts and are also detected over the stratocumulus clouds covering the South Atlantic Ocean along the coast of Namibia. Absorbing aerosols above clouds are associated with strong positive direct radiative forcing (warming) that are still underestimated in climate models (De Graaf etal.,2021). The absorption of solar radiation by absorbing above clouds may also cause a warming where the aerosol layer is located. This warming would alter the thermodynamic properties of the atmosphere, which would impact the vertical development of low-level clouds impacting the cloud top height and its brightness.

The airborne field campaign consisted in ten flights performed with the French F-20 Falcon aircraft in this region of interest. Several instruments were involved: the OSIRIS polarimeter, prototype of the next 3MI spaceborne instrument of ESA (Chauvigné etal.,2021), the LNG lidar, an airborne photometer called PLASMA, as well as fluxmeters and dropsondes used to measure thermodynamical quantities, supplemented with in situ aerosol measurements of particles size distribution.

In order to quantify the aerosols radiative impact on the Namibian regional radiative budget, we use an original approach that combines polarimeter and lidar data to derive heating rate of the aerosols. This approach is evaluated during massive transports of biomass burning particles. To calculate this parameter, we use a radiative transfer code and additional meteorological parameters, provided by the dropsondes. We will introduce, the flight of September 8, 2017, aerosol pollution was very important. Emissions and dust were carried along the Namibian coast, and an aerosol plume was observed above a stratocumulus. We will present vertical profiles of heating rates computed in the solar and thermal parts of the spectrum with this technique. Our results indicated particularly strong heating rate values retrieved above clouds due to aerosols, in the order of 8K per day, which is likely to perturbate the dynamic of the below cloud layers.

In order to validate and to quantify this new methodology, we used the flux measurements acquired during loop descents performed during dedicated parts of the flights, which provides unique measurements of flux distribution (upwelling and downwelling) and heating rates in function of the altitude.

Finally, we will discuss the possibility to apply this method to available spaceborne passive and active observations in order to provide the first estimates of heating rate profiles above clouds at global scale.

How to cite: Ventura, M., Waquet, F., Brobgniez, G., Parol, F., Mallet, M., Ferlay, N., Dubovic, O., Goloub, P., Flamant, C., and Formenti, P.: Synergy of active and passive airborne observations for the evaluation of the radiative impacts of aerosols. Application to the AEROCLO-SA field campaign in Namibia, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-17533, https://doi.org/10.5194/egusphere-egu23-17533, 2023.

EGU23-71 | ECS | Orals | ERE4.3

Spectroscopic Studies and Confirmatory Geochemical Analyses of Rare Earth Element Bearing Rocks from the Neoproterozoic Siwana Ring Complex, Rajasthan, India 

Saraah Imran, Ajanta Goswami, Angana Saikia, Hrishikesh Kumar Rai, and Bijan Jyoti Barman

Abstract:

Rare earth elements (REEs) are of high economic value owing to their electronic, magnetic, optical, catalytic, and phosphorescent properties, thereby making them an important part of the development of green technology. They exhibit characteristic sharp absorption features in reflectance spectra in the visible-near infrared (VNIR) to short-wave infrared (SWIR) region due to their 4f-4f orbital intra-configurational electronic transitions.

In this study laboratory based close-range imaging spectroscopy techniques are used along with confirmatory geochemical analytical techniques (petrography, ICPMS, SEM and EPMA) to study 20 samples collected from REE-bearing rocks of the Neoproterozoic Siwana Ring Complex (SRC), a collapsed caldera structure situated in Barmer District, Rajasthan (India).

The SRC is an anorogenic, rift-related bimodal volcano-plutonic rock association belonging to the Malani Igneous Suite. It comprises of felsic and basic volcanic lava flows, rhyolite, peralkaline granite, pyroclastics, tuff and later microgranite, aplite and felsite dykes.

The spectral reflectance curves of the samples collected using an ASD FieldSpec4 (350-2500 nm) exhibit characteristic absorption dips at 439, 491, 580, 740 and 800 nm indicating the presence of Nd3+. Other major absorption dips are attributed to the presence of Sm3+, U4+, etc. Various combinations of absorption features in the VIS-SWIR region indicate the presence of minerals like biotite, epidote, chlorite, nontronite, goethite, and REE fluorocarbonates. The Fourier Transform Infrared (FTIR) spectra of the samples collected using a Thermo Fisher Scientific Nicolet 6700 (400-4000 cm-1) show symmetric and asymmetric bending and stretching vibration features of Si-O, P-O and O-H bonds, which are diagnostic of minerals like aegirine, riebeckite, and REE minerals like monazite apart from other major silicate minerals like quartz and feldspar. The presence of these minerals is confirmed by mineral chemistry, bulk and trace element data.

The observations from the spectroscopic studies seem to correlate well with data obtained from various geochemical analyses. This study provides spectroscopic information on the rocks from SRC for the first time. It shows the proficiency of spectroscopic studies as a cost-effective and non-destructive technique for the identification of REE minerals which can be used before detailed geochemical and mineralogical studies as well as future exploration.

Keywords: Siwana Ring Complex, Spectroscopy, REE

Abbreviations:

ASD – Analytical Spectral Devices, Inc.

EPMA – Electron Probe Micro Analyzer

FTIR – Fourier Transform Infrared

ICPMS – Inductively Coupled Plasma Mass Spectrometry

REE – Rare Earth Elements

SRC – Siwana Ring Complex

SWIR – Short Wave Infrared

VNIR – Visible Near Infrared

How to cite: Imran, S., Goswami, A., Saikia, A., Kumar Rai, H., and Jyoti Barman, B.: Spectroscopic Studies and Confirmatory Geochemical Analyses of Rare Earth Element Bearing Rocks from the Neoproterozoic Siwana Ring Complex, Rajasthan, India, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-71, https://doi.org/10.5194/egusphere-egu23-71, 2023.

EGU23-1642 | ECS | Orals | ERE4.3

HyMap airborne imaging spectroscopy for mineral potential mapping of cupriferous mineralization in a semi-arid region based on pixel/sub-pixel hydrothermal alteration minerals mapping – A case study 

Soufiane Hajaj, Abderrazak El Harti, Amine Jellouli, Amin Beiranvand Pour, Saloua Mnissar Himyari, Abderrazak Hamzaoui, Mohamed Khalil Bensalah, Naima Benaouis, and Mazlan Hashim

Recently, hyperspectral datasets recognized a great interest in mineral exploration studies due to their high accuracy in detecting and mapping hydrothermal alteration minerals. Remote and mountainous regions are hardly accessible by geologists, while the spectral richness of imaging spectroscopy could provide detailed information about geology/mineralogy without having a direct contact with the ground surface. The Kerdous inlier in the Anti-Atlas belt of Morocco is recognized by several occurrences of Cu, Pb, Zn Au, Ag, and Mn mineral deposits. This study is carried out in Eastern Kerdous where the abandoned Idikel mine occurs in order to perform a high-resolution mineral potential map using Gamma-Fuzzy logic approach with twenty HyMap-derived layers. The HyMap-based thematic layers were generated using Directed Principal Component Analysis (DPCA), Relative Absorption Band Depth (RBD), and the Mixture Tuned Matched Filtering (MTMF) for pixel/sub-pixel mineral mapping. The hydrothermally altered regions within the study area reveal several Minerals/Mineral mixtures of hematite, illite, kaolinite, montmorillonite, muscovite, topaz, dolomite, and pyrophyllite. Then, the line density map extracted automatically from the HyMap data image was also integrated. The findings of the image processing were validated using field investigation, petrographic, and XRD analysis. This study demonstrates the great potential of the present research methodology and HyMap as a tool for mineral exploitation in similar areas in Morocco's western Anti-Atlas belt.

How to cite: Hajaj, S., El Harti, A., Jellouli, A., Beiranvand Pour, A., Mnissar Himyari, S., Hamzaoui, A., Khalil Bensalah, M., Benaouis, N., and Hashim, M.: HyMap airborne imaging spectroscopy for mineral potential mapping of cupriferous mineralization in a semi-arid region based on pixel/sub-pixel hydrothermal alteration minerals mapping – A case study, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-1642, https://doi.org/10.5194/egusphere-egu23-1642, 2023.

Underground mining is increasing in Korea, primarily due to the depletion of high quality mineral resources from surface open pit mining, and also due to the fact that environmental regulations are gradually tightened and strengthened. For sustainable mine design, safety and environmental issues are the most important factors forcing more specified and systematic guidelines to secure the stability of the mine openings and adits. However, with complex geological settings and various types of rock discontinuities, a geological mapping process to analyze the behavior of fractured rockmass is generally time-consuming. Information on the geologic structures are often collected by visual observation and analyzed based on two-dimensional drawings. Even worse, very limited and unrepresentative data are collected specially at operating mines leading to unreliable conclusions. Hence, construction of three-dimensional hydrogeological models adopting sophisticated surveying techniques has become a routine site investigation process. Laser scanners of high-end specifications are widely used in Korea. In this study, the Trimble X7 with automatic calibration and in-field registration capability has been used to collect accurate geospatial information at an underground limestone mine adopting the room-and-pillar method, with three drifts 9~12m wide and 6m high. For the two pillars of major stability concern, laser scanning was performed to obtain point-cloud data from which a total of 581 discontinuities were extracted. A discrete fracture network was simulated and the stability was evaluated based on the safety factor and displacement using a numerical model.

 

How to cite: Baek, H. and Kim, D.: Application of the 3-D laser scanning method for assessing the stability of fractured rockmass at an underground limestone mine in Korea, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-1750, https://doi.org/10.5194/egusphere-egu23-1750, 2023.

Rare earth elements (REE) have been a focus of global interest because of their irreplaceable role in developing “low carbon” technologies. The Bayan Obo is the world’s largest REE deposit, but its genesis is still highly debated. It is considered to have a close genetic association with carbonatite due to the presence of the carbonatite dykes around the orefield, as well as the geochemical similarities between these dykes and the orebody. However, the evolution of the carbonatite dykes and their REE mineralization are still poorly understood, hindering the interpretation of the genesis of the deposit. More than 100 carbonatite dykes have been found within the area of 0-3.5km nearby the orebodies of the deposit. These dykes show significant variations in mineralogy and geochemistry and were classified into dolomite (DC) and calcite carbonatite (CC). The rocks show an evolutionary sequence from DC to CC, and their corresponding REE contents increased remarkably, with the latter having very high REE content (REE2O3 up to 20 wt. %). The DC is composed of coarse-grained dolomite, magnetite, calcite, and apatite without apparent REE mineralization. The medium-grained calcites, and significant amounts of REE minerals, such as monazite, bastnäsite, and synchysite, make up CC. The REE minerals have a close relationship with barite, quartz, and aegirine. The REE patterns of dolomite and calcite in DC showed a steep negative slope with a strong LREE enrichment. In contrast, the calcite from CC has a near-flat REE pattern enriched in both LREE and HREE. Besides, apatite and magnetite in CC are characterized by strong REE enrichment compared to those from DC. Based on detailed petrology, mineralogy, and element geochemistry, we propose that strong fractional crystallization of initial carbonatitic melts led the REE enriched in the residual melt/fluid to form REE mineralization. In addition, sulfate, alkalis, and silica components play an important role in REE transportation and precipitation.

How to cite: Yang, J. and Song, W.: Mineralogy, major and trace element geochemistry of rock-forming and rare earth minerals in the Bayan Obo (China) carbonatite dykes: implications for REE mineralization, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-2318, https://doi.org/10.5194/egusphere-egu23-2318, 2023.

EGU23-3180 | ECS | Posters on site | ERE4.3

Radiogenic and stable Sr isotope geochemistry of regolith hosted REE deposits: a preliminary report 

Hamed Pourkhorsandi, Vinciane Debaille, Sophie Decrée, Jeroen de Jong, Ali Yaraghi, Georges Ndzana, Martin Smith, Kathryn Goodenough, and Jindřich Kynický

The increasing global demand for the rare earth elements (REE), that are critical for green energy production, justifies the necessity of understanding REE ore formation processes [1]. The main type of REE mineralization is mostly found in association with carbonatites and alkaline rocks [1,2]. In addition, in some cases the REE can also reach economical levels in secondary products called supergene REE resources [3]. Primary ore mineralizations mostly are composed of mineral phases that are highly unstable and easily soluble in the near-surface conditions in time. The secondary concentration of the REE in weathering regolith into economic deposits is more favourable than those in primary igneous rocks. As the main source of global heavy-REE, weathering deposits in southern China are the most studied ores of this type [4]. Recently, because of the recent surge in REE deposit exploration and their geological importance, other potentially similar deposits are being studied worldwide. Most of these works focus on mineralogical and elemental aspects of these systems. However, those weathering (in cooperation with alteration) systems are complex and a lot of questions on their formation remain unanswered.

In this work, we focus on the isotopic characterization of regolith hosted REE deposits. To better understand their formation, we utilize stable 88Sr/86Sr and radiogenic 87Sr/86Sr ratios, which have been used widely in understanding chemical weathering [5]. Mainly controlled by the incongruent weathering of primary minerals, Sr isotopes can help to identify the sources involved and the main factors affecting regolith hosted REE deposit formation. Strontium is especially important because, as Ca and K, it occurs in different REE-bearing primary and secondary minerals such as carbonates, ancylite, apatite, clays etc.

We will present different regolith profiles’ Sr isotopic data from Asia and Africa. Combining with the elemental and mineralogical data, we will devise a formation model for regolith hosted REE deposits.

References: [1] Goodenough et al. (2016) Ore Geo. Rev., 72, 838. [2] Chakhmouradian & Zaitsev (2012) Elements 8, 347. [3] Estrade et al. (2019) Ore Geo. Rev., 112, 103027. [4] Li et al. (2019) Econ. Geol., 114, 541. [5] Pett-Ridge et al. (2009) GCA, 73, 25.

 

How to cite: Pourkhorsandi, H., Debaille, V., Decrée, S., de Jong, J., Yaraghi, A., Ndzana, G., Smith, M., Goodenough, K., and Kynický, J.: Radiogenic and stable Sr isotope geochemistry of regolith hosted REE deposits: a preliminary report, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-3180, https://doi.org/10.5194/egusphere-egu23-3180, 2023.

EGU23-4661 | Posters on site | ERE4.3

Gamma radiation for rare earth elements (REEs) in deep-sea sediments 

Changyoon Lee, Yuri Kim, Yoon-Mi Kim, Sung Kyung Hong, and Seok-Hwi Hong

Gamma ray is routinely used for correlation, evaluation or classification of minerals and rocks on continent and ocean. Using natural gamma radiation (NGR) derived from Integrated Ocean Drilling Program (IODP) and Ocean Drilling Program (ODP), this study focuses on the correlation between lithology and REE (Rare Earth Element)-bearing sediments in two deep-sea areas, IODP Expedition 329 in the Southwest Pacific and ODP Leg 199 Sites in the Northeast Pacific basins, where values of the REEs are abundant. Deep-sea sediments are consisting mainly of clays, calcareous oozes and siliceous oozes. As a result of the correlation, the REEs prefer to the clays rather than oozes and high values of the REEs correspond with intervals of the clays where the upper sediments (0–70 mbsf) are. The clays show relatively high values of the gamma radiation and the differences between significant elements (Th, U and K) for gamma radiation, derived from geochemical analysis at every site, show two trends reflecting characteristics of regions. Therefore we suggest that the gamma radiation is fully useful for detecting REEs in the deep-sea sediments and plays a role as a predictable tool for finding quantitative REEs. 

How to cite: Lee, C., Kim, Y., Kim, Y.-M., Hong, S. K., and Hong, S.-H.: Gamma radiation for rare earth elements (REEs) in deep-sea sediments, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-4661, https://doi.org/10.5194/egusphere-egu23-4661, 2023.

Carbonatites are known to host over 95% of light rare earth element (REE) resource, and the REEs are commonly hosted in minerals with well-established extraction methods. Most REE mineralized carbonatites are associated with hydrothermal alteration/recrystallization. Identifying the source composition and role of recrystallization is crucial for understanding the formation of the giant carbonatite-associated REE deposit. Here we report the first in-situ carbon and magnesium isotopic compositions for the hosting dolomite in the Bayan Obo deposit.

In-situ carbon isotope analyses of dolomite from the coarse-grained (CM), fine-grained (FM) and heterogeneous-grained (HM) samples show a wide range of δ13C values (-5.19‰ to 2.08‰), which is distinct from the common mantle-derived carbonatite and slightly overlaps the range of sedimentary carbonate. CM dolomite displays almost homogeneous carbon isotope compositions (δ13C=-1.29‰ to 0.16‰) with the average δ13C of -0.82‰. Recrystallized dolomites from both FM and HM samples vary greatly, and FM dolomite generally displays a heavier δ13C range (-3.94‰ to 2.08‰) compared to that for HM dolomite (-5.19‰ to 0.64‰). CM dolomite also shows relative consistent Mg isotope compositions in the range of -0.27‰ to 0.05‰ with an average of -0.10‰, which is similar to the mantle value. δ26Mg values of FM and HM dolomites vary greatly from -1.18‰ to 0.06% with averages of -0.40‰ and -0.32‰, which are lighter compared to that of CM dolomite. The recrystallized dolomites (FM and HM) are characterized by depleted light REE (LREE) and increased Pb/CeN features compared to the pristine dolomite (CM). Moreover, the LREE depletion and Pb/CeN increase correlate with the lighter Mg isotope compositions. The highly variable C isotopes recorded by FM and HM dolomites (lighter or heavier compared to the pristine dolomite) involve both recrystallization and degassing. The combined in-situ Mg and C isotope compositions of the pristine dolomite suggest the Bayan Obo carbonatite sourced from the mantle previously fertilized by fluids derived from the carbonate-bearing subduction slab.

How to cite: Chen, W., Yang, F., and Lu, J.: In-situ C and Mg isotopes of dolomite from the giant Bayan Obo REE deposit: Implications for recrystallization and recycled carbonate in the source, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-4823, https://doi.org/10.5194/egusphere-egu23-4823, 2023.

As the world's largest rare earth elements (REEs) deposit, the giant Bayan Obo deposit accounts for more than one third of the world's REEs resources. Fenitization is an alkali metasomatism that widely occurs around the carbonatite dykes at Bayan Obo and recent studies reveal huge quantities of REEs could be transferred from the alkaline magma to fenite (Sokół et al., 2022). However, the contribution of fenitization to REE mineralization at Bayan Obo remains unclear. Here, we present bulk rock chemical compositions, in-situ chemical and C-Sr isotopic investigations of calcite and apatite together with Th-Pb ages of monazite, aiming to provide new constraints on REE mineralization during fenitization.

Carbonatite at Wu dyke is mainly composed of calcite, aegirine and barite associated with REE minerals dominated by bastnasite and parisite, which intruded into the surrounding wall rocks of quartz conglomerate. The associated fenites include the close Na-fenite and faraway K-fenite. Na-fenite contains calcite, riebeckite, aegirine and apatite with minor monazite and bastnasite in association with barite. K-fenite consists of K-feldspar and quartz with accessory riebeckite and albite. Both REE and SO3 contents decrease from the center to the wall rocks. REE are most enriched in the centered carbonatites (up to 7.39 wt%), and Na-fenites also display strong REE enrichment (9876-22492 ppm). Of note, high-grade Na-fenite is characterized by the highest LREE concentrations among fenites, whereas HREE is most enriched in medium-grade Na-fenite. The latter is dominantly controlled by apatite, which hosts abundant HREE (118-677 ppm). Calcite from fenites displays flat REE patterns with more depleted LREE (La/YbN=0.28-3.02) compared to that within carbonatite (La/YbN=1.66-6.52). Th-Pb ages of monazite from fenites cover a wide range from 420 Ma to 1.27 Ga, which suggests these fenites have also undergone the early Paleozoic hydrothermal alteration. In-situ Sr and C isotope analyses of calcite from carbonatite define a limited range (87Sr/86Sr=0.70344 to 0.70358 and δ13C=-4.36 to -5.1 ‰), which are consistent with a mantle origin . 87Sr/86Sr and δ13C values for calcite within Na-fenite show larger variations of 0.70358 to 0.70620 and -4.92 to -9.87 ‰, respectively. Negative shift in δ13C values suggest degassing through the fenitizing reaction of 18CO32-+2Na++3(Mg2+,Fe2+)+2Fe2++8SiO2+24H++0.5O2= Na2(Mg,Fe2+)3Fe3+2Si8O22(OH)2+18CO2+11H2O. More radiogenic Sr isotopic compositions of fenites result from both assimilation of wall rocks during fenitization and the redistribution of Sr isotopes among minerals during the Paleozoic hydrothermal alteration.

Carbonatite-exsolved fenitizing fluids result in predominant REE enrichment within Na-fenite accompanying with light and heavy REE mineralization. LREE mineralization is dominated by monazite precipitation, and HREE enrichment is mostly controlled by apatite. Sulfate is an important ligand for REE transportation and mineralization during fenitization. Barite crystallization and simultaneous precipitation of LREE-bearing minerals lead to fenitizing fluids abundant in HREE, promoting the further formation of HREE-rich apatite.

Reference:

Sokół K., Finch A.A., Hutchison W., et al., 2022. Quantifying metasomatic high-feld-strength and rare-earth element transport from alkaline magmas. Geology, https://doi.org/10.1130/G49471.1.

 

 

How to cite: Yang, F. and Chen, W.: Fenitization associated with the Wu carbonatite dyke at Bayan Obo (Inner Mongolia, China): Implications for REE mineralization, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-5183, https://doi.org/10.5194/egusphere-egu23-5183, 2023.

EGU23-8008 | Posters on site | ERE4.3

The metasomatism affecting karstic bauxites from the south-central Pyrenees, Catalonia (NE Spain) and its implications on the REE geochemistry in similar geological settings. 

Josep Roqué-Rosell, Pablo Granado, Juan Diego Martín-Martín, Jordi Ibáñez-Insa,, Ivanna Pérez Bustos, Roger Roca-Miró, and Abigail Jiménez Franco

Karstic bauxite deposits are the main resource of aluminum in Europe and are formed through a combination of weathering, leaching, and deposition processes known as bauxitization. Bauxites have recently been proposed as unconventional resources of rare-earth elements (REE) as well. The studied karstic bauxite deposits are located on the salt-detached Serres Marginals thrust sheet, at the external most unit of the south-central Pyrenees (Catalonia, NE Spain). The Pyrenean bauxites are found overlaying and filling karstic surfaces forming aligned pockets up to several meters thick. These deposits have been mined for more than 20 years and present high variability in SiO2, Al2O3 and Fe2O3 contents. Here, we characterize these deposits for the first time by a combination of field geology, XRD, FTIR and XRF to determine their formation, mineralogy, and geochemistry and to understand the causes affecting their compositional variations. Field data indicate that the bauxite deposits fill a paleokarst system affecting Dogger dolostones and/or Tithonian-Berriasian limestones. XRD data indicate that the studied karstic bauxites are mainly composed of Al-rich minerals kaolinite and boehmite, in addition to the Fe-oxide hematite, and lesser amounts of the Ti-oxides rutile and anatase. The detailed study of the FTIR spectra also confirmed the presence of diaspore and dickite. XRF data confirm the presence of varying amounts of Al, Fe and Si in addition to varying low contents of REE. These results suggest that boehmite was formed first during bauxitization and later transformed to diaspore, kaolinite and finally to dickite upon metasomatism. The presence of dickite in faults and fractures provides a direct proof for such fluid circulation. Our results suggest that the mechanisms responsible of the compositional variations in karstic bauxites are rather complex and fall beyond the standard bauxitization processes. The observed metasomatism should be further assessed, since the inferred fluid-rock interactions are susceptible to affect and mobilize REE not only in the south-central Pyrenees karstic bauxites but elsewhere in similar geological settings.

How to cite: Roqué-Rosell, J., Granado, P., Martín-Martín, J. D., Ibáñez-Insa,, J., Pérez Bustos, I., Roca-Miró, R., and Jiménez Franco, A.: The metasomatism affecting karstic bauxites from the south-central Pyrenees, Catalonia (NE Spain) and its implications on the REE geochemistry in similar geological settings., EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-8008, https://doi.org/10.5194/egusphere-egu23-8008, 2023.

EGU23-9090 | Orals | ERE4.3

Blast Hole Rock Cuttings analysis: Design and Implementation of an open Architecture LIBS System 

Ad Maas, Jorgina Akushika, and Federico Arboleda

This paper presents the development and implementation of a LIBS (Laser-Induced Breakdown Spectroscopy) system based on a robotic arm for fast chemical characterization of blast hole rock cuttings in open pit mining. The system is designed with an open architecture, allowing for the easy integration of additional sensors such as a spectrophotometer and a magnetic susceptibility meter. The use of the LIBS system significantly reduces the time required to characterize the raw material and obtain a broader characterization, including geological characterization. The preliminary results of this development demonstrate the potential of the LIBS system in improving the efficiency and accuracy of rock characterization in open pit mining operations.

How to cite: Maas, A., Akushika, J., and Arboleda, F.: Blast Hole Rock Cuttings analysis: Design and Implementation of an open Architecture LIBS System, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-9090, https://doi.org/10.5194/egusphere-egu23-9090, 2023.

Recently, due to the active spread of electric vehicles, the demand for batteries is increasing fast, and for this reason, the exploration for lithium that is an essential mineral for battery production, is increasing. In Korea, lithium exploration is also being conducted around deposits where lithium was identified in the past. However, most lithium mines are located in very rough terrain, so it is not easy to conduct a surface geological and geophysical exploration. Without considering complex topography, errors may occur in the inversion of surface geophysical exploration data, and in particular, it is necessary to use precise topographic information for the three-dimensional inversion. In this study, we would like to introduce a case study using high-resolution topographic data obtained from a drone-mounted LIDAR in the three-dimensional inversion of surface resistivity and IP data conducted for lithium exploration. The target area is the Boam Mine, located in the Middle East of Korea. Surface geophysical exploration was conducted along a road and ridge of the mountain, which are relatively easy to set up the survey line. Because existing topographic maps that are publically available did not include mining traces related to mining development and topographical changes formed by nearby roads, it is not adequate for the 3D inversion of surface resistivity and IP data. To acquire precise topographical information, aerial photography and LIDAR measurements using drones were performed. A numerical topographic model was constructed using the obtained high-precision DEM (digital elevation map). By applying this to the three-dimensional inversion, the distribution of the underground mineralization zone was estimated. The interpreted results were compared with the existing drilling results performed near the mine. Comparing the two results, drilling surveys using only surface geological information proceeded in the direction in which the mineralization zone did not develop. Drone LIDAR measurement is a costly exploration method and is difficult to use actively at all exploration sites. However, if three-dimensional inversion is required where the surface topography is very complex, as in this survey area, it could give more reliable inversion results.

How to cite: Son, J., Kim, C., and Bang, E.: Three-dimensional interpretation of DC resistivity/IP survey for Lithium exploration using high-precision topographic information from drone-mounted LIDAR., EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-10680, https://doi.org/10.5194/egusphere-egu23-10680, 2023.

EGU23-10689 | Posters on site | ERE4.3

Investigations of Vanadiferous Titanomagnetite Deposit using Drone Magnetic and Electrical Resistivity Surveys in Korea 

Changryol Kim, Jeongsul Son, Eunseok Bang, Gyesoon Park, and Bona Kim

Recently, the demands for energy storage minerals such as vanadium and lithium are increasing as the use of the batteries for electrical vehicles has increased. Vanadium is one of the energy storage minerals occurred in Korea. In this study, vanadium mineralized zones of the ore deposit, named as Gwanin deposit, was investigated using geophysical exploration techniques. The mineralized zone is known as vanadiferous titanomagnetite (VTM) deposit, originated from pre-cambrian igneous intrusions (850-870 m.a.), located in the northwest region of Korea. Since the vanadium has occurred along with magnetite (low electrical resistivity and high magnetic susceptibility) in the study area, geophysical exploration techniques such as magnetic and electrical resistivity surveys were employed. For magnetic exploration, the drone magnetic survey technique was used since it provides more precise and higher resolution data than any other aerial magnetic exploration techniques for relatively small and mountainous areas. In addition, electrical resistivity data were obtained from the six survey lines in the study area. 3D inversion was performed with magnetic and resistivity data. The anomaly zones of low electrical resistivities and high magnetic susceptibilities were interpreted as VTM mineralized zones from the two different inversion results. The mineralized zones were identified from the drilling investigation for overlapping locations of the anomaly zones. The results of the study have shown that magnetic and electrical resistivity techniques are very effective tools for exploring ore deposits of vanadium resource accompanied with magnetite. In the future, drone magnetic exploration technique combined with other (surface) geophysical exploration techniques would provide more effective results of precise geophysical surveys for relatively small and mountainous areas with similar ore deposit environments.

How to cite: Kim, C., Son, J., Bang, E., Park, G., and Kim, B.: Investigations of Vanadiferous Titanomagnetite Deposit using Drone Magnetic and Electrical Resistivity Surveys in Korea, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-10689, https://doi.org/10.5194/egusphere-egu23-10689, 2023.

Apatite with high REE content is common in alkaline rocks, carbonatites and products of hydrothermal processes. The REE concentrations could enter mineral structure by different substitution mechanisms (Fleet et al., 2000) and the factors controlling the composition of high-REE apatite are not completely understood. New experimental data (Stepanov et al., 2023) show that at 800 °C and 10 kbar apatite crystalizing from felsic melt with addition of NaCl contains 14 wt.% ΣREEOx and coexists with britholite (37.2 wt.% ΣREEOx). The results suggest that equilibrium has been established during the run and both apatite and britholite contained REE in [Si4+REE3+] to [Ca2+P5+] solid solution, whereas the coupled substitution [Na1+REE3+] to [2Ca2+] was insignificant despite crystallisation from an alkaline, Na-rich melt. Coupling of the new experimental data allowed to constrain the width of the miscibility gap between apatite and britholite, and suggest complete miscibility between apatite and britholite above 950 °C. The substitution [Na1+REE3+] apparently develops mainly in apatite replacement reactions. Therefore, REE content and substitution mechanisms could be useful tools for interpretation of magmatic and metasomatic/hydrothermal associations in alkaline volcanic and plutonic rocks.
References 
Fleet, M., Liu, X., Pan, Y., 2000. Rare-earth elements in chlorapatite [Ca-10(PO4)(6)Cl-2]: Uptake, site preference, and degradation of monoclinic structure. American Mineralogist 85, 1437–1446.
Stepanov, A.S., Zhukova, I.A., Jiang, S.-Y., 2023. Experimental constraints on miscibility gap and partitioning between britholite and chlorapatite in alkaline melt. American Mineralogist.

How to cite: Zhukova, I. and Stepanov, A.: Experimental data on REE in apatite in high-REE environments: distinguishing magmatic and metasomatic compositions, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-11255, https://doi.org/10.5194/egusphere-egu23-11255, 2023.

EGU23-11997 | Orals | ERE4.3

Hyperspectral mineral mapping for underground mining 

Moritz Kirsch, Mary Mavroudi, Sam Thiele, Sandra Lorenz, Laura Tusa, René Booysen, Erik Herrmann, Ayoub Fatihi, Robert Möckel, Thomas Dittrich, and Richard Gloaguen

Future mining will increasingly require rapid and informed decisions to optimise ore extraction and valuation. In this context, the use of hyperspectral imaging has been proven to be effective for geological mapping in surface mining operations. The potential of hyperspectral methods in underground mining environments, however, remains underexplored due to challenges associated with illumination and surface water. Our contribution addresses this gap by evaluating different lighting setups and the effect of moisture on the spectral quality of hyperspectral data in a laboratory setup. We also compared three commercially available, visible-near infrared to shortwave infrared sensors to assess their suitability for underground hyperspectral scanning. As a demonstration, we acquired hyperspectral data from three adjacent outcrops in the visitor’s mine of Zinnwald, Germany, where rocks of a Late Variscan Sn-W-Li greisen-type deposit are exposed in representative underground mining conditions. A photogrammetric 3D digital outcrop model was used to correct for illumination effects in the data. We then estimated mineral abundance and lithium content across the mine face employing an adapted workflow that combines quantitative XRD measurements with hyperspectral unmixing techniques. Laser-induced breakdown spectroscopy was used to validate the results. While there are still challenges to overcome, this study proves that hyperspectral imaging techniques can be applied underground to yield rapid and accurate geological information. This application will pave the way for the safe, digital and automated underground mine of the future.

How to cite: Kirsch, M., Mavroudi, M., Thiele, S., Lorenz, S., Tusa, L., Booysen, R., Herrmann, E., Fatihi, A., Möckel, R., Dittrich, T., and Gloaguen, R.: Hyperspectral mineral mapping for underground mining, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-11997, https://doi.org/10.5194/egusphere-egu23-11997, 2023.

EGU23-12056 | ECS | Posters on site | ERE4.3

ROBOMINERS resilient reflectance/fluorescence spectrometers 

Christian Burlet, Giorgia Stasi, Simon Godon, Roza Gkliva, Laura Piho, and Asko Ristolainen

ROBOMINERS (Bio-Inspired, Modular and Reconfigurable Robot Miners, Grant Agreement No. 820971, http://www.robominers.eu) is a European project funded by the European Commission's Horizon 2020 Framework Programme. The project aims to test and demonstrate new mining and sensing technologies on a small robot-miner prototype (~1-2T) designed to target unconventional and uneconomical mineral deposits (technology readiness level 4 to 5) (Lopez and al. 2020).

As part of the ROBOMINERS sensor array development, a set of mineralogical and geophysical sensors are designed to provide the necessary data to achieve a “selective mining” ability of the miner to reduce mining waste production and increase productivity of a small mining machine. To achieve this, the robot should have the ability to react and adapt in real time to geological changes as it progresses through a mineralized body. This study focuses on a set of compact sensors designed for ultrahigh-resilience and continuous operation in high pressure/vibrations/temperature environment. They are based on reflectance/fluorescence measurements in the visible/near infrared range, using a broadband light source (tungsten-halogen lamps) in reflectance mode and 365nm UV LED in fluorescence mode. 

The ROBOMINERS reflectance/fluorescence spectrometer “Mk1” was developed in collaboration with Taltech University. The spectrometer is built around a monolithic spectrometer (Hamamatsu C12800MA and a wifi capable microcontroller (Arduino RP2040 Connect).. As the ROBOMINERS prototype will be operated by ROS2 (Robotic Operating System v2 - https://www.ros.org/ ), we decided to implement a Micro-ROS publisher on the microcontroller.

The first field trials of the sensor have been carried out in the entrance of abandoned mine (baryte and lead mine, Ave-et-Auffe, Belgium), with the sensor integrated directly in the propulsion mechanism of the “RM3”’ ROBOMINERS prototype. This test allowed to demonstrate the immunity of the sensors to  to shocks, water and dust with no measurable de-calibration of the spectrometer.

References.

Lopes, B. Bodo, C. Rossi, S. Henley, G. Žibret, A. Kot-Niewiadomska, V. Correia, Advances in Geosciences, Volume 54, 2020, 99–108

 

 

How to cite: Burlet, C., Stasi, G., Godon, S., Gkliva, R., Piho, L., and Ristolainen, A.: ROBOMINERS resilient reflectance/fluorescence spectrometers, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-12056, https://doi.org/10.5194/egusphere-egu23-12056, 2023.

EGU23-13081 | Posters on site | ERE4.3

The surface chemistry of carbonatite soils: Implications for REE resources. 

Martin Smith, Charles Beard, Isaac Watkins, Sam Broom-Fendley, Frances Wall, Xu Cheng, Yan Liu, Wei Chen, and Jindrich Kynicky

The rare earth elements (REE), and in particular neodymium and dysprosium, are essential for the development of renewable energy. At present the REE are sourced from either low concentration weathered granitoid (ion adsorption clay) deposits in southern China, or from high concentration carbonatite-related deposits [1], especially the World’s dominant REE mine at Bayan Obo, China, but also including the Mt Weld weathered carbonatite, Australia. Weathered carbonatites (e.g. Tomtor, Russia; Mount Weld, Australia) are some of the world’s highest grade REE deposits. As part of the NERC Global Partnerships Seedcorn fund project WREED, we have carried out preliminary investigations in weathering products from carbonatite hosted REE deposits. Three end member deposit styles can be identified – in situ residual deposits, where carbonate dissolution has generated primary REE mineral enrichment on palaeosurfaces or in karst; supergene enrichment from dissolution and reprecipitation of REE phosphates and fluorcarbonates forming hydrated phosphates or authigenic carbonate minerals; clay and oxide caps (either from in situ weathering or from soil transport from surrounding rocks) that may hold the REE adsorbed to mineral surfaces (c.f. the ion adsorption deposits). High grade weathered carbonatite deposits typically consist of supergene horizons, that may be phosphate-rich due to dissolution and re-precipitation of apatite and monazite during the weathering process (Mount Weld [2][3]), overlain by later sediments that may be REE enriched by accumulation of residual minerals (e.g. Tomtor [4]). The mineralogy of the ore zone is linked to, but distinct from, the unweathered carbonatite rock, and includes phosphates, crandallite-group minerals, carbonates and fluorcarbonates and oxides. We have carried out leaching studies, SEM examination and XPS characterisation of soil and weathered rock samples from a range of deposits. Residual and supergene processes can result in enrichments up to 100x times bedrock concentrations, with residual enrichments in particular hosted in monazite and bastnäsite. Supergene enrichment results in more complex mineralogy which may present processing challenges. Clay-rich soils have much lower REE concentrations. However, sequential leaching studies demonstrate that a significant proportion of REE are present at trace levels in the oxide fraction in residual and supergene deposits. In clay caps the easily leachable fraction of REE matches that of ion adsorption deposits and may represent a potentially easily extractable resource.

 

References

[1] Wall and Chakhmouradian, 2012, Elements 8, 333-340;

[2] Duncan and Willett, 1990, Geology of Mineral Deposits of Australia pp. 591-597;

[3] Lottermoser, 1990, Lithos 24, 151-167;

[4] Kravchenko and Pokrovsky, 1995, Econ. Geol. 90, 676-689;

How to cite: Smith, M., Beard, C., Watkins, I., Broom-Fendley, S., Wall, F., Cheng, X., Liu, Y., Chen, W., and Kynicky, J.: The surface chemistry of carbonatite soils: Implications for REE resources., EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-13081, https://doi.org/10.5194/egusphere-egu23-13081, 2023.

EGU23-13899 | ECS | Posters on site | ERE4.3

Robot-aided autonomous hyperspectral mapping in mining environments 

Sandra Lorenz, Moritz Kirsch, Margret Fuchs, Sam Thiele, and Richard Gloaguen

Geological face mapping is a frequently recurring task in mining operations, the results of which have an immediate influence on the mines’ profitability, safety, and environmental impact. Hyperspectral imaging is an increasingly applied technology to improve the efficiency and accuracy of mapping tasks. The rapid and non-destructive acquisition of spectral material properties allows meaningful material information such as mineralogical surface composition to be obtained in a safe and efficient manner. The fusion product of backprojected hyperspectral data with 3D surface information (so-called “hyperclouds”) further enhances the data value by enabling easier data correction, integration, and implementation into digital archives and models. Mining environments, however, remain a challenge for operational hyperspectral mapping, particularly underground where inadequate lighting, access, and safety of operation make data collection difficult. Data processing and interpretation require expert knowledge and are typically performed semi-manually and offline. To be economically viable in such mining environments, the hypercloud technology has to mature toward autonomy and real-time delivery of results. In recent years, terrestrial autonomous platforms have entered the market that are suited to the challenging conditions of underground mining and can maneuver and navigate even in confined, uneven, and poorly lit environments. They provide optimal carriers for hyperspectral sensors, which have simultaneously evolved into lighter, faster, and more robust devices. However, implementing hyperspectral sensors as payload for terrestrial autonomous robots remains challenging, especially in terms of  technical compatibility, ensuring data quality under complex conditions,  and processing large amounts of data quickly and autonomously. In our contribution, we demonstrate the potential of autonomous terrestrial robots combined with hyperspectral technology and advanced data processing for the automation of geological mapping. We present results of hyperspectral data acquisition using an autonomous robotic platform in a confined underground mining environment and discuss strategies for adapted sensor design, autonomous validation, real-time hypercloud processing, and enhanced autonomous navigation supported by hyperspectral information. 

How to cite: Lorenz, S., Kirsch, M., Fuchs, M., Thiele, S., and Gloaguen, R.: Robot-aided autonomous hyperspectral mapping in mining environments, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-13899, https://doi.org/10.5194/egusphere-egu23-13899, 2023.

EGU23-15053 | Orals | ERE4.3

TIMREX – a European joint master programme to implement innovative mineral exploration achievements in geoscience education 

Ferenc Madai, Sibila Borojević Šoštarić, Gabriela Paszkowska, and Nils Jansson

Mineral resource exploration techniques and methodologies have undergone a very strong development in the last decade: e.g. portable and higher sensitive equipment, robotized exploration equipment, and tools for processing and interpreting of large, multidimensional datasets. In order to meeti the raw materials policy goals of the EU, these technologies should also be incorporated in higher education (Mádai, 2022).

 

TIMREX is a new EIT-Labelled joint master's program to train geoscience students focusing on innovative raw materials prospecting and exploration methods. The consortium consists of four academic partners – University of Miskolc, Hungary, University of Zagreb, Croatia, Wroclaw University of Science and Technology, Poland and Luleå University of Technology, Sweden. All four academic partners run their mineral exploration-focussed, geoscience engineering-type master programmes which comprise the ground for the joint master programme. Participating Universities are located within Fennoscandian, Fore-Sudetic and Tethyan/Carpathian-Balkan metallogenic belts hosting numerous primary, secondary and critical mineral resources essential for green transition of Europe. Scandinavian and West Balkan countries holds first and second place according to total mineral resources investments in Europe (data from 2019).

 

The TIMREX consortium incorporates eight non-academic partners who are at the frontier of mineral resource prospecting and exploration equipment and methodology development in the EU. They represent leading European mining companies such as Boliden Mineral and KGHM, but also SMEs and start-ups such as the Unexmin Georobotics (UGR) and the Geogold Kárpátia Ltd., as well as research institutes such as the Portuguese INESC TEC and the Slovenian Geological Survey (GeoZS).

Non-academic partners are actively involved in the TIMREX joint programme as trainers in field programs, internship mentors or thesis topic providers. Students of the programme can join research and development work at the partners. Examples are development of underwater robotized exploration methodologies (INESC TEC, UGR), drone-based multispectral surveys and complex dataset evaluation (Boliden, KGHM Cuprum, GeoZS, Geogold). The European Federation of Geologists provides a wider network of European prospectors and explorers to the joint programme and contributes to teaching of entrepreneurial skills. Therefore, TIMREX directly address major gaps of the Raw Materials sector: limited availability of qualified technical, scientific and managerial personnel involved in the whole mineral cycle (Borojević Šoštarić et al., 2022) as well as lack of generic skills crucial for increasing the innovation capacity of universities and their graduates (Grgasović and Borojević Šoštarić, 2021).

 

 

Borojević Šoštarić, S., Giannakopoulou, S., Adam, K. i Mileusnić, M. (2022). The future of mining in the Adria region: current status, SWOT and Gap analysis of the mineral sector. Geologia Croatica, 75 (Special issue), 317-334. https://doi.org/10.4154/gc.2022.26

Grgasović, P.; Šoštarić, S.B. (2021) Systematic Development of Generic Skills to Enhance Innovation Capacity of Eastern and Southeastern European Universities. Mater. Proc.

5, 99, 1-7. https://doi.org/10.3390/ materproc2021005099

Mádai F. (2022) Competence requirements of innovation and entrepreneurship oriented training programmes for the mineral exploration sector. In: Veresné Somosi M.; Lipták K.; Harangozó  Zs.(eds) "Mérleg és Kihívások - Fenntarthatóság" Miskolci Egyetem Gazdaságtudományi Kar (2022) pp. 537-547

How to cite: Madai, F., Borojević Šoštarić, S., Paszkowska, G., and Jansson, N.: TIMREX – a European joint master programme to implement innovative mineral exploration achievements in geoscience education, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-15053, https://doi.org/10.5194/egusphere-egu23-15053, 2023.

EGU23-15445 | ECS | Posters virtual | ERE4.3

Re-evaluating Caledonian magmatism and associated base metal mineralisation: a case study of the Black Stockarton Moor porphyry copper system 

Chloe Gemmell, David Currie, Iain Neill, Josh Einsle, and Careen MacRae

Following the British Geological Survey’s (BGS) 1970s – 1990s Mineral Reconnaissance Programme (MRP), there has been limited characterisation and quantification of base and precious metal mineralisation in the UK, with the notable exception of Au. Data gaps still exist regarding mineral paragenesis, geochronology, deportment of critical raw materials (CRM), and ore forming processes. With increased focus on CRM, NetZero, and supply risk we must improve our knowledge of deportment in base metal systems. The BGS Critical Minerals Intelligence Centre (CMIC) was recently established to aid the UK in meeting projected future CRM demand and will act as a nexus for industry and academia. Here, we establish a workflow and document a case study where academia and the CMIC have partnered to re-evaluate a potential mineral resource, a starting point for renewed studies elsewhere in the UK. 

The Black Stockarton Moor (BSM) post-subduction porphyry Cu system is thought to have formed by interaction of Devonian plutonic to sub-volcanic complexes with Silurian turbidites in the Southern Uplands of Scotland. No study of the BSM has been undertaken since the 1979 MRP report, thus whether it is of any modern value remains unproven. Field sampling and utilising the National Geological Repository at BGS will allow for optical and scanning electron microscopy (SEM) to quantitatively establish paragenesis and primary mineralogy. Sites will then be identified for chemical mapping to quantify CRM deportment in base metals using SEM-energy dispersive X-ray analysis (EDX), with areas of particular interest further quantified by laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS). Focused ion beam (FIB) nano-tomography will be used to identify the cm to nano-scale distribution of CRM. Finally, magmatism and mineralisation will be fully temporally constrained using U-Pb analysis of zircon, titanite, calcite and epidote and/or Re-Os analysis of sulphides as appropriate. On a large scale, this study will address one set of data gaps by re-invigorating our knowledge of the geology and geodynamic associations of mineralisation. However, by also identifying the quantities and associations of metals at the cm to micron scale, it addresses another, by constraining the extent and nature of processes responsible for the distribution of metals in such deposits. This workflow is to be refined for application to mineralisation elsewhere in the UK including work underway on the Strontian Caledonian granite and associated Pb-Zn mineralisation in the Northern Scottish Highlands.

How to cite: Gemmell, C., Currie, D., Neill, I., Einsle, J., and MacRae, C.: Re-evaluating Caledonian magmatism and associated base metal mineralisation: a case study of the Black Stockarton Moor porphyry copper system, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-15445, https://doi.org/10.5194/egusphere-egu23-15445, 2023.

EGU23-16567 | ECS | Posters on site | ERE4.3

Deep Electrical Resistivity Tomography as a mineral exploration tool: the Calamita distal Fe-skarn, Elba Island (Italy) 

Damian Braize, Julien Sfalcin, Matteo Lupi, Kalin Kouzmanov, Andrea Dini, and Gianfranco Morelli

To face the growing demand for raw materials, the discovery of new mineral deposits is essential for the future. Geophysical methods, and in particular electrical and electromagnetic tools, have an important role in mineral exploration. Recently, new technological developments made possible targetting deeper ore bodies and large areas with logistical challenges. We use the Deep Electrical Resistivity Tomography (DERT) method to investigate its application in mineral exploration. In particular, we use the Fullwaver technology developed by IRIS Instruments to study the full 3D resistive structure of the Calamita distal Fe-skarn deposit, Elba Island, Italy. This innovative hardware allows a full 3D deployment of autonomous and cable-less receivers and contrasts with traditional resistivity methods by its easy set-up and applicability in difficult contexts.

In November 2022, a 3D DERT survey has been carried out to investigate the Calamita deposit, consisting of massive magnetite-hematite ore bodies hosted in marbles overlaying micaschists of Tuscan Units. Skarn mineralogy/geochemistry and fluid inclusion characteristics suggest a magmatic source for the mineralizing fluids. 148 current injections have been performed on 48 receivers over an area of 2km² with the aim to reach exploration depths ranging from 600 m to 700 m. Geophysical data were combined with a high-resolution 3D Digital Elevation Model acquired by standard and thermal drone imagery.

The 3D inverted resistivity and induced polarization models match with the surface geology and shallow exploration drill hole data and highlight the architecture of Calamita deposit. Strong resistivity contrasts reveal the presence of sub-vertical conductive and chargeable pipes connecting the different skarn bodies at depth, interpreted to represent the paleo-hydrothermal upflow zones. The pipes point towards the inferred cupola of a magmatic intrusion that potentially triggered the formation of the ore deposit. High chargeability anomalies suggest the presence of hidden massive ore bodies and disseminated mineralisation on the flanks of the system.

DERT has the potential to investigate and explore mineral deposits in full 3D, with high sensitivity, and in logistically complex settings.

How to cite: Braize, D., Sfalcin, J., Lupi, M., Kouzmanov, K., Dini, A., and Morelli, G.: Deep Electrical Resistivity Tomography as a mineral exploration tool: the Calamita distal Fe-skarn, Elba Island (Italy), EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-16567, https://doi.org/10.5194/egusphere-egu23-16567, 2023.

EGU23-17258 | Orals | ERE4.3

Dig_IT – A human-centred Internet of Things platform for the sustainable digital mine of the future 

Diego Grimani, Lorenzo Bortoloni, Damiano Vallocchia, Maria Garcia Camprubi, and David de Paz

Dig_IT project aims to develop a human-centred IIoT platform connecting the mining ecosystem of assets, environment, and humans to increase mining efficiency: saving costs using optimised scheduling, increasing uptime using predictive operation and maintenance, identifying new revenue opportunities using advanced geological interpretation on exploration mining phase. To address industry needs of minimising accidents, optimising production processes and reducing costs, intelligent systems will provide real-time insights for the enterprise at all operational levels.

Dig_IT follows a market need & technology offer approach aiming at covering all aspects of technical, industrial and business requirements towards a sustainable future in mining. The project’s value chain and concept has been built with the utmost objective to provide new solutions addressing the needs for safety, efficiency and sustainability, bringing innovative and competitive solutions to the mining business, face future challenges regarding standards and legislation, and spread the knowledge to as many sectors of the European extractive industry as possible.

The project aims to achieve several objectives: design and validate a smart Industrial Internet of Things platform to improving efficiency and sustainability of mining operations, achieving on-line measurements of asset-bound mining operations and online distributed measurements for broad area sustainability and occupational work environment, and Big Data optimisation through improving data quality. Furthermore, the project aims to develop Digital Twins of the physical mine entities, systems and processes, a Smart Garment and an Intelligent Toolbox for mining personnel sensing OHSE parameters, a Decision Support System and a Predictive Operation System.

2.12.0.0

How to cite: Grimani, D., Bortoloni, L., Vallocchia, D., Garcia Camprubi, M., and de Paz, D.: Dig_IT – A human-centred Internet of Things platform for the sustainable digital mine of the future, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-17258, https://doi.org/10.5194/egusphere-egu23-17258, 2023.

EGU23-17279 | Orals | ERE4.3

Underwater measurements with UX robots; a new and available tool developed by UNEXUP 

Norbert Zajzon, Boglárka Anna Topa, Richárd Zolzán Papp, Jussi Aaltonen, José Almeida, Balazs Bodo, Stephen Henley, Marcio Pinto, and Gorazd Zibret

The UX-2 robot of the UNEXMIN technology represents the newest generation of underwater explorers capable of operating in flooded mines and other closed underwater environments meanwhile providing geoscientific information. The technology was developed by an international team of scientists during the UNEXMIN (https://www.unexmin.eu/) Horizon 2020 project (2016–2019) and the UNEXUP (https://unexup.eu/) EIT RawMaterials project (2020–2022). The concept was proven in various environments and the first generation of robots was built in the UNEXMIN project. Besides technological upgrades, the UNEXUP project was focusing also on marketing and commercialization thru UNEXMIN Georobotics Ltd. (https://unexmin-georobotics.com/), the spin-off of the consortium.

The technology proved its capabilities at numerous flooded sites in various harsh environments during the last years including, abandoned mines, caves, historical sites and even drinking water facilities.

Although very bad visibility was observed in the South Crofty mine, Camborne (UK), the robot could manoeuvre down to -300 m and investigate a narrow shaft relying mainly on sonar-based navigation.

The Csór water well, the main drinking source of Székesfehérvár (Hungary) was another location where the UX technology proved its usefulness and 3D-mapped the well with centimetre accuracy for reconstruction purposes.

In August of 2022, the UX robot created a 3D topography map and continuous water parameter measurements further exploring the flooded karstic cave Hranice Abyss (Czech Republic) down to -450 m – setting up the current word depth record.

Even remote-control and full autonomy were demonstrated in Kőbánya-mine, Budapest, Hungary. During the remote-control test, the Budapest team launched the robot, but the underwater robot operation was done from INESCTEC, Portugal.

Ecton copper mine (UK) used to be the deepest mine of its age in the 18th century, closed and partially flooded for more than 160 years. Now it is a listed National Monument in the UK and is under strict protection within a site of special scientific interest. Here the UX robots proved their value in discovering new workings, connections, and technological solutions helping the archaeologists which could not be recovered by other methods as well as elucidating the geological structure.

The salt mine of Solotvyno, Ukraine was a demanding challenge as the UX robot had to be capable of operating and measuring in freshwater as well as in fully saturated (ca. 330g/l) brine with 1.25 g/cm3 density, which was located below a freshwater layer.

The abandoned fluorspar mine of Würmtal, Pforzheim, Germany was the last site visited within the frame of the UNEXUP project where the UX robot revealed its unique capabilities by exploring a large part of the flooded workings. More than 3 km was covered laterally in a single dive down to the fluorspar vein, and colour- and UV-images of the ore were delivered successfully. UX robot also brought back data, helping to assess the stability of the walls.

The UNEXMIN project was funded by the European Union thru the Horizon 2020 research and innovation programme under the no. 690008 grant agreement.

The UNEXUP project was funded partially by the European Union thru EIT RawMaterials no. 19160.

2.12.0.0

How to cite: Zajzon, N., Topa, B. A., Papp, R. Z., Aaltonen, J., Almeida, J., Bodo, B., Henley, S., Pinto, M., and Zibret, G.: Underwater measurements with UX robots; a new and available tool developed by UNEXUP, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-17279, https://doi.org/10.5194/egusphere-egu23-17279, 2023.

PS2 – Space weather and space weathering: active and passive processes, observations and records from models, experiments and samples

EGU23-2066 | Posters on site | PS2.2

Statistical investigation of SKR caterpillar emissions 

Georg Fischer, Ulrich Taubenschuss, David Pisa, Laurent Lamy, Siyuan Wu, Sheng-yi Ye, Caitriona Jackman, and Elizabeth O'Dwyer

The radio emissions nicknamed "caterpillars" are believed to be a special form of Saturn kilometric radiation (SKR) at low to very low frequencies. They are coarse spectral structures lasting for several hours mostly below 40 kHz, and their constant central frequency with a typical bandwidth of 10-15 kHz makes them look like caterpillars in a time-frequency spectrogram. We found almost 600 caterpillar emissions with the RPWS (Radio and Plasma Wave Science) instrument throughout Cassini's tour around Saturn. We present a statistical investigation of their occurrence with respect to the position of Cassini, their duration, central frequency, bandwidth, polarization, intensity, and connection to SKR at higher frequencies. We also compare their occurrence with the occurrence of SKR low frequency extensions (LFEs) as many of them are found during so-called long LFEs. We will discuss and investigate the reasons for the loss of total polarization of caterpillars, which could be due to wave reflections at the magnetosheath or due to an incoherent superposition of X-mode with O-mode SKR.

How to cite: Fischer, G., Taubenschuss, U., Pisa, D., Lamy, L., Wu, S., Ye, S., Jackman, C., and O'Dwyer, E.: Statistical investigation of SKR caterpillar emissions, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-2066, https://doi.org/10.5194/egusphere-egu23-2066, 2023.

EGU23-2887 | Posters on site | PS2.2

Long-Lasting Solar Coherent Radio Bursts and Implications for Solar–Stellar Connection 

Sijie Yu, Bin Chen, Rohit Sharma, Timothy Bastian, Surajit Mondal, Dale Gary, Yingjie Luo, and Marina Battaglia

Discoveries of exo-auroral radio emission in the last two decades have led to an ongoing paradigm shift––many highly circularly polarized intense radio bursts detected in a variety of low-mass stars are likely signatures of auroral activities rather than flare-driven magnetic activities. Such discoveries have opened a new window in probing the magnetic field in stellar/substellar/exoplanetary systems. One of the outstanding challenges in discerning the two scenarios is characterizing the aurora-generating magnetic topologies of the stellar/substellar objects despite their large distances. Thanks to its proximity, the Sun provides much of the detailed context to study radio bursts similar to those in the stellar/substellar regime. A recent imaging spectroscopy observation with the Jansky VLA reveals a new type of radio bursts near a sunspot, which resembles exo-auroral radio emission in the literature both temporally and spectrally. Unlike the planetary aurora scenario, the detected radio signature is identified as electron cyclotron maser (ECM) emission from a sunspot driven by energetic electrons accelerated in flare activities. Comprehensive observations of sunspot auroral radio emissions will not only advance our understanding of the fundamental physical processes of ECM emissions on the Sun but also impose broad implications on stellar/substellar physics and exo-space weather sciences. These efforts will require long-term monitoring by a solar-dedicated, broad bandwidth radio telescope capable of imaging the Sun in dual circular polarization with a high image dynamic range and subsecond time resolution, which is still lacking. In this talk, after a brief introduction to ECM emissions from stars and the Sun, I will discuss the technical requirements in order to make a leap forward in observations of aurora-type ECM emissions from the Sun, and the expected science returns from a superior broadband radio imaging spectropolarimetry capabilities of a next-generation radio heliograph, such as the Frequency Agile Solar Radiotelescope (FASR) concept. 

How to cite: Yu, S., Chen, B., Sharma, R., Bastian, T., Mondal, S., Gary, D., Luo, Y., and Battaglia, M.: Long-Lasting Solar Coherent Radio Bursts and Implications for Solar–Stellar Connection, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-2887, https://doi.org/10.5194/egusphere-egu23-2887, 2023.

EGU23-4361 | Posters on site | PS2.2

Radio wAve Propagation In thE solaR wind (RAPIER) 

Vratislav Krupar, Oksana Kruparova, Jan Merka, and Jacob Pasanen

Type II and III radio bursts are associated with solar eruptive events–CMEs and solar flares. Since radio wave propagation in the interplanetary medium is strongly affected by random electron density fluctuations, radio bursts provide us with a unique diagnostic tool for solar wind remote plasma measurements.  Radio wAve Propagation In thE solaR wind (RAPIER) is a proposal submitted to the Heliophysics Theory, Modeling, Simulations (H-TMS) program, which is a component of the Heliophysics Research Program (NASA). Within this project, we intend to analyze spacecraft data and computer simulations to improve our knowledge of the generation and propagation of type II and III radio bursts and density fluctuations in the inner heliosphere. We will achieve this goal by answering the following science question: “What is the role of solar wind structures on radio burst propagation?” We will study the role of small and large scale density structures on the propagation of radio waves in the solar wind using computer simulations. Specifically, we will focus on disentangling the intrinsic variations in solar radio emissions from propagation effects. We will study the role of scattering by plasma density inhomogeneities on the propagation of radio waves using computer simulations. It allows us to remotely investigate density fluctuations near the Sun, where plasma turbulence evolves and dissipates to heat and accelerate solar wind plasma. Recent solar radio dedicated instruments in space (Parker and Solar Orbiter) allow us for the first time to accurately track radio bursts from the photosphere to the inner heliosphere, and to quantitatively test our radio wave propagation model.

How to cite: Krupar, V., Kruparova, O., Merka, J., and Pasanen, J.: Radio wAve Propagation In thE solaR wind (RAPIER), EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-4361, https://doi.org/10.5194/egusphere-egu23-4361, 2023.

EGU23-4514 | Posters on site | PS2.2 | Highlight

Plasma mechanism of exoplanetary radio emissions 

Maxim L. Khodachenko, Valery V. Zaitsev, Vladimir E. Shaposhnikov, Marina S. Rumenskikh, and Ildar F. Shaikhislamov

As an alternative to the traditionally considered electron cyclotron maser (ECM) mechanism of exoplanetary radio emission (RE), we study plasma maser mechanism. The latter, contrary to ECM operates in dense and weakly magnetized plasmas, where electron cyclotron frequency fc is less than Langmuir frequency fL [1]. Similar mechanism is known to contribute the generation of RE in solar corona, as well as in magnetospheres of the Solar System planets [2,3]. It is a two-step process. At first, the plasma waves are excited due to Cherenkov instability in a weakly anisotropic background plasma by a small admixture of hot electrons with a loss-cone type non-equilibrium distribution function. Then, the electromagnetic radiation at fRE arises due to, e.g., plasma wave scattering on the background ions (Rayleigh scattering, fRE = fL), or nonlinear coupling of two plasma waves (Raman scattering, fRE = 2fL). In the first case, the maser effect at plasma frequency fL takes place under certain conditions, leading to an exponential grow of the RE intensity with the growing energy of plasma waves. In the case of Raman scattering of two plasma waves, resulting in generation of the RE at doubled plasma frequency, the maser effect is absent, but the collisional dissipation of RE is significantly reduced at the same time. This improves the requirements regarding the brightness temperature of the RE source, to provide a detectable on Earth radiation flux. In both cases the frequency band of the exoplanetary RE is defined not by magnetic field, but by the structure of planetary plasmasphere and density distribution there.

We evaluate the efficiency of plasma mechanism of the RE generation and its detectability on Earth for the case of hot Jupiter HD189733b, for which the 3D structure of plasmasphere is simulated with the global multi-fluid self-consistent numerical model [4], taking into account the realistic stellar wind and radiation conditions. It is shown that the RE flux at doubled plasma frequency sharply increases from several mJy at 20MHz to several tens of Jy at 4 MHz. This means that the most favorable frequency range for detection of the RE from HD189733b falls into the decameter band in vicinity of the ionospheric cut-off.

1. Zaitsev, V.V., Shaposhnikov, V.E., MNRAS, 2022, 513, 4082 (DOI:10.1093/mnras/stac1140)

2. Zaitsev V. V., et al., A&A, 1986, 169, 345-354 (ISSN 0004-6361)

3. Zlotnik E. Y., et al., JGR Space Physics, 2016, 121, 5307-5318 (DOI: 10.1002/2016JA02265)

4. Rumenskikh, M. S., et al., ApJ, 2022, 927(2):238 (DOI: 10.3847/1538-4357/ac441d)

How to cite: Khodachenko, M. L., Zaitsev, V. V., Shaposhnikov, V. E., Rumenskikh, M. S., and Shaikhislamov, I. F.: Plasma mechanism of exoplanetary radio emissions, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-4514, https://doi.org/10.5194/egusphere-egu23-4514, 2023.

EGU23-5988 | Posters on site | PS2.2

Characteristics of spectral fine structure in Auroral Kilometric Radiation 

Ulrich Taubenschuss, Georg Fischer, David Pisa, Ondrej Santolik, and Jan Soucek

Auroral Kilometric Radiation (AKR) is a special type of nonthermal radio emission that is produced along auroral magnetic field lines at several thousand kilometers altitude above Earth's surface. Strong upward currents inside the AKR source region can lead to plasma instabilities and further to electrostatic solitary waves in the form of electron holes and ion holes. These small-scale plasma structures can modify the electron distribution function which is usually supposed to amplify the free-space wave modes, introducing various kinds of fine spectral features into the AKR emission pattern. We will discuss these fine spectral features based on observations from the Cluster Wideband Receiver (WBD). Spectral fine structure in AKR is frequently observed as fast frequency-drifting bursts of emission with time scales of milliseconds, or as features drifting more slowly over several seconds or a few minutes, like the well-known striations and banded emissions. The physical properties and parameter ranges of associated electron holes and ion holes are estimated based on statistics of observed WBD spectral patterns.

How to cite: Taubenschuss, U., Fischer, G., Pisa, D., Santolik, O., and Soucek, J.: Characteristics of spectral fine structure in Auroral Kilometric Radiation, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-5988, https://doi.org/10.5194/egusphere-egu23-5988, 2023.

EGU23-8736 | ECS | Posters virtual | PS2.2

DLITE—An inexpensive, deployable interferometer for solar radio burst observations 

George Carson, Jason Kooi, Joseph Helmboldt, Blerta Markowski, David Bonanno, and Brian Hicks

Solar radio bursts (SRBs) are brief periods of enhanced radio emission from the Sun which contain information concerning the plasma where the emission originates; consequently, SRBs can provide critical information concerning space weather events such as coronal mass ejections (CMEs). A new network of four-element interferometers is being developed and used to monitor SRBs. These interferometers, called the Deployable Low-band Ionosphere and Transient Experiment (DLITE) arrays, operate in a 30-40 MHz band and were originally designed to probe the Earth’s ionosphere using high resolution measurements (1.024-s temporal resolution, 16.276-kHz frequency resolution). The DLITE network has recently been demonstrated to be  a powerful tool for detailed observations of SRBs at these frequencies. We have used DLITE to detect long-duration Type II and Type IV SRBs. Each DLITE array provides a higher sensitivity (e.g. >10 dB) compared to single-receiver stations using the same antenna. We demonstrate DLITE's enhanced functionality by examining SRBs associated with a CME on May 11, 2022. The high resolution SRB data that DLITE provides can complement ground-based networks like e-Callisto or space-based observations, e.g., from Wind/WAVES. Future improvements could be made to DLITE arrays by utilizing the 20-80 MHz band and millisecond time-resolution possible by the antennas. This would expand DLITE’s detection ability to shorter Type I and Type III SRBs and improve its ability to track long-duration bursts.

 

How to cite: Carson, G., Kooi, J., Helmboldt, J., Markowski, B., Bonanno, D., and Hicks, B.: DLITE—An inexpensive, deployable interferometer for solar radio burst observations, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-8736, https://doi.org/10.5194/egusphere-egu23-8736, 2023.

EGU23-8808 | Posters on site | PS2.2

Observation of the Earth’s ionosphere variability by IONO/INSPIRE-SAT 7 experiment 

Patrick Galopeau, Mustapha Meftah, Philippe Keckhut, Kévin Grossel, Fabrice Boust, Mohammed Boudjada, and Hans Eichelberger

INSPIRE-SAT 7 is a French 2U CubeSat very similar to the satellite UVSQ-SAT which was launched on 24 January 2021. The main purpose of INSPIRE-SAT 7 is the measurement of the Earth’s radiation budget at the top of the atmosphere. Its total mass is ~3.0 kg and its averaged power consumption 3 W. It will orbit at a maximum altitude of 600 km on a Sun-synchronous orbit with a descending node at ~0930 LT. The IONO experiment embarked on INSPIRE-SAT 7 is dedicated to the sounding of the Earth’s ionosphere which results from the ionization of the upper atmosphere due to UV radiations and X-rays coming from the Sun. The electron density in the ionosphere depends on the local time, the season, and the solar activity. The propagation of the radio waves is affected by the electron density and also by refraction and reflection phenomena. We consider the following goals for the IONO instrument: improving ionosphere models, in particular the IRI (International Reference Ionosphere); study of the propagation of electromagnetic waves in the ionosphere and the factors which can disturb it (e.g., thunderstorms); analysis of temporal and spatial variability at different scales; study of the coupling between ionosphere and magnetosphere, and the electrical circuit between ionosphere and lithosphere. The observations collected by IONO will be compared to those produced by a VLF-LF antenna network designed for investigating the perturbations of the ionosphere, and the wave propagation, by seismic phenomena.

How to cite: Galopeau, P., Meftah, M., Keckhut, P., Grossel, K., Boust, F., Boudjada, M., and Eichelberger, H.: Observation of the Earth’s ionosphere variability by IONO/INSPIRE-SAT 7 experiment, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-8808, https://doi.org/10.5194/egusphere-egu23-8808, 2023.

EGU23-12283 | Posters on site | PS2.2

Separating fundamental and harmonic sources in LOFAR solar type III radio burst images 

Christian Vocks, Pietro Zucca, Mario Bisi, Bartosz Dabrowski, Diana Morosan, Peter Gallagher, Andrzej Krankowski, Jasmina Magdalenic, Gottfried Mann, Christophe Marque, Hanna Rothkaehl, and Barbara Matyjasiak

LOFAR low band interferometric images of type III solar radio bursts during an M class flare on 7 September 2017 show distinct sources with variations in their positions and intermittent dual source structures. We identify these as fundamental and harmonic emission, with the one or other being dominant at times. The data show that transport effects due to refraction and scattering play a significant role, both in source separation and drift of their apparent positions. We present a method of automatically separating fundamental and harmonic contributions that allows for obtaining separate lightcurves. Comparing the lightcurves of fundamental and harmonic pairs, e.g. 35 MHz and 70 MHz, enables studies of radio wave propagation in the solar corona. Harmonic sources at the lowest observable frequencies are relevant for the transition into the solar wind, and for joint observing campaigns with Parker Solar Probe and Solar Orbiter that are currently investigating the inner heliosphere.

How to cite: Vocks, C., Zucca, P., Bisi, M., Dabrowski, B., Morosan, D., Gallagher, P., Krankowski, A., Magdalenic, J., Mann, G., Marque, C., Rothkaehl, H., and Matyjasiak, B.: Separating fundamental and harmonic sources in LOFAR solar type III radio burst images, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-12283, https://doi.org/10.5194/egusphere-egu23-12283, 2023.

EGU23-13512 | Posters on site | PS2.2

Exploring Coronal Structures in Metric-Decametric Radio Imaging 

Kamen Kozarev, Pietro Zucca, Peijin Zhang, Oleg Stepanyuk, and Mohamed Nedal

Large-scale solar coronal structures may have very different signatures in low-frequency metric-decametric interferometric images than their optical/EUV counterparts, or even at higher frequencies. Notable examples are coronal holes and streamers. This may be due to scattering effects of the thermal emission in the corona, or to unexpected mechanisms contributing to the overall emission at these frequencies, such as gyrosynchrotron emission. In this work, we explore the effects of frequency and emission mechanisms (thermal and gyrosynchrotron) on large-scale coronal structures, comparing data with synthetic observations based on global magnetohydrodynamic modeling and forward modeling. We analyze observations by the LOw Frequency ARray (LOFAR) and Murchison Widefield Array (MWA) radio telescopes in a frequency range between 20-250 MHz. We address the unanswered question of why coronal holes often appear bright in the lowest frequencies observable on the ground, and whether this changes with the observer’s viewpoint. We attempt to segment and classify large-scale coronal structures based on their multiwavelength appearance and emission mechanism.

How to cite: Kozarev, K., Zucca, P., Zhang, P., Stepanyuk, O., and Nedal, M.: Exploring Coronal Structures in Metric-Decametric Radio Imaging, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-13512, https://doi.org/10.5194/egusphere-egu23-13512, 2023.

EGU23-9 | ECS | Orals | PS2.3

A new magnetosphere-ionosphere current system on Mars 

Jiawei Gao, Zhaojin Rong, Yong Wei, and Haoyu Lu

Using magnetic field data collected by Mars Atmosphere and Volatile EvolutioN (MAVEN), we investigated the external magnetic field distribution over low crustal field regions in the Martian ionosphere. Both draping and looping magnetic field are observed in the Martian dayside and nightside ionosphere at attitude range 150-600 altitude. Draping magnetic field is formed by the draped interplanetary magnetic field around the ionosphere obstacle, which is formed by the well-known induced magnetosphere current system. Looping magnetic field, observed in both ionosphere and magnetosphere, indicates a new current system coupling the ionosphere and magnetosphere. This new current system, different with the induced magnetosphere current system, has sunward component in the magnetosphere, and tailward component in the low altitude ionosphere. This current system is validated by both MAVEN observation and a global multi-fluid magnetohydrodynamic (MHD) simulation, which is most likely a universal phenomenon for a non-magnetized planetary with ionospheres interacted with high-speed solar wind.

How to cite: Gao, J., Rong, Z., Wei, Y., and Lu, H.: A new magnetosphere-ionosphere current system on Mars, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-9, https://doi.org/10.5194/egusphere-egu23-9, 2023.

EGU23-490 | ECS | Orals | PS2.3

The influence of upstream conditions on heavy ion escape at Mars 

Qi Zhang, Mats Holmström, Xiaodong Wang, and Hans Nilsson

We apply a recently presented method to estimate ion escape to Mars. The method combines in-situ observations and a hybrid plasma model (ions as particles, electrons as a fluid). Observed upstream solar wind conditions from the Mars Atmosphere and Volatile Evolution (MAVEN)  are used as input to the model.  We then vary ionospheric ion production until the solution fits the observed bow shock location.  With this method, we investigate how upstream conditions, including solar EUV, solar wind dynamic pressure, Interplanetary Magnetic Field (IMF) strength and cone angle, affect the heavy ions loss. The results indicate that the heavy ions escape rate is higher in high EUV and the tail flux is sensitive to EUV variety while the plume is not. The ion escape rate increases as solar wind dynamic pressure increases. 

How to cite: Zhang, Q., Holmström, M., Wang, X., and Nilsson, H.: The influence of upstream conditions on heavy ion escape at Mars, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-490, https://doi.org/10.5194/egusphere-egu23-490, 2023.

EGU23-2582 | Orals | PS2.3 | Highlight

Electric fields in a small scale comet magnetosphere 

Hans Nilsson

We present two new methods to study the electric fields and their effect on ions and electrons in a cometary environment. One method is to look at the energy spectra of cometary ions, ions that are produced by ionisation of the gas emanating from the comet nucleus. The new production of such ions falls off with distance r to the nucleus proportionally to the fall-off of the parent neutral gas, as 1/r2. For ions having been significantly accelerated, the energy of observed ions shows the electric potential difference between the point of ionisation and the observation point. When such ionisation occurs in a homogeneous electric field, the ion flux as function of energy is predicted to show a simple power law relation, the flux falling off as 1/E2. This is indeed sometimes seen. We also discuss the possibility to interpret ion energy spectra in terms of somewhat inhomogeneous electric fields.

To this we can now add a new method where by comparing the speed of solar wind H+ and He2+ after interaction with the comet environment we can estimate the electric potential of the observation point relative to the upstream solar wind. Combining these methods opens up a whole new possibility to study in detail the electric fields acting on small scales when two plasma populations interact. Our study is specific to the cometary environment we are looking at, but the physical interactions we study are universal.

 

How to cite: Nilsson, H.: Electric fields in a small scale comet magnetosphere, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-2582, https://doi.org/10.5194/egusphere-egu23-2582, 2023.

EGU23-2958 | ECS | Orals | PS2.3

Statistical Mapping of Magnetic Topology at Venus 

Shaosui Xu, Rudy Frahm, Yingjuan Ma, David Mitchell, Janet Luhmann, and Moa Persson

Venus lacks a significant intrinsic magnetic field, and thus, its atmosphere and ionosphere interact directly with the solar wind flow and magnetic field from the Sun. Interplanetary magnetic fields (IMF) can penetrate into the ionosphere when the upstream solar wind dynamic pressure is stronger than the ionospheric plasma pressure. Magnetic topology can be inferred at Venus if it is defined as the magnetic connectivity to the collisional atmosphere/ionosphere, rather than connectivity to the planet’s surface. Magnetic topology can be inferred from the pitch angle and energy distribution of superthermal (> ~1 eV) electrons. More specifically, the presence of loss cones in electron pitch angle distributions infers connectivity to the nightside collisional atmosphere and the presence of ionospheric photoelectrons (identified from electron energy distributions) indicates connectivity to the dayside collisional ionosphere. We design automated procedures to determine magnetic topology with electron and magnetic field measurements by the Venus Express spacecraft over its entire mission (2006-2014). This allows us to provide the first statistical mapping of magnetic topology at Venus. We also examine how the upstream drivers affect the low-altitude magnetic topology, revealing different magnetized states of the Venus ionosphere. We find that open and closed (a surprising topology not expected at Venus) fields cluster around the terminator and draped fields dominate other regions. Our results also reveal that there is more dayside magnetic connectivity in the -E (solar wind motional electric field) hemisphere than the +E hemisphere, and during solar maximum. During solar minimum, however, there is more nightside magnetic connectivity. Last but not the least, to understand the true nature of these magnetic topologies and broadly speaking the planet-solar wind interaction, we need to think about possible ways to measure the deeply penetrated magnetic fields at Venus and Mars.

How to cite: Xu, S., Frahm, R., Ma, Y., Mitchell, D., Luhmann, J., and Persson, M.: Statistical Mapping of Magnetic Topology at Venus, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-2958, https://doi.org/10.5194/egusphere-egu23-2958, 2023.

EGU23-3122 | ECS | Orals | PS2.3

Ionospheric Plasma Depletions at Mars: MAVEN Observations of In-situ Plasma and Wave properties 

Praveen Basuvaraj, František Němec, Leonardo Regoli, Christopher Fowler, Zdeněk Němeček, and Jana Šafránková

Since September 2014, NASA's Mars Atmosphere and Volatile Evolution (MAVEN) spacecraft has been measuring the in-situ ionospheric constituents of Mars. Recently, MAVEN detected the presence of large-scale plasma depletions (at least ten-fold) within the Martian ionosphere, also known as Plasma Depletion Events (PDEs). Geometrically, the Martian PDEs appear to be bubble-like plasma structures. Although the origin and formation of PDEs are not entirely understood, they are known to occur primarily on the nightside and in regions with stronger crustal magnetic fields.

In this study, we analyze the variation of magnetic field magnitude and direction and electric field power (2–100 Hz) associated with PDEs. We show that, in most cases, the magnetic fields do not considerably change within the plasma-depleted region. Conversely, the low-frequency electric field wave power is enhanced by up to two orders of magnitude at the peak depletion. Both ions and electrons within PDEs are highly magnetized. We present possible formation mechanisms of PDEs supported by recent findings.

How to cite: Basuvaraj, P., Němec, F., Regoli, L., Fowler, C., Němeček, Z., and Šafránková, J.: Ionospheric Plasma Depletions at Mars: MAVEN Observations of In-situ Plasma and Wave properties, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-3122, https://doi.org/10.5194/egusphere-egu23-3122, 2023.

EGU23-3369 | Orals | PS2.3 | Highlight

BepiColombo second Mercury flyby :  Ion composition measurements from the Mass Spectrum Analyzer (MSA) 

Dominique Delcourt, Lina Hadid, Yoshifumi Saito, Markus Fränz, Shoichiro Yokota, Björn Fiethe, Christophe Verdeil, Bruno Katra, Frédéric Leblanc, Henning Fischer, Yuki Harada, Dominique Fontaine, Norbert Krupp, Harald Michalik, Jean-Marie Illiano, Jean-Jacques Berthelier, Harald Krüger, Go Murakami, and Shoya Matsuda

On June 23rd 2022, BepiColombo performed its second gravity assist maneuver (MFB2) at Mercury. Just like the first encounter with Mercury that took place on October 1st 2021, the spacecraft approached the planet from dusk-nightside to dawn-dayside down to an extremely close distance (within about 200 km altitude from the planet surface). Even though BepiColombo is in a so-called “stacked configuration” during cruise, meaning that the instruments cannot be fully operated yet, these instruments can still make interesting observations. Particularly, despite their limited field-of-view, the particle sensors allow us to get a hint on the ion composition and dynamics very close to the planet well before the forthcoming orbit insertion around Mercury in December 2025. In this study, we present observations of the Mass Spectrum Analyzer (MSA) at Mercury during MFB2. MSA is part of the low energy sensors of the Mercury Plasma Particle Experiment (MPPE) consortium (PI: Y. Saito), which is a comprehensive instrumental suite for plasma, high-energy particle and energetic neutral atom measurements (Saito et al., 2021) onboard the Mercury Magnetospheric Orbiter (Mio). MSA is a “reflectron” time-of-flight spectrometer that provides information on the plasma composition and the three-dimensional distribution functions of ions with energies up to ~ 38 keV/q and masses up to ~ 60 amu (Delcourt et al., 2016). In this study, we show that both H+ and He2+ ions in the 1-10 keV range are present throughout the innermost magnetosphere near closest approach. In addition, during this MFB2 sequence, MSA observations provide evidences of He+ ions with energies of several hundreds of eVs. These ions likely originate from the planet exosphere and are rapidly circulated within the magnetosphere. During the outbound sequence of MFB2, MSA measurements also reveal copious amounts of keV protons of solar wind origin that propagate upstream after being reflected from the bow shock.

How to cite: Delcourt, D., Hadid, L., Saito, Y., Fränz, M., Yokota, S., Fiethe, B., Verdeil, C., Katra, B., Leblanc, F., Fischer, H., Harada, Y., Fontaine, D., Krupp, N., Michalik, H., Illiano, J.-M., Berthelier, J.-J., Krüger, H., Murakami, G., and Matsuda, S.: BepiColombo second Mercury flyby :  Ion composition measurements from the Mass Spectrum Analyzer (MSA), EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-3369, https://doi.org/10.5194/egusphere-egu23-3369, 2023.

EGU23-3699 | Posters on site | PS2.3

Mars pickup ion plume under different IMF conditions from MAVEN observations 

Yaxue Dong, David Brain, Robin Ramstad, Xiaohua Fang, Yingjuan Ma, James McFadden, Jasper Halekas, Jared Espley, and Shannon Curry

Ions originating from the upper atmosphere of Mars may be picked up by the impinging solar wind and interplanetary magnetic field (IMF), which forms an energetic ion plume from the dayside of the planet as a key feature of the Martian induced magnetosphere and an important ion escape channel. Consisting of mostly ions in the beginning phase of the pickup process, the orientation and morphology of the plume are largely controlled by upstream IMF conditions.

Using data from the NASA Mars Atmosphere and Volatile EvolutioN (MAVEN) mission, we will perform a thorough investigation of the pickup ion plume under different upstream IMF conditions. Previous statistical ion flux maps by Dong et al. [2015; 2017] from MAVEN data show the plume as a more spatially spread-out feature than that in many simulation models [e.g. Jarvinen et al. 2016 and others], which is possibly due the effects of highly variable IMF conditions for the data used in those maps. We will investigate how the plume appears with selected data under quasi-steady IMF conditions. Furthermore, we will compare the plume under strong and weak IMF conditions, as well as the conditions with IMF approximately perpendicular or parallel to the solar wind direction. The morphology of the plume and characteristics of escaping pickup ions under different IMF conditions will be discussed and compared with available model results to better understand how IMF affects the formation of the plume and ion escape through this channel.

How to cite: Dong, Y., Brain, D., Ramstad, R., Fang, X., Ma, Y., McFadden, J., Halekas, J., Espley, J., and Curry, S.: Mars pickup ion plume under different IMF conditions from MAVEN observations, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-3699, https://doi.org/10.5194/egusphere-egu23-3699, 2023.

EGU23-5058 | Orals | PS2.3

Solar Wind Energetic Neutral Atom Observation at Mars by MINPA Onboard the Tianwen-1 Orbiter 

Jijie Ma, Wenya Li, Linggao Kong, Yiteng Zhang, Peter Wurz, André Galli, Bingbing Tang, Lianghai Xie, Limin Wang, Fuhao Qiao, Lei Li, and Chi Wang

The Mars Ion and Neutral Particle Analyzer (MINPA), one of the three scientific payloads onboard the Tianwen-1 orbiter, was designed to measure ions and energetic neutral atoms (ENAs) at Mars. From November 2021, MINPA started to collect scientific data around Mars. Here, we present MINPA's first results of the solar-wind ENAs, which are produced through the charge exchange process between the solar wind hydrogen ions and the Martian neutral exosphere. We perform a comprehensive comparison between the inflight ENA data and ground calibration results to understand the energy and angular distributions of the solar-wind ENA signals. The possible contamination of these observations by ions and solar extreme ultraviolet (EUV) is evaluated by comparing the ENA measurements with the ion data. We will present several cases of the solar wind ENA observations, and their intensities are estimated to be 10^5~10^6 cm^-2 sr^-1 s^-1, which is in good agreement with previous in situ measurements and predictions using models.

How to cite: Ma, J., Li, W., Kong, L., Zhang, Y., Wurz, P., Galli, A., Tang, B., Xie, L., Wang, L., Qiao, F., Li, L., and Wang, C.: Solar Wind Energetic Neutral Atom Observation at Mars by MINPA Onboard the Tianwen-1 Orbiter, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-5058, https://doi.org/10.5194/egusphere-egu23-5058, 2023.

EGU23-5405 | Posters on site | PS2.3

Statistical Properties of Hot Flow Anomalies around Mars 

Mingyu Wu

Hot flow anomalies (HFAs) are not only a terrestrial, but also a solar-system-wide phenomenon that could cause strong perturbations of the planetary magnetosphere and ionosphere. Based on the observations of Mars Atmosphere and Volatile EvolutioN (MAVEN) upstream of the Martian bow shock from 2014 to 2020, we have investigated the statistical properties of HFAs around Mars in this study. Our observation results show that HFAs can distribute in a wide region from the dayside to the terminator region of Mars. On average, these HFAs can last 63 seconds and have a thickness of 28 local proton gyroradii. They are more prevalent when the ambient solar wind is denser and faster. HFAs occur most preferentially for IMF magnitude from 1-4 nT. Most of HFAs around Mars are formed during the interaction between tangential discontinues and the bow shock. Heavy ions originating from Mars do not appear to affect the formation of HFAs. Martian HFAs can lead to tens of times variations of solar wind dynamic pressure only in tens of seconds, which could strongly influence the heights of Martian ionopause and induced magnetosphere boundary.

How to cite: Wu, M.: Statistical Properties of Hot Flow Anomalies around Mars, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-5405, https://doi.org/10.5194/egusphere-egu23-5405, 2023.

EGU23-6347 | Posters on site | PS2.3 | Highlight

The mini induced magnetospheres at Mars. 

Eduard Dubinin, Markus Fraenz, Martin Paetzold, Silvia Tellmann, Ginna DiBraccio, and James McFadden

We report on observations made by the Mars Atmosphere and Volatile EvolutioN (MAVEN) spacecraft at Mars, in the region of the ion plume. We observe that in some cases, when the number density of oxygen ions is comparable to the density of the solar wind protons interaction between both plasmas leads to formation of mini induced magnetospheres (iMagnetospheres)  possessing all typical features of induced magnetospheres  observed at Mars or Venus: a pileup of the magnetic field at the ‘head’ of the ion cloud, magnetospheric cavity, partially void of solar wind protons, draping of the interplanetary magnetic field around the mini obstacle, formation of a magnetic tail with a current sheet, in which protons are accelerated by the magnetic field tensions. These new observations may shed a light on the mechanism of formation of induced magnetospheres.

How to cite: Dubinin, E., Fraenz, M., Paetzold, M., Tellmann, S., DiBraccio, G., and McFadden, J.: The mini induced magnetospheres at Mars., EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-6347, https://doi.org/10.5194/egusphere-egu23-6347, 2023.

EGU23-6449 | Posters on site | PS2.3 | Highlight

Scale size of cometary bow shocks 

Niklas J. T. Edberg, Anders I. Eriksson, Hans Nilsson, Herbert Gunell, Charlotte Goetz, Ingo Richter, Pierre Henri, and Johan de Keyser

With the upcoming Comet Interceptor mission aiming for a flyby of an hitherto unknown long-period comet, we investigate the expected scale size of the plasma environment to be encountered during this mission. As the target comet is not known, and may not be known before the launch of Comet Interceptor in 2029, we do not know the expected outgassing rate from the nucleus. Therefore, we have no knowledge of the expected scale size of the plasma environment, which can vary by orders of magnitude. Taking the bow shock size as a characteristic size of the plasma environment, we are interested in knowing how this grows with increasing outgassing rate. Previous cometary flyby missions have generated a small statistical dataset of outgassing rates vs. bow shock distances, while computer simulations of the solar wind interaction with various comets have yielded additional datapoints of this. We combine the measured values with a large fraction of these simulations to build up a dataset that spans over four orders of magnitude in both outgassing rate and bow shock distance. The bow shock distances are normalized to the solar wind conditions (400 km/s, 5 cm-3) and ionisation rate (7e-7 s-1) at 1 AU, and also to a flow velocity of 1 km/s of the outgassing neutrals. We then compare this dataset with the gas-dynamic model of Biermann et al., (1967) which was later expanded by Koenders et al., (2013) and find a good model-data agreement. Furthermore, assuming that the bow shock takes the shape of a conic section (as has been found empirically to be the case for most planetary bow shocks) we provide an outgassing rate-dependent bow shock model. This might be useful when planning the operation time-line of Comet Interceptor, or for any other future cometary flyby mission.

How to cite: Edberg, N. J. T., Eriksson, A. I., Nilsson, H., Gunell, H., Goetz, C., Richter, I., Henri, P., and de Keyser, J.: Scale size of cometary bow shocks, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-6449, https://doi.org/10.5194/egusphere-egu23-6449, 2023.

EGU23-6512 | ECS | Posters on site | PS2.3

The influence of magnetic topology on ionospheric structure at Mars: Observations of localized “magnetic depletions” 

Christopher Fowler, Zack Ortiz, Shaosui Xu, David Mitchell, Kathleen Hanley, Jared Espley, Laila Andersson, James McFadden, Janet Luhmann, and Shannon Curry

The interaction between Mars' crustal magnetic fields and the solar wind produces a variety of magnetic topologies whose characteristics depend upon the plasma regions that the magnetic field is embedded in. We utilize in-situ Mars Atmosphere And Volatile EvolutioN (MAVEN) measurements to identify localized ionospheric structures, observed as the spacecraft flies through this patchwork of different magnetic topologies. Events are characterized by sharp ‘drop outs’ in magnetic field strength that we term ‘magnetic depletions’. The plasma pressure dominates within magnetic depletions, while the magnetic pressure typically dominates outside of them. Abrupt changes in magnetic topology are coincident with the depletion boundaries. A preliminary statistical study spanning 3 months shows that events occur on ∼4% of MAVEN orbits, between altitudes of 170–360 km. Ionospheric electrons are collisionless and thus magnetized at these altitudes, and combined with the fact that magnetic diffusion timescales range from minutes to an hour, these characteristics suggest that such structures can be observed sporadically by MAVEN on its ∼4.5 hour orbit before being smeared out by magnetic diffusion. At lower altitudes high collision rates lead to diffusion timescales of seconds, while at higher altitudes electromagnetic waves, instabilities and other transport processes driven by the Mars-solar wind interaction can distort the magnetic field, making magnetic depletion events difficult to identify. Magnetic depletions highlight the ability of magnetic topology to drive localized ionospheric structure at Mars, a result that stems from the unique interaction between the solar wind, Mars' crustal magnetic fields, and it's ionosphere.

How to cite: Fowler, C., Ortiz, Z., Xu, S., Mitchell, D., Hanley, K., Espley, J., Andersson, L., McFadden, J., Luhmann, J., and Curry, S.: The influence of magnetic topology on ionospheric structure at Mars: Observations of localized “magnetic depletions”, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-6512, https://doi.org/10.5194/egusphere-egu23-6512, 2023.

EGU23-7071 | ECS | Orals | PS2.3

Evidence of planetary Oxygen and Carbon ions in the outer flank of Venusmagnetosheath 

Lina Hadid and the BepiColombo - MSA team (and members from MIA, MEA and MPO-MAG teams)

On August 10, 2021, the Mercury-bound BepiColombo spacecraft flew for the second time by Venus for a Gravity-Assist Maneuver. During this second flyby of Venus, a limited number of instruments were turned on, allowing unique observations of the planet and its environment. Among these instruments, the Mass Spectrum Analyzer (MSA) that is part of the particle analyzer consortium onboard the magnetospheric orbiter (Mio) was able to acquire its first plasma composition measurements in space. As a matter of fact, during a limited time interval upon approach of the planet, substantial ion populations were recorded by MSA, with characteristic energies ranging from about 20 eV up to a few hundreds of eVs. Comparison of the measured Time-Of-Flight spectra with calibration data reveals that these populations are of planetary origin, containing both Oxygen and Carbon ions. The Oxygen observations are to some extent consistent with previous in situ measurements from mass spectrometers onboard Venus Express and Pioneer Venus Orbiter. On the other hand, the MSA data provide the first ever in situ evidences of Carbon ions in the near-Venus environment at about 6 planetary radii. We show that the abundance of C+ amounts to about ~30% of that of O+. Furthermore, Changes in the orientation of the magnetic field suggest that these planetary ions are located in the distant magnetosheath flank in the immediate vicinity of the bow-shock region.

How to cite: Hadid, L. and the BepiColombo - MSA team (and members from MIA, MEA and MPO-MAG teams): Evidence of planetary Oxygen and Carbon ions in the outer flank of Venusmagnetosheath, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-7071, https://doi.org/10.5194/egusphere-egu23-7071, 2023.

EGU23-8206 | ECS | Posters virtual | PS2.3

MVSE Mission Phase A/0 Study: A Proposal for Understanding the Dynamics of Induced Magnetospheres 

Nadim Maraqten and Viktoria Kutnohorsky and the MVSE Mission Team

The dynamics of induced magnetospheres raise several unsolved questions. Among the most pressing is the interaction between the solar wind and induced magnetospheres, and the corresponding changes in magnetospheric structure and variation in heating processes. Furthermore, the reactions of an induced magnetosphere to solar eruptive events such as interplanetary coronal mass ejections, corotating interaction regions and solar flares are not well understood. The Magnetospheric Venus Space Explorers (MVSE) mission is designed to fill this gap by studying how the Sun drives the dynamics of the induced Venusian magnetosphere. Venus is an ideal laboratory for this due to its proximity to the Sun, similarity to Earth, and its accessibility. Investigating the induced Venusian magnetosphere enables direct comparisons with Earth’s active magnetosphere and other induced ones, such as those of several other planets, moons and comets. This complements former missions like Venus Express (VEX) and Pioneer Venus Orbiter (PVO) by filling data and knowledge gaps, hence improving magnetospheric modeling.

 

Figure 1: Orbits of the three scientific spacecraft and transfer/communication spacecraft around Venus facilitating simultaneous measurements in solar wind, bow shock and magnetotail

Three identical spin-stabilised scientific spacecraft equipped with in-situ plasma instrumentation are deployed in resonant orbits around Venus by a transfer stage, which then further operates as a communication relay station. With a phase difference of 180° relative to each other, two scientific spacecraft orbit Venus circularly with a 20 h period (r = 6 Venusian radii RV). The third spacecraft is in a resonant inner elliptical orbit with a 10 h period (pericythe = 1.3 RV; apocythe = 6 RV) . This configuration enables simultaneous measurements in three regions of interest (ROIs): i) up and ii) downstream the bow shock, as well as iii) in the magnetotail. In these ROIs, the magnetic field, the electric field and the ion-electron distribution functions are measured. To observe at least 10 coronal mass ejection events, a mission duration of three years around the solar maximum is planned.

Figure 2: Spacecraft stack consisting of one tansfer/communications vehicle and three scientific spacecraft

The concept of the MVSE mission was developed during ESA’s Alpbach Summer School 2022. It has been refined by adapting the concurrent engineering method during the Post Alpbach Summer School Event 2022. A total of 32 students from both engineering and science backgrounds worked on the mission with appreciated advice from experts of ESA and academia.

How to cite: Maraqten, N. and Kutnohorsky, V. and the MVSE Mission Team: MVSE Mission Phase A/0 Study: A Proposal for Understanding the Dynamics of Induced Magnetospheres, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-8206, https://doi.org/10.5194/egusphere-egu23-8206, 2023.

EGU23-8319 | Posters on site | PS2.3

Low-energy electron spectrometer to study the far environment of a dynamically new comet as a part of the Comet Interceptor payload 

Lubomir Prech, Nicolas André, Benoit Lavraud, Christophe Verdeil, Andrei Fedorov, and Jakub Vaverka and the LEES Technical and Scientific Teams

Comet Interceptor is the ESA F1 space mission aiming to explore a comet very likely entering the inner Solar System for the first time, or to encounter an interstellar object originating at another star, scheduled for launch in 2029 together with the ESA L-class Ariel spacecraft. Following the mission adoption in June 2022, the spacecraft and scientific payload development have advanced to the Phase C. In our contribution we present the status of development of the Low-energy electron spectrometer (LEES) that is a part of the Dust-Fields-Plasma multi-instrument suite deployed at the main spacecraft A (DFP-A).

The DFP-A/LEES sensor will determine the thermal and suprathermal electron densities, temperatures, and the velocity distribution functions of the local plasma environment of both the solar wind and coma. It will also measure the local properties of negatively charged ions and dust, and detect photoelectrons resulting from neutral-plasma interactions in order to infer the magnetic connectivity between the cometary environment and the spacecraft. The LEES measurements are needed to understand the ionization sources of the cometary neutral gas as well as to infer the plasma boundaries of the induced magnetosphere of the comet. The electron spectrometer is a further miniaturized version of the top-hat analyser inherited from the Stereo, Maven and BepiColombo missions. We present the overall design, simulation of the spacecraft electromagnetic and particle environment influence to the LEES measurements and the intermediate results of testing of the LEES components to survive a potential harsh dust environment during the comet flyby.   

How to cite: Prech, L., André, N., Lavraud, B., Verdeil, C., Fedorov, A., and Vaverka, J. and the LEES Technical and Scientific Teams: Low-energy electron spectrometer to study the far environment of a dynamically new comet as a part of the Comet Interceptor payload, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-8319, https://doi.org/10.5194/egusphere-egu23-8319, 2023.

EGU23-8912 | ECS | Orals | PS2.3

E-field at a low-activity comet derived from cometary ion velocity distributions 

Anja Moeslinger, Hans Nilsson, Gabriella Stenberg Wieser, and Hayley Williamson

The ion spectrometer ICA onboard the Rosetta mission has provided us with detailed measurements of the plasma environment around comet 67P/Churyumov-Gerasimenko. The distribution of cometary ions is an important indicator for the cometary plasma environment and its interaction with the solar wind. The cometary ion production at a comet decreases with increasing radial distance from the comet. The fluxes of observed ions are therefore also expected to fall off proportional to their point of origin relative to the comet. Due to electric fields, ions that are born further away are observed at higher energies at the spacecraft. The exact relation between the flux and the observed energy depends on the density distribution of cometary ions and the electric field around the comet.
We derive the bulk flow properties of the cometary pickup ion population with a fitting procedure. In our study, cometary pickup ions are all heavy ions with an energy above 40 eV as observed by ICA. The particle drift speed of the bulk flow can be used to estimate the average local electric field. This gives us a 3D estimate for the electric field close to the comet nucleus. Using this E-field estimate, we can back-trace the observed particles to determine an approximate location of where they were born. This ionisation point is further away for particles with higher energies. The relation between the flux of the observed ions and their origin provides us with information about the inhomogeneity of the cometary plasma environment between the observation point (30 km from the nucleus) and the ionisation point of the particle (hundreds of km away from the nucleus). 
We will present results of the ion distribution of cometary pickup ions above 40eV on a selected day (April 19th, 2016) of the Rosetta mission, along with the derived electric field estimate close to the nucleus. We will also show the results and implications of the particle trajectory backtracing.

How to cite: Moeslinger, A., Nilsson, H., Stenberg Wieser, G., and Williamson, H.: E-field at a low-activity comet derived from cometary ion velocity distributions, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-8912, https://doi.org/10.5194/egusphere-egu23-8912, 2023.

EGU23-9003 | Orals | PS2.3

Plasma turbulence within cometary plasma environments 

Francesco Pucci, Etienne Behar, Pierre Henri, Cyril Simon Wedlund, and Giulio Ballerini

We present a numerical work in which the interaction between a comet and the solar wind is studied in 2D in the plane perpendicular to the solar wind mean field direction. Our simulations are conducted with the hybrid Particle-in-Cell (PIC) code Menura that allows for the injection of a turbulent solar wind [1].

First, we consider the case of laminar solar wind and we present a study on the equivalent Mach number of the two-ion-species (cometary and solar wind) plasma surrounding the comet. We develop an expression for the Mach number having suitable limits in the two asymptotic cases of infinite cometary and solar wind ion density; our expression is derived by extending previous studies on bi-ion plasma models [2]. Through numerical simulations in which the cometary activity is varied, we show how our Mach number is able to unambiguously describe  the existence and location of the cometary shock.

Second, we compare two runs, one with a laminar and one with a turbulent solar wind in the case of moderate cometary activity. We divide the simulation domain into the regions upstream and downstream the cometary shock. We analyze how plasma turbulence properties are affected by the passage through the shock in the case of a turbulent solar wind. Then, we divide the downstream region into three different regions identified by different solar wind-to-cometary ion density ratios. We study the downstream turbulence properties in the case of laminar and turbulent impinging solar wind and how they vary in those regions.

 

[1] Behar, E., Fatemi, S., Henri, P., & Holmström, M. (2022, May). Menura: a code for simulating the interaction between a turbulent solar wind and solar system bodies. In Annales Geophysicae (Vol. 40, No. 3, pp. 281-297). Copernicus GmbH.

[2] Dubinin, E. M., Sauer, K., McKenzie, J. F., & Chanteur, G. (2002). Nonlinear waves and solitons propagating perpendicular to the magnetic field in bi-ion plasma with finite plasma pressure. Nonlinear Processes in Geophysics, 9(2), 87-99.

How to cite: Pucci, F., Behar, E., Henri, P., Simon Wedlund, C., and Ballerini, G.: Plasma turbulence within cometary plasma environments, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-9003, https://doi.org/10.5194/egusphere-egu23-9003, 2023.

EGU23-9224 | ECS | Posters on site | PS2.3

Expectations of the Ion-Profile in Mercury’s Magnetosphere during BepiColombo's Flybys 2021-2025 

Daniel Teubenbacher, Yasuhito Narita, Gunter Laky, Ali Varsani, Daniel Schmid, Uwe Motschmann, Simon Töpfer, Willi Exner, Philippe Bourdin, and Horia Comişel

The study of the structure and dynamics of Mercury’s magnetosphere is still an open research topic in space physics. Upon other mission objectives, the on-going BepiColombo mission will study the plasma environment around Mercury with multiple field and particle instruments. One of them is the Planetary Ion Camera (PICAM). It is an ion spectrometer designed to measure low-energy pick-up heavy ions (e.g. sodium). Due to ejection mechanisms and the solar wind influence, these particles are emitted from the surface of Mercury. The resulting electric currents, like perpendicular and field-aligned currents need to be studied to understand the global magnetospheric current structure as well as its variability due to the solar wind conditions.

In this study, numerical simulations with a global 3D hybrid model are used to investigate and forecast the typical ion profile with energies up to 5 keV during the BepiColombo flyby trajectories in the years 2021-2025. Magnetotail reconnection causes the acceleration of particles towards the planet. The resulting field-aligned current is studied to about 3 RM in tailward direction. The simulations are conducted with the AIKEF (Adaptive Ion Kinetic Electron Fluid) model. The kinetic treatments of the ions will enable to directly compare magnetospheric particle species model results with PICAM observations.

How to cite: Teubenbacher, D., Narita, Y., Laky, G., Varsani, A., Schmid, D., Motschmann, U., Töpfer, S., Exner, W., Bourdin, P., and Comişel, H.: Expectations of the Ion-Profile in Mercury’s Magnetosphere during BepiColombo's Flybys 2021-2025, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-9224, https://doi.org/10.5194/egusphere-egu23-9224, 2023.

EGU23-9425 | Orals | PS2.3

Precipitation of accelerated electrons at Mars 

Hassanali Akbari, Christopher Fowler, and Laila Andersson

Accelerated electron populations observed in the nightside ionosphere of Mars are investigated using measurements obtained by MAVEN’s Solar Wind Electron Analyzer. The measurements are of particular interest as they extend to altitudes as low as 130 km and to regions characterized by strong crustal magnetic fields, allowing us to investigate the evolution of the electron distributions in the complex crustal fields and determine the rate by which the accelerated populations precipitate into the Martian upper atmosphere.

The majority of the observed accelerated electrons are trapped in the crustal fields, bouncing between mirror points, presumably drifting across magnetic field lines, but without instantaneous access to the collisional atmosphere. The average energy flux of these electrons is significant when compared to that of the much more common ‘unaccelerated’ sheath electrons. Considering that the Martian crustal magnetic fields do not provide a closed path for drifting particles, the trapped electrons are bound to exit the crustal fields and either precipitate into the atmosphere or escape. Currently, we estimate that, despite their low detection rate (< 1%), the accelerated electrons account for about 10% of the total energy that is deposited into the nightside ionosphere by electron precipitation. Further, the peak energy of the accelerated electrons is generally found in the range of tens to hundreds of eV, consistent with the energy range previously suggested for the generation of discrete aurora emissions observed on Mars.

How to cite: Akbari, H., Fowler, C., and Andersson, L.: Precipitation of accelerated electrons at Mars, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-9425, https://doi.org/10.5194/egusphere-egu23-9425, 2023.

EGU23-9448 | ECS | Posters on site | PS2.3

Determining the Relation Between Electron-Neutral Collisions and Thermal Electron Temperature Profiles in the Mars Ionosphere 

Anna Turner, Christopher Fowler, and Laila Andersson

The thermal electron temperature, Te, is an important quantity in planetary ionospheres because many photochemical reaction rates depend on it. Te thus plays a role in driving ion composition, structure and dynamics. In addition, enhancements in Te with altitude have been shown to drive ambi-polar electric fields that can energize cold planetary ions and lead to ion escape to space.

The Mars Atmosphere and Volatile EvolutioN (MAVEN) mission acquires Te profiles on each orbit and as a result, a comprehensive data set exists that spans the full range of Mars local times, latitudes and solar zenith angles, allowing us to determine which physical processes control the Te profile shapes and temperature values. We focus on the “transition region,” where Te values can rapidly increase from small values (<500 K) at lower altitudes, to larger values (>1000 K), over a relatively narrow altitude range. The suite of plasma instruments carried by MAVEN allows us to investigate the role of, for example, electron-neutral collisions, ion temperature, wave heating, etc. This study focuses on the effect of electron-neutral collisions on the location and width of the Te transition region. We utilize observations of the neutral atmosphere made by MAVEN’s Neutral Gas and Ion Mass Spectrometer (NGIMS) instrument to calculate electron–neutral collision frequencies, which are compared to measured Te profiles. The calculated collision frequencies provide insight on when collisional processes dominate (over transport and electromagnetic waves, for example), and allow us to identify trends between driving processes and the shape and location of the Te transition region. Understanding the physical processes that control the form of Te profiles will inform us of the mechanisms key to structuring the current day Mars ionosphere. Such understanding will also provide key insight needed for studies of ionospheric escape to space and long-term evolution of the Martian atmosphere. 

How to cite: Turner, A., Fowler, C., and Andersson, L.: Determining the Relation Between Electron-Neutral Collisions and Thermal Electron Temperature Profiles in the Mars Ionosphere, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-9448, https://doi.org/10.5194/egusphere-egu23-9448, 2023.

EGU23-9550 | Orals | PS2.3

Solar Orbiter Observations of Ion Species during the Encounter with the Tail of Comet Leonard 

Timothy Stubbs, Antoinette Galvin, Stefano Livi, Kevin Delano, Lorna Ellis, Lynn Kistler, Ryan Dewey, Jim Raines, Susan Lepri, David Lario, Geraint Jones, Samuel Grant, Peter Wurz, Harald Kucharek, Christopher Owen, Andrei Fedorov, Philippe Louarn, Lorenzo Matteini, Lars Berger, and Robert Wimmer-Schweingruber and the The Heavy Ion Sensor (HIS) Science Team

Around 17 December 2021, the Solar Orbiter spacecraft was predicted to have had its closest approach to comet C/2021 A1 (Leonard) with a minimum streamline distance < 0.01 AU. This encounter provided an unprecedented opportunity to investigate in situ comet Leonard's interaction with the solar wind and the composition of pick-up ions produced by ionization and dissociation of outgassed neutrals from its coma. It was a long-period comet originating from the Oort Cloud with a nucleus about 1 km in diameter, with ground-based telescope observations after its perihelion pass (at ~0.62 AU on 3 January 2022) indicating that it had subsequently disintegrated. Prior to perihelion, outbursts had been reported as well as variations in brightness, which had resulted in speculation about an impending disintegration. However, the dimming in November 2021, before the Solar Orbiter encounter, was argued to be due to a transition from outgassing dominated by carbon dioxide to water. Comet Leonard was the brightest comet of the year and noted for its spectacular ion tail with complex structures, including knots and streamers. Preliminary analysis of in situ Solar Orbiter observations have revealed tell-tale signatures of a cometary encounter around the time of predicted closest approach, such as evidence for magnetic field line draping. However, the clearest evidence has come from Solar Wind Analyzer-Heavy Ion Sensor (SWA-HIS) observations of singly-charged oxygen ions, which are typically not of solar origin and are usually produced when the solar wind interacts with a comet or other Solar System body. In this presentation we use SWA-HIS and EDP-STEP data to investigate aspects of the solar wind interaction and composition of cometary pick-up ions from this active, long-period comet shortly before its disintegration.

How to cite: Stubbs, T., Galvin, A., Livi, S., Delano, K., Ellis, L., Kistler, L., Dewey, R., Raines, J., Lepri, S., Lario, D., Jones, G., Grant, S., Wurz, P., Kucharek, H., Owen, C., Fedorov, A., Louarn, P., Matteini, L., Berger, L., and Wimmer-Schweingruber, R. and the The Heavy Ion Sensor (HIS) Science Team: Solar Orbiter Observations of Ion Species during the Encounter with the Tail of Comet Leonard, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-9550, https://doi.org/10.5194/egusphere-egu23-9550, 2023.

Mercury possesses a miniature but dynamic magnetosphere driven primarily by the solar wind through magnetic reconnection. A prominent feature of the dayside magnetopause reconnection that has been frequently observed is flux transfer events (FTEs), which are thought to be an important player in driving the global convection at Mercury. Using the BATSRUS Hall MHD model with coupled planetary interior, we have conducted a series of high-resolution global simulations to investigate the generation and characteristics of FTEs under different solar wind Alfvénic Mach numbers (MA) and IMF orientations. In all simulations driven by steady upstream conditions, FTEs are formed quasi-periodically with recurrence time ranging from 2 to 9 seconds, and their characteristics vary in time as they evolve and interact with the surrounding plasma and magnetic field. Our statistical analysis of the simulated FTEs reveals that the key properties of FTEs, including spatial size, traveling speed and core field strength, all exhibit notable dependence on the solar wind MA and IMF orientation, and the trends identified from the simulations are generally consistent with previous MESSENGER observations. It is also found that FTEs formed in the simulations contribute a significant portion of the total open flux created at the dayside magnetopause that participates in the global circulation, suggesting that FTEs indeed play an important role in driving the Dungey cycle at Mercury.

How to cite: Jia, X. and Li, C.: Global Hall MHD simulations of Mercury's magnetosphere: Formation and properties of flux transfer events (FTEs) under different solar wind conditions, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-10183, https://doi.org/10.5194/egusphere-egu23-10183, 2023.

EGU23-11546 | Orals | PS2.3

Neutral Current Sheet Displacement in Reaction to the Radial Interplanetary Magnetic Field at Mercury: Statistical Results from MESSENGER Data. 

Daniel Heyner, Kristin Pump, David Hercik, Willi Exner, Yasuhito Narita, Ferdinand Plaschke, Daniel Schmid, Jim Slavin, and Martin Volwerk

Mercury possesses a weak planetary dipole moment and is subject to a strong solar wind inflow. Thus, a small magnetosphere is formed. On the nightside, a neutral current sheet elongates the magnetic field lines to form a magnetotail. From hybrid simulations it is known that this current sheet reacts to changes in the interplanetary magnetic field (IMF). In order to understand the magnetospheric reaction to changes in the solar wind, it is essential to further assess the neutral current sheet movements. The strongly radial IMF at Mercury facilitates magnetopause reconnection in high latitudes which decreases the magnetic pressure in one of the magnetospheric lobes depending on the radial IMF polarity. This produces a northward (or southward) shift of the neutral sheet. Here, we present statistical results from in-situ MESSENGER magnetic field data analysis on the IMF direction as well as the neutral sheet displacement. MESSENGER was a single probe in orbit around Mercury and, as such, it was blind to the solar wind state after having entered the bow shock. Thus, we need to estimate the current IMF radial polarity for the time frame with the probe located inside the magnetosphere. For this, we evaluate different interpolation methods with an adapted bootstrap analysis method on data taken within the upstream solar wind at Mercury. Eventually, the outcome of the statistical analysis on the neutral sheet displacement is compared to the results from hybrid simulations done in the past.

How to cite: Heyner, D., Pump, K., Hercik, D., Exner, W., Narita, Y., Plaschke, F., Schmid, D., Slavin, J., and Volwerk, M.: Neutral Current Sheet Displacement in Reaction to the Radial Interplanetary Magnetic Field at Mercury: Statistical Results from MESSENGER Data., EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-11546, https://doi.org/10.5194/egusphere-egu23-11546, 2023.

EGU23-11568 | ECS | Posters on site | PS2.3

On the Response of the near-Mercury Environment to Different Interplanetary Conditions from full-scale 3D Hybrid Simulations 

Emanuele Cazzola, Dominique Fontaine, and Ronan Modolo

While waiting for further insights from the upcoming data from the BepiColombo mission, this work presents some results from full-scale 3D hybrid (ions kinetic and electrons fluid) computer simulations of the near-Mercury environment under different interplanetary conditions. During its orbit Mercury passes from an high density high magnetic field intensity region (Perihelion) to a low density low magnetic field intensity region (Aphelion). Such environment change drastically influences the response of its magnetic environment, including the stand-off distance of both Bow-Shock and Magnetopause. Being these latter not distant from each other nor from the Hermean exosphere, such a dynamics may lead to important interactions between the planetary and interplanetary environments, as well as lead to unpredictable scenarios whenever the interplanetary conditions occasionally result more extreme than those average values curretly known.

Here we aim to give more insights  into the near-Mercury environments under more significant interplanetary conditions by means of full-scale 3D multi-species hybrid simulations, including the Aphelion and Perihelion conditions known to date, as well as more extreme conditions, and compare these results with currently available in-situ observations and recent similar computer simulations. 

How to cite: Cazzola, E., Fontaine, D., and Modolo, R.: On the Response of the near-Mercury Environment to Different Interplanetary Conditions from full-scale 3D Hybrid Simulations, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-11568, https://doi.org/10.5194/egusphere-egu23-11568, 2023.

EGU23-12193 | Posters on site | PS2.3

Investigating the past atmospheric escape rate from Mars using a semi-empirical model 

Romain Maggiolo, Maria Luisa Alonso Tagle, Herbert Gunell, Johan De keyser, Gaël Cessateur, Giovanni Lapenta, Vivianne Pierrard, and Ann Carine Vandaele

Water was abundant on early Mars but disappeared, likely escaping into interplanetary space.

Large-scale planetary magnetic fields were long thought to shield planetary atmospheres and limit atmospheric escape, suggesting that Mars lost most of its water after its intrinsic magnetic field vanished. However, observations of atmospheric escape from Mars, Venus and Earth as well as recent numerical models question the protective effect of planetary magnetic fields on atmospheric erosion.

We use a semi-empirical model of atmospheric escape to investigate the past oxygen and hydrogen escape rate from Mars. This model uses physical considerations and a magnetic field model to extrapolate present-day observations to past solar and planetary conditions. It accounts for the variation of the planetary magnetic field and of the solar wind dynamic pressure and EUV/UV flux. Our modelling results show that for a more active Sun, atmospheric escape peaks for a weak planetary magnetization level as both unmagnetized escape processes like ion pick-up and sputtering can occur at the same time as magnetized escape processes in the polar regions. This study suggests that the water loss rate from the Martian atmosphere may have peaked when Mars was (still) magnetized rather than when it was unmagnetized.

How to cite: Maggiolo, R., Alonso Tagle, M. L., Gunell, H., De keyser, J., Cessateur, G., Lapenta, G., Pierrard, V., and Vandaele, A. C.: Investigating the past atmospheric escape rate from Mars using a semi-empirical model, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-12193, https://doi.org/10.5194/egusphere-egu23-12193, 2023.

EGU23-12605 | ECS | Posters on site | PS2.3

Titan's tail structure: the multi-instrument study as observed by Cassini 

Konstantin Kim, Niklas Edberg, Oleg Shebanits, Jan-Erik Wahlund, and Erik Vigren

Titan’s  magnetotail is formed as a result of the interaction of Saturn’s magnetospheric flow with Titan’s ionosphere. While the ionosphere is created mainly by EUV radiation and impinging magnetospheric particles on the atmosphere, the tail is more governed by plasma outflow processes, the upstream magnetospheric flow properties (density, flow velocity) and the upstream magnetic field direction. The properties of Titan’s tail has previously been studied with both numerical simulations and in-situ measurements. For instance,  the escape rate has been shown to be of the order  of order ~1024 s-1, and case studies have revealed a highly dynamic tail structure.

In this work we make an attempt to combine observations of electrons and ions in Titan’s tail for all of the Cassini flybys. We use the Langmuir probe (RPWS/LP) and the Cassini Plasma Spectrometer (CAPS) ion and electron measurements. We put a spatial constraint on the tail’s geometry  and its orientation based on the measurements of electron and ion densities. The estimation of escape rate is revisited, and different sources of variability and their impact on the tail structure are discussed. Furthermore, the link between the convectional electric field E = -B and the electron densities distribution is studied. The interim result is that the electron density tends to have higher densities in the hemisphere of positive upstream electric field. This is observed in the altitudes below the dynamo region, which is the chemistry-dominated region. The explanation of the observed distribution tendency is discussed.

How to cite: Kim, K., Edberg, N., Shebanits, O., Wahlund, J.-E., and Vigren, E.: Titan's tail structure: the multi-instrument study as observed by Cassini, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-12605, https://doi.org/10.5194/egusphere-egu23-12605, 2023.

EGU23-12906 | ECS | Orals | PS2.3

Unexpected local magnetic depression around Mercury: BepiColombo flyby-2 discovery 

Daniel Schmid, David Fischer, Werner Magnes, Yasuhito Narita, Martin Volwerk, Wolfgang Baumjohann, Ayako Matsuoka, Hans-Ulrich Auster, Ingo Richter, Daniel Heyner, Ferdinand Plaschke, and Rumi Nakamura

BepiColombo MPO and Mio spacecraft encounter the Mercury magnetosphere six times from 2021 to 2025 during the flyby maneuvers. Each flyby trajectory is unique and includes the magnetospheric regions that were not covered by MESSENGER. Mio/MGF magnetic field data were successfully retrieved during the Mercury flyby-2 in June 2022 and the data were calibrated for the scientific use. The MGF measurements show a short-time intense magnetic field depression in close proximity to the planet at local midnight, which is neither expected from the earlier observations (Mariner-10, MESSENGER) nor from the hybrid plasma simulations of the Mercury magnetosphere. Both time-dependent and time-independent scenarios are possible, including the occurrence of a transient event driven by sudden changes in the solar wind (e.g., pressure puls) or in the magnetosphere (e.g., magnetic reconnection) and the crossing of a localized current layer separating the dipolar field region from the stretched tail-like magnetic field region. While more dedicated analyses (wave analysis, variation analysis), combination with the other data (plasmas and imaging), and numerical simulations for different scenarios would improve the quality of scientific interpretation of the depression event, our study demonstrates the scientific potential of BepiColombo that it will detect various kinds of transient events and localized structures in Mercury’s magnetosphere already during the flyby maneuvers.

How to cite: Schmid, D., Fischer, D., Magnes, W., Narita, Y., Volwerk, M., Baumjohann, W., Matsuoka, A., Auster, H.-U., Richter, I., Heyner, D., Plaschke, F., and Nakamura, R.: Unexpected local magnetic depression around Mercury: BepiColombo flyby-2 discovery, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-12906, https://doi.org/10.5194/egusphere-egu23-12906, 2023.

EGU23-13257 | ECS | Orals | PS2.3

Electron populations observed by Mercury Electron Analyzer onboard Mio/BepiColombo during its second Mercury flyby 

Sae Aizawa, Nicolas Andre, Yoshifumi Saito, Moa Persson, Jean-Andre Sauvaud, Andrei Fedorov, Shoichiro Yokota, Alain Barthe, Emmanuel Penou, Mathias Rojo, and Go Murakami

BepiColombo was launched in October 2018 and is currently en route to Mercury. Although its orbit insertion is planned for December 2025, BepiColombo will acquire new measurements during planetary flybys. During the cruise phase, the two spacecraft are docked together with Mio being protected behind the MOSIF sun shield. Thus, only partial observations of plasma distribution functions can be obtained by the Mercury Plasma Particle Experiment (MPPE) onboard Mio. However, since electrons have small Larmor radii and more isotropic distributions even in the solar wind, the two Mercury Electron Analyzer (MEA) of MPPE will provide us with new and unique measurements in the range of 5 eV to 3 keV when in solar wind mode and 3 eV to ~ 26 keV when in magnetospheric mode. We will present the interesting observations obtained by MEA onboard Mio/BepiColombo during its second Mercury flyby that happened on the 23rd of June, 2022. In particular we will focus on the properties of the low- and high-energy electron populations observed during its crossing of Mercury’s magnetosphere.

How to cite: Aizawa, S., Andre, N., Saito, Y., Persson, M., Sauvaud, J.-A., Fedorov, A., Yokota, S., Barthe, A., Penou, E., Rojo, M., and Murakami, G.: Electron populations observed by Mercury Electron Analyzer onboard Mio/BepiColombo during its second Mercury flyby, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-13257, https://doi.org/10.5194/egusphere-egu23-13257, 2023.

EGU23-13641 | ECS | Posters on site | PS2.3

Plasma parameters inside the cometopause of comet 67P-Churyumov/Gerasimenko 

Hayley Williamson, Gabriella Stenberg Wieser, Hans Nilsson, Anja Moeslinger, Martin Wieser, and Romain Canu-Blot

Inside the cometopause of comet 67P/Churyumov-Gerasimenko, where cometary ions dominate the ionosphere, is a region of great interest for studying the mass loading of the solar wind. The Rosetta Ion Composition Analyzer (ICA) observed both cometary and solar wind ions in this region during Rosetta’s two year mission orbiting comet 67P. Analysis of this data is complicated by instrumental and spacecraft effects on low energy cometary ion data, which comprises the bulk of the plasma. Recent work has been able to correct the ICA ion distributions for these effects and retrieve low energy ion Maxwellian temperatures and velocities, showing both a cold (< 1 eV) newly ionized plasma and higher energy, warmer pickup ions. Here, we present the varying cometary and solar wind ion temperatures inside the cometopause, with discussion of the causes for the changes in velocity and temperature throughout the time periods studied. In particular, pickup ion distributions vary significantly, from distributions similar to the newly ionized plasma at higher energies to one that decays exponentially with energy. Further, we calculate thermal and dynamic pressures of the cometary and solar wind ions using the retrieved temperatures and velocities, allowing us to analyze the pressure balance between the different plasma components. 

How to cite: Williamson, H., Stenberg Wieser, G., Nilsson, H., Moeslinger, A., Wieser, M., and Canu-Blot, R.: Plasma parameters inside the cometopause of comet 67P-Churyumov/Gerasimenko, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-13641, https://doi.org/10.5194/egusphere-egu23-13641, 2023.

Understanding the plasma interactions between induced Venus magnetosphere and solar wind is crucial, especially at the kinetic scale (below the proton Larmor radius). This is because different kinetic-scale electric field structures that are associated with plasma instabilities such as double layers are good indicator of wave-particle energy transfer (Malaspina et al., Geophysical Research Letters, 47, 2020). Structures such as double layers, phase-space holes can emit radio waves (Goodrich and Ergun, The Astrophysical Journal, 809, 2015) or scatter electrons with energy of the order of keV (Vasko et al., Journal of Geophysical Research: Space Physics, 122, 2017). Double layers can create plasma instabilities (Newman et al., Physical Review Letters, 87, 2001), provide heating and acceleration to different particles (Ergun et al., Journal of Geophysical Research: Space Physics, 109, 2004). These structures have already been found in several parts of the earth’s magnetosphere. But due to a lack of high resolution data, observations of these processes are sparse in the magnetospheres of the other planets. The seven encounters that the Parker Solar Probe (PSP) spacecraft will make with Venus’s induced magnetosphere will provide excellent opportunities to measure these processes in this planet. The current talk describes the presence of kinetic-scale electric field structures during the 4th encounter of PSP with Venus’s induced magnetosphere. For this purpose, high resolution electric field data from the PSP FIELDS instrument were used with alongside the FIELDS magnetometer data and data from the Solar Wind Electrons Alphas and Protons (SWEAP) instrument. From these observations, it is found that the PSP passed through Venus’s magnetosheath and tail region during this encounter.  This talk describes the possible presence of plasma double layers when PSP was at the boundary of the magnetosheath region. Phase-space holes are also identified near some of the double layers in this region.

How to cite: Sur, D. and Malaspina, D.: Observation of Possible Kinetic Structures at the Venus Magnetosphere using High Resolution Parker Solar Probe Data, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-14802, https://doi.org/10.5194/egusphere-egu23-14802, 2023.

EGU23-185 | Orals | GI6.8

Space weather during extreme SEPs: new assessment of worst case scenario 

Alexander Mishev, Sanja Panovska, and Ilya Usoskin

An important topic in the field of space physics is the quantification of the cosmic-ray-induced effects in the atmosphere and the corresponding space weather effects. Space weather effects, specifically the exposure to radiation at aviation altitudes, represent an important threat. Here, we focus on a specific class of events due to solar energetic particles (SEPs), viz. events that can be registered at ground level: ground-level enhancements and more particularly extreme events with cosmogenic imprints,i.e. that have been registered by 14C records.

Naturally, for assessment of space weather effects during extreme SEP events, it is necessary to possess precise information on their spectra. Here we present results and application of an analysis of SEPs using neutron monitor (NM) records, that is derivation of their spectra, and application of numerical models. Using reconstructed spectra during the strongest directly recorded event, that is GLE # 5, occurred on 23 February 1956, and employing a convenient rescaling,  we assessed the space weather effect during the strongest indirectly reconstructed historical extreme SEP event, that is, 774 AD. Subseqeuntly, employing a state-of-the-art reconstruction of the magnetic field we study the worst-case scenario representing a combination of a geomagnetic excursion, that is the Laschamp excursion ca. 42 kyr ago and a 774 AD-like event. The possible implications are discussed.

How to cite: Mishev, A., Panovska, S., and Usoskin, I.: Space weather during extreme SEPs: new assessment of worst case scenario, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-185, https://doi.org/10.5194/egusphere-egu23-185, 2023.

EGU23-287 | ECS | Orals | GI6.8

A New Open-Source Geomagnetosphere Propagation Tool (OTSO) and its Applications 

Nicholas Larsen, Alexander Mishev, and Ilya Usoskin

We present a new open-source tool for magnetospheric computations, that is modelling of cosmic ray propagation in the geomagnetosphere, named "Oulu - Open-source geomagneToSphere prOpagation tool" (OTSO). A tool of this nature is required to interpret experiments and study phenomena within the cosmic ray research field.  Here, we demonstrate several applications of OTSO, namely the computation of asymptotic directions of selected cosmic ray stations, effective rigidity cut-off across the globe at various conditions within the design, and general properties, including the magnetospheric models employed. OTSO was applied to the investigation of several ground-level enhancement events after which comparison and validation of OTSO with older widely used tools such as MAGNETOCOSMICS was performed, and good agreement was achieved. The necessary background for the analysis of two notable ground-level enhancements was produced using OTSO and their spectral and angular characteristics show good agreement with prior studies and spacecraft data. This validation of OTSO's current abilities reveals its usefulness to the cosmic ray research field and its open-source nature further allows for the tool to be developed beyond its current capabilities by users to meet the needs of the research community.

How to cite: Larsen, N., Mishev, A., and Usoskin, I.: A New Open-Source Geomagnetosphere Propagation Tool (OTSO) and its Applications, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-287, https://doi.org/10.5194/egusphere-egu23-287, 2023.

EGU23-3095 | Posters on site | GI6.8

Effects of heterogeneous soil moisture distributions in cosmic-ray neutron sensing - the case of irrigation monitoring 

Heye Bogena, Cosimo Brogi, Markus Köhli, Harrie-Jan Hendricks Franssen, Olga Dombrowski, and Johan Alexander Huisman

Soil moisture (SM) sensors are widely used to monitor soil water dynamics and support irrigation management with the aim of achieving better yields while reducing water consumption. Unfortunately, due to the small measuring volume of point-scale sensors, their soil moisture readings are often not representative for heterogeneous agricultural fields. Therefore, in such cases, sensors with larger sensing volume are needed to address spatially variable SM. A suitable technique is the cosmic ray neutron sensor (CRNS) as it integrates SM over a large volume with a radius of ~130-210 m and a penetration depth of ~15-85 cm. The CRNS method is based on the inverse relationship between measured environmental neutron density and the presence of hydrogen pools (e.g., SM) in the instrument surroundings. However, the ability of CRNS to accurately monitor areas with complex SM heterogeneities (e.g., small irrigated fields) and the influence of detector design were not yet investigated. In this study, we used the neutron transport model URANOS to simulate the effect of SM variations on a CRNS placed in the centre of squared irrigated fields (0.5 to 8 ha dimensions). For this, SM in the irrigated field and in the surrounding was altered between 0.05 and 0.50 cm3 cm-3 (500 simulations in total). In addition, we investigated the effect of employing high-density polyethylene (HDPE) moderators with different thickness (5 to 35 mm) as well as a 25 mm HDPE moderator with an additional gadolinium oxide thermal shielding. Results showed that, in heterogeneous SM scenarios, the 2 e-folding lengths footprint (R86) can become smaller or larger than what previous studies showed in homogeneous SM distributions. In addition, a thin HDPE moderator will result in relatively smaller R86 whereas thicker moderators and the addition of a thermal shielding will result in relatively larger R86. However, we found that a relatively small footprint is not directly related to a better monitoring of SM nearby the instrument. In fact, in all the investigated field dimensions, the 25mm HDPE moderator with gadolinium shielding showed the largest values of R86 but also the largest variations of detected neutrons with changing SM. In addition, such moderator showed the highest chances of detecting irrigation events that increase SM by 0.05 or 0.10 cm3 cm-3 in the irrigated area. Generally, detection was uncertain only for SM variations of 0.05 cm3 cm-3 in fields of 0.5 ha when initial SM was 0.02 cm3 cm-3 or higher. Although the results of this study suggest the feasibility of monitoring and informing irrigation with CRNS, we found that SM variations outside the irrigated field have a considerable influence on CRNS measurements. Especially in fields of 0.5 and 1 ha dimension, it can be impossible to distinguish whether a relative change in detected neutrons is due to irrigation or to SM variations in the surroundings. These results are relevant for irrigation monitoring and the combination of neutron transport simulations and real-world installations has the potential to establish CRNS as a decision support system for irrigation management.

How to cite: Bogena, H., Brogi, C., Köhli, M., Hendricks Franssen, H.-J., Dombrowski, O., and Huisman, J. A.: Effects of heterogeneous soil moisture distributions in cosmic-ray neutron sensing - the case of irrigation monitoring, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-3095, https://doi.org/10.5194/egusphere-egu23-3095, 2023.

EGU23-4506 | Orals | GI6.8

ORCA (Observatorio de Rayos Cósmicos Antártico), current status and future perspectives 

Juan José Blanco, Juan Ignacio García Tejedor, Sindulfo Ayuso de Gregorio, Óscar García Población, Alejandro López-Comazzi, Diego Sanz Martín, Ivan Vrublevskyy, Laura Gonzalvo Ballano, and Alberto Regadío

ORCA (2.37 GV) is a suit of two neutron monitors and a muon telescope. It was installed at Juan Carlos I Antarctic Base on January 2019 being in operation since. Because the low level of the solar activity, only a few of solar events have been detected. The GLE 73 and three Forbush decreases. A new ORCA like detector (ICaRO, 11.5 GV) is being installed at 2200 m a.s.l in Izaña Atmospheric Observatory (Tenerife Island, Spain). On the other hand, CaLMa neutron monitor (6.95 GV) will be updated with a muon telescope made by eight 1 m2 scintillators arranged in two layers of four scintillators at some point during the next two years. These three detector will measure muons and neutrons from cosmic ray interaction with atmosphere at three different locations allowing to study the solar activity from a new perspective

How to cite: Blanco, J. J., García Tejedor, J. I., Ayuso de Gregorio, S., García Población, Ó., López-Comazzi, A., Sanz Martín, D., Vrublevskyy, I., Gonzalvo Ballano, L., and Regadío, A.: ORCA (Observatorio de Rayos Cósmicos Antártico), current status and future perspectives, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-4506, https://doi.org/10.5194/egusphere-egu23-4506, 2023.

EGU23-6045 | Posters on site | GI6.8

The concentration of cosmogenic radionuclide 7Be from the perspective of space weather and long-term trends in the stratospheric temperature and wind 

Kateřina Podolská, Michal Kozubek, Miroslav Hýža, and Tereza Šindelářová

Cosmogenic radionuclide Beryllium 7Be concentration is primarily determined by the solar activity level and space weather conditions. The 7Be is generated by cosmic ray reactions in the stratosphere and in the upper troposphere, binds to atmospheric aerosols and is transported horizontally and vertically by wind and gravity. The highest values of cosmic radiation are observed during the solar minima because, at that time the penetrability of the Earth’s and Sun magnetosphere is greatest.

The concentrations of the radionuclide 7Be are reliable indicators of various atmospheric processes. In our work, we try to contribute to better understanding of the dynamics of processes by associating them with long-term trends of stratospheric temperature dynamics. We investigate the coupling of concentrations of the cosmogenic radionuclide 7Be in the longitudinal view during the years 1986–2022 (time series of activity concentration of 7Be in aerosols evaluated by the corresponding activity in aerosols on a weekly basis at the National Radiation Protection Institute Monitoring Section in Prague) to space weather parameters (Kp planetary index, disturbance storm time Dst, proton density, proton flux), and stratospheric dynamics parameters (temperature, zonal component of wind, O3). On short timescales the intensity of cosmic radiation decreases by few percent in several days. On a longer timescale the intensity of galactic cosmic rays is strongly influenced by the degree of solar activity and by variations in the geomagnetic field. This corresponds with findings that the zonal wind climatology differences were largest in the decades of 2000–2010 than between others observed decades.

How to cite: Podolská, K., Kozubek, M., Hýža, M., and Šindelářová, T.: The concentration of cosmogenic radionuclide 7Be from the perspective of space weather and long-term trends in the stratospheric temperature and wind, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-6045, https://doi.org/10.5194/egusphere-egu23-6045, 2023.

EGU23-6789 | Posters on site | GI6.8

Sensitivity of the Cosmic Ray Neutron Sensor (CRNS) to Seasonal Biomass Dynamics in Cherry and Olive Orchards 

Samir K. Al-Mashharawi, Marcel M. El Hajj, Kasper Johansen, Matthew F. McCabe, and Susan Steele-Dunne

Biomass estimation is important in many applications, such as carbon sequestration and precision agriculture. Developing a reliable method for biomass estimation from satellite, airborne and near-surface remote sensing sensors is an ongoing task due to the large uncertainty in current methods, which are often related to sensor limitations. Indeed, signals from optical sensors and synthetic aperture radar at high and medium frequencies suffer from saturation issues at high biomass levels. The Cosmic-Ray Neutron Sensor (CRNS) is a new non-invasive near-surface sensor used primarily to estimate soil water content (SWC), but it has also shown potential for retrieving other hydrological and environmental parameters such as biomass water equivalent and snow depth. The CRNS detects and counts the number of neutrons controlled by hydrogen atoms in the soil, air just above the ground, and vegetation. Biomass attenuates the intensity of cosmic ray neutrons, hence the ability to estimate biomass from a CRNS. Recent studies have used CRNS measurements to estimate biomass changes in crop areas and forest stands, while the use of CRNSs in orchards is limited. The objective of this study is to explore the potential of two CRNSs to estimate the biomass variation in irrigated cherry and olive tree orchards. The olive tree orchard is located in an arid region in northern Saudi Arabia (plantation density of 1667 trees/hectare) with an average tree height of 3 m and canopy diameter of 2 m. The cherry field is located in southern France (plantation density of 260 trees/hectare) with an average tree height of 3.5 m and canopy diameter of 5.5 m. Several soil moisture probes recording soil water content (SWC) at 15-min intervals at both sites were installed at different depths within the CRNS footprint. SWC measurements were used to assess the variations in the sensitivity of CRNS to soil moisture with increasing biomass. Tree parameters (height, canopy width, canopy length, leaf area index, and diameter at breast height) were measured in situ to estimate biomass using allometric equations. In addition, repetitive Light Detection and Ranging (LiDAR) scanning was performed over the cherry field to detect canopy volume changes over time. The results showed that the CRNS is sensitive to SWC variation, and this sensitivity is controlled by biomass evolution, indicating that CNRS measurements can also be used to estimate biomass. The sensitivity of CRNS neutron counts to SWC in the early season (before blooming) was twice as high as that during the mid- and late growing seasons (maximum leaf cover). The Cornish Pasdy model­, which models the measured neutron counts as a function of SWC and biomass contribution, was calibrated and then inverted to estimate the biomass in the cherry and olive tree orchards. 

How to cite: Al-Mashharawi, S. K., El Hajj, M. M., Johansen, K., McCabe, M. F., and Steele-Dunne, S.: Sensitivity of the Cosmic Ray Neutron Sensor (CRNS) to Seasonal Biomass Dynamics in Cherry and Olive Orchards, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-6789, https://doi.org/10.5194/egusphere-egu23-6789, 2023.

EGU23-11071 | ECS | Posters on site | GI6.8

Updated heliospheric modulation potential of cosmic rays and station-specific scaling factors for 1964-2021 

Pauli Väisänen, Ilya Usoskin, Riikka Kähkönen, Sergey Koldobskiy, and Kalevi Mursula

Galactic cosmic rays (GCR) are energetic particles originating from galactic or extra-galactic sources. When they arrive inside our heliosphere, they are modulated by the magnetic irregularities in the solar wind flow from the Sun, deflecting and slowing down the GCR particles. The level of this modulation varies according to solar activity, especially the 11-year solar cycle. The heliospheric modulation potential, denoted by ϕ, describes the average energy loss of particle in MV and quantifies the level of modulation. It can be determined using ground-based neutron monitor (NM) measurements of GCRs by multiple stations. Here we use the most recent version of the NM yield function and a RMSE-minimization method to compute a new and more accurate version of the modulation potential ϕ and station-specific scaling factors κ, which can be used to scale the level of count rates to the theoretical NM count rate given by the model. The new version offers daily resolution of ϕ and can be conveniently updated with new measurements, stations, or updates to datasets whenever they might occur. The scaling factors and their variation can be used to scale the data for physical analyses or to identify outliers, errors or physical phenomena which do not match with the model.

How to cite: Väisänen, P., Usoskin, I., Kähkönen, R., Koldobskiy, S., and Mursula, K.: Updated heliospheric modulation potential of cosmic rays and station-specific scaling factors for 1964-2021, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-11071, https://doi.org/10.5194/egusphere-egu23-11071, 2023.

EGU23-11326 | ECS | Posters on site | GI6.8

Monitoring soil moisture in the deeper vadose zone: A new approach using groundwater observation wells and cosmic ray neutrons 

Daniel Rasche, Jannis Weimar, Martin Schrön, Markus Köhli, Markus Morgner, Andreas Güntner, and Theresa Blume

Monitoring soil moisture at depths greater than one meter is generally challenging and often highly invasive as it requires opening large soil pits. As a result, this deeper vadose zone is often not monitored at all. On top of that, conventional soil moisture sensors usually have only a small measurement volume. On the other hand, soil moisture estimates derived from above-ground Cosmic-Ray Neutron Sensing (CRNS) are a representative average over an area of several hectares but only of the upper half meter of the soil. To this day, it is commonly believed that cosmic radiation cannot be used to monitor soil water content below this depth. As a consequence, large parts of the root-zone and deeper unsaturated zone have remained outside the observational window of the method. The estimation of soil moisture in greater depths typically requires additional invasive measurements, other active geophysical methods, or mathematical models which extrapolate surface soil moisture observations.

Against this background, we investigated the possibility of using passive detection of cosmogenic neutrons in existing monitoring infrastructure (e.g. groundwater wells). We hypothesized that this method provides a larger measurement volume than traditional techniques based on active neutron probes while requiring less safety restrictions.

Our neutron transport simulations demonstrated that this downhole-CRNS technique would be sensitive enough to detect changes of water content in depths down to 5 meters and above, depending on the temporal resolution of measurements. The simulations also revealed a large measurement radius of several tens of cm depending on the soil moisture content and soil bulk density.

From the theoretical results we derived a functional relationship between soil moisture and detectable neutrons and tested it in a groundwater observation well. Additional installations of supporting soil moisture sensors have been used to validate the model predictions as well as the neutron signals monitored by the CRNS detector. The study demonstrated the general applicability of downhole Cosmic-Ray Neutron Sensing for the estimation of soil moisture in greater depths and at temporal resolution of two days.

How to cite: Rasche, D., Weimar, J., Schrön, M., Köhli, M., Morgner, M., Güntner, A., and Blume, T.: Monitoring soil moisture in the deeper vadose zone: A new approach using groundwater observation wells and cosmic ray neutrons, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-11326, https://doi.org/10.5194/egusphere-egu23-11326, 2023.

EGU23-11905 | Posters virtual | GI6.8

SEVAN European particle detector network for the atmospheric, solar and space weather studies 

Tigran Karapetyan, Ashot Chilingarian, and Balabek Sargsyan

Experiments during recent years with SEVAN detectors on mountain tops in Armenia, Slovakia, and Bulgaria reveal the broad potential of SEVAN detectors; The SEVAN detector on Lomnicky Stit (Slovakia) measured the largest thunderstorm ground enhancements (TGE), with particle fluxes exceeding the background 100-times. With muon and gamma ray fluxes, the maximum values of the potential difference in thunderclouds were measured, equal to 350 MV at Mt. Aragats, and 500 MV at the sharp peak of Lomnicky Stit. In Nov 2019, SEVAN detectors were installed at DESY (Hamburg and Zeuthen sites). Fluxes of electrons, photons, and muons and weather parameters are continuously monitored at all sites (at different latitudes, longitudes, and altitudes). To fully exploit the scientific potential of the SEVAN detectors, in 2023 is planned to install a new detector in the Umwelt-Forschungs-Station (UFS, Schneefernerhaus, 2650 m asl) near the top of the Zugspitze (2962 m), a site with a long history of atmospheric research. The new SEVAN module will be compact (SEVAN-light), and will enable the energy spectra measurements in the range from 0.3 to 50 MeV, allowing unambiguously separating Radon progeny gamma radiation from runaway electron-photon avalanches.

How to cite: Karapetyan, T., Chilingarian, A., and Sargsyan, B.: SEVAN European particle detector network for the atmospheric, solar and space weather studies, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-11905, https://doi.org/10.5194/egusphere-egu23-11905, 2023.

Neutron monitor counting rates show, among others, a  $\sim$ 1.6--2.2-year period. This period has been associated with a solar origin affecting the cosmic ray propagation conditions through the heliosphere. The duration of this period varies from one Solar Cycle to another.
\cite{Comazzi_Blanco_2022} found the duration of the $\sim$ 1.6--2.2-year period ($\tau$) is linearly related to the averaged sunspot number ($SSN_a$) in each Solar Cycle.
In this piece of research, we have analyzed this relationship. This equation shows that shorter $\sim$1.6--2.2-year periods occur during stronger cycles when $SSN_a$ is higher. Drawing on this relationship given by $SSN_a = (-130 \pm 10) \: \tau + (330 \pm 30)$, we computed $\tau$ for the cycles previous to the existence of neutron monitors (Solar Cycles 7--19). 
By means of the Huancayo neutron monitor spectrum we checked the validity of this equation along the Solar Cycle 19. 
Once the previous relationship is checked, $\tau$ for the current Solar Cycle 25 is computed giving $\sim$ 2.22 years.

An internal mechanism of the solar dynamo called Rossby waves could produce these variations in the solar magnetic field  and, indirectly, in neutron monitor counting rates.
The harmonic of fast Rossby waves with $m=1$ and $n=8$ fit with the detected periodicity and the variation of the solar magnetic field strength from weaker to stronger Solar Cycles could explain the different periods detected in each cycle.
Finally, a solar magnetic field strength of $\sim$ 7--25 kG in the tachocline have been estimated based on the detected periodicities using the dispersion relation for fast Rossby waves. 

How to cite: López-Comazzi, A. and Blanco-Ávalos, J. J.: Study of the relationship between Sunspot number and the duration of the $\sim$1.6--2.2-year period in neutron monitor counting rates, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-11981, https://doi.org/10.5194/egusphere-egu23-11981, 2023.

EGU23-12576 | ECS | Posters on site | GI6.8

Cosmic rays on snow: A combined analysis of fractional snow cover derived from Sentinel-2, MODIS and Cosmic Ray Neutron Sensors across Europe 

Nora Krebs, Paul Schattan, Sascha Oswald, Martin Schrön, Martin Rutzinger, and Johann Stötter

Epithermal neutrons from cosmic ray showers are slowed by hydrogen atoms in snow. The drop in the fast neutron abundance in the atmosphere can be measured with above-ground Cosmic Ray Neutron Sensing (CRNS), allowing for an estimation of the Snow Water Equivalent (SWE). SWE is an important variable that has a substantial role in hydrological modelling and forecasts. However, up to now, SWE is conventionally measured at point-scale, which holds only little information about the average SWE in areas of heterogeneous terrain and where snow drift is a predominant process. CRNS offers the prospect of closing this gap by sensing neutrons within a footprint of 10–20 hectares. Currently, further investigations are needed to reduce the uncertainties in the signal conversion from neutron counts to SWE. In this study, we compare the daily signals of 65 CRNS stations across Europe with the corresponding Fractional Snow Cover (FSC) products from Sentinel-2 and MODIS (Moderate-resolution Imaging Spectroradiometer) with a 20 m and 500 m spatial resolution, respectively. By analysing the FSC products, we were able to identify characteristic ranges of neutron counts at snow presence (winter signals) and absence (summer signals). Comparing these ranges and their overlap among stations, we were able to distinguish typical signal properties of lowland, pre-Alpine and Alpine sites. We found that altitude-related properties, such as soil and vegetation characteristics govern the general neutron level at the study sites. Snowfall typically leads to a major drop in the neutron count rate that is superimposed on the summer neutron count level. High-altitude stations are generally characterized by low ranges of count rates in summer and by high ranges in winter, while low-altitude stations show a reversed trend. Our results demonstrate that the suitability of a station for SWE measurements with CRNS depends highly on the site-specific hydrogen pool fluctuations that can be linked to altitude. Especially in heterogeneous mountain terrain with low soil formation, the advantages of CRNS come into play and can provide a spatial average of SWE with low uncertainties.

How to cite: Krebs, N., Schattan, P., Oswald, S., Schrön, M., Rutzinger, M., and Stötter, J.: Cosmic rays on snow: A combined analysis of fractional snow cover derived from Sentinel-2, MODIS and Cosmic Ray Neutron Sensors across Europe, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-12576, https://doi.org/10.5194/egusphere-egu23-12576, 2023.

EGU23-15343 | Posters on site | GI6.8

Measurements of cosmic rays by a mini neutron monitor aboard the German research vessel Polarstern 

Bernd Heber, Sönke Burmeister, Hanna Giese, Konstantin Herbst, Lisa Romaneehsen, Carolin Schwerdt, Du Toit Strauss, and Michael Walter

Neutron monitors are ground-based devices that measure the secondary particle population, i.e., neutrons produced by, e.g., galactic cosmic rays (GCRs). Due to their functionality, they are integral counters whose flux is proportional to the variation of the input spectrum. However, the measured flux also depends on the geomagnetic position and the static pressure at the monitor's location. To better understand the instrument response, the Christian-Albrechts-Universität zu Kiel, DESY Zeuthen, and the North-West University in Potchefstroom, South Africa, agreed on regular monitoring of the GCR intensity as a function of latitude, by installing a portable device aboard the German research vessel Polarstern in 2012. The vessel is ideally suited for this research campaign because it covers extensive geomagnetic latitudes (i.e., goes from the Arctic to the Antarctic) at least once per year. Since the installation aboard the vessel, 12 latitude scans were performed, allowing us to compute the so-called yield function by experimental means presented in this contribution.

The Kiel team received funding from the European Union's Horizon 2020 research and innovation program under grant agreement No 870405. The team would like to thank the crew of the Polarstern and the AWI for supporting our research campaign.

How to cite: Heber, B., Burmeister, S., Giese, H., Herbst, K., Romaneehsen, L., Schwerdt, C., Strauss, D. T., and Walter, M.: Measurements of cosmic rays by a mini neutron monitor aboard the German research vessel Polarstern, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-15343, https://doi.org/10.5194/egusphere-egu23-15343, 2023.

EGU23-15523 | Posters on site | GI6.8

Buoy-based detection of low-energy cosmic-ray neutrons to monitor the influence of atmospheric effects 

Martin Schrön, Daniel Rasche, Jannis Weimar, Markus Köhli, Bertram Boehrer, Peter Dietrich, and Steffen Zacharias

Neutron monitors on the Earth’s surface are usually used to observe the dynamics of highly energetic cosmic-ray particles, assuming that local environmental conditions do not influence the measurement. In another young research field, low-energy cosmic-ray neutrons are used to monitor local dynamics of environmental water content. Water in soil, air, snow and vegetation determines the amount of ground albedo neutrons in the sensitive energy range from 1 eV to 100 keV. Plenty of small neutron detectors are operated on natural or agricultural sites all around the world. 

A major issue is the modulation of the neutron flux by the dynamics of incoming high-energy cosmogenic particles. Conventionally, independent data from neutron monitors are consulted to serve as a reference for the correction of the local detectors. However, the performance of this comparative correction approach is unreliable, because it does not account for geographical displacement, different energy windows of the detectors, or potential influence of atmospheric conditions on the referenced neutron monitor.

To test the traditional correction approaches for incoming cosmic radiation, air pressure, and air humidity, an experimental setup should avoid any influence of changes due to soil moisture. Therefore, a set of neutron detectors have been deployed in a buoy at the center of a lake for six months. The measurement period also included a Forbush Decrease in September, 2014. 

We found that the neutron signals correlated with air pressure, air humidity, and secondary cosmic radiation. The thermal neutron response to air humidity has been revealed to be different from the epithermal neutron response, while air pressure and incoming radiation similarly   influenced the thermal and epithermal signals. The results have been used to evaluate different existing strategies for air humidity correction of low-energy neutron data. Additionally, the potential effect of lake temperature on the thermal neutron count rate has been investigated. We have also analyzed the performance of the buoy  signal together with different neutron monitors in their capability to correct for the changes of incoming radiation and for the Forbush Decrease during the measurement period.

Overall, the study demonstrates how low-energy neutron detectors on a buoy  could be used to assess the influence of atmospheric and cosmogenic factors on the signal without the influence of soils. Despite the low count rate over water, the general principle could also serve as an alternative to remote neutron monitors as a more local reference signal at more comparable energies.

How to cite: Schrön, M., Rasche, D., Weimar, J., Köhli, M., Boehrer, B., Dietrich, P., and Zacharias, S.: Buoy-based detection of low-energy cosmic-ray neutrons to monitor the influence of atmospheric effects, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-15523, https://doi.org/10.5194/egusphere-egu23-15523, 2023.

EGU23-15741 | ECS | Orals | GI6.8

Rigidity dependence of cosmic ray diurnal anisotropy using 22 years of GRAPES-3 muon telescope data 

Meeran Zuberi and the The GRAPES-3 Collaboration

The GRAPES-3 muon telescope (G3MT) has been recording high statistics of muons at a rate of ~50000 per second for the past two decades allowing us to probe the tiny variations in the muon flux caused by solar phenomena. The directional capabilities of G3MT enable us to look into 169 independent directions with a large median rigidity ranging from 64 to 141 GV. We have examined the 22 years (2000-2021) of G3MT data using the Fourier series technique to obtain the daily SDA amplitude and phase. The measured SDA amplitude and phase show a strong rigidity dependence. We found that the phase dominantly has the 22-year variation controlled by the drift effect due to solar polar magnetic field reversal, regardless of their rigidity. However, the higher rigidity bin phase variation shows an additional component of the 11 years controlled by the diffusion. The details of this work will be discussed during the talk.

How to cite: Zuberi, M. and the The GRAPES-3 Collaboration: Rigidity dependence of cosmic ray diurnal anisotropy using 22 years of GRAPES-3 muon telescope data, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-15741, https://doi.org/10.5194/egusphere-egu23-15741, 2023.

EGU23-15980 | ECS | Orals | GI6.8

Yield function of the DOSimetry TELescope (DOSTEL) count and dose rates aboard an aircraft 

Lisa Romaneehsen, Sönke Burmeister, Hanna Giese, Bernd Heber, and Konstantin Herbst

The Earth is continuously exposed to galactic cosmic rays. The magnetized solar wind in the heliosphere and the Earth's magnetic field alters the flux of these particles. If cosmic rays hit the atmosphere, they can form secondary particles. The total flux measured within the atmosphere depends on the atmospheric density above the observer. Therefore, the ability of a particle to approach an aircraft depends on its energy, the altitude, and the position of the plane. The cutoff rigidity describes the latter.
The radiation detector of the detector system NAVIDOS (NAVIgation DOSimetry) is the DOSimetry Telescope (DOSTEL), measuring the count and dose rates in two semiconductor detectors. From 2008 to 2011, two instruments were installed in two aircraft. First, we corrected the data for pressure variation by normalizing them to one flight level and determined their dependence on the cutoff rigidity by fitting a Dorman function to the observation. The latter was used to compute the yield function, which describes the ratio of incoming primary cosmic rays, approximated by a force field solution, to the measured count and dose rate for a particular instrument. As for neutron monitors, the sensitivity increases substantially above a rigidity of about 1 GV.
We received funding from the European Union's Horizon 2020 research and innovation program under grant agreement No 870405. 

How to cite: Romaneehsen, L., Burmeister, S., Giese, H., Heber, B., and Herbst, K.: Yield function of the DOSimetry TELescope (DOSTEL) count and dose rates aboard an aircraft, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-15980, https://doi.org/10.5194/egusphere-egu23-15980, 2023.

EGU23-16004 | ECS | Posters on site | GI6.8

Impact and relevance of soil density changes on cosmic-ray neutron sensing for soil water estimation 

Katya Dimitrova Petrova, Lena Scheiffele, Lucile Verrot, Martin Schrön, and Josie Geris

Cosmic ray neutron sensor (CRNS) technology is becoming increasingly popular for monitoring volumetric soil water content (SWC) at the field (hectare) scale in a variety of environments. Applications include permanently installed (stationary) or the use of mobile (rover, trains, etc.) platforms. In agricultural settings, permanently installed CRNS have proven particularly useful for providing time series of footprint average SWC estimates. To derive the SWC product at a site, CRNS needs to be calibrated using gravimetric SWC, soil organic matter and bulk density (BD). Those variables may in the best case be derived from a large number of soil samples, collected ideally on multiple occasions and under a range of hydrometeorological conditions. Most CRNS applications use an average site-specific value of bulk density derived for a site from ≥1 field calibration and it is considered static over time.

However, while this is a safe assumption for many environments, in agricultural settings, management activities (e.g. tillage) may introduce substantial changes in BD over time. This may affect the accuracy of the CRNS SWC estimates, which in turn could affect management decisions (e.g. on irrigation) or modelling efforts, relying on these SWC inputs.

The importance of BD as a source of uncertainty in CRNS SWC estimation has been recognized with dedicated laboratory and neutron simulation experiments quantifying the effects. However, field-based studies are lacking. Therefore, the objective of this work is to quantify the impact and relevance of temporal variability in soil bulk density on the estimation of CRNS SWC in a variety of environments with different level of agricultural land use management. We used data from three sites (Scotland, Germany and China) with stationary CRNS, where BD was sampled on ≥3 or more occasions for sensor calibration. The sites display a varying intensity of land use management, cover different soil types and contrasting weather conditions. We quantify the differences in estimates of SWC by using the range of average BD values at a site and compare these differences to other sources of uncertainty (e.g. the integration time of neutron counts). We additionally consider existing theories on the interaction of neutrons and soil bulk density to evaluate the impact of BD changes. Finally, we make recommendations on when BD variability and thus its sampling over time may become important for the derivation of CRNS SWC outputs.

How to cite: Dimitrova Petrova, K., Scheiffele, L., Verrot, L., Schrön, M., and Geris, J.: Impact and relevance of soil density changes on cosmic-ray neutron sensing for soil water estimation, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-16004, https://doi.org/10.5194/egusphere-egu23-16004, 2023.

EGU23-17336 | ECS | Orals | GI6.8

Cosmic Ray Soil Moisture Sensors as an Asset to Space Weather Monitoring Activities 

Fraser Baird and Keith Ryden

Cosmic Ray Sensors (CRS) are used worldwide to measure soil moisture at intermediate scales, exploiting the neutrons produced in the air showers created by cosmic ray particles interacting with the atmosphere. Neutron Monitors also exploit these atmospheric neutrons, but they are shielded from local soil moisture variations so that information about the cosmic ray flux near Earth can be deduced from their observations. Neutron monitors remain the state of the art for observing variations in high-energy cosmic rays and are critically important to understanding ground-level enhancements of atmospheric radiation caused by high energy solar energetic particles.

This contribution explores how the UK CRS network (COSMOS-UK) can complement the neutron monitor network in monitoring these ground-level enhancements, as well as other space weather-driven variations in the ground-level neutron flux. Observations of such variations using COSMOS-UK are presented and discussed, and the sensitivity of COSMOS-UK to ground-level enhancements is also shown. Finally, the prospects and challenges of improving the space weather utility of CRS networks are discussed.

How to cite: Baird, F. and Ryden, K.: Cosmic Ray Soil Moisture Sensors as an Asset to Space Weather Monitoring Activities, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-17336, https://doi.org/10.5194/egusphere-egu23-17336, 2023.

EGU23-17421 | Orals | GI6.8

Cosmic ray muons as a proxy for in-cruise galactic cosmic ray protons in 3He gas proportional counters 

Jack T. Wilson, Patrick N. Peplowski, Zachary W. Yokley, David J. Lawrence, and Richard C. Elphic

3He gas proportional counters have an extensive history in planetary neutron spectroscopy and several upcoming missions including Psyche, VIPER, MMX and Dragonfly will include this technology. In space, Galactic Cosmic Ray (GCR) protons deposit energy in the 3He gas in these detectors via ionization. This energy deposition constitutes a background on top of the neutron capture pulse-height spectrum that is particularly prominent at low energies. As planetary nuclear spectroscopy experiments are often count-rate limited using the full pulse height spectrum, including the proton and triton wall effect regions, has significant value. This will be particularly true for the upcoming VIPER mission that will explore the permanently shaded regions at the Moon’s south pole using the Neutron Spectrometer System (NSS).  The NSS does not include a neutron generator, so the count rates are low, and the rover will not spend long at any location.  However, using lower-energy parts of the spectrum requires understanding the GCR-originating background, which none of the previous missions were able to measure due to their low-energy cutoffs. GCR protons with mean energy around 400 MeV deposit similar amounts of energy to the 4 GeV mean-energy muons present at ground level as both represent minimum ionizing particles within the 3He sensors.  We therefore developed an experiment using a pair of plastic scintillators in coincidence with a 3He tube to measure energy deposition from muons while excluding room background gamma rays.  Here we will present results of this experiment to characterize the angular response to cosmic ray muons of a 3He flight spare detector from the VIPER NSS and explore the implications of these results for analysis of planetary neutron data sets.

How to cite: Wilson, J. T., Peplowski, P. N., Yokley, Z. W., Lawrence, D. J., and Elphic, R. C.: Cosmic ray muons as a proxy for in-cruise galactic cosmic ray protons in 3He gas proportional counters, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-17421, https://doi.org/10.5194/egusphere-egu23-17421, 2023.

EGU23-17487 | ECS | Posters on site | GI6.8

Cosmic-ray neutron production and propagation inside snow packs characterized by multi-particle Monte Carlo simulations 

Jannis Weimar, Paul Schattan, Rebecca Gugerli, Benjamin Fersch, Darin Desilets, Martin Schrön, Markus Köhli, and Ulrich Schmidt

Cosmic-ray neutron sensors buried below a snow pack provide a passive and autonomous monitoring technique of snow water equivalent (SWE). The effective neutron flux is attenuated inside the snow volume resulting in an inverse relationship between neutron intensity and the water equivalent of the snow column above the sensor. Neutrons are moderated and absorbed within the snow. Simultaneously, highly energetic cosmic rays produce further neutrons via spallation and evaporation processes. A comprehensive assessment of the neutron flux therefore requires multi-particle simulations which involve all relevant incoming particle species and transient particles from cosmic-ray showers which play a crucial role in neutron production.

In our study, we used the Monte Carlo toolkit MCNP6 and validated its high-energy evaporation and spallation models against a measured data set of a neutron intensity profile in water. Based on that we fitted analytical functions to a large variety of simulation setups that describe the neutron intensity as a function of SWE and the moisture content of the soil below the sensor. Moreover, single-particle tracking revealed that the radial footprint of the method does not exceed few meters for detectors below thick snow layers. In the case of shallow snow, however, the diffusive long-range neutron flux in the atmosphere may penetrate through the snow pack to the buried sensor and thereby increases the influence of distant objects. Since the diffusive flux is further sensitive to the atmospheric water content, we developed an air humidity correction tailored to snow-buried neutron detectors.

In general, the study aims at a holistic understanding of neutron production and transport processes in snow and the adjacent soil and air volumes in order to improve SWE monitoring by buried cosmic-ray neutron sensors and compares the simulation results to field data.

How to cite: Weimar, J., Schattan, P., Gugerli, R., Fersch, B., Desilets, D., Schrön, M., Köhli, M., and Schmidt, U.: Cosmic-ray neutron production and propagation inside snow packs characterized by multi-particle Monte Carlo simulations, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-17487, https://doi.org/10.5194/egusphere-egu23-17487, 2023.

EGU23-550 | ECS | Orals | ST2.2

Identifying the zoo of waves in Magnetosheathjets using MMS burst data 

Eva Krämer, Maria Hamrin, Herbert Gunell, Tomas Karlsson, Konrad Steinvall, Oleksandr Goncharov, and Mats André

The magnetosheath is a region downstream of the bow shock filled with turbulent, decelerated solar wind plasma which is flowing earthwards. This solar wind flow sometimes shows signatures of localized structures with enhanced dynamic pressure, so called magnetosheath jets. These jets are often  associated with low angles between the bow shock normal and the interplanetary magnetic field (IMF) direction, the so called quasi-parallel bow shock. Less often they are also found behind the quasi-perpendicular bow shock.


As jets propagate through the magnetosheath, they interact with the surrounding plasma. Studying waves inside, and in the vicinity of, jets is a step towards understanding the interaction of jets with the surrounding plasma. So far whistler waves, electrostatic waves, waves in the lower hybrid frequency range as well as low frequency waves have been reported. However, the sources of these waves are unknown. In addition, further types of waves may be associated with the jets.


We conduct a study on waves in magnetosheath jets using burst mode data of the Magnetospheric Multiscale (MMS) mission. The magnetic and electric field data are provided with a sampling rate of 8 kHz, while previous studies used data sets with much lower sampling rates. The high time resolution allows us to study different waves over a large frequency range and investigate properties of these waves. In addition, we discuss possible generation mechanisms.

How to cite: Krämer, E., Hamrin, M., Gunell, H., Karlsson, T., Steinvall, K., Goncharov, O., and André, M.: Identifying the zoo of waves in Magnetosheathjets using MMS burst data, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-550, https://doi.org/10.5194/egusphere-egu23-550, 2023.

EGU23-929 | ECS | Posters on site | ST2.2

Velocity distribution functions and non‐Maxwellianity of magnetosheath jets using MMS 

Savvas Raptis, Tomas Karlsson, Andris Vaivads, Martin Lindberg, and Henriette Trollvik

The interaction between the solar wind and Earth’s magnetic field results in the formation of a supercritical bow shock. Downstream of this shock wave, the magnetosheath region emerges, in which high-speed plasma flows can be formed.  These jets have been connected to several shock and foreshock properties. Moreover, due to their unique properties (i.e., higher density and velocity compared to the ambient flow), they can cause a variety of different phenomena, including magnetopause reconnection, excitation of ULF waves and electron acceleration.

In this work, we use Magnetosphere Multiscale (MMS) mission to demonstrate jets’ complex structure by investigating their velocity distribution functions. Specifically, we focus on how their VDFs change over time and on whether they exhibit non-Maxwellian properties. By comparing with the VDFs taken from the background magnetosheath, we show that full particle plasma moments provide an inadequate description of jet plasma properties. Furthermore, we present different metrics to quantify the non-Maxwellian features exhibited by jet observations. Finally, we discuss how the observed kinetic properties of jets may provide insight into jets generation, wave excitation and evolution.

How to cite: Raptis, S., Karlsson, T., Vaivads, A., Lindberg, M., and Trollvik, H.: Velocity distribution functions and non‐Maxwellianity of magnetosheath jets using MMS, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-929, https://doi.org/10.5194/egusphere-egu23-929, 2023.

EGU23-1222 | ECS | Posters on site | ST2.2

Study of the Local Bow Shock Environment during Magnetosheath Jet Formation: Vlasiator Results 

Jonas Suni, Minna Palmroth, Markus Battarbee, Lucile Turc, Markku Alho, Giulia Cozzani, Maxime Dubart, Urs Ganse, Harriet George, Evgeny Gordeev, Maxime Grandin, Konstantinos Horaites, Konstantinos Papadakis, Yann Pfau-Kempf, Vertti Tarvus, Fasil Tesema, Ivan Zaitsev, and Hongyang Zhou

Magnetosheath jets are a class of phenomena that are usually defined as structures of enhanced dynamic pressure in the magnetosheath. The origins of some jets have been traced back to steepening ULF waves in the foreshock, but other formation mechanisms have also been described. In this study we use four 2D simulation runs of the global magnetospheric hybrid-Vlasov simulation Vlasiator to investigate the formation of magnetosheath jets at the bow shock. We use 2D views of the simulation and virtual spacecraft to investigate the plasma and magnetic field properties around and at the times and locations of jet formation. We find that of the 796 jets analysed this way, 91% appear to form in association with foreshock structures of enhanced dynamic pressure impacting the bow shock. These jets mainly form downstream of the ULF foreshock, while the remaining 9% are generally found near the ULF foreshock edges toward the flanks and have different properties from the foreshock structure-associated jets.

How to cite: Suni, J., Palmroth, M., Battarbee, M., Turc, L., Alho, M., Cozzani, G., Dubart, M., Ganse, U., George, H., Gordeev, E., Grandin, M., Horaites, K., Papadakis, K., Pfau-Kempf, Y., Tarvus, V., Tesema, F., Zaitsev, I., and Zhou, H.: Study of the Local Bow Shock Environment during Magnetosheath Jet Formation: Vlasiator Results, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-1222, https://doi.org/10.5194/egusphere-egu23-1222, 2023.

EGU23-1305 | Posters on site | ST2.2

Mirror mode-like structures around unmagnetised planets: 1. Mars as observed by the MAVEN spacecraft 

Cyril Simon Wedlund, Martin Volwerk, Christian Mazelle, Sebastián Rojas Mata, Gabriella Stenberg Wieser, Yoshifumi Futaana, Jasper Halekas, Diana Rojas-Castillo, César Bertucci, and Jared Espley

Temperature anisotropy-driven instabilities such as the mirror mode and ion cyclotron instabilities are responsible for the generation of waves in the turbulent magnetosheath of planets. We present two statistical studies of mirror mode-like structures in the magnetosheaths of (mostly) unmagnetised planets such as Mars and Venus, characterised in the same way and with the same tools with the help of on-board magnetometers. In this presentation, we discuss observations by the MAVEN spacecraft. As in our companion Venus study (see poster by Volwerk et al. in the same session), we use magnetic field-only measurements to constrain and identify these quasi-linear compressive structures and discuss ways to mitigate false positive detections based on one instrument only. After calculating the residence time of the spacecraft in the Martian magnetoenvironment, we show two-dimensional statistical maps of mirror mode-like occurrence rates with respect to EUV solar flux levels, Mars Year, and atmospheric seasons. We find detection probabilities of about 1% at most, with two main regions of occurrence, one behind the collisionless shock, the other close to the induced magnetospheric boundary, with the clearest modulation of the probability due to EUV solar flux conditions. Finally, we qualitatively compare our results with past studies at Mars.

How to cite: Simon Wedlund, C., Volwerk, M., Mazelle, C., Rojas Mata, S., Stenberg Wieser, G., Futaana, Y., Halekas, J., Rojas-Castillo, D., Bertucci, C., and Espley, J.: Mirror mode-like structures around unmagnetised planets: 1. Mars as observed by the MAVEN spacecraft, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-1305, https://doi.org/10.5194/egusphere-egu23-1305, 2023.

EGU23-1532 | Posters on site | ST2.2

Mirror mode-like structures around unmagnetised planets: 2. Venus as observed by the Venus Express spacecraft 

Martin Volwerk, Cyril Simon Wedlund, David Mautner, Sebastian Rojas Mata, Gabriella Stenberg Wieser, Yoshifumi Futaana, Markus Fraenz, Christian Mazelle, Diana Rojas-Castillo, Cesar Bertucci, and Magda Delva

Temperature anisotropy-driven instabilities such as the mirror mode and ion cyclotron instabilities are responsible for the generation of waves in the turbulent magnetosheath of planets. We present here a statistical study of mirror mode-like structures in the magnetosheath of Venus as observed by the Venus Express spacecraft. As in our Mars study (see poster by Simon Wedlund et al. in the same session), we use magnetic field-only measurements to constrain and identify these quasi-linear compressive structures and discuss ways to mitigate false positive detections based on one instrument only. After calculating the residence time of the spacecraft in the Venusian magnetoenvironment, we show two-dimensional statistical maps of mirror mode-like occurrence rates with respect to EUV solar flux levels, and type of bow shock (quasi-perpendicular vs quasi-parallel). We find detection probabilities of about 10% at most, with two main regions of occurrence, one behind the collisionless shock, the other close to the induced magnetospheric boundary, with the small modulation of the probability due to EUV solar flux conditions.

How to cite: Volwerk, M., Simon Wedlund, C., Mautner, D., Rojas Mata, S., Stenberg Wieser, G., Futaana, Y., Fraenz, M., Mazelle, C., Rojas-Castillo, D., Bertucci, C., and Delva, M.: Mirror mode-like structures around unmagnetised planets: 2. Venus as observed by the Venus Express spacecraft, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-1532, https://doi.org/10.5194/egusphere-egu23-1532, 2023.

EGU23-2438 | ECS | Orals | ST2.2

The bow shock and magnetosheath responses to density depletion structures 

Xi Lu, Hui Zhang, Antonius Otto, Terry Liu, and Xingran Chen

Hot flow anomalies (HFAs) are typical and important foreshock transients characterized by large flow deflection and plasma heating. HFAs can deform the Earth’s bow shock by dynamic pressure perturbation resulting in disturbance in the magnetosphere and ionosphere. Traditionally, HFAs are believed to be associated with discontinuities. But recently, HFA-like structures were simulated by an magnetohydrodynamics (MHD) model without the discontinuity prerequisite. In this study, we give three HFA examples to verify this MHD formation mechanism. For the first event, we use multi-points observation from the THEMIS mission to track the formation of the HFA accompanying with a density depletion upstream. For the other two events, we compare observations from the MMS mission and the ARTEMIS mission with the MHD simulation results using density depleted solar wind flux tubes to investigate the physical process of HFA formation. The comparison of simulation and observation shows general agreement particularly in the presence of a core with strong heating and velocity deflection, and two compression regions (shocks) with clear maxima in the ram pressure with a strongly inclined normal boundary at the leading edge and moderately inclined at the trailing edge. Agreement was better when the MHD simulations used a transient change to quasi-parallel solar wind magnetic field during the events. Result suggests that ram pressure may be an excellent diagnostic for HFAs both in the solar wind and in the magnetosheath.

How to cite: Lu, X., Zhang, H., Otto, A., Liu, T., and Chen, X.: The bow shock and magnetosheath responses to density depletion structures, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-2438, https://doi.org/10.5194/egusphere-egu23-2438, 2023.

EGU23-2702 | Posters on site | ST2.2

MESSENGER observations of short, large-amplitude magnetic structures (SLAMS) in the Mercury foreshock 

Tomas Karlsson and Ferdinand Plaschke

We have investigated approximately four years of MESSENGER data to identify short, large-amplitude magnetic structures (SLAMS) in the Mercury foreshock. Defining SLAMS as well-defined structures with a magnetic field strength of at least a factor of 3 higher than the background magnetic field, when MESSENGER is located in the solar wind, we find 435 SLAMS. The SLAMS are found either in regions of a general ultra-low frequency (ULF) wave field, at the boundary of such a ULF wave field, or isolated from the wave field. We invetigate several properties of the SLAMS, such as temporal scale size, amplitude, and polarization. We find that SLAMS are mostly found during periods of low interplanetary magnetic field strength, indicating that they are more common for higher solar wind Alfvénic Mach number (MA). We use the Tao solar wind model to estimate solar wind parameters to verify that MA is indeed larger during SLAMS observations than otherwise. Finally, we also investigate how SLAMS observations are related to foreshock geometry.

How to cite: Karlsson, T. and Plaschke, F.: MESSENGER observations of short, large-amplitude magnetic structures (SLAMS) in the Mercury foreshock, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-2702, https://doi.org/10.5194/egusphere-egu23-2702, 2023.

EGU23-2963 | ECS | Posters virtual | ST2.2

Electron acceleration by intense whistler-mode waves at foreshock transients 

Xiaofei Shi, Anton Artemyev, Vassilis Angelopoulos, Terry Liu, and Xiao-Jia Zhang

The shock wave is a primary interface for plasma heating and charged particle acceleration. In collisionless solar wind plasma, such acceleration is attributed to the wave-particle resonant interactions. This letter focuses on electron acceleration by one of the most widespread high-frequency electromagnetic wave emissions, whistler-mode waves. Using spacecraft observations of the Earth's foreshock transient, we demonstrate that intense whistler-mode waves may resonate nonlinearly with $\sim 10-100$eV solar wind electrons and accelerate them to $\sim 100-500$eV. Accelerated electron population has a butterfly pitch-angle distribution, in agreement with theoretical predictions. The presented evidence of the efficiency of nonlinear resonant acceleration suggests that this mechanism may play an important role in solar wind electron injection into the shock-drift acceleration.

How to cite: Shi, X., Artemyev, A., Angelopoulos, V., Liu, T., and Zhang, X.-J.: Electron acceleration by intense whistler-mode waves at foreshock transients, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-2963, https://doi.org/10.5194/egusphere-egu23-2963, 2023.

EGU23-3155 | ECS | Posters on site | ST2.2

Jet-like structures in different regions of the magnetosheath 

Oleksandr Goncharov, Jana Šafránková, Zdeněk Němeček, and Niki Xirogiannopoulou

Plasma structures with the enhanced dynamic pressure, density or speed are often observed in the Earth’s magnetosheath. These structures, known as jets and fast plasmoids, can be registered in the magnetosheath, downstream both the quasi-perpendicular and quasi-parallel bow shocks (BS). Using measurements by the Magnetospheric Multiscale (MMS) spacecraft, Goncharov et al. (2020) showed similarities in the plasma properties of the jets and fast plasmoids. However, they pointed out that the different magnetic fields inside the structures suggest that the formation mechanisms are different. Hybrid simulations by Preisser et al. (2020) have shown differences in the mechanisms of jet and embedded plasmoid formation. On the other hand, structures registered close to the BS/magnetopause or in the sub-solar/flank magnetosheath are not fully the same. Based on our comparative analysis, we discuss features of jet-like structures, their properties, occurrence, evolution, and relation to the magnetosheath parameters.

How to cite: Goncharov, O., Šafránková, J., Němeček, Z., and Xirogiannopoulou, N.: Jet-like structures in different regions of the magnetosheath, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-3155, https://doi.org/10.5194/egusphere-egu23-3155, 2023.

EGU23-3199 | ECS | Posters on site | ST2.2

Characteristics of foreshock subsolar compressive structures and their connection to magnetosheath jet-like phenomena 

Niki Xirogiannopoulou, Oleksandr Goncharov, Jana Šafránková, and Zdeněk Němeček

The turbulent foreshock region upstream of the quasi- parallel bow shock is dominated by waves and reflected particles that interact with each other and create a large number of different foreshock phenomena. The plasma structures with the enhanced magnetic field (Short Large Amplitude Magnetic Structures, SLAMS), and density spikes, named plasmoids, are frequently observed. They are one of the suggested sources of transient flux enhancements (TFE) or jets in the magnetosheath. Using measurements of the Magnetospheric Multiscale Spacecraft (MMS) and OMNI solar wind database between 2015 and 2018 years, we have found that there is a category of events exhibiting both magnetic field and density enhancements simultaneously and we introduce the term “mixed structure” for them. Consequently, we divided our set of observations into three groups and present a comparative statistical analysis in the subsolar foreshock. Based on our results and previous research, we discuss their properties, possible origin, occurrence rate under different upstream conditions and their relation to the jets and plasmoids in the magnetosheath. We suggest that plasmoids and SLAMS are different phenomena created in the foreshock under different upstream conditions and that the enhanced density, rather than magnetic field magnitude, is principal for creation of magnetosheath jets.

How to cite: Xirogiannopoulou, N., Goncharov, O., Šafránková, J., and Němeček, Z.: Characteristics of foreshock subsolar compressive structures and their connection to magnetosheath jet-like phenomena, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-3199, https://doi.org/10.5194/egusphere-egu23-3199, 2023.

EGU23-3758 | ECS | Posters on site | ST2.2

Kinetic simulation of proton mirror instability 

Chun-Kai Chang and Lin-Ni Hau

Mirror mode waves with anticorrelated density and magnetic field perturbations have been widely observed in the planetary magnetosheaths and solar wind. In this study we examine the time evolution of proton mirror instability based on the hybrid particle simulation with the focus being on the thermodynamics of mirror waves. A set of double-polytropic (DP) laws are adopted to infer the corresponding thermodynamic conditions characterized by the polytropic exponents, γand γ. It is shown that the γ⊥, values at the saturation stages are in the ranges of γ⊥ = 0.64±0.21 and γ = 1.07±0.12 which are consistent with the observations and linear kinetic theory (Hau et al. 2021). The saturated plasma β are well fitted by the modified DP MHD mirror condition of γβ = β2/(2+γβ) with γ≈ 0.8, γ ≈ 1.3 which may be used as a new mirror criterion for the mirror waves observed in the solar system.

How to cite: Chang, C.-K. and Hau, L.-N.: Kinetic simulation of proton mirror instability, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-3758, https://doi.org/10.5194/egusphere-egu23-3758, 2023.

In the foreshock region of planetary and terrestrial bow shocks, interaction of reflected solar wind ions with the incident solar wind and the interplanetary magnetic field gives rise to a variety of transient plasma structures and instabilities, and the ion dynamics and ion kinetic scale processes drive the foreshock environment. In this comparative study, we consider specific examples of transient foreshock structures upstream of Mars and Earth and contrast differences between theri formation process, contributing ion populations, and source region of ion populations. Due to the smaller size of Mars and its bow shock compared to Earth and with respect to upstream ion convective gyroradius, reflected ions with hybrid trajectories that straddle between the quasi-perpendicular and quasi-parallel bow shocks can contribute to formation of foreshock transients. The size of transient foreshock structures upstream of Mars differs compared to Earth, which influences their propagation and impact through the magnetosheath and lower plasma boundaries.

How to cite: Madanian, H.: Formation of Transient Foreshock Structures Upstream of Mars and Earth: A Comparative Study, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-4004, https://doi.org/10.5194/egusphere-egu23-4004, 2023.

EGU23-4366 | Posters on site | ST2.2

On the scale sizes of magnetic holes 

Ferdinand Plaschke, Martin Volwerk, Tomas Karlsson, Charlotte Götz, Daniel Heyner, Heli Hietala, Johannes Z. D. Mieth, Daniel Schmid, Cyril Simon-Wedlund, and Zoltan Vörös

Magnetic holes are significant depressions of the interplanetary magnetic field (IMF) that can be found embedded in the solar wind everywhere within the heliosphere. They resemble mirror mode magnetic structures that form as a response to excess perpendicular temperatures. Magnetic holes situated at IMF discontinuities (current sheets) may also be the result of reconnection. Magnetic holes occur more often under fast solar wind conditions, and their scale sizes are known to be on the order of thousands to tens of thousands of km, determined essentially from temporal width and plasma velocity observations. So far, the scale sizes have only been estimated for the directions parallel to the respective solar wind plasma flows. In this study, we attempt to calculate the first distributions of the scale sizes for the orthogonal, flow-perpendicular directions. Therefore, we use multi-point observations of magnetic holes by the ARTEMIS spacecraft in lunar orbit. The method we use has been previously applied to plasma jets present in the magnetosheath of Earth. The knowledge of the flow-perpendicular scale sizes is important to assess the holes’ impact on planetary magnetospheres and cometary environments.

How to cite: Plaschke, F., Volwerk, M., Karlsson, T., Götz, C., Heyner, D., Hietala, H., Mieth, J. Z. D., Schmid, D., Simon-Wedlund, C., and Vörös, Z.: On the scale sizes of magnetic holes, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-4366, https://doi.org/10.5194/egusphere-egu23-4366, 2023.

EGU23-4522 | Orals | ST2.2

Kinetic modeling of the interaction of solar wind discontinuities with the bow shock-magnetosheath-magnetopause system 

Jean Berchem, Giovanni Lapenta, Philippe Escoubet, and Simon Wing

Modeling the interaction of solar wind discontinuities with the bow shock-magnetosheath-magnetopause system is an important step in comprehending the effects of solar wind structures on the magnetosphere. Our procedure is to first run a global MHD simulation to predict the overall configuration of the solar wind-magnetosphere system before the discontinuity interacts with the bow shock. Then fields and plasma moments within a large sub-domain of the global MHD simulation are used to set the initial conditions of an implicit PIC simulation of the interaction of the discontinuity with the dayside magnetosphere. This procedure allows us to follow the evolution of kinetic processes as the discontinuity interacts with the bow shock and propagates through the magnetosheath before impacting the dayside magnetopause. In this presentation, we show some results of the interaction of a rotational discontinuity where the interplanetary magnetic field, initially southward, turns northward. As expected, the discontinuity slows down abruptly after interacting with the bow shock, the transverse component of the magnetic field being greatly enhanced in the process.  While the initial MHD state of the magnetosheath was laminar, kinetic waves and instabilities lead to a turbulent state for all plasma moments and electromagnetic fields. In particular, transients are observed ahead of the discontinuity as it propagates Earthward. At later stages of the simulation, the discontinuity interacts with the magnetopause. Magnetic field lines are bent strongly in the transverse direction, affecting reconnection processes with the production of large magnetic flux ropes.

How to cite: Berchem, J., Lapenta, G., Escoubet, P., and Wing, S.: Kinetic modeling of the interaction of solar wind discontinuities with the bow shock-magnetosheath-magnetopause system, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-4522, https://doi.org/10.5194/egusphere-egu23-4522, 2023.

EGU23-6637 | Orals | ST2.2 | Highlight

Transmission of foreshock waves through Earth's bow shock 

Lucile Turc, Owen W. Roberts, Daniel Verscharen, Andrew P. Dimmock, Primoz Kajdic, Minna Palmroth, Yann Pfau-Kempf, Andreas Johlander, Maxime Dubart, Emilia K.J. Kilpua, Kazue Takahashi, Naoko Takahashi, Markus Battarbee, and Urs Ganse

The foreshock, extending upstream of the quasi-parallel shock and populated with shock-reflected particles, is home to intense wave activity in the ultra-low frequency range. The most commonly observed of these waves are the '30-second' waves, fast magnetosonic waves propagating sunward in the plasma rest frame, but carried earthward by the faster solar wind flow. These waves are thought to be the main source of Pc3 magnetic pulsations (10-45 s periods) in the dayside magnetosphere, but how the waves can transmit through the bow shock and across the magnetosheath had remained unclear. Global hybrid-Vlasov simulations performed with the Vlasiator model provide us with the global view of foreshock wave transmission across near-Earth space. We find that the foreshock waves modulate the plasma parameters just upstream of the bow shock, which in turn periodically changes the shock compression ratio and the downstream pressure. This launches fast-mode waves propagating through the magnetosheath all the way to the magnetopause, where they can further transmit into the dayside magnetosphere. We compare our numerical results with MMS observations near the subsolar point, where we identify earthward-propagating fast-mode waves at the same period as the foreshock waves, consistent with our simulation results. Our findings show that the wave propagation across the bow shock is much more complex than the simple direct transmission of the foreshock waves which was inferred in early studies.

How to cite: Turc, L., Roberts, O. W., Verscharen, D., Dimmock, A. P., Kajdic, P., Palmroth, M., Pfau-Kempf, Y., Johlander, A., Dubart, M., Kilpua, E. K. J., Takahashi, K., Takahashi, N., Battarbee, M., and Ganse, U.: Transmission of foreshock waves through Earth's bow shock, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-6637, https://doi.org/10.5194/egusphere-egu23-6637, 2023.

EGU23-6972 | Posters on site | ST2.2

How do magnetic holes cross a bow shock? Results from the kinetic hybrid plasma model Menura 

Pierre Henri, Cyril Simon Wedlund, Francesco Pucci, Etienne Behar, and Giulio Ballerini

Linear magnetic holes (LMH) are magnetic field depressions in the solar wind found everywhere in the heliosphere and sometimes downstream of planetary bow shocks. LMH, with only very little rotation of the magnetic field B across the structure, are often considered as the evolutionary endpoint of mirror modes, thus retaining certain characteristics of their parent structure: embedded in a plasma with large temperature anisotropy, large plasma beta, anticorrelation between B and the plasma density. One question is how and under which conditions these large depressions may survive a shock crossing, as observations have recently shown that such a crossing is possible. In other words: what is the interaction between two nonlinear space plasma structures that both scale as the ion gyroradius? To answer this question, we present here the first hybrid simulations of the evolution of a LMH crossing the bow shock boundary of a medium-activity comet using the hybrid Particle-In-Cell (PIC) model Menura. We first create a LMH with mirror mode characteristics in the pristine solar wind and, then, convect it down toward a comet, through the shock, into the cometary magnetosheath. We study its morphology along its path, and how the magnetosheath is impacted locally and as a whole. This work also aims at preparing fundamental space plasma physics aspects of the upcoming multi-spacecraft Comet Interceptor mission.

How to cite: Henri, P., Simon Wedlund, C., Pucci, F., Behar, E., and Ballerini, G.: How do magnetic holes cross a bow shock? Results from the kinetic hybrid plasma model Menura, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-6972, https://doi.org/10.5194/egusphere-egu23-6972, 2023.

EGU23-8347 | Posters on site | ST2.2

A Statistical Study of Foreshock Environment under Radial IMF Conditions 

Gilbert Pi, Anna Salohub, Niki Xirogiannopoulou, Zdeněk Němeček, and Jana Šafránková

The foreshock is a turbulent region in front of the quasi-parallel bow shock. The reflected particles from the bow shock and interaction with oncoming waves in the solar wind create it. The foreshock is usually located at the dawn side. However, the foreshock region is relocate to the nose of the bow shock and covers all the dayside magnetospheric system when IMF points to radial or anti-radial directions. This change creates many unusual phenomena in the magnetospheric system, such as the magnetopause expansion, and generates the foreshock transients, such as spontaneous Hot Flow Anomalies (sHFA). Previous studies revealed that foreshock transients are preferred to occur under a radial IMF condition, however, what is the reason for this preference is still unclear. Using THEMIS and MMS data, the analysis presents a statistical analysis to reveal the foreshock characteristics under the radial IMF to check the reasons for the preference of foreshock transients. The primary solar wind parameters in the foreshock and/or solar wind under these conditions are revealed. The ULF wave behavior is also taken account.

How to cite: Pi, G., Salohub, A., Xirogiannopoulou, N., Němeček, Z., and Šafránková, J.: A Statistical Study of Foreshock Environment under Radial IMF Conditions, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-8347, https://doi.org/10.5194/egusphere-egu23-8347, 2023.

EGU23-8664 | ECS | Orals | ST2.2

Classifying the magnetosheath using local measurements from MMS 

Ida Svenningsson, Emiliya Yordanova, Yuri V. Khotyaintsev, Mats André, and Giulia Cozzani

The Earth’s magnetosheath is a dynamic region and its properties strongly depend on the angle between the bow shock normal and the solar wind magnetic field (θbn). If the shock is quasi-parallel (θbn < 45°), the magnetosheath is magnetically connected to the foreshock, causing strong fluctuations and structures propagating from upstream to downstream. A quasi-perpendicular shock (θbn > 45°) produces a less structured and more stationary magnetosheath characterized by compression and high ion temperature anisotropy. These distinct configurations make it possible to study how different plasma environments affect various processes such as turbulence, heating, and wave-particle interactions. Therefore, such studies require an accurate classification of the magnetosheath. This is not easily achieved, especially close to the magnetopause where the shock crossing for the plasma of interest cannot be observed.

Previously, Karlsson et al. (2021) used data from the Cluster mission to propose a promising classification method using local measurements of the magnetic field standard deviation, high-energy ion flux, and ion temperature anisotropy. In this work, we are building on this study and extending it to the Magnetospheric Multiscale (MMS) mission, having a different orbit than Cluster. We compare this local classification to θbn estimated from upstream conditions and well-known bow shock models, and discuss the advantages and disadvantages of the different methods.

 

Reference: Karlsson, T., Raptis, S., Trollvik, H., & Nilsson, H. (2021). Classifying the magnetosheath behind the quasi-parallel and quasi-perpendicular bow shock by local measurements. Journal of Geophysical Research: Space Physics, 126, e2021JA029269.

How to cite: Svenningsson, I., Yordanova, E., Khotyaintsev, Y. V., André, M., and Cozzani, G.: Classifying the magnetosheath using local measurements from MMS, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-8664, https://doi.org/10.5194/egusphere-egu23-8664, 2023.

EGU23-9082 | ECS | Orals | ST2.2

Observational Analysis of Small-scale Structures in the Earth's Magnetosheath 

Rebecca Harvey and Qiang Hu

Magnetic flux ropes with a wide range of scale sizes generally have high magnetic helicity, a magnetohydrodynamic (MHD) quantity that characterizes the knottedness of the field lines that can be used to identify flux rope structures. The identification and analysis of structures moving across boundaries such as the Earth's bow shock will give insight into how their properties change across this boundary as well as further our understanding of the interrelation between these structures. Recent spacecraft missions are returning higher time resolution data than before, allowing for more advanced studies of this phenomenon. Using high time-resolution data from the Magnetospheric Multiscale (MMS) mission and Time History of Events and Macroscale Interactions during Substorms (THEMIS) mission, we identify small-scale flux ropes using wavelet analysis and determine how they change across boundaries. Wavelet analysis of single-spacecraft data can produce better resolved time and spatial information that will complement other methods of flux rope identification. Wavelet transforms are performed across hours-long intervals, organized by the orbit configuration of the spacecraft. The resulting spectrograms are then searched to identify small-scale structures. A number of parameters, including duration, scale size, maximum magnetic field, and average plasma temperature of the flux rope intervals identified are also recorded and summarized. Comparing the values of magnetic field, plasma beta, and other parameters at the corresponding times and locations leads to interpretations for the flux rope events such as whether they are compressed, decelerated, or undergo any other changes as they evolve.

How to cite: Harvey, R. and Hu, Q.: Observational Analysis of Small-scale Structures in the Earth's Magnetosheath, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-9082, https://doi.org/10.5194/egusphere-egu23-9082, 2023.

EGU23-9423 | Orals | ST2.2

On the Speed of Interplanetary Shocks Propagating through the Magnetosheath 

Clément Moissard, Axel Bernal, Philippe Savoini, Dominique Fontaine, Ronan Modolo, Vincent David, and Bayane Michotte de Welle

Interplanetary shocks are some of the main drivers of geomagnetic storms. Before they can impact the geomagnetic environment, they propagate through the magnetosheath where their properties and geometry can be modified. What is the velocity of interplanetary shocks propagating through the magnetosheath? Previous numerical simulations and observations have given a wide range of apparently contradictory answers to this question, but they seem to all agree that interplanetary shocks generally slow down as they enter the magnetosheath: the interplanetary shocks’ velocity in the magnetosheath have been reported to be between 0.25 and 0.93 times their velocity in the solar wind. In this work, we offer two competing simple models to predict the propagation velocity of shocks through the magnetosheath. These models are applied to a list of shocks detected by currently operational spacecraft (e.g. Wind, MMS) as well as to results obtained from a hybrid PIC simulation. We show that our models both reconcile previous results and imply that interplanetary shocks could - in certain space weather-relevant situations - travel faster in the magnetosheath than they did in the solar wind. 

How to cite: Moissard, C., Bernal, A., Savoini, P., Fontaine, D., Modolo, R., David, V., and Michotte de Welle, B.: On the Speed of Interplanetary Shocks Propagating through the Magnetosheath, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-9423, https://doi.org/10.5194/egusphere-egu23-9423, 2023.

EGU23-9495 | Orals | ST2.2

On the production of magnetosheath jets during a CME and SIR passage: A case study 

Luis Preisser, Ferdinand Plaschke, Florian Koller, Manuela Temmer, Owen Roberts, and Zoltan Vörös

Large scale solar wind (SW) structures called Coronal Mass Ejections (CMEs) and Stream Interaction Regions (SIRs) propagate through the interplanetary medium, where they might impact Earth and cause jet-like disturbances in the magnetosheath. Such jets are short scale structures characterized by an enhancement in dynamic pressure that propagate through the Earth’s magnetosheath (EMS) transporting mass, momentum and energy being able to affect and perturb the Earth’s magnetosphere.
Jets have been studied for 20 years, but how different SW conditions triggered by CMEs and SIRs affect jet production is a topic that has only recently begun to be studied. In this work we characterize jets observed by THEMIS during a CME and a SIR passage. We find clear differences in number and size between the jets associated with the CME regions arriving at the EMS as well as in comparison with the characteristics of jets associated with the SIR passage. Comparing WIND and THEMIS data we discuss how these differences are linked to the SW conditions in the context of a recent statistical study (Koller et al. 2022) and with different jet generation mechanisms.

How to cite: Preisser, L., Plaschke, F., Koller, F., Temmer, M., Roberts, O., and Vörös, Z.: On the production of magnetosheath jets during a CME and SIR passage: A case study, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-9495, https://doi.org/10.5194/egusphere-egu23-9495, 2023.

EGU23-9960 | ECS | Orals | ST2.2

Solar wind parameters influencing magnetosheath jet formation: low and high IMF cone angle regimes 

Laura Vuorinen, Heli Hietala, and Adrian T. LaMoury

Magnetosheath jets are dynamic pressure enhancements that are frequently observed downstream of the Earth's bow shock. Earthward propagating jets are significantly more likely to occur downstream of the quasi-parallel shock than the quasi-perpendicular shock. However, as the quasi-perpendicular geometry is the more common configuration at the Earth's bow shock, quasi-perpendicular jets can constitute a significant fraction of jets observed at Earth. Moreover, at other more quasi-perpendicular shock environments, such as at interplanetary shocks or the bow shocks of outer planets, they would be expected to form an even more significant portion of jets. We study the solar wind influence on jet formation in the quasi-parallel and quasi-perpendicular regimes by investigating jets in the Earth’s subsolar magnetosheath separately during low and high IMF cone angles. We find that during low IMF cone angles (downstream of the quasi-parallel shock) jet occurrence near the bow shock is not sensitive to other solar wind parameters. However, during high IMF cone angles (downstream of the quasi-perpendicular shock) jet occurrence is higher during low B, low n, high beta, and high MA conditions. This suggests that quasi-perpendicular jet formation is related to shock dynamics amplified by higher beta and MA. These observations from a wide range of solar wind parameters also allow us to make predictions of jet occurrence at other planetary systems.

How to cite: Vuorinen, L., Hietala, H., and LaMoury, A. T.: Solar wind parameters influencing magnetosheath jet formation: low and high IMF cone angle regimes, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-9960, https://doi.org/10.5194/egusphere-egu23-9960, 2023.

EGU23-10536 | ECS | Orals | ST2.2 | Highlight

MAVEN Observations of Steepened Ultra-Low Frequency Waves in the Upstream Martian Foreshock Region 

Gangkai Poh, Jared Espley, Shaosui Xu, Guan Le, Norberto Romanelli, Jasper Halekas, Gina DiBraccio, and Jacob Gruesbeck

In this study, we present the analysis of steepened ultra-low frequency (ULF) waves in the foreshock region upstream of Mars’ bow shock observed by the Mars Atmosphere and Volatile EvolutioN (MAVEN) spacecraft at Mars. A survey of MAVEN magnetic field and plasma measurements shows quasi-periodic gradual increases followed by a sharp decrease in the magnetic field magnitude (Btotal). Higher frequency waves were also commonly, but not always, observed at the trailing edge of the large-amplitude increase in Btotal. These observations are consistent with the signatures of shocklets observed in the solar wind region upstream of Earth’s and planetary bow shocks. Shocklets are believed to be formed as a result of the steepening of fast magnetosonic waves generated by reflected ions in the quasi-parallel foreshock region. We also performed the minimum variance analysis (MVA) and statistical analysis technique to determine the wave properties (e.g. polarization, wave propagation, amplitude and frequency) of the shocklets and higher frequency waves observed in its trailing edge. Our results showed that these shocklets are left-handed polarized in the spacecraft frame, with mean amplitude δB/B of ~3.5 and time separation between adjacent shocklet events of ~40s. We also analyzed measurements (ions and electrons) from MAVEN’s plasma instruments to investigate the energization process of the particles during the observations of shocklets. We will discuss the possible generation mechanisms for these steepened ultra-low frequency waves at Mars, and any implications for the martian plasma environment downstream of Mars’ bow shock. 

How to cite: Poh, G., Espley, J., Xu, S., Le, G., Romanelli, N., Halekas, J., DiBraccio, G., and Gruesbeck, J.: MAVEN Observations of Steepened Ultra-Low Frequency Waves in the Upstream Martian Foreshock Region, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-10536, https://doi.org/10.5194/egusphere-egu23-10536, 2023.

EGU23-10616 | ECS | Orals | ST2.2

Generation of sub-ion scale magnetic holes from electron shear flow instabilities in plasma turbulence 

Giuseppe Arrò, Francesco Pucci, Francesco Califano, and Giovanni Lapenta

Magnetic holes are coherent structures associated with a strong depression in the magnetic field amplitude. Such structures are ubiquitous in space plasmas and are observed in the solar wind, in planetary bow shocks and magnetosheaths, in the Earth's magnetotail and around comets. Magnetic holes may have very different sizes and properties. The largest ones have a size of hundreds of ion gyroradii while the smallest ones are sub-ion scale structures of the order of a few electron gyroradii. The drop in magnetic field amplitude associated with magnetic holes is often sustained by an increase in plasma density and enhanced ion and electron temperature anisotropies, with temperatures that are typically higher in the plane perpendicular to the local magnetic field. These properties seem to suggest that the generation of magnetic holes may result from the nonlinear evolution of mirror modes whose growth is fed by perpendicular temperature anisotropies and that are characterized by anticorrelated magnetic field and density perturbations. Some observational and numerical studies seem to support the idea of a scenario in which magnetic holes are generated by the mirror instability but in many cases this picture is not consistent with observations, especially in the case of sub-ion scale magnetic holes for which a number of possible generation mechanisms have been considered. Hence, the origin of magnetic holes is still controversial and under debate. 

Plasma turbulence is also known as a driver for the generation of coherent structures and may play a key role in the formation of magnetic holes, especially in the solar wind and in the Earth's magnetosheath that are in a turbulent state. Indeed, numerical simulations of plasma turbulence show that sub-ion scale magnetic holes can develop self-consistently out of small scale magnetic fluctuations that locally reduce the magnetic field amplitude and trap hot electrons. However, it is still unclear how such small scale fluctuations can emerge in a turbulent plasma where energy is typically injected at large scales. In this work, we study the formation of sub-ion scale magnetic holes by means of fully kinetic particle-in-cell simulations of plasma turbulence. We show that by injecting energy at scales relatively large with respect to ion scales, the turbulence naturally tends to generate sub-ion scale electron velocity shear layers associated with elongated magnetic field grooves. These elongated magnetic dips then become unstable and break up into sub-ion scale magnetic holes characterized by an intense azimuthal electron current and a strong perpendicular electron temperature anisotropy. We show that the properties of magnetic holes generated by this mechanism are consistent with satellite observations. Our results may provide a possible explanation of how magnetic holes develop in a realistic turbulent environment.

How to cite: Arrò, G., Pucci, F., Califano, F., and Lapenta, G.: Generation of sub-ion scale magnetic holes from electron shear flow instabilities in plasma turbulence, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-10616, https://doi.org/10.5194/egusphere-egu23-10616, 2023.

EGU23-10625 | ECS | Orals | ST2.2

Modification of magnetosheath jet occurrence and properties within CMEs and SIRs 

Florian Koller, Ferdinand Plaschke, Luis Preisser, Manuela Temmer, Owen Roberts, and Zoltan Vörös

Large-scale solar wind (SW) structures like coronal mass ejections (CMEs) and stream interaction regions (SIRs) significantly alter the plasma within the Earth’s magnetosheath and change the foreshock region. Thus, they modulate the number and the parameters of dynamic pressure transients in the magnetosheath, which we call magnetosheath jets. We use THEMIS spacecraft data from 2008 to 2022 to detect these jets in the magnetosheath and OMNI data for the SW within the same time range. We investigate which properties in each SW structure primarily influence the jet occurrence. We find that CMEs cause a reduction in jet occurrence due to the mix of high magnetic field strength, high plasma beta, low Mach number, and high cone angles. These conditions most likely disrupt the building of a proper foreshock region and thus hinder the major generation mechanism for jets in the magnetosheath. On the other hand, high speed streams in SIRs show favorable conditions for jet generation in all plasma parameters, most importantly due to the high probability for low cone angles, the low density, high velocity, and low magnetic field strength. We analyze how the jet parameters differ in each type of  SW structure and discuss how this influences the geoeffectiveness of jets.

How to cite: Koller, F., Plaschke, F., Preisser, L., Temmer, M., Roberts, O., and Vörös, Z.: Modification of magnetosheath jet occurrence and properties within CMEs and SIRs, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-10625, https://doi.org/10.5194/egusphere-egu23-10625, 2023.

EGU23-11073 | Orals | ST2.2

Probing the foreshock wave boundary 

Seth Dorfman, Kun Zhang, Lucile Turc, Urs Ganse, and Minna Palmroth

Foreshock ultralow frequency (ULF) waves play an important role in the dynamics upstream of planetary bow shocks and can affect the downstream magnetosheath region.  Due to limited available spacecraft measurements, the waves are often analyzed with incomplete information about their overall spacial structure. Common wave vector analysis techniques built around these limitations often invoke the divergence free condition of the magnetic field without considering the possibility that the wave amplitude profile could have a strong spacial dependence.  We explore the consequences of this assumption in the Earth's ion foreshock using both ARTEMIS spacecraft data and a 2-D hybrid Vlasov simulation conducted using the Vlasiator code.  The observed foreshock ULF waves have a finite extent in the direction perpendicular to the Interplanetary Magnetic Field, and incorrect application of standard techniques at the boundary yields a false wave vector orientation that may be used as a novel edge detection method.  Our results stand as a cautionary tale for wave analysis in other space physics contexts where the wave geometry is less clear.

Supported by NASA Grant 80NSSC20K0801. Vlasiator is developed by the European Research Council Starting grant 200141-QuESpace, and Consolidator grant GA682068-PRESTISSIMO received by the Vlasiator PI. Vlasiator has also received funding from the Academy of Finland. See www.helsinki.fi/vlasiator

How to cite: Dorfman, S., Zhang, K., Turc, L., Ganse, U., and Palmroth, M.: Probing the foreshock wave boundary, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-11073, https://doi.org/10.5194/egusphere-egu23-11073, 2023.

EGU23-12129 | ECS | Posters on site | ST2.2

Global 3D simulation of the interaction between a turbulent solar wind and a magnetic dipole 

Etienne Behar, Pierre Henri, Giulio Ballerini, Francesco Pucci, and Cyril Simon-Wedlund

Far from an ideal laminar flow, the solar wind impacting planetary magnetospheres contains a spectrum of fluctuations extending to virtually all scales. The study of the effects of such fluctuations on a magnetosphere was until recently lacking a numerical tool which would provide a self-consistent global picture of such an interaction. Using a novel 2-step approach, the open source, hybrid-PIC code Menura is employed to first develop a 3D turbulent cascade in an otherwise homogeneous plasma, to then inject this turbulent solution in a domain containing a permanent dipole. We show how solar wind turbulence is affected by the crossing of the shock, and conversely how the global shape of the magnetosphere is evolving compared to its laminar counterpart. We additionally highlight how transient phenomena and coherent structures are naturally occurring in the foreshock and the sheath due to the local direction of the turbulent magnetic field.

How to cite: Behar, E., Henri, P., Ballerini, G., Pucci, F., and Simon-Wedlund, C.: Global 3D simulation of the interaction between a turbulent solar wind and a magnetic dipole, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-12129, https://doi.org/10.5194/egusphere-egu23-12129, 2023.

EGU23-12611 | Posters on site | ST2.2

Kinetic effects and their role on the entry and transport of finite-size plasma jets inside the Hermean magnetosphere 

Gabriel Voitcu, Marius Echim, Eliza Teodorescu, and Costel Munteanu

The dynamics of finite-size plasma irregularities/jets streaming across magnetic discontinuity regions, as the magnetopause, is a key process for better understanding the transport of mass, momentum and energy from the solar wind towards planetary magnetospheres. In this paper we investigate the kinetic effects and their role on the entry and transport of localized solar wind/magnetosheath plasma structures inside the Hermean magnetosphere under northward orientation of the interplanetary magnetic field. For this purpose, we use three-dimensional particle-in-cell simulations adapted to the interaction between plasma elements/irregularities/jets of finite spatial extent and the typical magnetic field of Mercury’s magnetosphere. Our simulations reveal the penetration of solar wind plasma across the Hermean magnetopause and transport inside the magnetosphere. The entry process is controlled by the magnetic field increase at the magnetopause. For reduced jumps of the magnetic field (i.e. for larger values of the interplanetary magnetic field), the magnetospheric penetration is enhanced. The equatorial dynamics of the plasma element is characterized by a dawn-to-dusk asymmetry, the braking being stronger in the dawn flank. More plasma penetrates into the dusk flank and advances deeper inside the magnetosphere than in the dawn flank. The simulation results are discussed in the context of the impulsive penetration mechanism.

How to cite: Voitcu, G., Echim, M., Teodorescu, E., and Munteanu, C.: Kinetic effects and their role on the entry and transport of finite-size plasma jets inside the Hermean magnetosphere, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-12611, https://doi.org/10.5194/egusphere-egu23-12611, 2023.

EGU23-15140 | ECS | Posters on site | ST2.2

Morphology case study of magnetic holes in the pristine solar wind 

Henriette Trollvik, Tomas Karlsson, and Savvas Raptis

Magnetic holes (MHs) are deep depressions in the magnetic field found in the solar wind and in planetary magnetosheaths. Based on Cluster multi-point data from the pristine solar wind, we investigate the morphology of MHs exhibiting no to little rotation in the magnetic field (linear MHs). We introduce a new coordinate system, to better see the variation in the structure, and to be able to connect to solenoid-based models. We will present two events; One is an event where the observations suggest a long cylindrical shape, where the observations are compared to an infinitely long solenoid model. For this event we only consider a 2D model. The other event is where the observations suggest a truncated cylinder shape, where the event is compared to a 3D model of a truncated solenoid. We will show how well the models are able to reconstruct the observations and present some results. 

How to cite: Trollvik, H., Karlsson, T., and Raptis, S.: Morphology case study of magnetic holes in the pristine solar wind, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-15140, https://doi.org/10.5194/egusphere-egu23-15140, 2023.

EGU23-15282 | Orals | ST2.2

Morphology and evolution of foreshock structures in a high-Mach number hybrid-Vlasov simulation of Earth's magnetosphere 

Markus Battarbee, Martin Archer, Heli Hietala, Ferdinand Plaschke, Minna Palmroth, and Lucile Turc and the the Vlasiator team

Counter-streaming particles reflected from the Earth's bow shock towards the Sun build up the ion foreshock, exciting right-handed ultra-low frequency (ULF) waves, which convect with the solar wind back to the bow shock. As these waves move Earthward, they steepen and interact with each other, forming a complex wave field consisting of various foreshock structures. Observations of foreshock structures have classified them as, for example, ULF waves, shocklets, short large-amplitude magnetic structures (SLAMS), cavitons, and spontaneous hot flow anomalies (SHFAs). We present results from a high Mach number 2D-3V hybrid-Vlasov Vlasiator simulation of the Earth's bow shock and foreshock during quasi-radial IMF and place them in the context of spacecraft observations. We combine spatial analysis of bulk characteristics within the foreshock with virtual spacecraft observations to evaluate the morphology of foreshock structures as they form, and how they subsequently evolve as they approach the Earth's bow shock.

How to cite: Battarbee, M., Archer, M., Hietala, H., Plaschke, F., Palmroth, M., and Turc, L. and the the Vlasiator team: Morphology and evolution of foreshock structures in a high-Mach number hybrid-Vlasov simulation of Earth's magnetosphere, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-15282, https://doi.org/10.5194/egusphere-egu23-15282, 2023.

EGU23-7 | ECS | Orals | ST1.10

Modeling the 2020 November 29 solar energetic particle event using EUHFORIA and iPATH models 

Zheyi Ding, Nicolas Wijsen, Gang Li, and Stefaan Poedts

We present the implementation of a coupling between EUropean Heliospheric FORcasting Information Asset (EUHFORIA) and improved Particle Acceleration and Transport in the Heliosphere (iPATH) models. In this work, we simulate the widespread solar energetic particle (SEP) event of 2020 November 29 and compare the simulated time-intensity profiles with measurements at Parker Solar Probe (PSP), the Solar Terrestrial Relations Observatory (STEREO)-A, SOlar and Heliospheric Observatory (SOHO), and Solar Orbiter (SolO). We examined the temporal evolution of shock parameters and particle fluxes during this event and we find that adopting a realistic solar wind background can significantly impact the expansion of the shock and, consequently, the shock parameters. Time-intensity profiles with an energetic storm particle event at PSP are well reproduced from the simulations. In addition, the simulated and observed time-intensity profiles of protons show a similar two-phase enhancement at STA. These results illustrate that modeling a shock using a realistic solar wind is crucial in determining the characteristics of SEP events. The decay phase of the modeled time-intensity profiles at Earth is in good agreement with the observations, indicating the importance of perpendicular diffusion in widespread SEP events. Taking into account the possible large curved magnetic field line connecting to SolO, the modeled time-intensity profiles show a good agreement with the observation. We suggest that the broadly distorted magnetic field lines, which are due to a stream interaction region, may be a key factor in understanding the observed SEPs at SolO.

How to cite: Ding, Z., Wijsen, N., Li, G., and Poedts, S.: Modeling the 2020 November 29 solar energetic particle event using EUHFORIA and iPATH models, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-7, https://doi.org/10.5194/egusphere-egu23-7, 2023.

EGU23-1741 | ECS | Posters virtual | ST1.10

Energy Spectrum of Solar Energetic Electron Events Over 25 Years 

Wen Wang, Linghua Wang, Zixuan Liu, Samuel Krucker, and Robert F. Wimmer-Schweingruber

Solar Energetic electron (SEE) events are the most common solar particle acceleration phenomenon detected in situ in the interplanetary medium and the energy spectrum of SEE events carries crucial information on the acceleration and/or transport processes of SEEs. In our research, we investigate the peak flux energy spectrum of 458 SEE events with a clear velocity dispersion detected at energies from ≤ 4.2 keV to ≥ 108 keV by Wind/3DP from 1994 December through 2019 December, utilizing a pan-spectrum fitting method. According to the fitted spectral parameters, these 458 events are self-consistently classified into five spectral shapes: 304 DDPL events, 32 UDPL events, 23 SPL events, 44 ER events and 55 LP events. The DDPL events can be further divided in to two types: 231 EB≥20 keV DDPL events and 73 EB<20 keV DDPL events, since the distribution of break energy EB exhibits a primary peak around 60 keV and a secondary peak around 7 keV, separated by a dip at ~20 keV. The EB≥20 keV (EB<20 keV) DDPL events exhibit a power-law spectral index of 2.0+0.2-0.2(2.1+0.3-0.3) (values shown in a form of A+B-C means the median value with the first and the third quartiles) at energies below EB=5.6+2.3-2.4 keV (60+23-12 keV) and index of 3.3+0.5-0.3 (3.9+0.6-0.7) at energies above.The UDPL events have a spectral index of 3.0+0.3-0.3 at energies below EB=5.1+4.2-1.8 keV and index of 2.2+0.2-0.3 at energies above. The SPL events shows a spectral index of 2.8+0.5-0.2. The ER events exhibit a spectral index 1.9+0.3-0.3 at energies below Ec=30+19-10 keV. The six spectrum types also behave differently in the relationship between spectral parameters and in solar cycle variations. Furthermore, propagation effects in the IPM from the Sun to 1 AU appear to have no obvious influence on the spectral shape of most SEE events. These results suggest that the formation of SEE events can involve complex processes/sources.

How to cite: Wang, W., Wang, L., Liu, Z., Krucker, S., and Wimmer-Schweingruber, R. F.: Energy Spectrum of Solar Energetic Electron Events Over 25 Years, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-1741, https://doi.org/10.5194/egusphere-egu23-1741, 2023.

EGU23-2518 | ECS | Orals | ST1.10

Solar activity relations in energetic electron events measured by the MESSENGER mission 

Laura Rodríguez-García, Laura Balmaceda, Raúl Gómez-Herrero, Athanasios Kouloumvakos, Nina Dresing, David Lario, Yannis Zouganelis, Annamaria Fedeli, Francisco Espinosa Lara, Ignacio Cernuda, George Ho, Robert Wimmer-Schweingruber, and Javier Rodríguez-Pacheco

We perform a statistical study of the relations between the properties of solar energetic electron (SEE) events measured by the MESSENGER mission from 2010 to 2015 and the parameters of the respective parent solar activity phenomena to identify the potential correlations between them. During the time of analysis MESSENGER heliocentric distance varied between 0.31 and 0.47 au.

The main conclusion of the study is as follows. For this particular sample of events, with a majority of SEE events being widespread in heliolongitude and displaying relativistic electron intensity enhancements, a shock-related acceleration mechanism might be relevant in the acceleration of near-relativistic electrons. This conclusion is mainly based on three results. (1) The high and significant correlation found between the SEE peak intensities and the shock speed. (2) The ∼4 orders of magnitude in the SEE peak intensities for the same CME-driven shock speed that might be related to the presence of supra-thermal seed population that made local shock acceleration more efficient. (3) The asymmetry to the east of the range of connection angles (CAs) for which the SEE events present higher peak intensities and higher correlations with the solar activity, which might be related to the evolution of the magnetic field connection to the shock front. We note that the CA is defined as the angular distance between the footpoint of the magnetic field connecting to the spacecraft and the longitude of the source region.

How to cite: Rodríguez-García, L., Balmaceda, L., Gómez-Herrero, R., Kouloumvakos, A., Dresing, N., Lario, D., Zouganelis, Y., Fedeli, A., Espinosa Lara, F., Cernuda, I., Ho, G., Wimmer-Schweingruber, R., and Rodríguez-Pacheco, J.: Solar activity relations in energetic electron events measured by the MESSENGER mission, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-2518, https://doi.org/10.5194/egusphere-egu23-2518, 2023.

EGU23-4398 | ECS | Posters on site | ST1.10

Analysis of the Energetic Storm Particle events of 6-7 September 2017 

Federica Chiappetta, Monica Laurenza, Fabio Lepreti, Simone Benella, and Giuseppe Consolini

Most of the energetic particles observed in the heliosphere are accelerated from a few keV up to MeV by shock fronts which are associated with the transit of coronal mass ejections (CMEs). The study of energetic storm particle events (ESP) can be very helpful for the investigation of the acceleration processes of particles at the shocks. We considered two ESP events occurring 6-7 September, 2017. The data used to study kinetic energy spectra are proton flux enhancements provided by WIND and ACE spacecraft that are both at the Lagrangian point L1, close to 1 AU along the Sun-Earth direction. The energy ranges are from 70 keV to 70 MeV and from 40 keV to 4.8 MeV, respectively. In order to broaden the range of the analyzed energies, we combine these data with the proton fluxes from SoHO spacecraft, also located at L1, which detects particles with energies from 1.3 MeV to 130 MeV. We used the Weibull functional form, the double power law and the Ellison-Ramaty form to fit the observed spectra. The implications of the obtained results for particle acceleration are discussed, taking also into account the properties of the shocks and of the magnetic turbulence in their surroundings.

This research has been carried out in the framework of the CAESAR project, supported by the Italian Space Agency and the National Institute of Astrophysics through the ASI-INAF n. 2020-35-HH.0 agreement for the development of the ASPIS prototype of scientific data centre for Space Weather.”

How to cite: Chiappetta, F., Laurenza, M., Lepreti, F., Benella, S., and Consolini, G.: Analysis of the Energetic Storm Particle events of 6-7 September 2017, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-4398, https://doi.org/10.5194/egusphere-egu23-4398, 2023.

Radiation is one of the most important risks to deep space exploration programs such as manned missions to the Moon and Mars. In preparation for such programs, it requires a thorough understanding of interplanetary space weather conditions and a timely forecast of their potential effects as a baseline for the development of mitigation strategies. 

 

Radiation damage in space comes mainly from two sources, Galactic Cosmic Rays (GCRs) and Solar Energetic Particles (SEPs). In particular, intense SEP events could result in very high doses in a short time period that may exceed the threshold to induce deterministic radiation effects and to result in severe damages to humans and equipment leading to the failure of the entire mission. SEP events with radiation hazards, despite of being rather infrequent and sporadic, are however very difficult to forecast and remain as a major challenge for space weather studies in preparation for future deep space and Mars missions.

 

Specifically speaking, the SEP radiation reaching an astronaut on a Mars may be completely different from of that detected at (or predicted for) Earth’s vicinity, including the SEP onset time, spectra evolution, radiation intensity etc. This is due to (1) the different location of Mars and connectivity to the acceleration source which allow it to have difference access to the SEP population, and (2) the different planetary environment which modifies the energy and composition of the particles due to the interactions of primary particles with the atmosphere/regolith and the generation of secondaries. The synergistic analysis and modeling of these two processes are particularly important to understand and eventually forecast SEPs and their radiation effects on Mars in preparation for mitigating their potential hazardous effects.  We also emphasize the utmost importance of utilizing multi-spacecraft particle measurements at Mars and also other heliospheric locations to better understand such extreme events and their radiation effects for future deep space explorers.

How to cite: Guo, J.: The Impact of Solar Energetic Particles at Mars’ radiation environment: A synergistic approach combining measurements and Modeling efforts, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-5292, https://doi.org/10.5194/egusphere-egu23-5292, 2023.

EGU23-7171 | Posters on site | ST1.10

Modelling of atmospheric transport of SEP-induced cosmogenic 10Be  using CCM SOCOL-AER2-BE 

Kseniia Golubenko, Eugene Rozanov, Gennady Kovaltsov, Mélanie Baroni, and Ilya Usoskin

10Be is a cosmogenic isotope continuously produced in the Earth’s atmosphere by galactic cosmic rays (GCRs) and sporadically by solar energetic particles (SEPs). The long-living isotope, as measured in polar ice cores, typically with an annual resolution, serves as a proxy for long-term cosmic-ray variability, whose signal can, however, be distorted by atmospheric transport and deposition that need to be properly modelled. Atmospheric transport of 10Be depends on production, atmospheric circulation, and local orography. For an accurate physical description of the isotope's transport and deposition, we use the chemical climate model (CCM) SOCOL-AER2-BE. In combination with the production model CRAC, our model was verified using real measurements of beryllium in ice cores for Antarctic and Greenland locations. The model results agree with the measurements at the absolute level, implying that the production, decay, and lateral deposition are correctly reproduced. However, the exact time variability is not always well reproduced, particularly for the Greenland shore sites implying significant regional effects. Potentially, extreme SPEs that are orders of magnitude stronger than those observed during the recent decades can be recorded in cosmogenic isotope data, and a proper model is needed to study them. Here we present a model of the production and transport of 10Be for a major solar energetic particle event (GLE 69) and analyze the geographical pattern of the beryllium concentration.

How to cite: Golubenko, K., Rozanov, E., Kovaltsov, G., Baroni, M., and Usoskin, I.: Modelling of atmospheric transport of SEP-induced cosmogenic 10Be  using CCM SOCOL-AER2-BE, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-7171, https://doi.org/10.5194/egusphere-egu23-7171, 2023.

EGU23-7905 | ECS | Orals | ST1.10 | Highlight

Development of an In-Progress Forecasting Model to Forecast Radiation Dose Rates Once a Ground-Level Enchancement has Begun 

Chris Davis, Charlotte Waterfall, Fan Lei, Silvia Dalla, Keith Ryden, Ben Clewer, and Clive Dyer

During major solar energetic particle events, radiation dose rates in Earth's atmosphere at aviation altitudes can increase by orders of magnitude relative to dose rates during quiet times in events known as Ground-Level Enhancements (GLEs). In the case of events of a scale such that they occur once every few decades, radiation dose rates could become high enough that they pose a threat to aircraft crew and electronics. It is not currently possible to predict when such an event will occur, and existing software systems are only capable of nowcasting the current atmospheric radiation dose rates using real-time data sources. However, while it is not possible to forecast when a major event will occur, it may be possible to generate forecasts for radiation dose rates once an event has been registered to have begun. The ability to provide forecasts for dose rates once a GLE has started would be vital for airlines and for pilots in any future where aircraft might be rerouted to avoid regions of high radiation, as pilots need to be able to know not just their current radiation dose rates but radiation dose rates at possible locations where their plane might be in say half an hour's time. We report on the development of a software system to do this. This 'in-progress' radiation dose rate forecasting system will be developed by integrating the FOrecasting Relativistic particles during GLE Events (FORGE) system being developed at the University of Central Lancashire with an anisotropic extension to the Models for Atmospheric Ionising Radiation Effects+ (MAIRE+) system being developed at the University of Surrey. We report on the development of both of these systems and their integration.

How to cite: Davis, C., Waterfall, C., Lei, F., Dalla, S., Ryden, K., Clewer, B., and Dyer, C.: Development of an In-Progress Forecasting Model to Forecast Radiation Dose Rates Once a Ground-Level Enchancement has Begun, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-7905, https://doi.org/10.5194/egusphere-egu23-7905, 2023.

EGU23-8936 | ECS | Orals | ST1.10

Particle Energisation in a 3D Collapsing Magnetic Trap Model With a Braking Jet  

Kate Mowbray and Thomas Neukirch

Investigating the motion of charged particles in time- and space-dependent electromagnetic fields is central to many areas of space and astrophysical plasmas. Here we present results of studying the energy changes of particle orbits that are trapped in inhomogeneous and time-dependent magnetic fields with rapidly shortening field lines. These so-called collapsing magnetic trap (CMT) models can be useful to better understand the particle energisation processes occurring below the reconnection region in a solar flare. Braking jets may be associated with magnetic reconnection, for example when a sunward flow slows down as it approaches a stronger region of magnetic field. We generalise a 2D CMT model with braking jet (Borissov et al., 2016) to three dimensions and investigate the dynamics of particles in this 3D CMT model. The resulting particle orbits show a sensitive dependence of particle energies on the initial conditions of orbits, with initial pitch angles playing a particularly important role. This sensitive dependence relates to the time evolution of trapping regions that develop in the braking jet region of the CMT, ensuring that some orbits spend a significant time in the loop legs of field lines, whilst others escape these regions for the duration of the simulation. These loop leg trapped particle orbits see significantly lower energy gains than those orbits that repeatedly pass the loop top, with some of these particles even losing energy. This gives us greater insight into the importance of the curvature of collapsing loop tops for the Fermi acceleration mechanism acting on the particles. 

 

Borissov A. et al., Solar Physics 291, Issue 5, 1385 

How to cite: Mowbray, K. and Neukirch, T.: Particle Energisation in a 3D Collapsing Magnetic Trap Model With a Braking Jet , EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-8936, https://doi.org/10.5194/egusphere-egu23-8936, 2023.

A joint analysis approach is used to study flare signatures both in the low and higher corona. STIX, AIA and LOFAR data provide an extensive picture about different aspects of flare characteristics. Recent data by the STIX instrument complement the picture of accelerated electrons, which propagate along magnetic field lines towards the Sun. These observations are linked to the LOFAR data, which contain information about the elctrons propagating away from the Sun through the corona above the active region. Although, the active region and its thermal evolution (Differential Emission Measure (DEM) reconstruction of AIA data), flare accelerated electrons and their radio traces (LOFAR, STIX) are in principal all associated with the energy release during the flare process, they are often studied seperatly. Hence, the investigation of possible relations is part of this project. Solar magnetic fields as a binding element between low and high corona, accelerated electrons and heated flare loops are included in the analysis via a Potential Field Source Surface (PFSS) model.

How to cite: Bröse, M. and Vocks, C.: Flare-accelerated electrons and their traces in the solar corona observed by space- and ground-based instruments, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-9582, https://doi.org/10.5194/egusphere-egu23-9582, 2023.

EGU23-10509 | ECS | Posters on site | ST1.10

Radial Variation of Suprathermal Particles Associated with Corotating Interaction Regions 

Robert Allen, George Ho, Glenn Mason, Athanasios Kouloumvakos, Robert Wimmer-Schweingruber, and Javier Rodríguez-Pacheco

The first three years of Solar Orbiter operations have enabled robust sampling of the intensity and composition of suprathermal particles within the inner heliosphere. This includes a multitude of observations of suprathermal ions associated with Corotating Interaction Regions (CIRs), with corresponding observations at 1 au with measurements from the Ultra-Low-Energy Isotope Spectrometer (ULEIS) on the Advanced Composition Explorer (ACE) mission and the Suprathermal Ion Telescope (SIT) on the Solar-Terrestrial Relations Observatory-Ahead (STEREO-A) spacecraft. Comparing observations between these spacecraft allows for a statistical view of the radial variations of CIR-associated suprathermal particles by composition in the inner heliosphere, allowing for greater insight into energetic particle transport within the inner heliosphere. This study expands on early results from Solar Orbiter and ACE to now encompass the first three years of Solar Orbiter operations, as well as include STEREO-A measurements. Comparisons to historical studies of CIR-associated energetic protons are also expanded in the survey of CIR-associated suprathermal particles from Solar Orbiter, ACE, and STEREO-A.

How to cite: Allen, R., Ho, G., Mason, G., Kouloumvakos, A., Wimmer-Schweingruber, R., and Rodríguez-Pacheco, J.: Radial Variation of Suprathermal Particles Associated with Corotating Interaction Regions, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-10509, https://doi.org/10.5194/egusphere-egu23-10509, 2023.

EGU23-11362 | ECS | Posters virtual | ST1.10

Solar Energetic Electron Events with a Spectral Bump 

Wenyan Li, Linghua Wang, and Wen Wang

The energy spectrum of solar energetic electron (SEE) events carries crucial information on the origin/acceleration of energetic electrons at the Sun. Using  the Wind 3DP electron measurements at ~1 to 200 keV during 1995-2019, we select 11 good SEE events with a bump-like break in the peak flux vs. energy spectrum, different from the typical SEE events with a double-power-law spectrum. For the selected 11 events, the background-subtracted electron peak flux versus energy spectrum fits well to two functions: the sum of a single-power-law and a Gaussian function (spectral function #1) and the product of a single-power-law and the natural exponential form of a Gaussian function (spectral function #2). For the spectral function #1 (#2), on average, the fitted spectral index is 2.6±0.4 (2.7±0.6), significantly larger than the low-energy power-law index of typical SEE events, while the fitted center energy of spectral bump is 24±7 keV (75±38 keV) and the ratio of bump width and center is 2.0±0.7 (3.4±2.8). Among these 11 events, respectively, ~78%, ~89%, ~90%, 100% and ~55% are associated with GOES SXR flares, RHESSI HXR flares, west-limb CMEs, type III radio bursts and type II  radio bursts. Thus, these bump events have a stronger association with flares, coronal mass ejections (CMEs) and type II radio bursts, compared to the typical SEE events. In addition, we find a positive correlation between the center energy of bump and the CME speed. Therefore, we come up with an acceleration picture of these bump SEE events: the power-law portion is probably accelerated by flares with the acceleration efficiency larger at lower energies, while the bump portion is likely accelerated in CME-related processes with the acceleration efficiency increasing with the CME speed.

How to cite: Li, W., Wang, L., and Wang, W.: Solar Energetic Electron Events with a Spectral Bump, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-11362, https://doi.org/10.5194/egusphere-egu23-11362, 2023.

EGU23-12330 | ECS | Orals | ST1.10 | Highlight

When are energetic electrons producing NO directly in the upper stratosphere? 

Josephine Salice, Hilde Nesse, Noora Partamies, Emilia Kilpua, Andrew Kavanagh, Eldho Babu, and Christine Smith-Johnsen

Compositional NOx changes caused by energetic electron precipitation (EEP) at a specific altitude are called the EEP direct effect. Changes co-dependent on vertical transport are referred to as the EEP indirect effect. The relative importance of EEP’s direct and indirect effect on NO and its subsequent impact on ozone and dynamic changes remain unresolved. The challenges are partly due to inadequate particle measurement and the relative scarcity of NO observations over the polar MLT region. Moreover, lower production rates in the mesosphere make it challenging to determine EEP’s direct impact on NO since small in-situ enhancements cannot be easily distinguished from the descending NO-rich air masses in the winter hemisphere. In this study, the uncertainty of the EEP observations is bypassed by exclusively identifying events applying NO-observations from the SOFIE instrument on board the AIM satellite. SOFIE daily averaged data from 2007 to 2014 is used to create a climatology based on the mean of the lower half of the data (lower 50 percentile mean). A direct EEP-produced NO-event at 90 km (“90km-event”) is identified when the NO density surpasses the climatology by 100%. If the NO density exceeds 25% above the climatology at 80, 70, 60, and 50 km, the event qualifies as a “50km-event”. By contrasting the 90km and 50km events, the characteristics of the solar wind and geomagnetic indices, as well as observed electron fluxes from POES, are studied. The goal is to unravel when EEP can produce NO directly in the upper stratosphere. The result will contribute to developing a parameterization of EEP from the radiation belt that includes both the direct and indirect impact of EEP to decipher the total EEP effect on the ozone and atmospheric dynamics.

How to cite: Salice, J., Nesse, H., Partamies, N., Kilpua, E., Kavanagh, A., Babu, E., and Smith-Johnsen, C.: When are energetic electrons producing NO directly in the upper stratosphere?, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-12330, https://doi.org/10.5194/egusphere-egu23-12330, 2023.

EGU23-13801 | ECS | Posters virtual | ST1.10

Witnessing a Forbush Decrease with a Microscintillator Ionisation Detector over the Atlantic Ocean 

Justin Tabbett, Karen Aplin, and Susana Barbosa

A novel ionisation detector, previously deployed on meteorological radiosonde flights, has demonstrated responsivity to X-rays and gamma radiation, and additionally, is thought to be sensitive to ionising radiation from cosmic rays. The PiN detector, composed of a 1x1x0.8 cm3 CsI(Tl) microscintillator coupled to a PiN photodiode, was deployed on the NRP Sagres sailing vessel on a cruise in the Atlantic between Portugal and the Azores in 2021. The instrument can determine both the count rate and energy of incoming ionising radiation particles.

The instrument was operational during the voyage in November 2021 when a coronal mass ejection event induced a sudden decrease in the observed cosmic ray intensity, known as a Forbush decrease. We present data recorded by the ionisation detector during this period, to characterise the instrument’s ability to detect cosmic ray events, and we compare the performance with neutron monitoring stations Oulu in Finland, and Dourbes in Belgium. As the PiN detector provides spectral and count rate data, it is possible to group events by their energy, and investigate the count rates of specific energy regimes. This approach is useful as many sources – including high and low energy ionising radiation from cosmic rays – contribute to the background energy spectrum. As a result, more meaningful comparisons and relationships can be established with the neutron monitoring stations.

How to cite: Tabbett, J., Aplin, K., and Barbosa, S.: Witnessing a Forbush Decrease with a Microscintillator Ionisation Detector over the Atlantic Ocean, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-13801, https://doi.org/10.5194/egusphere-egu23-13801, 2023.

EGU23-14711 | Orals | ST1.10

Monitoring of Solar Energetic Particles and Cosmic Rays with the RADEM instrument onboard the ESA JUICE mission 

Wojtek Hajdas, Patricia Goncalves, Marco Pinto, Andre Galli, and Olivier Witasse

The main goal of the radiation monitor RADEM flying onboard the ESA JUICE mission is to provide continuous information on particle fluxes and their energy spectra. The monitor measures electrons up to 40 MeV and protons up to 250 MeV. Such a range of energies detected by RADEM enables covering the most hazardous regimes in terms of radiation damage. Spectroscopic information on particle energies is provided using eight quasi-logarithmic energy bins. RADEM has also a dedicated heavy-ion detector designed to measure a variety of heavy ion species with their LET between 0.1 and 10 MeV/cm/mg-1. Moreover, the monitor contains an additional detector sensitive to the direction of incoming radiation. It expands the instrument's angular coverage up to 35% of the sky. Apart from its spectroscopic and angular distribution functions, RADEM will continuously provide values of the radiation dose deposited by each particle species. Its telemetry data will be stored in the data center for the JUICE mission operated by the European Space Astronomy Centre. After preprocessing the higher-level data will become available to the JUICE scientific team. RADEM will be switched on shortly after the JUICE launch planned for April 2023 and after a short commissioning phase will start its nominal operation. Apart from regular and short tuning and calibration periods, it will remain operating for the rest of the mission i.e. almost 10 years. While its primary purpose is to monitor the mission levels for safety concerns of the spacecraft and its scientific payload, its measurements open a unique opportunity for conducting real-time, continuous observations during its full cruise to Jupiter. RADEM will study all aspects of the radiation phenomena characteristic to the Earth and Solar System. Correlations with other instruments will allow for advanced observations of particle event propagation and a better understanding of processes related to the dynamics of particle environments including their links with solar activity and magnetic fields across the solar system. In particular, during its first two years of the cruise to Jupiter, RADEM will precisely map the radiation environment between Venus and Mars, providing uninterrupted time-resolved spectroscopy and dosimetry data from Solar Energetic Particles and Cosmic Rays.

How to cite: Hajdas, W., Goncalves, P., Pinto, M., Galli, A., and Witasse, O.: Monitoring of Solar Energetic Particles and Cosmic Rays with the RADEM instrument onboard the ESA JUICE mission, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-14711, https://doi.org/10.5194/egusphere-egu23-14711, 2023.

EGU23-15517 | Posters on site | ST1.10

Proton energy spectra of energetic storm particle events and their relation with magnetic turbulence and intermittency nearby interplanetary shocks 

Fabio Lepreti, Federica Chiappetta, Monica Laurenza, Simone Benella, and Giuseppe Consolini

Shock waves propagating in the interplanetary space are efficient sources of energetic particles. In situ spacecraft observations, especially particle fluxes which can be used to obtain energy spectra, provide very useful data for the investigation of the acceleration mechanisms occurring at shocks. In this work we analyse the kinetic energy spectra of several proton flux enhancements associated with energetic storm particle (ESP) events observed by various spacecraft. ESP events occurring both in association with and in absence of Solar Energetic Particles (SEPs) are considered. Moreover, ESP events associated both with quasi-perpendicular and quasi parallel shocks are investigated.  Different functional forms (i.e. Weibull function, double power law, and Ellison-Ramaty) are used to fit the observed spectra and the obtained results are discussed in relation to the shock properties and to the magnetic turbulence and intermittency in the upstream and downstream regions. More specifically, the properties of magnetic turbulence and intermittency are analysed by calculating power spectral densities and structure functions of the fluctuations of the magnetic field components and the implications for particle acceleration are examined.

This research has been carried out in the framework of the CAESAR project, supported by the Italian Space Agency and the National Institute of Astrophysics through the ASI-INAF n. 2020-35-HH.0 agreement for the development of the ASPIS prototype of scientific data centre for Space Weather.

How to cite: Lepreti, F., Chiappetta, F., Laurenza, M., Benella, S., and Consolini, G.: Proton energy spectra of energetic storm particle events and their relation with magnetic turbulence and intermittency nearby interplanetary shocks, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-15517, https://doi.org/10.5194/egusphere-egu23-15517, 2023.

EGU23-15621 | ECS | Posters on site | ST1.10

The effect of magnetic reconnection on ICME-related GCR modulation 

Emma Davies, Camilla Scolini, Réka Winslow, and Andrew Jordan

The large-scale magnetic structure of interplanetary coronal mass ejections (ICMEs) has been shown to cause temporary decreases in the galactic cosmic ray (GCR) flux measured in situ by spacecraft, known as Forbush decreases (Fds). In some ICMEs, the magnetic ejecta exhibits a magnetic flux rope structure; the strong magnetic field strength and closed field line geometry of such ICME magnetic flux ropes has been proposed to act as a shield to GCR transport. However, as ICMEs propagate, they undergo many processes including interactions and magnetic reconnection with the interplanetary magnetic field (IMF) in large-scale solar wind structures and other solar transients. In this study, we investigate how ICME interaction and reconnection during propagation affects Fd size, shape, and duration. We hypothesize that the alteration of the ICME magnetic topology due to reconnection (specifically the opening of the closed magnetic field configuration in the ICME flux rope) will have a strong effect on the ICME’s ability to modulate GCRs. To test this hypothesis, we compare the Fds of ICMEs that likely underwent reconnection during propagation with ones that likely did not.

To this end, we identify ICMEs that exhibited open magnetic field line topologies (i.e., ones that likely underwent reconnection) and we compare their effects on GCRs with those of ICMEs that exhibited closed topologies (both ends connected to the Sun). We use magnetic field, solar wind plasma, and suprathermal electron pitch angle distribution data at ACE and Wind to select the ICMEs. Furthermore, we use data by the SOPO and McMurdo neutron monitors at Earth to investigate how the magnetic structure of the ICME ejecta modulates the GCRs by comparing the resulting Fds for the selected ICMEs. The results of our study yield new insights into how the modulation of GCRs is affected by ICME evolution and interaction during propagation and whether reconnection of the ICME flux rope weakens its modulation of GCRs.

How to cite: Davies, E., Scolini, C., Winslow, R., and Jordan, A.: The effect of magnetic reconnection on ICME-related GCR modulation, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-15621, https://doi.org/10.5194/egusphere-egu23-15621, 2023.

EGU23-16136 | Posters on site | ST1.10

Energetic Electron Precipitation during Slot Region Filling Events 

Hilde Nesse, Eldho Midhun Babu, Josephine Salice, and Bernd Funke

The region separating the inner and outer radiation belt, typically devoid of energetic electrons, is termed the slot region. The outer edge of the slot region marks the equatorward edge of the energetic electron precipitation (EEP) originating from the outer radiation belt. Its varying location is strongly linked to the plasmasphere and geomagnetic activity. As such, geomagnetic indices are used to estimate the equatorward extent of the EEP region. There are, however, numerous reports where the energetic electrons cross these boundaries and fill the slot region, during which energetic electrons that can precipitate into the atmosphere long after the geomagnetic activity subsides. This is a missing source of energy input in current EEP estimates based on geomagnetic indices.

This study explores the occurrence rate, reformation, local time dependence, and energy deposition of slot region filling events. Medium energy electron measurements from the NOAA/POES over a full solar cycle from 2004 to 2014 are applied. We combine observations from the MEPED 0° and 90° detectors together with theory of pitch angle diffusion by wave-particle interaction to estimate the precipitating fluxes. To explore the energy dependent characteristics, each of the MEPED energy channels, > 43, >114, and >292 keV are evaluated independently. Finally, we investigate the potential EEP impact on the NO density utilizing seven years of Envisat MIPAS NO observations from 2005 to 2011.

How to cite: Nesse, H., Babu, E. M., Salice, J., and Funke, B.: Energetic Electron Precipitation during Slot Region Filling Events, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-16136, https://doi.org/10.5194/egusphere-egu23-16136, 2023.

EGU23-16177 | Orals | ST1.10 | Highlight

Risks of space radiation exposure to exploration astronauts: limitations in predictions based on the ground experiments and possible solutions 

Salman Khaksarighiri, Robert Wimmer-Schweingruber, Jingnan Guo, Cary Zeitlin, Thomas Berger, and Daniel Matthiä

Future expeditions into interplanetary space, and in particular to the Moon and Mars, will expose astronauts to very high levels of cosmic radiation, which are known due to years of research and instruments that have been sent to space. It is, however, a limitation in understanding the risks of this radiation for the human body due to difficulties in simulating the complex space environment on Earth or complex human phantom and the inability to extrapolate human clinical outcomes based on animal models or simulation results. 
As human spaceflight continues on its path to success, we need to develop appropriate and effective mitigation strategies for future missions to improve our understanding of the space radiation risk by identifying the constraints of radiation research on the Earth and finding possible solutions based on the existing technologies to be closer to the reality as much as possible and better understand human physiology in space.  
As part of this paper, we have identified several factors that hinder our understanding of radiation risks for human crews and have identified ways to cope with these restrictions for a better understanding and preparation for human spaceflights in the future.

How to cite: Khaksarighiri, S., Wimmer-Schweingruber, R., Guo, J., Zeitlin, C., Berger, T., and Matthiä, D.: Risks of space radiation exposure to exploration astronauts: limitations in predictions based on the ground experiments and possible solutions, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-16177, https://doi.org/10.5194/egusphere-egu23-16177, 2023.

PS4 – Interiors, crusts and atmospheres of the terrestrial planets: formation, evolution and fate (in partnership with GD)

EGU23-1163 | ECS | Posters on site | PS4.1

Effects of the Lunar Regolith Structure and of the Solar Wind Properties on the Backscattered Energetic Neutral Atoms Flux 

Sébastien Verkercke, Jean-Yves Chaufray, François Leblanc, Eduardo Bringa, Diego Tramontina, Liam Morrissey, and Adam Woodson

Airless planetary bodies’ surfaces, such as the Moon’s or Mercury’s, are composed of porous regoliths which interact directly with the impinging solar wind. In the case of the Moon, this incoming flux of solar protons has been observed to be partially neutralized and backscattered as Energetic Neutral Atoms (ENA) with reflection coefficients believed to be ranging between 0.1 and 0.2 depending on the study and/or the measurement. Such a large range of reflection coefficients reflects the diversity in the regolith’s interactions with the solar wind and underlines the lack of understanding of the lunar regolith and its influence on the particles impacting it.

The ENA flux is thought to depend on the structure of the upper regolith layer and the solar wind characteristics. By using a model combining a Monte Carlo approach to describe a solar proton’s journey through the lunar surface, with molecular dynamics to characterize its interactions with the regolith’s grains, we highlighted key parameters which influence the backscattered ENA flux and analyzed their roles in these interactions. To describe the structure of the lunar regolith we used the open-source code LAMMPS Molecular Dynamics Simulator, which allows a realistic description of grain-on-grain contacts using a Johnson-Kendall-Roberts (JKR) contact model. The porosity of the modeled regolith is shown to be dictated by the surface energy of the grains. By considering silicate grains and a realistic range of surface energy for this material, we studied regoliths’ porosities ranging from ~0.5 to 0.85. This work showed that a large porosity favors deeper penetration of the protons inside the regolith, which increases the number of collisions, and thus the energy lost by the impinging protons and their absorption. By accounting for particular directions of observation with respect to the solar wind direction, we showed that the angular distribution of the backscattered ENA is anisotropic. We here used IBEX observations and its characteristic 90° observation angle as a demonstration of the influence of this anisotropy. We finally analyzed the effects of both the energy distribution of the hydrogen atoms after a collision with a grain and the solar wind properties on the ENA energy flux spectrum shape. The modelled spectrum was also compared to the observations of Chandrayaan-1. This work aims for a better understanding of the interactions ongoing at this interface and intents to look into the possibility to deduce information on the surface structure solely from ENA flux measurements.

How to cite: Verkercke, S., Chaufray, J.-Y., Leblanc, F., Bringa, E., Tramontina, D., Morrissey, L., and Woodson, A.: Effects of the Lunar Regolith Structure and of the Solar Wind Properties on the Backscattered Energetic Neutral Atoms Flux, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-1163, https://doi.org/10.5194/egusphere-egu23-1163, 2023.

EGU23-1299 | ECS | Orals | PS4.1

A mineral sputter model in agreement with solar wind ion irradiation experiments 

Noah Jäggi, Andreas Mutzke, Herbert Biber, Paul S. Szabo, Johannes Brötzner, Friedrich Aumayr, Peter Wurz, and André Galli

The sputtering of material is mostly modeled using Binary Collision Approximation programs. Several advances were made in the last few years focusing on modeling mineral sputtering by ion impacts relevant for rocky planets exposed to solar wind. The most recent contribution, from Biber et al. [1], includes not only sputter yields, but also angular distribution data for the mineral enstatite. The existing data, although scarce, are important to validate mineral sputter simulations. A widely applicable model is integral for obtaining and interpreting information of particles ejected from exposed rocky bodies such as Mercury and the Moon. Moreover, ease of use is crucial whenever a new approach is proposed, which is to compete with the default model found in the user-friendly, but inaccurate TRIM code [2]. 

To best recreate experimental data from mineral sputtering, previously suggested approaches rely on increased surface binding energies as well as increased sample densities [3,4]. We review the capabilities and limitations of these and propose a new model to best approximate experimental results. In contrast to the earlier models, our approach achieves unprecedented agreement with available experimental data under normal incidence (Fig. 1). It thereby does not require any manual adjustments of simulation parameters to achieve realistic mineral densities and does not depend on computationally intensive determination of species-specific surface binding energies [4].

The new model considers a surface binding energy for species leaving the sample as well as a bulk binding energy within the sample based on the enthalpy of formation. The latter prevents long collision cascades due to energy loss in the sample whenever a bond of a mineral-forming compound (i.e., an oxide or sulfide) is broken. Favoring short collision cascades leads to a more prominent forward-tilt of the ejecta distribution as it is seen in experiments. The increased energy loss within the sample also causes a peak broadening in the energy distribution of ejected particles whilst shifting the peak positions slightly towards larger energies. We expect to see this behavior on oxygen-bearing minerals as the same tendencies were observed in energy distributions of irradiated oxidized metals [5,6,7]. While we wait for further experimental data our improved quantitative formulation of the mineral sputter process is a valuable contribution for achieving state of the art exosphere models for the Moon and Mercury.

Fig. 1: Sputter yield of various models in SDTrimSP compared to TRIM and experimental data [1]. Short forms: SB — surface binding energies (default); BB — bulk binding energies; SBB-C — combined SB and BB model, differentiating bound and free atoms within predefined compounds. 

 

[1] Biber, H., et al. (2022). Planet. Sci. J., 3, 271.

[2] Hobler, G. (2013). Nucl. Instrum. Methods Phys. Res. B, 303, 165–169.

[3] Szabo, P.S., et al. (2020). Astrophys. J., 891(1), 100.

[4] Morrissey, L. S., et al. (2022). Astrophys J. Lett., 925(1), L6.

[5] Dullni, E. (1984). Nucl. Instrum. Methods Phys. Res. B, 2(1–3), 610–613.

[6] Wucher, A., & Oechsner, H. (1986). Nucl. Instrum. Methods Phys. Res. B, 18(1–6), 458–463.

[7] Wucher, A., & Oechsner, H. (1988). Surf. Sci., 199(3), 567–578. 

How to cite: Jäggi, N., Mutzke, A., Biber, H., Szabo, P. S., Brötzner, J., Aumayr, F., Wurz, P., and Galli, A.: A mineral sputter model in agreement with solar wind ion irradiation experiments, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-1299, https://doi.org/10.5194/egusphere-egu23-1299, 2023.

EGU23-1968 | Orals | PS4.1

Hisaki space telescope observations of the large oscillations of Martian hydrogen and oxygen upper atmospheres 

Kei Masunaga, Naoki Terada, Nao Yoshida, Yuki Nakamura, Takeshi Kuroda, Kazuo Yoshioka, Yudai Suzuki, Hiromu Nakagawa, Tomoki Kimura, Fuminori Tsuchiya, Go Murakami, Atsushi Yamazaki, Tomohiro Usui, and Ichiro Yoshikawa

Analyzing extreme ultraviolet spectra of the Martian upper atmosphere obtained from the Hisaki space telescope, we found anti-correlation between hydrogen (HI Ly-β) and oxygen (OI 1356 Å and OI 1304 Å) airglow brightness during one of the major regional dust storms in Mars Year 33 (Masunaga et al., 2022). Ly-β brightness gradually increased by a factor of 2 over the observation period (LS=213°–232°) while oxygen airglow temporarily decreased by a factor of 3 during the dust storm period. We also found that their brightness varied alternately with a periodicity of ~6–8 days. The magnitude of their periodic airglow variations was ~20–50% for the whole disk, and the periodicity was consistent with that of atmospheric waves observed by the Curiosity Rover on the surface of Mars. These results suggest that hydrogen and oxygen abundances in the Martian upper atmosphere are highly controlled by dust- and wave-couplings between the lower and upper atmosphere, possibly altering the efficiency of hydrogen and oxygen escape from Mars.

 

Reference

Masunaga, K., N. Terada, N. Yoshida, Y. Nakamura, T. Kuroda, K. Yoshioka, Y. Suzuki, H. Nakagawa, T. Kimura, F. Tsuchiya, G. Murakami, A. Yamazaki, T. Usui, and I. Yoshikawa, Alternate oscillations of Martian hydrogen and oxygen upper atmospheres during a major dust storm, Nature Communications, 13, 6609, 2022

How to cite: Masunaga, K., Terada, N., Yoshida, N., Nakamura, Y., Kuroda, T., Yoshioka, K., Suzuki, Y., Nakagawa, H., Kimura, T., Tsuchiya, F., Murakami, G., Yamazaki, A., Usui, T., and Yoshikawa, I.: Hisaki space telescope observations of the large oscillations of Martian hydrogen and oxygen upper atmospheres, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-1968, https://doi.org/10.5194/egusphere-egu23-1968, 2023.

Titan's palaeoclimate after the onset of the putative last major methane outgassing event 700 Myr ago is simulated by a global climate model. If the atmosphere was methane-depleted prior to outgassing, outgassed methane initially causes warming due to increased greenhouse effect. Further outgassing leads to methane snowfall, which in turn cools the troposphere and surface by an ice-albedo feedback and thereby initiates a lengthy ice age. Formation of ice sheets begins in the polar region, but with increasing methane inventory the entire globe is eventually covered by surface methane frost as thick as 100 m, with local accumulation on elevated terrains. Among various time-dependent input parameters the methane inventory by far exerts the greatest control over the climate evolution. As Titan's climate transitions from a dry state via a partially ice-covered state to a globally ice-covered state, the circulation and precipitation pattern change profoundly and the tropospheric temperature further decreases. Globally ice-covered snowball Titan is characterized by weak meridional circulation, weak seasonality and widespread snowfall. Frost ablation begins after the end of outgassing due to photochemical destruction of atmospheric methane. It is conceivable that Titan's polar seas resulted from melting of the polar caps within the past 10 Myr and subsequent drainage to the polar basins. Surface methane frost could only melt when the frost retreated to the polar region, which led to global warming by lowering of the surface albedo at low latitudes and increased greenhouse effect.

How to cite: Tokano, T. and Lorenz, R. D.: Palaeoclimate evolution on Titan after episodic massive methane outgassing simulated by a global climate model, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-2061, https://doi.org/10.5194/egusphere-egu23-2061, 2023.

EGU23-2306 | ECS | Orals | PS4.1

Convection and Clouds under Different Planetary Gravities Simulated by a Small-domain Cloud-resolving Model 

Jiachen Liu, Jun Yang, Yixiao Zhang, and Zhihong Tan

In this study, we employ a cloud-resolving model (CRM) to investigate how gravity influences convection and clouds in a small-domain (96 km by 96 km) radiative-convective equilibrium (RCE). Our experiments are performed with a horizontal grid spacing of 1 km, which can resolve large (> 1 km2) convective cells. We find that under a given stellar flux, sea surface temperature increases with decreasing gravity. This is because a lower-gravity planet has larger water vapor content and more clouds, resulting in a larger clear-sky greenhouse effect and a stronger cloud warming effect in the small domain. By increasing stellar flux under different gravity values, we find that the convection shifts from a quasi-steady state to an oscillatory state. In the oscillatory state, there are convection cycles with a period of several days, comprised of a short wet phase with intense surface precipitation and a dry phase with no surface precipitation. When convection shifts to the oscillatory state, water vapor content and high-level cloud fraction increase substantially, resulting in rapid warming. After the transition to the oscillatory state, the cloud net positive radiative effect decreases with increasing stellar flux, which indicates a stabilizing climate effect. In the quasi-steady state, the atmospheric absorption features of CO2 are more detectable on lower-gravity planets because of their larger atmospheric heights. While in the oscillatory state, the high-level clouds mute almost all the absorption features, making the atmospheric components hard to be characterized.

How to cite: Liu, J., Yang, J., Zhang, Y., and Tan, Z.: Convection and Clouds under Different Planetary Gravities Simulated by a Small-domain Cloud-resolving Model, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-2306, https://doi.org/10.5194/egusphere-egu23-2306, 2023.

EGU23-2829 | Orals | PS4.1

The Climate of Earth and Earth-like (Exo)planets in Coupled Evolution Models: Insights from 3D GCM. 

Cédric Gillmann, Johnny Seales, Pedram Hassanzadeh, and Adrian Lenardic

We investigate the past evolution of the climate of Earth and Earth-like planets as a coupled interior/atmosphere system. We compare climatic states obtained through parameterized modelling versus a physics-based 3D General Circulation Model (GCM). Finally, we identify characteristics in the 3D simulations that most affect the climate, and how that impacts the reliability of parameterized modeling.

In long-term planetary evolution studies, surface conditions are often characterized using global average temperatures, and calculated using simple models (i.e., Eddington approximation, 1D radiative convective gray atmosphere). For instance, these models treat albedo and cloud cover in a parameterized way and are not always able to assess local variations (i.e., latitudinal). A more self-consistent approach uses a 3D GCM, which requires extensive computing resources and time. This makes GCMs unpractical for long-term evolution modelling. Instead, here, successive windows into the past states of the atmosphere/surface are modeled.

The past thermal history of Earth’s interior is used as a representative case for a range of possible past states and evolution of the mantles of Earth-like exoplanets. This feeds a parameterized model for mantle thermal and dynamic evolution. From the computation of melt generation and volcanism, the volatile delivery from the mantle into the atmosphere is estimated. This produces a variety of atmospheric composition evolutionary pathways, which, in turn, govern planetary climate evolution.

We use the ROCKE3D GCM during significant windows of the long-term evolution to understand the differences between the parameterized (coupled evolution) and more complete (GCM) approaches. We compare average surface temperatures and albedos obtained in both simulations. We then evaluate the ice coverage obtained in GCM simulations and compare it to the usual criteria for habitability (such as average temperatures above 273-258 K). Finally, we assess the reasons for discrepancies between the models.

In particular, we study the influence of the total atmosphere pressure, and its composition (N2, CO2, O2, CH4), consistently with Earth observation, as well as solar insolation and length of day variation, depending on the different eras we consider. We further study the impact of continental distribution (i.e., present-day-like or supercontinent distributions) and topography. We use the mantle dynamics simulation output based on the thermal history to assess the characteristics of the surface features. The trend of the variations of average temperature through time (and CO2 abundances) is consistent in parameterized vs. GCM models. Perturbation around the reference model result in stronger temperature variations in the GCM due to albedo feedback. Indeed the albedo variations can be significant in 3D simulations and are not considered in the parameterized approach. Supercontinent setups result in markedly dryer land than present-day Earth. Even models with average temperatures below 273-268 K have significant ice-free ground in all continental setups.

How to cite: Gillmann, C., Seales, J., Hassanzadeh, P., and Lenardic, A.: The Climate of Earth and Earth-like (Exo)planets in Coupled Evolution Models: Insights from 3D GCM., EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-2829, https://doi.org/10.5194/egusphere-egu23-2829, 2023.

EGU23-2921 | Posters virtual | PS4.1

Airless body surface weathering by dielectric breakdown 

Andrew Jordan and Morgan MacLeod

A number of studies have suggested that dielectric breakdown weathering (“sparking”) may occur on airless bodies in the Solar System. To experience dielectric breakdown, a regolith must be exposed to a sufficiently high fluence of energetic charged particles (>1010 cm-2), and this fluence must be deposited on a timescale less than the regolith’s discharging timescale, which increases with decreasing temperature. Consequently, dielectric breakdown occurs in regolith that is both cold and exposed to high fluxes of solar energetic particles (SEPs) or radiation belt particles. If breakdown occurs, then it causes space weathering by melting and vaporizing microscopic channels through regolith near the surface.

We describe our recent experimental, observational, and theoretical work investigating where dielectric breakdown may be an important space weathering process. In the inner Solar System, airless bodies are exposed sporadically to SEP events with high fluences. At 1 AU, the flux of SEPs is nearly isotropic, and thus they may cause dielectric breakdown over the coldest (<120 K) regions of the Moon’s nightside. We present observational evidence for this nightside process and the results of preliminary experiments investigating its microscopic effects. In addition, we briefly discuss the possibility that dielectric breakdown weathering also occurs on Mercury, the moons of Mars, and some asteroids.

In the outer Solar System, where the fluxes of SEP events are significantly reduced, dielectric breakdown is more likely to be caused by radiation belts. In particular, moons in Jupiter’s radiation belts are exposed to the highest continuous fluxes of energetic charged particles in the Solar System. Furthermore, Jupiter’s radiation belts have caused dielectric breakdown in spacecraft dielectrics. We describe the range of evidence showing that dielectric breakdown may occur on some of the Galilean moons (Io, Europa, and Ganymede) and Jupiter’s four innermost moons (Amalthea, Thebe, Adrastea, and Metis).

How to cite: Jordan, A. and MacLeod, M.: Airless body surface weathering by dielectric breakdown, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-2921, https://doi.org/10.5194/egusphere-egu23-2921, 2023.

EGU23-2968 | Posters on site | PS4.1

New insights into the mesosphere of Venus from MERTIS measurements during the two BepiColombo flybys 

Gabriele Arnold, Rainer Haus, Joern Helbert, Mario D'Amore, Alessandro Maturilli, Thomas Saeuberlich, and Harald Hiesinger

Analyses of measurements made by MERTIS1 (MErcury Radiometer and Thermal Infrared Spectrometer) during the BepiColombo mission's close flyby 2 of Venus (FB2) have already demonstrated the instrument's capacity to explore the planet's mesosphere at near equatorial latitudes. The MERTIS instrument was designed to study the hot surface of Mercury. It performed well beyond its design limits when analyzing the Venusian mesosphere because of the much lower radiances. MERTIS’ measurements are the first spectrally resolved observations of Venus in the thermal spectral range longward of 5 µm since the Venera-15 Fourier spectrometer experiment in 19832. It could be shown that MERTIS FB2 data enable reliable retrievals of mesospheric temperature profiles and cloud parameters between 60 and 75 km altitude. They are in good agreement with the results of the Venera-15 mission. This indicates the stability of the Venusian atmosphere on time scales of decades3,4.

In this paper we discuss preliminary results from MERTIS measurements of the first flyby (FB1) in October 2020. During the first flyby the spacecraft approached the planet from the solar direction over the dayside. The closest approach (CA) occurred at about 11,000 km distance above the evening terminator of the planet, and then the spacecraft moved away from the planet to the anti-solar direction. In this time the apparent size of Venus increased from slightly larger than one MERTIS pixel (0.7 mrad) to more than 1 degree. MERTIS performed close-up dayside observations from early morning to late afternoon via noon time on Venus at latitudes between 50°S and 85°N and obtained about 785,000 hyperspectral observations with the spectrometer channel. Thus, FB1 observations permit much larger latitude coverage from 50°S to 85°N compared to FB2. To process the FB1 data in terms of both a reasonable signal-to-noise ratio and comparable observing conditions, individual spectra were averaged over 5° latitude belts and 0.5 h local time intervals. We further excluded extreme observation geometries for latitudes northward of 80°N and southward of 40°S as well as very weak spectra. As a result, we are able to generate a reliable data base for use in radiative transfer analyses for the Venusian mesosphere. We present preliminary results on the temperature fields of the mesosphere as a function of local time, altitude, and latitude.

 

Hiesinger, H. et al. Space Sci. Rev. 216, 6 (2020).

Oertel, D. et al. Adv. Space Res. 5, 25-36 (1985).

Arnold, G. et al., SPIE Optic+Photonics, San Diego, Proceedings Volume 12233, doi.org/10.1117/12.2632548 (2022).

Helbert, J. et al. submitted to Nature Astronomy (2023).

How to cite: Arnold, G., Haus, R., Helbert, J., D'Amore, M., Maturilli, A., Saeuberlich, T., and Hiesinger, H.: New insights into the mesosphere of Venus from MERTIS measurements during the two BepiColombo flybys, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-2968, https://doi.org/10.5194/egusphere-egu23-2968, 2023.

EGU23-4363 | ECS | Posters on site | PS4.1

A quantum-mechanical investigation of O(3P) + CO scattering cross sections at superthermal collision energies 

Malathe Khalil, Sanchit Chhabra, Marko Gacesa, Amal Al Ghaferi, and Nayla El-Kork

The Martian atmospheric gas loss may have played a role in transforming Mars from a warmer, water-containing planet into a cold and dry one. This loss is attributed to different phenomena, including photodissociation of H2O followed by Jeans escape and photochemical escape of hot O atoms.  It was proposed that collisions with hot (super-thermal) neutral atoms can eject light species from the atmosphere such as He [1], D[2], H2 [3], and OH[4]. Here, collisions with super-thermal oxygen atoms are the most important because of its kinetic energy and abundance. Carbon monoxide (CO) has been used as a probe for studying the planet’s atmospheric composition and the dynamics involved [5]. In this study, we computed the elastic and inelastic integral and differential cross-sections for CO collisions with energetic O(3P) and its isotopes using a full coupled-channel quantum mechanical formalism at collision energies from 0.4 to 5 eV. The O+CO interactions were described using recently constructed potential energy surfaces of 3A′, 3A″, and 23A″ symmetry [6], dissociating to the atomic ground state. The state-to-state, elastic, and inelastic cross-sections were calculated for individual surfaces as well as their statistical average [7]. We applied the new cross sections in a simple 1D column transport model to provide revised escape and energy transfer rates of O(3P) and its isotopes in thermal CO gas, at the conditions corresponding to the upper atmosphere of Mars, where CO is abundant.

References:

[1]       S. Bovino, P. Zhang, F. A. Gianturco, A. Dalgarno, and V. Kharchenko, “Energy transfer in O collisions with He isotopes and Helium escape from Mars,” Geophys. Res. Lett., vol. 38, no. 2, pp. 2–6, 2011, doi: 10.1029/2010GL045763.

[2]       P. Zhang, V. Kharchenko, M. J. Jamieson, and A. Dalgarno, “Energy relaxation in collisions of hydrogen and deuterium with oxygen atoms,” J. Geophys. Res. Sp. Phys., vol. 114, no. 7, pp. 1–14, 2009, doi: 10.1029/2009JA014055.

[3]       M. Gacesa, P. Zhang, and V. Kharchenko, “Non-thermal escape of molecular hydrogen from Mars,” Geophys. Res. Lett., vol. 39, no. 10, pp. 1–6, 2012, doi: 10.1029/2012GL050904.

[4]       M. Gacesa, N. Lewkow, and V. Kharchenko, “Non-thermal production and escape of OH from the upper atmosphere of Mars,” Icarus, vol. 284, pp. 90–96, 2017, doi: 10.1016/j.icarus.2016.10.030.

[5]       M. Zhang and D. Shi, “Transition properties of the X 1 Σ + , I 1 Σ − , A 1 Π , D 1 Δ , B 1 Σ + , and a 3 Π states of carbon monoxide,” Comput. Theor. Chem., vol. 1202, no. May, p. 113302, 2021, doi: 10.1016/j.comptc.2021.113302.

[6]       R. L. Ja, G. M. Chaban, and M. Field, “Collisional Dissociation of CO : ab initio Potential Energy Surfaces and Quasiclassical Trajectory Rate Coe cients,” pp. 1–54, 2019.

[7]       S. Chhabra, M. Gacesa, M. S. Khalil, A. Al Ghaferi, and N. El-kork, “A quantum-mechanical investigation of O(3P) + CO scattering cross sections at superthermal collision energies,” Mon. Not. R. Astron. Soc., no. October, 2022, doi: https://doi.org/10.1093/mnras/stac3057.

 

How to cite: Khalil, M., Chhabra, S., Gacesa, M., Al Ghaferi, A., and El-Kork, N.: A quantum-mechanical investigation of O(3P) + CO scattering cross sections at superthermal collision energies, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-4363, https://doi.org/10.5194/egusphere-egu23-4363, 2023.

EGU23-4647 | Orals | PS4.1

Space weathering observed on the samples returned from Ryugu 

Takaaki Noguchi and the the Hayabusa2 Initial Analysis “Sand” Team and the Hayabusa2 Initial Analysis Team Core

The samples returned from the near-Earth asteroid (162173) Ryugu by the Hayabusa2 spacecraft provide the first opportunity for laboratory study of space weathering signatures on the most abundant C-type asteroids. Many (about 60%) of them are thought to have experienced high degrees of the aqueous alteration as shown in CI and CM carbonaceous chondrites. Hayabusa2 measured in situ near-infrared reflectance spectra of Ryugu using the NIRS3 spectrometer. The shallow 2.7-µm absorption band in the spectra was interpreted as a signature of thermal metamorphism or solar radiation heating. However, all the investigations of Ryugu grains performed to date show that the Ryugu materials are genetically common to CI chondrites. The Ryugu grains are abundant in phyllosilicates (saponite and serpentine), magnetite, Fe-Ni sulfides, and carbonates. This study about the space weathering of Ryugu grains explains this discrepancy. Ryugu is exposed to the major agents of space weathering of airless bodies. However, the resultant space-weathering products are substantially different from that of the Moon and Itokawa, both of which are composed of anhydrous minerals. Weathered Ryugu grains show areas of surface amorphization and partial melting of phyllosilicates, in which reduction from Fe3+ to Fe2+ and dehydration developed. Comparison of space-weathered materials with the run products of a helium irradiation experiment on non-space-weathered grains and of laser irradiation experiments of Murchison CM chondrite shows that the amorphization of phyllosilicates may be caused by solar wind irradiation and the partial melting, by micrometeoroid impact heating. Space weathering likely contributed to dehydration by dehydroxylation of Ryugu surface phyllosilicates that had already lost interlayer water molecules and to the weakening of the 2.7-µm hydroxyl (–OH) band in reflectance spectra. For C-type asteroids in general, this indicates that a weak 2.7-µm band can signify space weathering-induced surface dehydration, rather than bulk volatile loss.

How to cite: Noguchi, T. and the the Hayabusa2 Initial Analysis “Sand” Team and the Hayabusa2 Initial Analysis Team Core: Space weathering observed on the samples returned from Ryugu, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-4647, https://doi.org/10.5194/egusphere-egu23-4647, 2023.

EGU23-5262 | ECS | Orals | PS4.1

Combining Visible/Infrared Spectroscopy and Transmission-Electron-Microscopy To Investigate Space-Weathering Induced Changes In Hydrated Silicates 

Stefano Rubino, Cateline Lantz, Alice Aléon-Toppani, Donia Baklouti, Zahia Djouadi, David Troadec, Ernesto Palomba, Ferenc Borondics, Hugues Leroux, and Rosario Brunetto

The study of small bodies in our solar system is fundamental for understanding its youth and evolution. These "primitive" bodies are "undifferentiated" (their components did not separate according to their density, irreversibly altering their mineralogy). They have evolved very little since their birth, spurring a composition relatively close to that of the primordial proto-planetary disk (Scott et al. 2018). However, other processes such as thermal alteration, aqueous alteration, shocks, or space weathering can affect these bodies’ surfaces. This may introduce certain compositional biases in remote-sensed data focusing on the surface of these bodies. Therefore, it is paramount to understand the processes affecting the surface of primitive asteroids to correctly assess their composition.

There are several ways to study the surface of primitive asteroids, such as remotely, by acquiring spectroscopic data (gaining access to surface chemical and mineralogical composition). It is also possible to study these bodies in a laboratory environment, by working on analogous materials such as certain classes of "primitive" meteorites (Greenwood et al. 2020) (carbonaceous chondrites), on terrestrial analogues such as hydrated silicates - which dominates the mineral composition of “primitive” bodies (Usui et al. 2018), or directly on extra-terrestrial materials brought back by sample return missions (Yokoyama et al. 2022, Nakalura et al. 2022, Noguchi et al. 2022).

In this work, we replicate in a laboratory environment the effects of space weathering (SpWe) on the surface of primitive asteroids. We focus on the effects of solar wind, the dominant SpWe process on "young" surfaces (Brunetto et al. 2015, Clark et al. 2002). We have chosen three terrestrial minerals analogous to a "primitive" surface - three hydrated minerals (two serpentines and one saponite) - of which we have produced several pellets which have been bombarded using He and Ar ions. In doing so, we made analogous materials of weathered primitive surface matter. These analogues were then characterized by infrared spectroscopy, from the visible to the far-infrared range, to study chemical changes prompted by ion bombardment. This was done by investigating how certain spectroscopic features – characteristic of hydrated silicates – changed upon ion-bombardment. We detected several effects, such as darkening in the visible range, visible slope reddening and bluing as well as a systematic shift towards longer wavelength affecting the position of several spectroscopic features.

This was followed by a study at a smaller scale, using electron microscopy. We first characterized the surface of our weathered analogues using scanning electron microscopy, and then investigated the morphological and physicochemical changes taking place in the bombarded layer, at a nanometre scale, using transmission electron microscopy. Strong vesiculation effects of various kinds were identified in the ion bombarded amorphized layers, as well as textural changes and some elemental concentration evolution (such as the loss of oxygen in the utmost top surfaces, preferential amorphization of magnesium, etc.).

The coupling between these two techniques, Vis/IR spectroscopy and electron microscopy, has allowed us to start probing the relations between SpWe induced effects seen at different scales.

How to cite: Rubino, S., Lantz, C., Aléon-Toppani, A., Baklouti, D., Djouadi, Z., Troadec, D., Palomba, E., Borondics, F., Leroux, H., and Brunetto, R.: Combining Visible/Infrared Spectroscopy and Transmission-Electron-Microscopy To Investigate Space-Weathering Induced Changes In Hydrated Silicates, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-5262, https://doi.org/10.5194/egusphere-egu23-5262, 2023.

EGU23-6164 | Posters on site | PS4.1

Simulation of the Ca emission at Mercury and comparison with the observations by PHEBUS/BepiColombo during the first two flybys 

Jean-Yves Chaufray, François Leblanc, Rozenn Robidel, Eric Quémerais, and Dimitra Koutroumpa

Due to the lack of a thick atmosphere, the surface of Mercury is regularly bombarded by micrometeoroids at a rate depending on the position of Mercury around the Sun. One consequence of these impacts is an alteration of its surface (space weathering) and the ejection of its material around Mercury forming a tenuous exosphere. Even if the detail on the origin of the exospheric atomic calcium, observed systematically by MESSENGER is not fully understood, it is mostly associated to such impacts. In order to interpret the MESSENGER observations, we have recently developed a time dependent 3D model of the Ca exosphere of Mercury and successfully reproduced the seasonal variations observed by MESSENGER at dawn during its orbital phase. In this presentation, we will compare the simulated brightness from this model with the observations performed by PHEBUS onboard BepiColombo during the first two flybys of Mercury and discuss the differences.

How to cite: Chaufray, J.-Y., Leblanc, F., Robidel, R., Quémerais, E., and Koutroumpa, D.: Simulation of the Ca emission at Mercury and comparison with the observations by PHEBUS/BepiColombo during the first two flybys, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-6164, https://doi.org/10.5194/egusphere-egu23-6164, 2023.

EGU23-6215 | Orals | PS4.1

The Yearly Variability of the Sodium Exosphere of Mercury: a Toy Model 

Alessandro Mura, Christina Plainaki, Anna Milillo, Valeria Mangano, Tommaso Alberti, Stefano Massetti, Stefano Orsini, Martina Moroni, Elisabetta De Angelis, Rosanna Rispoli, and Roberto Sordini

Observations of the sodium exosphere of Mercury show a peculiar yearly variability, with two intensity maxima at aphelion and perihelion. Here we present an analytical model for the total Na exosphere content, and we compare our results with ground-based observations. The model is able to reproduce the observed data, both in magnitude and in the seasonal variability. The combined effect of the planetary rotation with the modulation of sources and losses magnitude along the orbit, is able to produce a source of Na at dawn, which is needed to explain the observed maximum at aphelion. Also, we demonstrate that a process producing a consistent Na supply rate at the nightside, which can either be plasma or micrometeoroid precipitation, is needed as well. With the help of the model, we also propose a possible explanation for the dusk enhancement of Na that was seen in the MESSENGER data during the inbound leg of Mercury's orbit.

How to cite: Mura, A., Plainaki, C., Milillo, A., Mangano, V., Alberti, T., Massetti, S., Orsini, S., Moroni, M., De Angelis, E., Rispoli, R., and Sordini, R.: The Yearly Variability of the Sodium Exosphere of Mercury: a Toy Model, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-6215, https://doi.org/10.5194/egusphere-egu23-6215, 2023.

EGU23-6979 | ECS | Posters on site | PS4.1

Weathering of airless body surfaces by the heavy minor ions of the solar wind: inputs from Wind ion observations 

Quentin Nenon, Jim Raines, and Andrew Poppe

The role and importance of solar wind ions heavier than helium for the weathering of airless body surfaces across the solar system remain debated. In addition, the contribution to surface weathering of suprathermal and energetic heavy ions, which have extremely low densities compared to thermal ions but high energy, is an open question.

In this presentation, we will take advantage of the advanced ion instrumentation and long duration of the Wind mission to finely characterize the spectrum and anisotropy of the heavy minor ions that bombard airless body surfaces. Specifically, we will combine heavy ion measurements from the Wind-SWICS (thermal ions), Wind-STICS (suprathermal), and Wind-STEP (energetic) experiments.

We will constrain the long-term averaged properties of the heavy ion populations, which are relevant for the development of long-term surface weathering effects. We will also study the heavy ion populations during solar wind events, relevant for short-term alteration effects. Finally, we will detail the impact of our ion-data-based results on the global field of space weathering.

How to cite: Nenon, Q., Raines, J., and Poppe, A.: Weathering of airless body surfaces by the heavy minor ions of the solar wind: inputs from Wind ion observations, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-6979, https://doi.org/10.5194/egusphere-egu23-6979, 2023.

EGU23-7540 | ECS | Orals | PS4.1

Electron-induced radiolysis of water ice and the buildup of O2 

Chantal Tinner, André Galli, Fiona Bär, Antoine Pommerol, Martin Rubin, Audrey Vorburger, and Peter Wurz

Irradiation by energetic ions, electrons, and UV photons induces sputtering and chemical processes (radiolysis) on the surfaces of icy moons and comets. Radiolysis of water ice has important implications for the chemistry and evolution of these celestial bodies. In this work, we carried out a series of laboratory experiments to investigate the products of radiolysis and the retention of O2 in porous water ice samples when irradiated with high-energy electrons.

To conduct our experiments, we irradiated two types of water ice samples with high energy electrons (0.5 keV to 5 keV ) and measured the resulting chemical species using time of flight mass spectrometry. The experiments were performed under conditions replicating the icy moons’ surface conditions ( K and -7 mbar). Our results showed production of H2 and O2 radicals, but other predicted radiolysis species, such as H2O2 and O3, were not detected so far; their abundances remain below 0.005 by number compared to the release of O2. This is in contrast to previous studies, which have reported the production of OH and H2O2 through the radiolysis of water ice.

We also studied the retention of oxygen in the ice. By computing the timescales of rise for the O2 signal upon irradiation, we observed that it rises faster for non-pristine (follow-up) ice irradiations. This suggests that O2 (or an O2 precursor) produced during the first irradiation can be retained in the ice.

For some irradiations, the electron energy and current were chosen higher to provoke the water ice's sublimation. The water release showed different properties depending on the porosity and grain size of the irradiated ice.

Overall, our results contribute to our understanding of the radiolysis of water ice and its role in the chemistry and evolution of ice-covered bodies in the solar system. Further studies will be needed to fully understand the factors that influence the production and retention of different chemical species during the radiolysis of water ice.

How to cite: Tinner, C., Galli, A., Bär, F., Pommerol, A., Rubin, M., Vorburger, A., and Wurz, P.: Electron-induced radiolysis of water ice and the buildup of O2, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-7540, https://doi.org/10.5194/egusphere-egu23-7540, 2023.

Decyphering the chemical composition and atmospheric conditions of terrestrial planets around other stars is one of the main driver of exoplanetary science. In fact, atmospheric characterisation of Earth-like planets is expected to bring the first insights into the possibility of biological activity on another planet than Earth. Although the road to the detection of such potential biomarkers is long and challenging, recent spectacular progress have been achieved about the composition, climates and evolution of giant exoplanets with new instruments in space (with the James Webb Space Telescope or the Characterising Exoplanets Satellite) and on the ground (with high-resolution spectrographs at giant telescopes). Today, future projects are being designed to bridge the gap between hot gas giants and temperate terrestrial planets and take us closer and closer to this scientific goal. In this talk, I will review the current challenges and exciting perspectives about the atmospheric characterisation of terrestrial exoplanets.

How to cite: Ehrenreich, D.: Challenges and perspectives for the characterisation of the atmospheres and exospheres of 'terrestrial’ exoplanets, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-7647, https://doi.org/10.5194/egusphere-egu23-7647, 2023.

EGU23-8494 | Posters on site | PS4.1

Influence of radiative forcing on Titan’s lake energy balance and sea breeze circulation 

Scot Rafkin, Audrey Chatain, and Alejandro Soto

Solar and infrared radiative transfer, including the effects of scattering, have been included in the mesoscale Titan WRF (mtWRF) model of Titan’s atmosphere.  A previous study with this model in the absence of radiative forcing indicated that atmosphere-lake sensible and latent heat fluxes could diminish to magnitudes comparable to radiative fluxes due to the development of a cold and stable marine boundary layer.  Consequently, it was hypothesized that radiative forcing could be important, contrary to prior expectations, and should be included in future studies. With these results we confirm the radiative hypothesis and demonstrate that radiative forcing must be included in order to more accurately simulate the energy and mass exchange between Titan’s lakes and atmosphere. Solar heating of the lake mixed layer partially offsets the latent flux cooling during the daytime, and downwelling atmospheric IR flux provides heat to the cold lake.  Due to changes in thermal contrast between the air over the lake and the land compared to non-radiative solutions, the sea breeze atmospheric structure is altered, including the development of a pronounced diurnal circulation cycle.  All of these effects perturb the energy and mass exchange, which has local meteorological implications and exerts a control on the global methane cycle.

How to cite: Rafkin, S., Chatain, A., and Soto, A.: Influence of radiative forcing on Titan’s lake energy balance and sea breeze circulation, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-8494, https://doi.org/10.5194/egusphere-egu23-8494, 2023.

EGU23-8541 | ECS | Orals | PS4.1

Callisto’s atmosphere: First evidence for H2, and the implications this has for Europa’s and Ganymede’s atmosphere 

Shane Carberry Mogan, Orenthal J. Tucker, Robert E. Johnson, Lorenz Roth, Juan Alday, Audrey Vorburger, Peter Wurz, Andre Galli, H. Todd Smith, Apurva V. Oza, Lucas Liuzzo, and Andrew R. Poppe

We explore the parameter space for the contribution to Callisto's H corona observed by the Hubble Space Telescope from sublimated H2O and radiolytically produced H2 using the Direct Simulation Monte Carlo (DSMC) method. The spatial morphology of this corona produced via photo- and magnetospheric electron impact-induced dissociation is described by tracking the motion of and simulating collisions between the hot H atoms and thermal molecules including a near-surface O2 component. Our results presented indicate that sublimated H2O produced from the surface ice, whether assumed to be intimately mixed with or distinctly segregated from the dark non-ice or ice-poor regolith, cannot explain the observed structure of the H corona. On the other hand, a global H2 component can reproduce the observation, and is also capable of producing the enhanced electron densities observed at high altitudes by Galileo's plasma-wave instrument, providing the first evidence of H2 in Callisto's atmosphere. Finally, we discuss the implications of these results, in particular how they compare to Europa and Ganymede.

How to cite: Carberry Mogan, S., Tucker, O. J., Johnson, R. E., Roth, L., Alday, J., Vorburger, A., Wurz, P., Galli, A., Smith, H. T., Oza, A. V., Liuzzo, L., and Poppe, A. R.: Callisto’s atmosphere: First evidence for H2, and the implications this has for Europa’s and Ganymede’s atmosphere, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-8541, https://doi.org/10.5194/egusphere-egu23-8541, 2023.

EGU23-8602 | ECS | Posters on site | PS4.1

Constraining the radiolytic production of Callisto’s O2 atmosphere 

Shane R. Carberry Mogan, Lucas Liuzzo, Andrew R. Poppe, and Sven Simon

Herein we constrain the radiolytic production rate of O2 from Callisto's exposed ice patches as well as the corresponding steady-state abundance of O2 in Callisto's atmosphere. That is, by simulating the fluxes of thermal plasma and energetic particles irradiating Callisto's surface, taking into account energy deposition within the atmosphere, we determine the initial source flux of O2 to estimate the corresponding column density for Callisto's O2 component, which we compare to those suggested in the literature. This study provides constraints for Callisto's O2 atmosphere in preparation for future observations, particularly those that will be made by the JUpiter ICy moons Explorer (JUICE) and Europa Clipper spacecraft, as well as the Hubble Space Telescope (HST). Further, based on this analysis at Callisto, we can better our understanding on how the atmospheres of other icy satellites in the Solar System can evolve to their observed state.

How to cite: Carberry Mogan, S. R., Liuzzo, L., Poppe, A. R., and Simon, S.: Constraining the radiolytic production of Callisto’s O2 atmosphere, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-8602, https://doi.org/10.5194/egusphere-egu23-8602, 2023.

EGU23-8619 | Posters on site | PS4.1

Planetary and synoptic-scale atmospheric disturbances from images of Mars during Martian Year 36 

Agustín Sánchez-Lavega, Ethan Larsen, Jorge Hernández-Bernal, Teresa del Río-Gaztelurrutia, Iñaki Ordóñez-Etxeberria, and Alejandro Cardesin Moinelo

Four surface stations (rovers Curiosity, Perseverance, and Zhurong, and the Insight platform) were operating on Mars along Martian Year 36 (7 February 2021 – 26 December 2022), all them equipped with a suite of meteorological sensors and cameras. In addition, eight orbiters are currently studying the planet from different perspectives and instruments. To help to interpret and put in context the meteorological measurements at the surface by these stations, we present here a study of the atmospheric disturbances, at the planetary and synoptic scales, based on images of Mars obtained from cameras onboard Mars Express and Mars Reconnaissance Orbiter [1, 2]. We report on the properties of the disturbances that evolved at the edge of the North Polar Cap (latitudes ~ 40°N to 70°N) during the springtime season in the northern hemisphere. These are dust storms and synoptic-scale cloud systems with arc, frontal, irregular and spiral shapes, typically growing from the baroclinic instabilities in the intense eastward jet present in this epoch of the Martian year.  We also report on the evolution of the aphelion cloud belt (Ls ~ 0° – 180°), including among other phenomena the recurrent annular-double cyclone (Ls ~ 125°) and the cloud development at Hellas basin (Ls ~ 145° – 300°). Finally, we present an analysis of the dust storms that evolved at different latitudes, concentrating in particular in the regional storm that evolved over Perseverance in early January 2022.

 

References

[1] Sánchez-Lavega, A. et al., Icarus 299, 194-205 (2018)

[2] Bell III, J. F. et al., J. Geophys. Res. Planets 114, E003315, 1-41 (2009)

How to cite: Sánchez-Lavega, A., Larsen, E., Hernández-Bernal, J., del Río-Gaztelurrutia, T., Ordóñez-Etxeberria, I., and Cardesin Moinelo, A.: Planetary and synoptic-scale atmospheric disturbances from images of Mars during Martian Year 36, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-8619, https://doi.org/10.5194/egusphere-egu23-8619, 2023.

EGU23-9581 | Orals | PS4.1

Evidence of Hot Hydrogen in the Exosphere of Mars Resulting in Enhanced Water Loss 

John Clarke, Dolon Bhattacharyya, Majd Mayyasi, Valery Shematovich, Dimitri Bisikalo, Jean-Yves Chaufray, Ed Thiemann, Jasper Halekas, Carl Schmidt, Jean-Loup Bertaux, Michael Chaffin, and Nick Schneider

The history of water escape from Mars has been a topic of intense interest among the scientific community. Water escape from Mars is generally studied by measuring the escape rate of atomic hydrogen from its exosphere and tracing it back in time to determine the total amount lost by the planet. However, the loss rates are estimated assuming thermal properties for the H atoms, and are therefore a lower limit. Past analyses of spacecraft observations presented indirect evidence for the existence of an energetic non-thermal H population. However, all these observations lacked a clear detection. Here we present the first unambiguous observational signature of non-thermal H at Mars, consistent with solar wind charge exchange as the primary driver for its production. The calculated non-thermal H escape rates reach as high as ~26% of the thermal escape rate near aphelion. An active Sun today would increase the present-day escape rate of H and a younger energetic Sun likely contributed towards a significant loss of water from Mars, thereby shortening the martian water escape history timeline.

How to cite: Clarke, J., Bhattacharyya, D., Mayyasi, M., Shematovich, V., Bisikalo, D., Chaufray, J.-Y., Thiemann, E., Halekas, J., Schmidt, C., Bertaux, J.-L., Chaffin, M., and Schneider, N.: Evidence of Hot Hydrogen in the Exosphere of Mars Resulting in Enhanced Water Loss, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-9581, https://doi.org/10.5194/egusphere-egu23-9581, 2023.

EGU23-9917 | Orals | PS4.1

Hydroxylation of Lunar Soil with Solar Wind 

Li Hsia Yeo, Jason McLain, and Rosemary Killen

Introduction:  Solar wind, which comprises high energy hydrogen ions, continuously strikes the lunar surface, which is rich in oxygen. This presents an opportunity for hydroxylation - the creation of OH on lunar soil. Both OH and H2O have been detected on the lunar surface, with some variability in abundance throughout the lunar day. It is important to understand how space weathering contributes to the production and proliferation of hydrogen-bearing resources such as water within the lunar environment.

OH shows a distinct absorption feature in the infrared (IR) at ~3 µm-1 that can be readily studied. Fourier Transform Infrared (FTIR) Spectroscopy is a fast and accurate way to detect changes in the infrared spectra of lunar soil. Previous studies have examined the changes in IR spectra of amorphous silica and olivine, as well as lunar soil before and after hydrogen irradiation. However, the evolution of the OH band and other IR features has not been studied during hydrogen radiation itself. It is especially important to not expose the samples to terrestrial air, which will contaminate the samples with water.

 

Method and Results: We present FTIR spectra on Apollo-era soil samples obtained simultaneously with high energy hydrogen plasma irradiation, similar to the solar wind. Samples are first prepared by baking under vacuum to drive off any surface water. Samples are also brought through thermal cycling and heated to 400K (lunar dayside maximum temperature) in-situ, and changes in their IR spectra are reported. Comparisons between Apollo samples with different minerology and with a control of crushed SiO2 are also provided. Results show broad but distinct growths in the 3 µm-1 absorption band for lunar samples compared to a sharper peak for SiO2. Since the samples are not exposed to terrestrial water during measurements, the evidence of hydroxylation presented is likely due to hydrogen irradiation.

 

How to cite: Yeo, L. H., McLain, J., and Killen, R.: Hydroxylation of Lunar Soil with Solar Wind, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-9917, https://doi.org/10.5194/egusphere-egu23-9917, 2023.

EGU23-10653 | Posters on site | PS4.1

A preliminary investigation of the spectral signatures of excited electronic states of OH in the Martian atmosphere 

Rania Al Abdallah, Mubarak Almehairbi, Marko Gaseca, and Nayla El-Kork

Mars has changed from a warmer, water-containing planet into a cold and arid environment. Collisions of superthermal oxygen and other atoms with surrounding gases may lead to the escape of light atmospheric molecules, such as D1, OH2, He3, and H24, from the Martian atmosphere. Such processes have probably contributed to the thinning of its atmosphere and the transformation of Mars' climate.

OH molecules can be produced in the Martian atmosphere by the photodissociation of water vapor and in several chemical reactions, such as the reactions of thermal molecular hydrogen and energetic oxygen atoms O + H2 → H + OH 5. Emission and absorption spectra of OH molecules within the Martian atmosphere can lead to a better understanding of these processes. For example, they can help monitor the variation of its abundance with altitude 6. In general, astronomical spectra of specific molecules can be better interpreted through a detailed identification of their line list.

In this work, we present an extensive line list for the B2S+ - X2P and D2S- - X2P electronic transitions of OH, including line intensities, line positions with the relevant quantum numbers of the upper and lower states, e/f parity and oscillator strength, calculated using PGOPHER7 program. The line intensities are found based on calculated ab-initio Transition Dipole Moment Function and potential energy curves obtained using the quantum computational chemistry program MOLPRO8, using CASSCF method followed by MRCI including Davidson correction term (+Q). LEVEL9 program is used to compute Transition Dipole Moment Matrix Elements in Hund's case (b) using the procedure of Numerov-Cooley10 which are then transformed to Hund's case (a) as required by PGOPHER.

 

1 P. Zhang, V. Kharchenko, M. Jamieson, and A. Dalgarno, "Energy Relaxation in Collisions of Hydrogen and Deuterium with Oxygen Atoms," J.  Geophys. Res. 114, A07101 (2009).  

2 M. Gacesa, N. Lewkow, and V. Kharchenko, "Non-thermal escape of molecular hydrogen from Mars," Icarus, L10203 (2012).

3 S. Bovino et al., "Energy Transfer in O Collisions with He Isotopes and Helium Escape from Mars," Geophys. Res. Lett., 38, L02203 (2011).

4 M. Gacesa, P. Zhang, and V. Kharchenko, "Non-thermal escape of molecular hydrogen from Mars," Geophys. Res. Lett., 39, L10203 (2012).

5 M. Gacesa, N. Lewkow and V. Kharchenko, "Non-thermal production and escape of OH from the upper atmosphere of Mars". Icarus, 284, pp.90-96 (2017).

6 S. Raghuram, A. Bhardwaj, & M. Dharwan, “Model for Nitric oxide and its dayglow emission in the Martian upper atmosphere using NGIMS/MAVEN measured neutral and ion densities”. Icarus, 382, 115010 (2022).

7 CM. Western, PGOPHER: a program for simulating rotational, vibrational and electronic spectra. J Quant Spectrosc Radiat Transf., 186:221–42 (2017).

8 HJ. Werner, PJ. Knowles, G. Knizia, FR. Manby, M. Schütz, Molpro: a general purpose quantum chemistry program package. J Chem Phys., 2:242–53 (2011).

9 RJ. LeRoy, "LEVEL: A computer program for solving the radial Schrödinger equation for bound and quasibound levels." J Quant Spectrosc Radiat Transf., 186:167–78 (2017).

10 J. W. Cooley, "An improved eigenvalue corrector formula for solving the Schrödinger equation for central fields," Math. Comput., vol. 15, no. 76, pp. 363–374, (1961).

 

How to cite: Al Abdallah, R., Almehairbi, M., Gaseca, M., and El-Kork, N.: A preliminary investigation of the spectral signatures of excited electronic states of OH in the Martian atmosphere, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-10653, https://doi.org/10.5194/egusphere-egu23-10653, 2023.

EGU23-10685 | Posters on site | PS4.1

Dust Activities in the Southern High-latitudes of Mars 

Keith K. C. Chow

Dust activities in the southern high-latitude region around the southern solstice period have been observed in many Martian years. Theses dust events occur near the southern cap-edge region and play a major role in the observed dust climate. However, they generally cannot be simulated in the existing Mars general circulation models. In this report, we will introduce a parameterization scheme for simulating these dust events in the Mars climate model MarsWRF. In this scheme, the dust lifting threshold stress is adjusted with the surface temperature difference between the regolith and ice in the southern polar region. By this approach, dust events in the southern cap-edge region have been simulated around the southern solstice period. As a result, the simulated temperature in the southern high-latitude region is increased and the resulting vertical temperature profile is closer to that from observation. In addition, westward propagating dust events observed in a previous study have been simulated with a propagating speed similar to that observed. Results of numerical experiments suggest that the flow associated with the sublimation of the CO2 ice in the southern cap edge is very important to the occurrence of these dust events in this region.

How to cite: Chow, K. K. C.: Dust Activities in the Southern High-latitudes of Mars, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-10685, https://doi.org/10.5194/egusphere-egu23-10685, 2023.

EGU23-11814 | Orals | PS4.1

Observational constraints on the water group torus in the orbit of Jupiter moon Europa 

Lorenz Roth, H. Todd Smith, Kazuo Yoshioka, Tracy Becker, Aljona Blöcker, Nathaniel Cunningham, Nickolay Ivchenko, Kurt Retherford, Michael Velez, Joachim Saur, and Fuminori Tsuchiya

Europa is the innermost of Jupiter's three large icy moons. The existence of a torus of neutral gas in Europa's orbit has been inferred from in-situ plasma measurements as well as remote mapping of energetic neutral atoms around Jupiter. Simulations suggest that such a neutral gas torus can be sustained by escape from Europa’s global atmosphere and consists primarily of molecular hydrogen. Recently, the Juno spacecraft confirmed the torus through measurements of H2+ ions.  However, the neutrals in this torus have never been observed more directly. Here we present observations by the highly sensitive Cosmic Origins Spectrograph of the Hubble Space Telescope (HST/COS) from 2020 and 2021. COS scanned the equatorial plane of the Jupiter system across the orbital distance of Europa between 8 and 10 planetary radii west of the planet . We report constraints from the COS high-resolution spectra on the primary neutral gasses (H2, H, O, and O2) near Europa's orbit and compare them to simulation results from the neutral torus model developed by Smith et al. (2019).

How to cite: Roth, L., Smith, H. T., Yoshioka, K., Becker, T., Blöcker, A., Cunningham, N., Ivchenko, N., Retherford, K., Velez, M., Saur, J., and Tsuchiya, F.: Observational constraints on the water group torus in the orbit of Jupiter moon Europa, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-11814, https://doi.org/10.5194/egusphere-egu23-11814, 2023.

EGU23-12587 | ECS | Posters on site | PS4.1

How obliquity controls the surface appearance of Triton, Pluto and other volatile-rich Transneptunian objects 

Tanguy Bertrand, François Forget, and Emmanuel Lellouch

Triton is often seen as Pluto’s sibling, as both objects share similar sizes, densities, and atmospheric and surface ice composition. Yet Triton’s surface appearance, including its topography, surface albedo and volatile ice distribution, strongly differs from Pluto’s. For instance, Triton is relatively flat and uniformly bright, with permanent nitrogen ice deposits likely covering its entire southern hemisphere. In contrast, Pluto’s landscape includes tall mountains and deep basins, a surface with very bright and very dark features, and permanent nitrogen ice deposits located in the mid-latitudes and equatorial regions, and in particular in the topographic basin Sputnik Planitia.

These differences suggest a different geological history. In fact, Triton and Pluto are both thought to have formed beyond Neptune and then to have evolved differently. On the one side, Pluto remained in the Kuiper Belt and was hit by a twin to form the Pluto-Charon moon system. On the other side, Triton was captured by Neptune, as strongly suggested by its retrograde and highly inclined orbit around the Ice Giant planet, and its interior subsequently experienced intense tidal deformation and heating. Geological activity on Triton may still be powered today by tidal activity.  

Previous modeling studies also highlighted the importance of the Milankovitch parameters (obliquity, eccentricity, solar longitude of perihelion) on Pluto in controlling the surface temperatures and therefore the ice sublimation and condensation rates. In particular, the high obliquity of Pluto’s spin axis seems to explain the presence of massive volatile ice deposits in the equatorial regions. Could Triton’s and Pluto’s volatile ice distributions be distinct mainly because of differences in obliquity?

To answer this question, we performed new numerical simulations of Pluto’s and Triton’s volatile transport using the same climate model for both simulations, and the same initial states, but changing only the topography as well as the obliquity and orbital parameters specific to each object. The comparison of these simulations highlight the impact of obliquity in controlling the location of the permanent deposits of volatile ices on Pluto and Triton. At the conference, we will present these results and show that the impact of obliquity on Pluto and Triton, and on similar volatile-rich Transneptunian objects, goes beyond the volatile ice distribution.

How to cite: Bertrand, T., Forget, F., and Lellouch, E.: How obliquity controls the surface appearance of Triton, Pluto and other volatile-rich Transneptunian objects, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-12587, https://doi.org/10.5194/egusphere-egu23-12587, 2023.

EGU23-13306 | Posters on site | PS4.1

Ephemeral carbon dioxide ice clouds in the upper mesosphere of Venus 

John Plane, Thomas Mangan, Anni Määttänen, and Benjamin Murray

Observations show that the temperature above 100 km in Venus’ atmosphere intermittently falls below 100 K, when both H2O and CO2 become supersaturated. Profiles show temperatures can fall below 60 K at heights between 115-125 km, presumably as a result of large amplitude gravity waves.  Cosmic dust particles entering the atmosphere are predicted to ablate between 110 and 125 km. This provides a source of metallic vapours (principally Mg and Fe atoms), which then form metal carbonate molecules known as meteoric smoke particles (MSPs).  Because these molecules are highly polar, they are excellent nuclei for CO2- and H2O-ice particle formation.

In this study we examine the feasibility and kinetics of CO2-ice cloud formation, using both classical nucleation theory (CNT) and bottom-up kinetic nucleation theory (KNT). For CNT, a dimensionless non-isothermal coefficient is included to reduce the nucleation rate of CO2 ice particles, since the atmospheric concentration of the nucleating species (CO2) comprises a significant fraction of the total atmosphere. For heterogeneous CNT on MSPs, a surface diffusion approach is used where molecules can diffuse on the surface to form a critical cluster for nucleation and the effect of dissipation of critical clusters is accounted for. Application of CNT shows that whereas homogeneous nucleation should be too slow for significant cloud formation, heterogeneous nucleation rates around 1 cm-3 s-1 for CO2 ice should be possible in the colder regions (< 80 K).

For KNT, the rate coefficients for the sequential addition of CO2 molecules up to MgCO3(CO2)40 were calculated explicitly with Rice Ramsperger Kassel Markus (RRKM) theory, using a solution of the Master Equation based on the inverse Laplace transform method. The rates of dissociation of the clusters i.e. MgCO3(CO2)n+1 → MgCO3(CO2)n + CO2, were calculated by detailed balance. In order to explore the evolution of the CO2-ice clouds, a 1-dimensional model was constructed to describe the nucleation, growth, sedimentation and sublimation of the ice particles. The model is initiated with a vertical profile of atmospheric density and temperature determined using the Solar Occultation in the InfraRed (SOIR) instrument on a specified orbit of Venus Express, and then follows the fate of an MSP seed particle as it grows, sediments and finally sublimates on entering a warmer region. Two categories of cloud tend to be produced from the observed temperature profiles. The first peaks around 120 km with particles around 100-200 nm radius; and the second type persists for longer and peaks around 110 km, with particles that can exceed 2 μm in radius. Most clouds are predicted to occur at high latitudes (>70o). Using a probable underestimate of the MSP concentration (100 cm-3), the optical extinction of these clouds at 220 nm should be readily observable by the SOIR instrument. However, the clouds are short-lived because of rapid sedimentation (typically 300 s, the longest-lived around 1200 s), so that the detection of these ephemeral “hail showers” will be challenging.

How to cite: Plane, J., Mangan, T., Määttänen, A., and Murray, B.: Ephemeral carbon dioxide ice clouds in the upper mesosphere of Venus, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-13306, https://doi.org/10.5194/egusphere-egu23-13306, 2023.

EGU23-13614 | Posters virtual | PS4.1

Observability of Callisto’s exosphere with MAJIS/JUICE 

Emiliano D'Aversa, Giuseppe Sindoni, Fabrizio Oliva, Manuel Lopez Puertas, Gabriella Gilli, Christina Plainaki, Federico Tosi, Giuseppe Piccioni, Gianrico Filacchione, François Poulet, Yves Langevin, Nicolas Ligier, John Carter, Alessandra Migliorini, Francesca Altieri, Davide Grassi, and Paolo Haffoud

The most direct evidence that the icy Galilean satellite Callisto is able to sustain a significant neutral exosphere dates back to the detection of the CO2 non-LTE emission at 4.3 μm wavelength, measured by the NIMS instrument onboard the NASA Galileo spacecraft [1]. Other exospheric emissions have been observed in the UV spectral range, basically tracing the ionised exospheric component ([2], [3]). The analysis of such emissions in the framework of exospheric models (see e.g. [4], [5]) allowed to establish an overall composition dominated by O2 and H2O, with minor contributions by CO2 and CO. However, direct observations of neutral species other than CO2 are still missing, and their actual abundances, as well as spatial and temporal variability, are poorly constrained.

The MAJIS (Moon And Jupiter Imaging Spectrometer, [6]) instrument, on board the ESA JUICE spacecraft, is expected to contribute in this field, by searching for non-LTE emissions falling in its spectral range, from 0.50 to 5.54 μm. In particular, we evaluate the chance of detection of signals at the satellite’s limb emitted by the CO2 complexes at 4.3 μm and 2.3 μm, by the H2O complex at 2.3 μm, by O2 at 1.27 μm, and by the CO bands at 4.7 μm and 2.3 μm. We calculate the populations of molecular levels by using the GRANADA algorithm [7], then the emissions intensities, for reference abundances of the molecular species and for limb-viewing geometry, by taking advantage of the KOPRA algorithm [8].

Detection limits for all the abovementioned species are obtained in the approximation of horizontal uniformity of exospheric layers and adopting a vertical scaling compatible with the scale height in [1]. Surface density detection limits around 6.2 .106 cm-3, 6.6 .106 cm-3, 3.4 .109 cm-3, 3.4 .107 cm-3 are found for CO2, H2O, O2, and CO respectively. For both CO2 and H2O, these results indicate a high detection probability during the Callisto flybys planned in the current JUICE trajectory version (crema 5.0, [9]). Detection of O2 could also be possible if appropriate observing strategies are adopted. Detection of CO is instead very challenging, being its expected abundance well below the detection limit.

 Acknowledgements

This work is supported by the Italian Space Agency (ASI-INAF grant 2018-25-HH.0). IAA researchers acknowledge financial support from the State Agency for Research of the Spanish MCIU through the Center of Excellence Severo Ochoa" award to the Instituto de Astrofísica de Andalucía (CEX2021-001131-S/fund by MICIN/AEI/10.13039/501100011033).

References

[1] Carlson,R.W.,1999, Science 283 (5403): 820–21. [2] Kliore,A.J., 2002, Journ.Geophys.Res. doi: 10.1029/2002ja009365. [3] Cunningham,N.J. et al., 2015, Icarus. doi:10.1016/j.icarus.2015.03.021. [4] Vorburger,A., et al., 2015, Icarus. doi:10.1016/j.icarus.2015.07.035. [5] Liang, M., 2005, Journ.Geophys.Res. doi:10.1029/2004je002322. [6] Guerri I., et al., 2018, Proc.of SPIE Vol.10690 106901L-1. doi: 10.1117/12.2312013. [7] Funke,B., et al., 2012, Journ.Quant.Sp.Rad.Tran. doi:10.1016/j.jqsrt.2012.05.001. [8] Stiller,G.P., et al., 2002. Journ.Quant.Sp.Rad.Tran. doi:10.1016/s0022-4073(01)00123-6. [9] ESA SPICE Service, JUICE Operational SPICE Kernel Dataset, doi:10.5270/esa-ybmj68p.

How to cite: D'Aversa, E., Sindoni, G., Oliva, F., Lopez Puertas, M., Gilli, G., Plainaki, C., Tosi, F., Piccioni, G., Filacchione, G., Poulet, F., Langevin, Y., Ligier, N., Carter, J., Migliorini, A., Altieri, F., Grassi, D., and Haffoud, P.: Observability of Callisto’s exosphere with MAJIS/JUICE, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-13614, https://doi.org/10.5194/egusphere-egu23-13614, 2023.

EGU23-13635 | ECS | Posters on site | PS4.1

Exo-Io Simulations of Toroidal Exospheres 

Moritz Meyer zu Westram, Apurva Oza, and André Galli

Although exomoons, natural satellites beyond our solar system, are still undetectable in direct searches with state-of-the-art instruments, their existence has been hypothesized to explain various inconsistencies in exoplanetary spectra. Exogenic sources of sodium and potassium have been considered at multiple exoplanets, where abundances exceed the exoplanet’s source rates, and hydrostatic exoplanet atmospheres are limited in their ability to explain increased line broadening seen in Na & K spectra, where an orbiting body naturally provides broadening with variable ±∼10-20 km/s.
A semi-analytic atmospheric escape and evolution model dishoom approximates the minimum mass flux needed for an exomoon to provide volcanic material for the absorption of star light. We develop a 3-D test-particle Monte Carlo simulation module called SERPENS (Simulating the Evolution of Ring Particles Emergent from Natural Satellites) to be coupled to dishoom. SERPENS is designed to be highly adaptive, open-source, and easy to use. We simulate the neutral outgassing and evolution of a satellite at multiple candidate exoplanet-exomoon systems including HD189733 b II, HD209458 b I, WASP-49 A b I, HAT-P-1 b I, and WASP-96 b I, in order to provide a number density n[cm−3] and line-of-sight column density N[cm−2] map of the particle environment in a non-hydrostatic medium, characteristic of a volcanic exosphere akin to Jupiter’s Na exosphere fueled by Io. The neutral species maps are then fed into a non-hydrostatic radiative transfer model, Prometheus, which computes an exospheric spectrum that can be directly compared to ongoing ground and space-based spectra of candidate exomoon systems. We model masses ranging from Earth, Io, and Enceladus to emulate long-term effects of mass loss and present the respective particle distributions. Photoionization is set as the prime constraint for the lifetime of atoms and molecules.
In contrast to previous works, our code SERPENS focuses on exomoons and their imprint as a neutral
and plasma torus. SERPENS is designed to eject particles via sputtering and thermal evaporation at
regular time intervals allowing us to simulate an evolving cloud/torus. Multiple species including Na, K
and SO2, as well as their chemical networks, are supported.
Our results demonstrate how exomoons similar to Io, referred to as exo-Ios, can affect line-of-sight column densities depending on the phase of the exomoon at the time of observation. This means that it is possible to model time-variable spectra by taking into account the phase of the exomoon.

How to cite: Meyer zu Westram, M., Oza, A., and Galli, A.: Exo-Io Simulations of Toroidal Exospheres, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-13635, https://doi.org/10.5194/egusphere-egu23-13635, 2023.

EGU23-14084 | ECS | Orals | PS4.1

Aggregation and charging of mineral cloud particles underhigh-energy irradiation 

Nanna Bach-Møller, Christiane Helling, Uffe Gråe Jørgensen, and Martin Bødker Enghoff

Previous studies have found that high-energy radiation like cosmic rays and stellar energetic particles, can induce the initial nucleation of cloud particles from molecular clusters, but the effect on larger existing particles is still poorly understood.

This study explores the question “How is the aggregation of mineral cloud particles affected by high-energy radiation and humidity?”. We present experiments conducted in an atmosphere chamber on the charging and aggregation of 50nm SiO2 particles under varying degrees of gamma radiation and relative humidity. 
We observe an aggregation of the SiO2 particles to form larger clusters, and that this aggregation is inhibited by irradiation with gamma radiation. We find that non-irradiation SiO2 particles are generally more positively charged in comparison to a bipolar charge distribution, and that gamma radiation shifts the particles to a more negative charge. The effect of gamma radiation on the aggregation and charge of the particles is present both at lower (~20%) and higher (~60%) relative humidity. When varying the relative humidity from ~20% to ~80% we find no significant direct effect of relative humidity on the aggregation of the particles. These results are presented and discussed in relation to previous studies of nucleation and condensation.

In recent years, exoplanet research has focused on how we can interpret atmosphere observations through models, and here cloud formation has proven to be a challenge. Clouds are known to play a role in both the energy balance and chemistry of atmospheres, as well as directly affecting the spectrum observed from a planet. Exoplanet clouds are believed to be very chemically heterogeneous and SiO2 is one of the species that easily condense, making SiO2 relevant both as a nucleation seed on Earth-like planets and as a cloud species on Exoplanets. Since cloud formation has been found to be affected not only by the atmospheric properties, but also by high-energy radiation from outside the atmosphere it indicates that the host star and interstellar environment of an exoplanet might affect its clouds.

How to cite: Bach-Møller, N., Helling, C., Gråe Jørgensen, U., and Bødker Enghoff, M.: Aggregation and charging of mineral cloud particles underhigh-energy irradiation, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-14084, https://doi.org/10.5194/egusphere-egu23-14084, 2023.

EGU23-16013 | ECS | Orals | PS4.1

Latitudinal and Longitudinal Structure of Io's Atmosphere explained by an Atmosphere that is purely Sublimation Driven 

Anne-Cathrine Dott, Joachim Saur, Stephan Schlegel, and Darrell Strobel

How much Io's SO2 atmosphere is driven by direct volcanic outgasing or the sublimation of SO2 surface frost is still debated. Since the sublimation supported part of the atmosphere is highly surface temperature dependent, the atmosphere is expected to have a lower SO2 column density on the nightside consistent with observations of a decreased column density in eclipse. Furthermore, the atmosphere is observed to be thicker in equatorial regions compared to the poles and when Jupiter is in Perihelion.
To investigate how well observed structures of Io's SO2 distribution can be explained with a purely sublimation driven atmosphere, we developed a time dependent surface temperature model including the effect of thermal inertia. Analyzing the conductive heat transfer from Io's surface towards its interior and vice versa, which is mainly determined by the thermal diffusivity α, allows us to show that many observations can be well explained by assuming a sublimation dominated atmosphere. Simulations show that α=3.1x10-6 m2 / s yields an averaged atmospheric SO2 column density decreasing from 1016 to 2.5x1014 cm-2 from the equator to the poles. In a parameter study regarding the thermal inertia we discuss the influence of different values of the thermal inertia on the diurnal surface temperature and column density variation and find that a thermal diffusivity lower by a factor of 10 results in an atmosphere having both features, a less pronounced latitudinal dependence but a strong day-night asymmetry. Due to Io's inclination, we also find features of the surface temperature and column density that vary seasonally. 

How to cite: Dott, A.-C., Saur, J., Schlegel, S., and Strobel, D.: Latitudinal and Longitudinal Structure of Io's Atmosphere explained by an Atmosphere that is purely Sublimation Driven, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-16013, https://doi.org/10.5194/egusphere-egu23-16013, 2023.

EGU23-16456 | ECS | Orals | PS4.1

Quantifying sputter yields of lunar soils 

Johannes Brötzner, Herbert Biber, Noah Jäggi, Andreas Nenning, Paul Stefan Szabo, Killian Odin, Bernhard Rizek, André Galli, Peter Wurz, and Friedrich Aumayr

One of the influences that the Moon experiences in the space environment is the bombardment of the surface by solar wind ions, mostly protons and alpha particles. A consequence of this irradiation is the liberation of material through the process of sputtering. The ejected particles subsequently take part in the formation of the lunar exosphere [1]. Understanding the sputtering of the Moon’s surface and experimentally constraining the process quantities like sputter yield and angular distribution of ejecta is thus necessary to properly model the exosphere creation [2].

For this purpose, previous studies used analogue materials to investigate their erosion. We now present studies of two types of samples prepared from actual lunar soil obtained during the Apollo 16 mission: First, regolith material was pressed into stainless steel holders to form pellets, analogue to the sample preparation described in [3]. Apart from the application of pressure necessary for the pellet formation, the specimens were not further altered. Moreover, pulsed laser deposition was carried out to grow thin films onto quartz resonators using one such pellet as donor. While these films were checked to have the same chemical composition as the source material, they are however flat and vitreous.

Using such a resonator with the deposited lunar material as a Quartz Crystal Microbalance (QCM), we studied the mass depletion of the sample layer due to He⁺ and H⁺ ion bombardment in situ and in real time. Because this direct means of measuring the sputter yield cannot be applied to the rough and more pristine regolith pellets, another QCM was used. This second microbalance maintains a fixed distance d to the centre of the irradiated target and allows for variation of the polar angle β with respect to the target surface normal. The setup enables us to probe the angular distribution of particle flux by collecting a fraction of the liberated material. It is sketched in figure 1. With the thin film irradiations used as calibration, these differential sputter yields give indirect insight into the total mass sputtered away as a function of ion incidence angle. This approach has already proven to work well with analogue materials for the surfaces of celestial bodies [4]. We will present our experimental findings for both thin film and pellet irradiations along with simulation approaches to model these results. This study represents an important extension of previous experiments to actual lunar surface samples and will thus provide essential insights into constraining sputtering of the surface of the Moon and other planetary bodies.

Figure 1: Illustration of the experimental setup. Using the catcher QCM, the sputtered ejecta flux can be probed along the emission angle β under various incidence angles α.

[1] Hapke, B. et al; J. Geophys. Res. 106 (2001): 10039
[2] Wurz, P. et al; Icarus 192 (2007): 486
[3] Jäggi, N. et al; Icarus 365 (2021): 114492
[4] Biber, H. et al; Planet. Sci. J. 12 (2022)

How to cite: Brötzner, J., Biber, H., Jäggi, N., Nenning, A., Szabo, P. S., Odin, K., Rizek, B., Galli, A., Wurz, P., and Aumayr, F.: Quantifying sputter yields of lunar soils, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-16456, https://doi.org/10.5194/egusphere-egu23-16456, 2023.

EGU23-16730 | Posters on site | PS4.1

Mineralogical control of fracturing and micro-flaking due to thermal fatigue 

Ottaviano Rüsch and Markus Patzek

Thermal fatigue driven by diurnal temperature variations can lead to the physical modifications of rocks and boulders that populate airless surfaces [1-2]. These modifications affect regolith evolution, e.g., particle size, porosity and roughness, and thus influence reflected and emitted radiation observed by spacecraft, Earth- and space-based telescopes. In order to study in detail how this process affects rocks of different mineralogy and under different environments (temperature, vacuum) we use a custom-made thermal cycling chamber operating in high vacuum and at cryogenic temperatures. The investigation on achondrite meteorite samples demonstrated moderate cracking after thermal cycling relative to chondritic samples and revealed a new phenomenon, i.e., formation and detachment of micro-flakes for lunar anorthositic samples [3]. The investigation of chondritic samples subjected to thermal cycling revealed i) formation and extension of cracking due to thermal fatigue for Jbilet Winselwan (CM2), Murchison (CM2) and Tagish Lake (C2ung); ii) absence of newly formed cracks for El Hammami (H5) and Allende (CV3), iii) absence of micro-flaking for all the above-mentioned samples. In addition, we find that in CM chondrites, cracking is often associated with hydrous fine-grained rims that surround chondrules and, in some cases, cracks diverging radially from the chondrules through the rim into the clastic matrix. These results illustrate how the mineralogy and texture, in particular the spatial context with minerals of different coefficient of thermal expansion (hydrous phyllosilicates and olivine/pyroxene), play an important role in crack formation and/or extension.

References : [1] Delbo M. et al. (2014) Nature, 508(7495), 233-236, doi:10.1038/nature13153. [2] Molaro J. L. et al. (2015) JGR: Planets, 120(2), 255-277, doi:10.1002/2014JE004729. [3] Patzek M. and Rüsch O. (2022) JGR: Planets 127.10. doi:10.1029/2022JE007306

How to cite: Rüsch, O. and Patzek, M.: Mineralogical control of fracturing and micro-flaking due to thermal fatigue, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-16730, https://doi.org/10.5194/egusphere-egu23-16730, 2023.

EGU23-16977 | ECS | Orals | PS4.1

Determining the Sputtered Secondary Ion Densities at Phobos and Deimos: A combined computational and experimental study 

Micah Schaible, Liam Morrissey, Menelaos Sarantos, and Robert Johnson

Introduction: Space weathering by ion irradiation is ubiquitous on the surfaces of airless bodies in the Solar System. Sputtering occurs when solar wind (SW) or magnetosphere ions (MI) impact the suraces of bodies in space. Asteroids and moons are too small to maintain a significant atmosphere, and therefore they are directly exposed to ionizing radiation from the solar wind and magnetospheric plasmas. Incident ions can transfer sufficient energy to surface species to cause them to desorb and potentially escape to space. A small fraction of the sputtered species can escape as ions, called sputtered secondary ions (SSI). Mass, charge, and energy analysis of the sputtered ions using secondary ion mass spectrometry is highly diagnostic of the irradiated surface composition. The upcoming JAXA MMX mission will carry a Mass Spectral Analyzer (MSA) instrument will be capable of making measurements of SSI around its target bodies Phobos and Deimos (P&D). However, there is currently limited estimates of SSI yields from relevant surface compositions under relevant irradiation conditions, and the expected SSI fluxes around P&D are not well constrained.

Background: Although P&D are exposed to both the SW and MI and SSI are expected to be present throughout their orbits. However, several challenges arise when attempting to derive a precise surface composition from a measured SIMS spectra, or when estimating the expected count rates and elemental ratios that will be observed by MSA for a given composition: (i) the relative abundances measured by SIMS are not directly correlated with the actual surface composition, and (ii) the relative and absolute SSI yields (# of SSI ejected per incident ion) likely depend on the surface chemistry and exposure history, and on the incident ion type and energy.

Results: A combined computational and experimental approach has been used in order to better constrain the solar wind sputtering rates of small, rocky bodies. First, a series of SIMS measurements in the laboratory were carried out to determine the relative ion sputtering ratios from several lunar samples of known composition. Then, using Monte Carlo simulations of sputtering due to both solar wind and magnetosphere ions and the measured SSI energy distributions to determine the total sputtering yields, the total abundance and relative composition of sputtered ions can be determined for an arbitrary small body. This work will (1) estimate the the SSI yields from analog Mars and Carbonaceous Chondrite analog materials and correlate the expected yields with the surface composition, and (2) provide estimates the SSI fluxes and densities during their orbits around Mars. Further, this work will demonstrate how measurement of the elemental ratios of SSI can be used to estimate the potential origins scenarios for small bodies.

How to cite: Schaible, M., Morrissey, L., Sarantos, M., and Johnson, R.: Determining the Sputtered Secondary Ion Densities at Phobos and Deimos: A combined computational and experimental study, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-16977, https://doi.org/10.5194/egusphere-egu23-16977, 2023.

EGU23-17142 | Posters on site | PS4.1

Variation of the Moon’s Solar-Induced Hydrogen Cycle during a Solar Storm 

Prabhakar Misra, Kennedi White, William M. Farrell, and Orenthal J. Tucker

Observations of surficial OH/H2O in regolith grains on the Moon’s surface indicate variability on diurnal timescales 1–3 consistent with the variability of the solar wind proton flux and local surface temperature. Recent Monte Carlo models accounting for hydrogen diffusion and the degassed H2 exosphere support the theory of solar wind implantation being the primary driver of the lunar hydrogen cycle 4. In this presentation, we will report modeling results of the dynamical response of surficial OH content and the H2 exosphere during a Coronal Mass Ejection event, for which the proton flux can be a factor of 20 larger than nominal solar wind conditions 5,6. Observations of the response of hydrogen in the lunar environment during a solar storm event would provide strong support for solar wind implantation being the principal mechanism producing surface OH content and H2 exosphere.

Acknowledgment: Financial support from LEADER (NASA Award# 80NSSC20M0019) is gratefully acknowledged.

1. Li, S. et al. New formation processes of lunar surface water in Earth’s magnetotail. Nat Astron Accepted, (2023).

2. Li, S. & Milliken, R. E. Water on the surface of the Moon as seen by the Moon Mineralogy Mapper: Distribution, abundance, and origins. Sci Adv 3, 1–12 (2017).

3. Grumpe, A., Wöhler, C., Berezhnoy, A. A. & Shevchenko, V. v. Time-of-day-dependent behavior of surficial lunar hydroxyl/water: Observations and modeling. Icarus 321, 486–507 (2019).

4. Tucker, O. J., Farrell, W. M. & Poppe, A. R. On the Effect of Magnetospheric Shielding on the Lunar Hydrogen Cycle. J Geophys Res Planets 126, (2021).

5. Killen, R. M., Hurley, D. M. & Farrell, W. M. The effect on the lunar exosphere of a coronal mass ejection passage. Journal of Geophysical Research E: Planets 117, 1–15 (2012).

6. Farrell, W. M. et al. Solar-Storm/Lunar Atmosphere Model (SSLAM): An overview of the effort and description of the driving storm environment. J Geophys Res Planets 117, (2012).

How to cite: Misra, P., White, K., Farrell, W. M., and Tucker, O. J.: Variation of the Moon’s Solar-Induced Hydrogen Cycle during a Solar Storm, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-17142, https://doi.org/10.5194/egusphere-egu23-17142, 2023.

EGU23-3592 | Posters on site | PS4.2

Magma oceanography of the dense, ultrashort-period sub-Earth GJ 367b 

Gregor Golabek, Tim Lichtenberg, and Paul Tackley

The dawn of high-resolution observations with the James Webb Space Telescope will enable spatially resolved observations of ultrashort-period rocky exoplanets. Some of these planets orbit so closely to their star that they lack an atmosphere [1], which gives direct access to their surfaces and opens a window to infer their geodynamics [2]. The physical parameters of the ultrashort-period sub-Earth GJ 367b have been observationally constrained to a planetary radius of about 0.72 to 0.75 Earth-radii and a mass between 0.48 and 0.55 Earth-masses, implying a density of 6200 to 8500 kg/m3 [3, 4], which puts this planet in a Mercury-like interior regime with a thin mantle overlying a fractionally large core.
The dayside temperature ranges between 1500 to 1800 K, thus suggesting the presence of a permanent magma ocean or dayside magma pond on the surface, induced by stellar irradiation. The large uncertainty on the age of the stellar system, between 30 Myr [4] and about 8 Gyr [3], however, introduce severe uncertainties related to the compositional and thermal evolution of the planetary mantle. In this study we perform global 2D spherical annulus StagYY simulations [5, 6] of solid state mantle convection and surface melting with the goal to constrain the geometric and compositional properties of
the planet. Constraining the spatial dimensions of thermodynamic properties of partially molten, atmosphere-less planets like GJ 367b offers unique opportunities to constrain the compositional fractionation during magma ocean epochs and provides avenues to constrain the delivery and loss cycle of atmophile elements on strongly irradiated exoplanets.

References:
[1] L. Kreidberg and 18 co-authors. Absence of a thick atmosphere on the terrestrial exoplanet LHS 3844b. Nature, 573:87–90, August 2019.
[2] T. G. Meier, D. J. Bower, T. Lichtenberg, P. J. Tackley, and B.-O. Demory. Hemispheric Tectonics on LHS 3844b. Astrophys. J. Lett., 908:L48, February 2021.
[3] K.W.F. Lam and 78 co-authors. GJ 367b: A dense, ultrashort-period sub-earth planet transiting a nearby red dwarf star. Science, 374:1271–1275, 2021.
[4] W. Brandner, P. Calissendorff, N. Frankel, and F. Cantalloube. High-contrast, high-angular resolution view of the GJ367 exoplanet system. Mon. Notices Royal Astron. Soc., 513:661–669, June 2022.
[5] J. W. Hernlund and P. J. Tackley. Modeling mantle convection in the spherical annulus. Phys. Earth Planet. Int., 171:48–54, 2008.
[6] P. J. Tackley. Modelling compressible mantle convection with large viscosity contrasts in a three-dimensional spherical shell using the yin-yang grid. Phys. Earth Planet. Int., 171:7–18, 2008.

How to cite: Golabek, G., Lichtenberg, T., and Tackley, P.: Magma oceanography of the dense, ultrashort-period sub-Earth GJ 367b, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-3592, https://doi.org/10.5194/egusphere-egu23-3592, 2023.

EGU23-4231 | ECS | Orals | PS4.2

Radar backscattering properties of lava flows on Earth and Venus 

Allegra Murra, Marco Mastrogiuseppe, Giovanni Alberti, Letizia Gambacorta, and Roberto Seu

VERITAS mission, recently selected as part of NASA's Discovery program, will allow the investigation of the geological history of Venus, the mapping of its surface to study volcanic and tectonic processes and giving to scientists a unique opportunity to understand its geological activity. The spacecraft will carry the instrument VISAR, an interferometric X-band synthetic aperture radar (SAR) that will provide global 30 m medium resolution imagery of the surface and topographic maps with a spatial resolution of 250 m and a height accuracy of 5 m.

Looking at VERITAS mission, our work combines information obtained both from Digital Elevation Models (DEM) and SAR data acquired over time, in order to study terrestrial lava flows properties. We selected the Pacaya volcano in Guatemala and, supported by the corresponding geological maps, we identified and isolated some of its relevant lava flows. We used  SENTINEL-1 SAR data acquired at C band and surface local incidence angle obtained from high resolution DEMs,  to study lava flows backscattering coefficient behavior with respect to the incidence angle variation, along with EM formulation. Through fitting theoretical models, scattering laws provided us an estimate for lava flows dielectric properties and roughness. Our research shows a backscattering behavior which changes among different lava flows, in addition we find a seasonal behavior of the backscattering as function of the wet/dry periods of Pacaya. This behavior would not have been detectable without the initial lava flows segmentation, performed before the overall analysis. This selection indeed made possible the study of backscattering coefficient of regions with separately uniform and stationary surface parameters.

How to cite: Murra, A., Mastrogiuseppe, M., Alberti, G., Gambacorta, L., and Seu, R.: Radar backscattering properties of lava flows on Earth and Venus, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-4231, https://doi.org/10.5194/egusphere-egu23-4231, 2023.

EGU23-7105 | Orals | PS4.2

Venus Atmospheric Structure Investigation (VASI) on the DAVINCI Probe 

Ralph Lorenz and the VASI Team

The only near-surface temperature/pressure profile of the atmosphere of our twin planet, Venus, was obtained in 1985 by the VEGA-2 lander. The handful of other probe missions have very limited vertical resolution, or sensor failures in the lowest few km.  Unlike altitudes above 40km, which have been relatively well-surveyed by radio occultation profiles from orbiter missions, the fine temperature structure of lowest part of the Venus atmosphere must be interrogated by direct measurement. This structure is important in several respects. First, the structure and composition reflects the interactions between surface and atmosphere of an ‘exoplanet in our back yard’ which may be much more typical than are those of Earth. Secondly, there are indications that particularly interesting phenomena may occur on Venus, not seen in the atmospheres of Earth, Mars or Titan (but analogous to aspects of ocean stratification on Earth): the VEGA-2 profile is impossible to reconcile with a profile that is both convectively stable and compositionally uniform. A favored hypothesis is that the lowest few kilometers are compositionally denser (lower N2). The supercritical thermodynamics of carbon dioxide add to the rich possibilities in this region.

The exchange of angular momentum between the retrograde, slowly-rotating Venus and its dense atmosphere is reflected in the wind profile, which can now be interpreted by global circulation models. Again, while cloud-top (60-70km) winds are now well-known from Akatsuki and preceding missions, very little data exist on winds in the hidden lowest 40km.  Doppler tracking, turbulence measurements, and trajectory reconstruction from descent imaging will shed unprecedented light on the lower atmospheric dynamics.

DAVINCI was selected for flight in 2021 and is presently under development for launch in 2029. This presentation will review how the VASI’s measurements of pressure, temperature and wind, far superior in resolution and/or quantity to those of previous missions, may improve our understanding of Venus and complement DAVINCI’s composition measurements and imaging.

How to cite: Lorenz, R. and the VASI Team: Venus Atmospheric Structure Investigation (VASI) on the DAVINCI Probe, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-7105, https://doi.org/10.5194/egusphere-egu23-7105, 2023.

EGU23-7619 | Posters on site | PS4.2

First long-term study of the Venus' Cloud Discontinuity with uninterrupted observations 

Javier Peralta, António Cidadão, Luigi Morrone, Clyde Foster, Mark Bullock, Eliot F. Young, Itziar Garate-Lopez, Agustín Sánchez-Lavega, Takeshi Horinouchi, Takeshi Imamura, Emmanuel Kardasis, Atsushi Yamazaki, and Shigeto Watanabe

The discontinuity/disruption is a recurrent atmospheric wave observed to propagate during decades at the deeper clouds of Venus (47-56 km above the surface), while its absence at the top of the clouds (~70 km) suggests that it might dissipate at the upper clouds and contribute to the puzzling atmospheric superrotation through wave-mean flow interaction.

Thanks to a campaign of ground-based observations performed in coordination with JAXA's Akatsuki mission since December 2021 until July 2022, we aimed to undertake the longest uninterrupted monitoring of the cloud discontinuity up to date to obtain a pioneering long-term characterization of its main properties and better constrain its recurrence and lifetime. The dayside upper, middle and nightside lower clouds were studied with images taken with suitable filters acquired by Akatsuki/UVI, amateur observers and NASA's IRTF/SpeX, respectively. Hundreds of images were inspected in search of discontinuity events and to measure properties like its dimensions, orientation or rotation period.

We succeeded in tracking the discontinuity at the middle clouds during 109 days without interruption. The discontinuity exhibited properties nearly identical to measurements in 2016 and 2020, with an orientation of 91º±8º, length of 4100±800, width of 500±100 km and a rotation period of 5.11±0.09 days. Ultraviolet images during 13-14 June 2022 suggest that we have witnessed for the first time a manifestation of the discontinuity at the top of the clouds during ~21 hours, facilitated by an altitude change in the critical level for this wave due to slower zonal winds.

How to cite: Peralta, J., Cidadão, A., Morrone, L., Foster, C., Bullock, M., Young, E. F., Garate-Lopez, I., Sánchez-Lavega, A., Horinouchi, T., Imamura, T., Kardasis, E., Yamazaki, A., and Watanabe, S.: First long-term study of the Venus' Cloud Discontinuity with uninterrupted observations, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-7619, https://doi.org/10.5194/egusphere-egu23-7619, 2023.

EGU23-8270 * | Orals | PS4.2 | Highlight

Exo-Venus, Exo-Earth, Exo-Dead in the Trappist-1 System? 

Michael Way

Since the discovery of the Trappist-1 system a number of studies have explored which of these planets are within the canonical habitable zone with Trappist-1e the most likely Exo-Earth-like of the bunch [e.g. 1,2,3,4]. At the same time they also tend to indicate that Trappist-1d is likely an exo-Venus.  Using the ROCKE-3D General Circulation Model [5] we investigate whether Trappist-1d is likely to be an Exo-Venus, an Exo-Earth, or is a bare rock (Exo-Dead). We apply our previous approach to understand the climate history of Venus [6] to explore Trappist-1d.

[1] Wolf, E.T. (2017) ApJ 839:L1

[2] Turbet et al. (2018) A&A 612, A86

[3] Krissansen-Totton, J. and Fortney, J.J. (2022) PSJ 933:115

[4] Kane, S.R. et al. (2021) AJ 161:53 

[5] Way, M.J. et al. (2017) ApJS 213:12

[6] Way, M.J. and Del Genio, A.D. (2020) JGR Planets, 125, e2019JE006276

How to cite: Way, M.: Exo-Venus, Exo-Earth, Exo-Dead in the Trappist-1 System?, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-8270, https://doi.org/10.5194/egusphere-egu23-8270, 2023.

EGU23-8312 | ECS | Posters on site | PS4.2

Characterisation of the sensitivity to bias using a gain matrix formulation for the VeSUV/VenSpec-U instrument onboard ESA’s EnVision mission 

Lucile Conan, Emmanuel Marcq, Benjamin Lustrement, Ann Carine Vandaele, and Jörn Helbert

Selected in 2021 as the fifth class M mission of ESA’s “Cosmic Vision” programme, EnVision is one the three next exploration mission of Venus, alongside NASA’s VERITAS and DAVINCI. EnVision will bring a holistic approach, by studying the surface and subsurface, different layers of the atmosphere, past and present volcanic activity, as well as coupling processes. To that end, the payload will include a synthetic aperture radar for surface mapping (VenSAR, NASA), a subsurface radar sounder and a radioscience experiment to monitor gravimetric and atmospheric properties.

Finally, the spectrometer suite VenSpec will investigate the surface and atmospheric compositions to analyse their relations with internal activity, using the thermal IR imager VenSpec-M and the high-resolution IR spectrometer VenSpec-H. The UV channel of the suite VenSpec-U, also called VeSUV, will focus on the atmosphere above the clouds, and aims more specifically at characterising the abundance and variability of sulphured gases such as SO and SO2, and the unidentified UV absorber. To do so, VeSUV will operate in pushbroom mode in the 190-380 nm range with an improved spectral resolution between 205 and 235 nm, and will observe the backscattered sunlight on the dayside of Venus at a spatial sampling ranging from 3 to 24 km.

In order to characterise the instrument’s performances, the sensitivity to bias is analysed using a gain matrix formulation. A perturbation is locally introduced on a synthetic spectrum and a fitting algorithm involving the same radiative transfer model is used to retrieve the atmospheric parameters, for several values of perturbation. As they are small, the assumption of a linear relation between the perturbation and the resulting error on the estimated parameters is made, their ratio corresponding to the matrix element. This method allows a conversion between the measured signal and the atmospheric parameters independently from the bias spectrum (e.g. straylight, calibration error, contamination during mission), as it is computed separately for each wavelength.

How to cite: Conan, L., Marcq, E., Lustrement, B., Vandaele, A. C., and Helbert, J.: Characterisation of the sensitivity to bias using a gain matrix formulation for the VeSUV/VenSpec-U instrument onboard ESA’s EnVision mission, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-8312, https://doi.org/10.5194/egusphere-egu23-8312, 2023.

EGU23-8703 * | Orals | PS4.2 | Highlight

Venus as a natural laboratory to infer observational prospects of close-in-orbit rocky exoplanets with a 3D model 

Gabriella Gilli, Diogo Quirino, Thomas Navarro, Martin Turbet, Lisa Kaltenegger, Thomas Fauchez, Jeremy Leconte, Sebastien Lebonnois, and Luisa Lara

Venus is in the spotlight of the public and scientific community after the selection of 3 missions: DAVINCI and VERITAS by NASA and EnVision by ESA/NASA. It remains an open question how Venus and the Earth started so similar but become such different worlds. Thus, studying Venus is essential for understanding the links between planetary evolution and the habitability of terrestrial planets, including those outside our Solar System. Several Earth-sized exoplanets have been recently detected in short-period orbits of a few Earth days around low-mass stars [1]. Those planets have stellar irradiation levels of several times that of the Earth, suggesting that a Venus-like climate is more likely than an Earth-like [2]. Consequently, the atmosphere of our closest planet Venus represents a relevant case to address observational prospects of rocky close-in orbit exoplanets.

In this work we used the Generic Planetary Climate Model (historically known as the LMD Generic GCM), a 3D model developed for exoplanet and paleoclimate studies ([3], [4], [5], [6], [7]), to simulate the atmosphere of two potential Venus’s analogues: TRAPPIST-1c [1] and LP 890-9c [8], both orbiting M-dwarf stars. We assumed that the planets are tidally-locked, and they have evolved into a modern Venus-like atmosphere (e.g. CO2-dominated, 92-bar surface pressure), with an H2SO4 prescribed cloud layer following Venus Express observations ([9]). Our 3D climate simulations show the presence of an eastward equatorial superrotation jet for Trappist-1c (Quirino et al. in preparation), in agreement with previous prediction of highly irradiated synchronous rotators (e.g., [10]), and an effective day-to-night heat redistribution by three superrotation jets (one equatorial and two high-latitudes) for Speculoos-2c (Quirino et al. MNRAS, submitted).

The results will be shown in terms of simulated temperature/wind fields and the potential characterization of the atmosphere of those planets by JWST and future instrumentations discussed. For instance, under the hypothesis that the planets evolved in a modern Venus, our predicted transmission spectra show that even the strongest CO2 bands around 4.3 μm will be challenging to be detected by the JWST (10 ppm for LP 890-9c and around 40 ppm for Trappist-1c). Those simulations provide new insights for JWST proposals and highlight the influence of clouds on the spectra of hot rocky exoplanets.

References:

[1] Gillon et al. 2017 Nature 542, [2] Kane et al. 2018 ApJ. 869, [3] Forget & Leconte, 2014 Phil. Trans R. Soc.A372., [4] Turbet et al. 2016 A&A 596. A112, [5] Wordsworth et al. 2011 ApJL 733. L48, [6] Leconte et al. 2013, Nature, 504, 286, [7] Turbet et al. 2020 Space Sci. Rev. 216, 100 [8]  Delrez et al. 2022, A&A,Vol.667, id.A59, [9] Haus et al. 2015, PSS, 117, 262, [10] Showman & Polvani 2011, ApJ, 738,71.

Acknowledgments: GG is funded by the Spanish MCIU, the AEI and EC-FEDER funds under project PID2021-126365NB-C21, and IAA’s team acknowledges financial support from the grant CEX2021-001131-S funded by MCIN/AEI/ 10.13039/501100011033

How to cite: Gilli, G., Quirino, D., Navarro, T., Turbet, M., Kaltenegger, L., Fauchez, T., Leconte, J., Lebonnois, S., and Lara, L.: Venus as a natural laboratory to infer observational prospects of close-in-orbit rocky exoplanets with a 3D model, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-8703, https://doi.org/10.5194/egusphere-egu23-8703, 2023.

EGU23-8806 | ECS | Posters on site | PS4.2

The effects of water and intrusive magmatism on the evolution and dynamics of Venus 

Marla Metternich, Paul Tackley, Diogo L. Lourenço, and Cedric Thieulot

Observations of Venus reveal tectonic expressions and recent volcanism, showing that the planet is still active. Tectonically deformed areas such as ridges or tesserae indicate surface mobility, however, no signs of active plate tectonics like on Earth have been found. The tectonics and volcanism of Venus and other terrestrial planets are defined by the active mantle convection mode. A key component of tectonics is rheology, which is affected by water as shown by numerous studies[1].  However, the effects of water have been mostly ignored when studying Venus because its interior has been assumed to be dry. This notion is being challenged by indications of strong hydrodynamic escape to space that requires volcanic replenishment[2]. Therefore, water should be present in Venus’ interior, even if its content is not known. Importantly, the potential effects of water in the dynamics and evolution of Venus are poorly understood. This calls for the consideration of complex dynamic thermo-magmatic models that track water and take into account intrusive and extrusive magmatism.

In this study, we use the code StagYY to perform state-of-the-art 2D numerical models in a spherical annulus geometry to assess the effects of water on the tectono-magmatic evolution of Venus[3]. Particular attention will be given to changes in mantle viscosity, melt generation and crustal properties such as thickness and surface age. We explore model settings related to melting, intrusive magmatism, and water presence. Results show that intrusion depth influences the thermal evolution and related magmatism. Moreover, preliminary results show that the rate of water outgassing is directly related to changes in the thermo-magmatic evolution of Venus. Water outgassing rates have further implications on surface conditions and atmospheric compositions over time. In the future, coupling these improved mantle convection models to atmospheric evolution models may unveil new insights into the thermal and tectonic history that has shaped Venus into the planet we observe today.

How to cite: Metternich, M., Tackley, P., Lourenço, D. L., and Thieulot, C.: The effects of water and intrusive magmatism on the evolution and dynamics of Venus, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-8806, https://doi.org/10.5194/egusphere-egu23-8806, 2023.

EGU23-8996 * | Orals | PS4.2 | Highlight

Thermal evolution and interior structure of Venus 

Ana-Catalina Plesa, Michaela Walterová, Julia Maia, Iris van Zelst, and Doris Breuer

The dense atmosphere of Venus and the planet’s young surface, dominated by volcanic features, bear witness to its past and potentially ongoing volcanic activity. While unique among the terrestrial planets of our Solar System, Venus is likely similar to a myriad of extrasolar worlds [1]. Thus, investigating Venus’s interior structure, thermal history, and magmatic processes may guide our understanding of the evolution and present-day state of an entire class of exoplanets.

The present-day geodynamic regime of Venus’s mantle is still debated, but models agree that magmatism played a major role in shaping the atmosphere and surface that we observe today [2]. In this contribution we will summarize the evidence for recent and possibly ongoing magmatic activity in the interior of Venus and show how we can combine current and future observations with thermal evolution models to constrain the planet’s present-day interior structure, dynamics, and magmatic activity. 

We calculate the tidal deformation and moment of inertia in our models to provide estimates on deep interior parameters. While the tidal Love number k2, which is sensitive to the size and state of the core, has been determined from Magellan and Pioneer Venus Orbiter tracking data with large uncertainties [3], the phase lag of the deformation, whose value is particularly sensitive to the thermal state of the interior, has not yet been measured. A rough estimate of the core size of 3500 km with large (>500 km) uncertainties comes from the moment of inertia factor that was determined from Earth-based radar observations [4].  

Our models address the recent volcanic activity that was suggested by several observations [e.g., 5]. In particular, we focus on investigating the constraints coming from estimates of the elastic lithosphere thickness, which is linked to the thermal state of the lithosphere at the time of the formation of geological features. Gravity and topography analyses indicate small elastic thicknesses for a variety of locations including coronae [6], steep-sided domical volcanoes [7], and crustal plateaus [8]. The young age of many surface features on Venus suggests a warm lithosphere at present-day, potentially linked to partial melting in the interior. Moreover, a recent study found that the inferred heat flux at 75 locations on Venus associated with recent volcanic and tectonic activity is similar to the values measured on Earth in areas of active extension [9].  

Future measurements of the NASA VERITAS and ESA EnVision missions aim to constrain present-day volcanic and tectonic activity as well as the thickness of major layers (crust, mantle, and core) in the interior of Venus. These measurements will provide unprecedented information to address the interior structure and thermal history of our neighbor, who can teach us about the diversity of evolutionary paths that rocky planets around other stars might have followed.

[1] Kane et al., 2019. [2] Rolf et al., 2022. [3] Konopliv and Yodder, 1996. [4] Margot et al., 2021. [5] Smrekar et al., 2010. [6] O’Rourke & Smrekar, 2018. [7] Borrelli et al., 2021. [8] Maia and Wieczorek, 2022. [9] Smrekar et al., 2022. 

How to cite: Plesa, A.-C., Walterová, M., Maia, J., van Zelst, I., and Breuer, D.: Thermal evolution and interior structure of Venus, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-8996, https://doi.org/10.5194/egusphere-egu23-8996, 2023.

EGU23-9086 | ECS | Orals | PS4.2

Estimating the seismicity of Venus by scaling Earth’s seismicity 

Iris van Zelst, Julia Maia, Moritz Spühler, Ana-Catalina Plesa, Raphaël F. Garcia, Richard Ghail, Anna J. P. Gülcher, Anna Horleston, Taichi Kawamura, Sara Klaasen, Philippe Lognonné, Csilla Orgel, Mark Panning, Leah Sabbeth, and Krystyna Smolinksi

With the selection of multiple missions to Venus by NASA and ESA planned to launch in the coming decade, we will greatly improve our understanding of Venus as a planet. However, the selected missions cannot tell us anything about the seismicity on Venus, which is a crucial observable to constrain the tectonic activity and geodynamic regime of the planet, and its interior structure. 

Here, we provide new, preliminary estimates of Venus’ global annual seismic budget and the expected frequency of venusquakes per year. We obtain this estimate by scaling the seismicity of the Earth recorded in the CMT catalogue. We test different potential scaling factors based on e.g., the difference in mass, radius, potential seismogenic volume, etc. We also sort the earthquakes into their respective tectonic settings, which allows us to exclude irrelevant tectonic settings present on Earth, but most likely not on Venus from our analysis. This enables us to present a range of potential seismic budgets and venusquake frequencies per tectonic setting on Venus.  

This then provides a new estimate of the potential amount of seismicity on Venus. However, it is uncertain how valid this simple scaling approach is from Earth to Venus. Indeed, previous attempts of scaling the volcanism of Earth to Venus (Byrne & Krishnamoorthy, 2022; Van Zelst, 2022) resulted in numbers that aligned with independent estimates, but are still unconstrained and hard to verify until the announced missions fly. Therefore, in order to provide a more robust and holistic view of Venus’ anticipated seismicity, estimates using various different, independent methods should ideally be considered.

To provide exactly that, we set up the ISSI team ‘Seismicity on Venus: Prediction & Detection’. This is an interdisciplinary team of experts in seismology, geology, and geodynamics. Together we aim to assess the seismic activity on Venus from a theoretical and instrumental perspective. In addition to presenting our preliminary seismicity estimates from scaling Earth to Venus, we therefore also use this contribution to briefly introduce the team and its goals and present the preliminary findings from our first, week-long, dedicated in-person meeting aimed at further characterising Venus’ seismicity. 

References

Byrne, Paul K., and Siddharth Krishnamoorthy. "Estimates on the frequency of volcanic eruptions on Venus." Journal of Geophysical Research: Planets 127.1 (2022): e2021JE007040.

van Zelst, Iris. "Comment on “Estimates on the Frequency of Volcanic Eruptions on Venus” by Byrne & Krishnamoorthy (2022)." Journal of Geophysical Research: Planets (2022): e2022JE007448.

How to cite: van Zelst, I., Maia, J., Spühler, M., Plesa, A.-C., Garcia, R. F., Ghail, R., Gülcher, A. J. P., Horleston, A., Kawamura, T., Klaasen, S., Lognonné, P., Orgel, C., Panning, M., Sabbeth, L., and Smolinksi, K.: Estimating the seismicity of Venus by scaling Earth’s seismicity, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-9086, https://doi.org/10.5194/egusphere-egu23-9086, 2023.

EGU23-9112 | ECS | Posters virtual | PS4.2

The effect of a climatic thermal runaway on the tectonic regime of Venus 

Antonio Manjón-Cabeza Córdoba and Tobias Rolf

The origin of the observed differences between Earth and Venus remains a mystery. On Earth, surface deformation is focused at narrow plate margins resulting in plate tectonics (or a mobile-lid regime). On Venus, a global network of connected plate margins is absent, but the surface is young and has preserved evidence of at least regional crustal mobility. Therefore, the planet must be in a yet-to-be-defined regime distinct from plate tectonics, for example an episodic-lid regime. The array of Venus missions planned for the next decade provides us with an unprecedented chance to refine our knowledge of this tectonic regime, but to use the upcoming data, we need hypotheses to test and a physical framework in which to contextualize the data. To explain the discrepancy on the tectonic regime, a popular hypothesis is that Venus’ higher surface temperatures foster a stiffer lithosphere due enhanced grain growth. Thermally assisted grain growth is supposed to increase the lithospheric viscosity, since diffusion creep depends on grain size, and therefore subduction becomes less efficient. In a previous work [Manjón-Cabeza Córdoba, A., Rolf, T., and Arnould, M: Feasibility of the mobile-lid regime controlled by grain size evolution. EGU General Assembly 2022], we showed that high grain reduction can decrease the interval of yield stresses for which the episodic regime applies, but the results on grain growth were not too conclusive. Here, we present a new set of convection models in spherical annulus geometry using different surface temperatures to specifically address the differences between Earth and Venus. Our results suggest that the effect of the climate thermal runaway depends on the strength of the lithosphere. For yield stresses that yield Earth-like behaviors at lower surface temperatures, an increase in surface temperature does not result in the episodic regime, but rather a sluggish-dripping regime with relatively low plateness. We conclude that either Venus is not in an episodic-regime, or a different explanation must be put forward for the tectonic regime of Venus (e.g., lack of liquid water at the surface).

How to cite: Manjón-Cabeza Córdoba, A. and Rolf, T.: The effect of a climatic thermal runaway on the tectonic regime of Venus, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-9112, https://doi.org/10.5194/egusphere-egu23-9112, 2023.

EGU23-9783 | ECS | Posters virtual | PS4.2

Constraining Venus’ convection regime from Baltis Vallis topography 

Nathan McGregor, Francis Nimmo, Cedric Gillmann, Gregor Golabek, Alain Plattner, and Jack Conrad

Baltis Vallis (BV) is a 6,800-km long lava channel on Venus with a present-day uphill flow direction. The apparently uphill flow must be a consequence of deformation changing the topography after flow emplacement. The topography of BV thus retains a record of Venus’ convection history, as mantle convection causes time-dependent surface deformation. Venus’ mean surface age is likely in the range 300-500 Ma. The observed deformation of BV indicates that mantle convection was active over the past ∼400 Myr and provides constraints on the length scales and vertical amplitudes involved. We place constraints on Venus’ present-day internal structure and dynamics by comparing dynamical topography produced by numerical convection codes with the topography of BV.

We simulate time-dependent stagnant-lid mantle convection on Venus with a suite of coupled interior-surface evolution models for a range of assumed mantle properties. We compare the simulated topographies of model BV profiles to the actual topography of BV using two metrics. The first metric is the root-mean-square (RMS) height. A model is considered successful if its RMS height is similar to the RMS height of BV. The second metric is the “decorrelation time”. Given a particular model time τ, the correlation between model BV topography at a later time τ2 and an earlier time τ1 is calculated. When this correlation first falls to zero, the decorrelation time is then τ2 – τ1. The decorrelation time is inspired by the observation of BV’s present-day uphill flow and the inference that the present-day topography must be uncorrelated with the original topography when BV formed flowing downhill. We compare this decorrelation time to the surface age of Venus (∼400 Ma). A model is considered successful if the decorrelation time is less than the surface age of Venus.

From 14 mantle convection models, each initialized with different parameters, we identified two convection models that best fits our metrics. These models have a viscosity contrast ∆η of 108 and 107, respectively, and both have a Rayleigh number Ra of 108. Although Venus’ heat flux is highly uncertain, our model fluxes are consistent with some inferred heat fluxes. Models with higher total surface heat fluxes tend to yield lower decorrelation times; our favored models have some of the highest heat fluxes. We also find that models with a higher Ra tend to have a lower RMS height, in agreement with Guimond et al. (2022).

Our favored models have vigorous convection beneath a stagnant lid, and high surface heat fluxes. The viscosity of the lower mantle in these models is ∼1020 Pa s, roughly two orders of magnitude lower than that of Earth’s. The majority of the surface heat flux is due to melt advection, indicating high rates of volcanic resurfacing. While current data are insufficient to test these predictions, once paired with forthcoming observations from several new Venus missions, our work will be able to bring Venus’ interior into sharper focus.

How to cite: McGregor, N., Nimmo, F., Gillmann, C., Golabek, G., Plattner, A., and Conrad, J.: Constraining Venus’ convection regime from Baltis Vallis topography, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-9783, https://doi.org/10.5194/egusphere-egu23-9783, 2023.

EGU23-9889 * | Orals | PS4.2 | Highlight

EnVision: a Nominal Science Phase Spanning Six Venus Sidereal Days 

Thomas Widemann, Anne Grete Straume, Adriana Ocampo, Thomas Voirin, Lynn Carter, Scott Hensley, Lorenzo Bruzzone, Joern Helbert, Ann Carine Vandaele, Emmanuel Marcq, and Caroline Dumoulin

EnVision was selected as ESA’s 5th M-class mission, targeting a launch in the early 2030s. The mission is a partnership between ESA and NASA, where NASA provides the Synthetic Aperture Radar payload. The scientific objective of EnVision is to provide a holistic view of the planet from its inner core to its upper atmosphere. The mission phase B1 started in December 2021 to complete trade-offs, consolidate requirements, interfaces and system specifications. Phase B1 will be concluded with the Mission Adoption Review planned in fall 2023, followed by Mission Adoption in 2024. To meet its science objectives, the EnVision mission needs to return a significant volume of science data to Earth, with a large distance-to-Earth dynamic range (from 0.3 to 1.7 AU), from a low Venus polar orbit, in the hot Venus environment (exacerbated by the operation of highly dissipative units), while operating three spectrometers in an almost cryogenic level environment. This needs to be achieved within constraints on the spacecraft mass as well as Agency programmatic boundaries. Achieving the science objectives under these multiple constraints without oversizing the spacecraft calls for a careful planning of science operations, making the science planning strategy a critical driver in the design of the whole mission, against which the spacecraft and ground segment are then sized.

The payload reference operations scenario simulation demonstrates that all identified surface targets can be imaged with VenSAR, with a performance fully compliant with the science requirements. The first two cycles allow imaging once 80% of the identified Regions of Interest (RoIs) at 30 m resolution. The following two cycles are mostly devoted to 2nd observations of these areas for stereo-topography mapping and the two last cycles to 3rd observations of the “activity” type. Dual polarization and high resolution SAR observations can be performed at any longitude at least once across the 6 cycles. Our strategy is to obtain the widest range of data types that enables us to put the highest resolution datasets into regional and global context. Similarly, understanding atmospheric processes requires a combination of global-scale mapping with targeted observations resolving smaller-scale processes.

How to cite: Widemann, T., Straume, A. G., Ocampo, A., Voirin, T., Carter, L., Hensley, S., Bruzzone, L., Helbert, J., Vandaele, A. C., Marcq, E., and Dumoulin, C.: EnVision: a Nominal Science Phase Spanning Six Venus Sidereal Days, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-9889, https://doi.org/10.5194/egusphere-egu23-9889, 2023.

According to laboratory experiments and geomorphological observations, it is likely that the very large Artemis coronae is an exemple of plume-induced subduction. As an hot mantle plume  breaks the denser lithosphere and flows above it, it forces it to sink. So the subduction trenches are localized along the rim of the plume and strong roll-back is observed. Predicted roll-back velocities are between 1 and 10 cm/yr for Artemis case. Subduction always occurs along partial circles, which is due to the brittle character of the upper part of the lithosphere. As roll-back subduction proceeds, the coronae expands and an accreting ridge system develops inside the coronae. 

Laboratory experiments show that the ridge shape is governed primarily by the axial failure parameter  \Pi_F , which depends on the spreading velocity, the mechanical strength of the lithospheric material and the axial elastic lithosphere thickness. Experiments with the largest  \Pi_F  present quite unstable ridge axis with a large lateral sinuosity, transform faults, numerous microplates, and axis jumps. Some of the latter can even cause subduction onset along the abandoned section of the ridge axis. Due to Venus hot surface temperature, this large  \Pi_F regime is the most likely inside Artemis. Magellan data indeed shows a large feature, Britomartis Chasma, that has already  been proposed to be an accretion ridge.  It displays a large sinuosity, comparable to what is predicted by the laboratory experiments. The topography data resolution is not good enough to see transform faults, though. But their presence would explained some of the largest axis offsets. Moreover, the center of Britomartis presents a deep trough, next to a very tall hill. This may be due to core complex formation, but also to the initiation of subduction following an axis jump. Only high-resolution data, such as provided by VERITAS mission, will be able to discriminate between the two options. 

How to cite: Davaille, A.: Conditions for accretion and subduction initiation inside Venus Artemis Coronae, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-12356, https://doi.org/10.5194/egusphere-egu23-12356, 2023.

EGU23-12463 | Posters on site | PS4.2

Correlations between minor species in the Venus mesosphere from the SOIR/Venus Express spectrograph 

Arnaud Mahieux, Aaron Yangambi Libote, Séverine Robert, Ariana Piccialli, Loïc Trompet, and Ann Carine Vandaele

The Solar Occultation in the Infrared (SOIR) instrument was an infrared echelle grating spectrometer on board the Venus Express spacecraft of ESA that sounded the Venus mesosphere using the solar occultation technique [1] from 2006 to 2014. Working at very high resolution, it performed 500+ solar occultations during which many species could be targeted, wherein CO [1], H2O [2], HDO [3], HCl, HF [4], SO2 [5], OCS, SO3, H2S, CS [6], etc., aside from CO2 [7], the main atmosphere constituent. From the measured spectra, we could derive vertical profiles covering the 65 to 160 km region at maximum extent, each species being detected in specific altitude ranges, depending on the strength of their respective spectral absorption bands and concentrations. Temperature profiles were also derived considering the CO2 vertical profiles and the hydrostatic equation [7]. During each solar occultation, SOIR could measure up to four spectral intervals corresponding to the diffraction orders of the echelle grating, allowing us to simultaneously target specific species in different altitude regions.

 

In this work, we are seeking correlations between the concentrations of the minor species, and between the minor species and the temperature profiles, that were measured simultaneously. We will summarize those possible concentration dependencies focusing on possible latitude or time trends. We will also report on possible temperature dependence on the concentrations of those species.

 

[1] Vandaele , A.C., et al. (2016), Icarus, 272.

[2] Chamberlain, S., et al. (2020), Icarus, 346.

[3] Fedorova, A., et al. (2008), J. Geophys. Res., 113.

[4] Mahieux, A., et al. (2015), Planet. Space Sci., 113-114.

[5] Mahieux, A., et al. (2015), Planet. Space Sci., 113-114.

[6] Mahieux, A., et al. (2023), Icarus, Under review.

[7] Mahieux, A., et al. (2015), Planet. Space Sci., 113-114.

How to cite: Mahieux, A., Yangambi Libote, A., Robert, S., Piccialli, A., Trompet, L., and Vandaele, A. C.: Correlations between minor species in the Venus mesosphere from the SOIR/Venus Express spectrograph, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-12463, https://doi.org/10.5194/egusphere-egu23-12463, 2023.

EGU23-14293 | ECS | Posters on site | PS4.2

3D Venusian Ionosphere model: Venus PCM 

Antoine Martinez, Jean-Yves Chaufray, and Sébastien Lebonnois

For twenty years, a Planetary Climate Model (PCM) has been developed for the Venus atmosphere at “Institut Pierre-Simon Laplace” (IPSL), in collaboration between LMD and LATMOS, from the surface up to 250 km altitude (Lebonnois et al., 2010; 2016; Martinez et al., 2023). Recently, the Venus PCM (former IPSL Venus GCM) has been updated with the addition of photoionization and ion-neutral chemistry to simulate the Venusian ionosphere at altitudes where the photoequilibrium assumption is valid (below 180-200 km at dayside), based on the Martian ionospheric model described in González-Galindo et al., 2013.

By simulating the ionosphere and comparing the results with observations from spacecraft missions, we have been able to better understand the processes at work in the Venusian ionosphere. Here, we will focus on the main ion species (O+, CO2+, O2+, H+, CO+) and on the modeling of the Venusian ionosphere by Venus PCM through the comparison of the ionosphere composition with Pioneer Venus observation (PV-OIMS, PV-OETP). We also explore the effects of the addition of ambipolar diffusion on the vertical density profile of the main ions, based on the work of Chaufray et al., 2014 for the Martian ionosphere.

References:

  • Chaufray, J.-Y., Gonzalez-Galindo, F., Forget, F., Lopez-Valverde, M., Leblanc, F., Modolo, R., Hess, S., Yagi, M., Blelly, P.-L., and Witasse, O. (2014), Three-dimensional Martian ionosphere model: II. Effect of transport processes due to pressure gradients, J. Geophys. Res. Planets, 119, 1614– 1636, doi:10.1002/2013JE004551.
  • Lebonnois, S., Hourdin, F., Eymet, V., Crespin, A., Fournier, R., Forget, F., 2010. Superrotation of Venus’ atmosphere analyzed with a full general circulation model. J. Geophys. Res. (Planets) 115, 6006. https://doi.org/10.1029/2009JE003458.
  • Lebonnois, S., Sugimoto, N., Gilli, G., 2016. Wave analysis in the atmosphere of Venus below 100-km altitude, simulated by the LMD Venus GCM. Icarus 278, 38–51. https://doi.org/10.1016/j.icarus.2016.06.004.
  • González-Galindo, F., J.-Y. Chaufray, M. A. López-Valverde, G. Gilli, F. Forget, F. Leblanc, R. Modolo, S. Hess, and M. Yagi (2013), Three-dimensional Martian ionosphere model: I. The photochemical ionosphere below 180 km, J. Geophys. Res. Planets, 118, 2105–2123, doi:10.1002/jgre.20150.
  • Martinez, A., Lebonnois, S., Millour, E., Pierron, T., Moisan, E., Gilli, G., Lefèvre, F., Exploring the variability of the Venusian thermosphere with the IPSL Venus GCM, Icarus, 2023, 115272, 0019-1035, https://doi.org/10.1016/j.icarus.2022.115272

How to cite: Martinez, A., Chaufray, J.-Y., and Lebonnois, S.: 3D Venusian Ionosphere model: Venus PCM, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-14293, https://doi.org/10.5194/egusphere-egu23-14293, 2023.

EGU23-15108 | ECS | Posters on site | PS4.2

Evolution of Venusian rifts: Insights from Numerical Modeling 

Alessandro Regorda, Cedric Thieulot, Iris van Zelst, Zoltán Erdös, Julia Maia, and Susanne Buiter

Venus is a terrestrial planet with dimensions similar to the Earth and, although it is generally assumed that it does not host plate-tectonics, there are indications that Venus might have experienced, or still does experience, some form of tectonics. In fact, there are widespread observations of rifts on Venus called ‘chasma’ (plural ‘chasmata’), from radar-image interpretation of normal-fault-bounded graben structures (Harris & Bédard, 2015).

The rifts on Venus have been likened to continental rifts on Earth such as the East African (e.g., Basilevsky & McGill, 2007) and Atlantic rift system prior to ocean opening (Graff et al., 2018), even if they are commonly wider than their terrestrial equivalent (e.g., Foster & Nimmo, 1996). However, despite being a prominent feature on its surface, little is known about the mechanisms responsible for creating rifts on Venus beyond the assumption that they are extensional features (Magee & Head, 1995).

Since rifting on Earth in both continental and oceanic settings has been extensively studied through modeling, we adapted 2D thermo-mechanical numerical models of rifting on Earth to Venus in order to study how rifting structures observed on the Venusian surface could have been formed. More specifically, we investigated how rifting evolves under the high pressure and temperature conditions of the Venusian surface and the lithospheric structure proposed for Venus.

Our results show that a strong crustal rheology such as diabase is needed to localize strain and to develop a rift under the harsh surface conditions of Venus. The evolution of the rift formation is predominantly controlled by the crustal thickness, with a 25 km-thick diabase crust required to produce mantle upwelling and melting. Lastly, we compared the surface topography produced by our models with the topography profiles of different Venusian chasmata. We observed a good fit between models characterised by different crustal thicknesses and the Ganis and Devana Chasmata, suggesting that differences in rift features on Venus could be due to different crustal thicknesses.

 

References

Basilevsky, A. T., & McGill, G. E. (2007). Surface evolution of Venus. In Exploring Venus as a terrestrial planet (p. 23-43). American Geophysical Union. doi: 10.1029/176GM04

Foster, A., & Nimmo, F. (1996). Comparisons between the rift systems of East Africa, Earth and Beta Regio, Venus. Earth and Planetary Science Letters, 143 (1), 183-195. doi: 10.1016/0012-821X(96)00146-X

Graff, J., Ernst, R., & Samson, C. (2018). Evidence for triple-junction rifting focussed on local magmatic centres along Parga Chasma, Venus. Icarus, 306 , 122-138. doi: 10.1016/j.icarus.2018.02.010

Harris, L. B., & Bédard, J. H. (2015). Interactions between continent-like ‘drift’, rifting and mantle flow on Venus: gravity interpretations and Earth analogues. In: Volcanism and Tectonism Across the Inner Solar System. Geological Society of London. doi: 10.1144/SP401.9

Magee, K. P., & Head, J. W. (1995). The role of rifting in the generation of melt: Implications for the origin and evolution of the Lada Terra-Lavinia Planitia region of Venus. Journal of Geophysical Research: Planets, 100 (E1), 1527-1552. doi: 10.1029/94JE02334

How to cite: Regorda, A., Thieulot, C., van Zelst, I., Erdös, Z., Maia, J., and Buiter, S.: Evolution of Venusian rifts: Insights from Numerical Modeling, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-15108, https://doi.org/10.5194/egusphere-egu23-15108, 2023.

EGU23-16340 | Posters on site | PS4.2

VERITAS gravity investigations: measuring Venus’ rotational state, moment of inertia, Love numbers, and atmospheric tides 

Luciano Iess, Fabrizio de Marchi, Gael Cascioli, Erwan Mazarico, Joseph Renaud, Daniele Durante, Sander Goossens, and Suzanne Smrekar

The key scientific objective of the NASA/JPL Discovery-class mission VERITAS (Venus Emissivity, Radio science, INSAR, Topography And Spectroscopy) is understanding the links between the interior, surface, and atmospheric evolution.

After a 6-months cruise and a 11-months aerobraking phases, VERITAS is planned to operate during four Venus cycles (4x243 Earth days) in a near circular polar orbit (180x255km in altitude at 85.4 deg. inclination) providing gravity science data thanks to the 2-way X/Ka band Doppler link and VISAR (Venus Interferometric Synthetic Aperture Radar) instrument.

The radio science data and VISAR landmark features (tie points) will allow a precise determination of the rotational state of Venus: we show that the precession rate can be measured with an accuracy of 13’’/cy. From this result, the moment of inertia factor (MOIF) C/MR2, can be estimated with a 0.3% accuracy (10x improvement). Moreover, the expected accuracy of the tidal Love number measurement is 0.2%: this will allow to resolve the ambiguity of the core state (solid/liquid) and to distinguish between different interior models (core radius, mantle viscosity) [1].

The atmosphere of Venus is subject to a time-dependent mass redistribution due to pressure and temperature variations induced by solar heating. This phenomenon is called “thermal tide" and it moves eastward along the Venus’ surface with a 117d period (i.e. about a Venus solar day).

Thermal tides can be detected as a time-variable perturbation to the Venus gravity field due to 1) the moving atmospheric masses (direct effect) and to 2) the planet’s response to the variations of the surface loading (indirect effect, parametrized through the load Love numbers).

We show that VERITAS radio science and VISAR data can also be used to measure the load Love numbers up to degree 4 with good accuracy (4% for degree 2). In particular, the degree 2 coefficient can provide independent, and complementary, information on the mantle viscosity and composition.

Moreover, a simultaneous measurement of the degree 2 tidal (k2, h2) and loading (k2') Love numbers can be used to provide finer bounds on the mantle viscosity and possibly to constrain the mantle rheology.

[1] G. Cascioli, S. Hensley, F. De Marchi, D. Breuer, D. Durante, P. Racioppa, L. Iess, E. Mazarico and S. E. Smrekar (2021) Planet. Sci. J. 2 220

How to cite: Iess, L., de Marchi, F., Cascioli, G., Mazarico, E., Renaud, J., Durante, D., Goossens, S., and Smrekar, S.: VERITAS gravity investigations: measuring Venus’ rotational state, moment of inertia, Love numbers, and atmospheric tides, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-16340, https://doi.org/10.5194/egusphere-egu23-16340, 2023.

EGU23-17505 | Orals | PS4.2

Venus as an Exoplanet: Effect of varying stellar, orbital, planetary and atmospheric properties upon composition, habitability and detectability 

John Lee Grenfell, Benjamin Taysum, Fabian Wunderlich, Jörn Helbert, Gabriele Arnold, Konstatin Herbst, Miriam Sinnhuber, and Heike Rauer

The newly selected Venus missions EnVISION and VERITAS (Venus Emissivity, Radio Science, InSAR, Topography, and Spectroscopy) by ESA and NASA offer new opportunities for studying Venus but will also contribute to furthering our knowledge of Venus as an exoplanet. Hot, rocky planets are favoured exoplanet targets due to generally more frequent transits than cooler Earth-like objects. In our work presented here, we simulate Venus as an exoplanet using our coupled climate-photochemical model 1D-TERRA. In the simulations, we vary stellar, orbital, planetary and atmospheric parameters and study the effect of these parameters upon atmospheric composition, climate and spectral detectability with forthcoming missions. 

How to cite: Grenfell, J. L., Taysum, B., Wunderlich, F., Helbert, J., Arnold, G., Herbst, K., Sinnhuber, M., and Rauer, H.: Venus as an Exoplanet: Effect of varying stellar, orbital, planetary and atmospheric properties upon composition, habitability and detectability, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-17505, https://doi.org/10.5194/egusphere-egu23-17505, 2023.

EGU23-475 | ECS | Orals | PS4.3

The meteorology of Elysium Planitia (Mars) as determined from InSight observations and numerical modeling 

María Ruíz-Pérez, Jorge Pla-García, Aymeric Spiga, Scot C. R. Rafkin, Nils Mueller, Claire Newman, Sara Navarro, Josefina Torres, Alain Lepinette, Donald Banfield, Luís Mora, and Jose Antonio Rodríguez-Manfredi

Air temperature, ground temperature, pressure, and wind speed and direction data obtained from the APSS (Auxiliary Payload Sensor Suite) and HP3 radiometer (RAD) onboard the InSight (Interior Exploration using Seismic Investigations, Geodesy and Heat Transport) lander are compared to data from the Mars Regional Atmospheric Modeling System. A full diurnal cycle at four different seasons (Ls 0º, 90º, 180º and 270º) is investigated at the lander location at 4.5° N 135.6° E in Elysium Planitia on Mars (Figure shows comparison results for Ls 180º). This work extends the atmospheric observations perform by [1]. Model results are shown to be in good agreement with observations. The good agreement provides justification for utilizing the model results to investigate the broader meteorological environment of Elysium Planitia in a companion paper. The observed air temperature, pressure and winds are taken at ∼1m above ground, while MRAMS provides those values at the lowest atmospheric model level of ∼14 m. As expected, the MRAMS air temperature values at this height tend to be cooler than the observed in the morning and early afternoon, and then tend to be warmer in the late afternoon and through the night. Also, the difference in height should not have a large impact on wind direction, but modeled wind speeds at ∼14 m are faster than the observed at 1.5 m due to frictional effects. Small discrepancies in ground temperatures could be attribute to a different initialization of thermal inertia, dust and clouds in the model when compared with the data. The diurnal pressure amplitude at Elysium Planitia varies from 2.52% to 4.5% depending on the season. The total amplitude is then considerably smaller compared to Gale crater (up to ∼13%, [2]). [3] attributed the amplification at Gale due to a mesoscale hydrostatic adjustment process in regions of topographic slopes. We also use a Computational Fluid Dynamics (CFD) to study the mechanical disturb of the wind directions due to other instruments onboard the lander and it effect into the wind directions discrepancy between modeling and observations [4]. For low wind speeds (~3.4 m/s), there is an important mechanical contamination in the 330º-30º wind directions range for FM1 and in the 210-330º range for FM2 (Figure bottom left), mostly during nighttime.                                                         

Figure 1. Observed and modeled diurnal air temperature, ground temperature, pressure, wind speed and wind direction signal at Ls 180. MRAMS are the black dots. InSight data taken within a few sols of the Ls 180 are shown in different colors, which each color representing data from a single sol. CFD results with the mechanical disturb (from the higher value -0- to the lower value -1.2-) of the wind directions due to other instruments onboard the lander for low wind speeds (~3.4 m/s) are shown in the bottom left.

 

How to cite: Ruíz-Pérez, M., Pla-García, J., Spiga, A., C. R. Rafkin, S., Mueller, N., Newman, C., Navarro, S., Torres, J., Lepinette, A., Banfield, D., Mora, L., and Rodríguez-Manfredi, J. A.: The meteorology of Elysium Planitia (Mars) as determined from InSight observations and numerical modeling, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-475, https://doi.org/10.5194/egusphere-egu23-475, 2023.

EGU23-735 | ECS | Orals | PS4.3

The meteorology of Jezero crater (Mars) as determined from MEDA observations and numerical modeling 

Jorge Pla-Garcia, Claire Newman, Asier Munguira, Agustín Sánchez-Lavega, Ricardo Hueso, Teresa del Río Gaztelurrutia, and Jose Antonio Rodríguez-Manfredi and the Mars 2020 MEDA team

Pressure, ground temperature, air temperature close to the surface and at 40 m height, and wind speed and direction data obtained from MEDA [Rodriguez-Manfredi et al. 2021] onboard Perseverance rover are compared to data from MRAMS [Rafkin and Michaels 2019]. A full diurnal cycle at twelve different times of a complete martian year (Ls 30º, 60º, 90º, 105º, 160º, 180º, 210º, 240º, 270º, 300º, 330º and 360º) are investigated at the rover location at 18.44°N; 77.45°E inside Jezero crater on Mars. Figure shows comparison results for Ls 90º. This work extends the predictions shown in [Pla-García et al. 2020, Newman et al. 2021]. A diurnal structure variation of the pressure throughout the year is shown both in modeling and observations. The diurnal pressure amplitude is generally well matched in the model but the phase of the diurnal tide is shifted about ~90 min. The general shape of the diurnal cycle of surface temperature are similar between the two datasets. MRAMS surface properties are interpolated from data sets obtained from TES thermal inertia (nighttime) and albedo, with insufficient resolution to capture the known variation of thermal inertia in Jezero crater and the misestimating the diurnal amplitude. The lowest MRAMS thermodynamic level is ∼14 m above the ground, so modeled air temperatures tend to be cooler than MEDA observations at ∼1.5 m above the surface in the morning and early afternoon, and then tend to be warmer in the late afternoon and through the night. This is a direct result of the steep afternoon superadiabatic lapse rate and a strong nocturnal inversion [Schofield et al. 1997]. There is a good match in wind directions between MRAMS and MEDA, but MRAMS wind speeds are generally higher than those observed with MEDA, especially between 23:00 and dawn. The difference in height should not have a large impact on wind direction but can contribute to the wind speed differences due to frictional effects with the surface. Those wind speed differences are indeed bigger during nighttime, where MRAMS winds between 01:00 and sunrise could be so strong because the downslope winds penetrate a little bit too far into the crater for that time of sol when compared with other modeling predictions [Newman et al. 2021]. It is also noticeable that the wind speeds are systematically extremely low after sunset both in MRAMS and MEDA, following the collapse of daytime convection [Banfield et al. 2020], but then at 20:00 the wind speeds start to increase again both in modeling and observations. Although there are some periods with differences, generally there is a good agreement between MRAMS results and MEDA observations, and this agreement provides justification for utilizing the model results to investigate the broader meteorological environment of the Jezero crater region in a companion paper

Figure. Observed and modeled diurnal air temperature, ground temperature, pressure, wind speed and wind direction signal at Ls 90. MRAMS are the black dots. MEDA data taken within a few sols of the Ls 90 are shown in blue.

How to cite: Pla-Garcia, J., Newman, C., Munguira, A., Sánchez-Lavega, A., Hueso, R., del Río Gaztelurrutia, T., and Rodríguez-Manfredi, J. A. and the Mars 2020 MEDA team: The meteorology of Jezero crater (Mars) as determined from MEDA observations and numerical modeling, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-735, https://doi.org/10.5194/egusphere-egu23-735, 2023.

EGU23-985 | ECS | Orals | PS4.3

Influence of Magnetic Fields on Precipitating Solar Wind Hydrogen at Mars 

Sarah Henderson, Jasper Halekas, Jared Espley, and Meredith Elrod

Solar wind protons can interact directly with the hydrogen corona of Mars through charge exchange, resulting in energetic neutral atoms (ENAs) able to penetrate deep into the upper atmosphere of Mars. ENAs can undergo multiple charge changing interactions, leading to an observable beam of penetrating protons in the upper atmosphere. We seek to characterize the behavior of these protons in the presence of magnetic fields using data collected by the Mars Atmosphere and Volatile EvolutioN (MAVEN) spacecraft. We find that backscattered penetrating proton flux is enhanced in regions where the magnetic field strength is greater than 200 nT. We also find a strong correlation at CO2 column densities less than 5.5 × 1014 cm−2 between magnetic field strength and the observed backscattered and downwardflux. We do not see significant changes in penetrating proton flux with magnetic field strengths on the order of 10 nT.

How to cite: Henderson, S., Halekas, J., Espley, J., and Elrod, M.: Influence of Magnetic Fields on Precipitating Solar Wind Hydrogen at Mars, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-985, https://doi.org/10.5194/egusphere-egu23-985, 2023.

Chemical weathering is an important indicator of past climate and redox state [1-3]. On Mars, weathering profiles may have formed in basaltic sediments or volcanic ash that were altered by surface water and were subsequently buried and persevered in the geological record. Orbital remote sensing of the global Martian surface has detected dioctahedral clay minerals within Noachian layered sedimentary rocks, which are consistent with the precipitation-driven pedogenic weathering of mafic sediments [1]. Noachian sedimentary rocks with spectral signatures of subaerial weathering have been detected in thousands of locations across the surface of Mars [1,4].

In this study, orbital imagery, spectroscopy, topographic data and crater chronology are investigated to explore the geologic context, stratigraphy, and relative age of >200 weathering profiles across the Martian southern highlands [4]. The youngest might be Early Hesperian, although virtually all are older than 3.7 Ga. Weathering profiles exist across a wide range of elevations (>11 km), from −5 to 6 km, indicating they developed as a result of top-down, precipitation-driven chemical weathering and this was a global phenomenon. We discovered that almost all exposures show a similar, single stratigraphic relationship of Al/Si material overlying Fe/Mg clays, rather than several, interbedded mineralogy transitions. This points to either a single warming event or, more likely, a chemical resetting scenario in which the most recent event overprints the prior weathering pattern. The time necessary to develop a typical profile is estimated to be several million years, which corresponds to only a portion of the Noachian period. As a result, the broad estimated age span ~700–800 My appears incompatible with a single climate excursion. We consider that the presence of weathering profiles in many geologic units at a wide range of ages over a long period of geologic time and at a wide range of elevations, suggests a top-down, precipitation-driven chemical weathering was global in scope. Fe-mobility was a crucial component of chemically weathering, which happened geologically rapidly under anoxic conditions that might potentially warm the martian surface via reduced greenhouse gas. Collectively, these results indicate that multiple weathering episodes are driven by multiple reduced greenhouse conditions on ancient Mars.

[1] Carter et al. 2015, Icarus, 248, 373-382. [2] Bishop et al., 2018, Nature Astronomy, 2(3), 206-213. [3] Liu et al., 2021, Nature Astronomy,5(5), 503-509.[4] Ye & Michalski, Communication Earth & Environments, 3(1), 1-14.

How to cite: Ye, B. and Michalski, J.: Compositional stratigraphy on Mars as evidence of hundreds of millions of years of greenhouse conditions on Mars, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-2249, https://doi.org/10.5194/egusphere-egu23-2249, 2023.

EGU23-2924 | ECS | Posters on site | PS4.3

Constraining the Chemistry of Sub-cm Diagenetic Features with Curiosity's Alpha Particle X-ray Spectrometer 

Scott VanBommel, Jeff Berger, Ralf Gellert, Catherine O'Connell-Cooper, Lucy Thompson, Michael McCraig, Albert Yen, John Christian, Abigail Knight, and Nicholas Boyd

The Alpha Particle X-ray Spectrometer (APXS) onboard the Mars Science Laboratory (MSL) rover Curiosity has acquired approximately 1,300 geochemical analyses since landing in 2012. The APXS utilizes a combination of X-ray fluorescence and particle-induced X-ray emission to determine the chemical composition of materials within its 15+ mm diameter field of view (FOV) [1, 2]. Diagenetic features provide a means to further understand and constrain the habitability of Curiosity's landing site, Gale crater. These features often present as veins or nodules with an areal extent on the sub-cm scale. APXS analyses of these features therefore contain a mixture of signals from the feature and host substrate.

To probe the composition of these sub-FOV features, Curiosity has developed a technique whereby multiple APXS measurements are conducted in close proximity to the primary target (referred to as a raster). The data are then analyzed to not only localize APXS FOVs, mitigating arm placement uncertainty which is on the order of 1-2 cm [2], but also infer the composition of the various endmembers within the workspace. The original raster analysis method (e.g., [2, 3]) has proven useful at deconvolving the chemistry of diagenetic features from the surrounding substrate. However, this method utilizes APXS oxide data as the primary input. These data are derived assuming a homogeneous sample for the purposes of calculating and correcting for matrix effects (the attenuation of induced X-rays by other elements in the sample). In instances of clear chemical heterogeneities, these matrix corrections can result in skewed compositions of the derived endmembers, such as a vein or nodule.

Here we present an improvement to this method whereby we utilize low-level data products and isolate matrix effect calculations for each individual endmember (e.g., [4]). The derived results show significant improvements (10-30%) compared to the oxide method in stoichiometric ratios when applied to calcium sulfate veins, an ideal proof-of-concept sample. Subsequent analyses of magnesium-sulfate dominated nodules hint at other potential mobile elements within the fluids present during diagenesis, such as P, Mn, Ni, and/or Zn. Similar elements were enriched in nodules at the Ayton/Groken field site, where P2O5 and MnO concentrations in the nodular material totaled over 25 wt% at a ~2:1 P:Mn molar ratio [4]. The improved analytical method will be particularly useful as Curiosity continues to explore the Marker Band and sulfate unit.

[1] Gellert & Clark (2015), Elements, 11.
[2] VanBommel et al. (2016), XRS, 45.
[3] VanBommel et al. (2017), XRS, 46.
[4] VanBommel et al. (2023), Icarus, 392.

How to cite: VanBommel, S., Berger, J., Gellert, R., O'Connell-Cooper, C., Thompson, L., McCraig, M., Yen, A., Christian, J., Knight, A., and Boyd, N.: Constraining the Chemistry of Sub-cm Diagenetic Features with Curiosity's Alpha Particle X-ray Spectrometer, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-2924, https://doi.org/10.5194/egusphere-egu23-2924, 2023.

The focus of this presentation is the three-dimensional visualization of Mars dust storms from spacecraft images. The dust storm height is determined by their shadows. Image parameters such as the solar incidence angle, solar azimuth angle, latitude, and longitude are taken into account. Interactive three-dimensional maps of dust storms are created. This presentation includes satellite images from MARCI/MRO (Mars Color Imager/Mars Reconnaissance Orbiter) in the years 2020-2021. This adds to a better understanding of Mars dust storms. This works uses the MeteoMARS tool [1], the NASA PDS Imaging Node [2], the NASA Integrated Software for Imagers and Spectrometers, and the QGIS software [3].

[1] http://meteomars.pamplonetario.org/

[2] https://pds-imaging.jpl.nasa.gov/

[3] https://www.qgis.org/en/site/

How to cite: Alzeyoudi, M. and Gebhardt, C.: The Three-Dimensional Visualization of Mars Dust Storms Based on Deriving Digital Elevation Maps from Satellite Imagery, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-3247, https://doi.org/10.5194/egusphere-egu23-3247, 2023.

This presentation adds to Mars dust storm research based on numerical models and spacecraft images. The focus is the conversion of MarsWRF model data into synthetic satellite images of Mars dust storms. MarsWRF is a Mars version of the terrestrial numerical weather and climate model WRF (Weather Research and Forecasting Model) and part of the PlanetWRF models for planetary atmospheres research. Dust storms are obtained by running the MarsWRF model with the interactive-dust-lifting-technique [1]. Synthetic satellite imagery is generated from MarsWRF model data by using the radiative transfer model DISORT, which provides the top-of-the-atmosphere reflectance data. The results are synthetic satellite images, mostly for visible light wavelength. We compare synthetic satellite images of dust storm events at different times of the Martian Year.

[1] Gebhardt, C., Abuelgasim, A., Fonseca, R. M., Martín-Torres, J., & Zorzano, M.-P. (2020). Fully interactive and refined resolution simulations of the Martian dust cycle by the MarsWRF model. Journal of Geophysical Research: Planets, 125, e2019JE006253. https://doi.org/10.1029/2019JE006253

How to cite: Alkaabi, F. and Gebhardt, C.: Synthetic satellite images of Mars dust storms based on MarsWRF dust cycle simulations and the radiative transfer model DISORT, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-3435, https://doi.org/10.5194/egusphere-egu23-3435, 2023.

EGU23-4218 | ECS | Orals | PS4.3

Radar Sounding Waveform Fitting for Roughness parameters estimation 

Letizia Gambacorta, Marco Mastrogiuseppe, and Roberto Seu

SHARAD (Shallow Radar) and MARSIS (Mars advanced Radar for subsurface and ionosphere sounding) are two low frequency sounder radars in orbit around Mars whose aim is to assess the distribution of on-ground and buried water, to provide the material composing its crust and to study its topography at global scale. The estimation of dielectric properties using radar data, can be pursued by means of different methods, including a parametric data inversion approach. Our method provides for the estimation of surface permittivity and loss tangent by exploiting the ratio between the return powers from the surface and the subsurface at different frequencies. As the roughness of the surface as well as the subsurface, affects  the returned power, inversion techniques are often applied  on moderately flat surfaces, where the power loss due to roughness can be considered negligible.

In this work we present an approach for the estimation of surface roughness properties and power loss compensation via waveform fitting, whose shape is modified in relation to the  characteristics of the surface impinged by the emitted electromagnetic wave. Such fitting procedure exploits a large-scale roughness model for the power return obtained under the Kirchhoff approximation hypotheses and comprising both the coherent and the non-coherent components of the scattered field. Our method allows to estimate the roughness regime of the selected area in terms of height standard deviation and root mean squared slope and therefore to compensate for  power losses in relation with the estimated parameters.

The performances of the fitting procedure are tested using a ray-tracing simulator of the range-compressed SHARAD and MARSIS received signal. As a fist step we applied the analysis on isotropic gaussian surfaces with different roughness characteristics showing the possibility to recover the power lost due to roughness effects. Moreover, the analysis will be performed on MOLA simulated products to represent MARS surface and finally, will be applied to SHARAD real data acquired over the volcanic region of Elysium Planitia.

How to cite: Gambacorta, L., Mastrogiuseppe, M., and Seu, R.: Radar Sounding Waveform Fitting for Roughness parameters estimation, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-4218, https://doi.org/10.5194/egusphere-egu23-4218, 2023.

EGU23-4484 | ECS | Posters on site | PS4.3 | Highlight

2D hydraulic modelling of the ancient paleolake in Gusev Crater, Mars. 

Marco Antonio Perez Carazo, Daniel Vazquez Tarrio, Ronny Steveen Anangono Tutasig, and Susana del Carmen Fernandez Menendez

The application of hydraulic models on Mars is still a scarcely discussed topic in the scientific literature, despite the interest of  these models to study paleofloods and to understand the geological past of the planet. In this work, we present the application of a 2D-hydraulic model (using HECRAS) in Gusev crater aiming to study the hydrodynamics of a paleolake that would have been formed in the crater about 3,5 Ga ago.

Using a corrected and optimized 100m resolution Digital Elevation Model derived from MOLA ( Mars Orbiter Altimeter) data, we first identify and map the different evidences of water marks. Different flow rates and commonly used friction values were combined to obtain several flow hypotheses, which in turn were simulated with the 2D model. Our main aim was to study the flow patterns inside the crater and the inlet and outlet conditions in order to check if the water levels obtained with our simulations correspond to what the mapped benchmarks may suggest.

The Ma’adim valley feeding Gusev crater ends in a fluvial-lake delta. The flat top morphology  of this delta suggests that streamflow processes must have occurred on its top during its formation. Then, one of our major research assumptions is based on finding flow rates consistent with a fully submerged. In this regard, model outcomes obtained with flow rates covering the whole delta are consistent with previous discharge estimations compiled from the scientific bibliography.

Moreover, we also took advantage of the last capabilities of the hydraulic modeling software to go further than just simulating water flows. That said, we varied the concentration of sediments within the fluid and other fluid parameters such as internal shear stress and dynamic viscosity to model a hyperconcentrated flow, which has been already proposed  as forming flow conditions for the delta. At the same time, we also analyzed turbulence and flow recirculation processes trying to stablish a relation with the sediment distribution within the crater.

Based on our work, we conclude that the downstream boundary conditions in the hydraulic model is the main source of uncertainty in the modelling of Gusev crater,while changes in roughness has a minor influence on model outcomes. Finally, we raised the question on how low gravity in Mars may have affected sediment transport by water and how the nature of this process may have been different than in the Earth.

How to cite: Perez Carazo, M. A., Vazquez Tarrio, D., Anangono Tutasig, R. S., and Fernandez Menendez, S. C.: 2D hydraulic modelling of the ancient paleolake in Gusev Crater, Mars., EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-4484, https://doi.org/10.5194/egusphere-egu23-4484, 2023.

EGU23-4548 | Posters on site | PS4.3

Advanced Reconnaissance Missions Needed for Human Exploration of Mars 

Azita Valinia

Planning is underway at NASA to return humans to the Moon by 2025 and from there to Mars in 2030-40s. This paper discusses some of the future Mars reconnaissance missions needed in advance of the first human landing on Mars to ensure astronaut safety and mission success. These include: 1) high resolution mapping of the Martian terrain for identifying optimum landing sites for scientific exploration and safe entry, descent, and landing of crewed missions and safe crew operations; 2) surface weather reconnaissance on Mars which could entail a network of orbital and on-surface meteorological assets; and 3) real-time space weather forecasting on Mars which could require positioning of radiation monitoring assets as well as computational capabilities in Mars orbit. Details regarding needed reconnaissance missions for safe crew operations and corresponding potential future mission concepts  will be discussed.

How to cite: Valinia, A.: Advanced Reconnaissance Missions Needed for Human Exploration of Mars, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-4548, https://doi.org/10.5194/egusphere-egu23-4548, 2023.

EGU23-4896 | Orals | PS4.3 | Highlight

Observations of the Perseverance rover at the Jezero crater delta front using the SuperCam instrument 

Nicolas Mangold, Gwenael Caravaca, Erwin Dehouck, Olivier Beyssac, Pierre Beck, Elise Clavé, Agnès Cousin, Gilles Dromart, Olivier Forni, Thierry Fouchet, Olivier Gasnault, Sanjeev Gupta, Stéphane Le Mouélic, Lucia Mandon, Sylvestre Maurice, Pierre-Yves Meslin, Cathy Quantin-Nataf, Clément Royer, and Roger Wiens and SuperCam team

The Perseverance rover landed on the floor of Jezero crater in February 2021. The initial set of images taken from the landing site of the residual butte Kodiak showed a deltaic architecture consistent with a paleolake, but at a level ~100 m lower than expected, suggestive of a closed lake system. After spending ~1 year studying the crater floor, the rover reached the front of the deltaic fan in April 2022. Here, we report observations of the facies, structure and composition of these sedimentary deposits using the SuperCam instrument. SuperCam can take images for texture analysis with the Remote Micro-Imager (RMI), visible and infrared reflectance (VISIR) spectra as well as Raman spectra for mineralogical analysis, and data from laser induced breakdown spectroscopy (LIBS) for chemical analysis. The rover investigated the basal strata of the delta along two traverses at the SE of the delta front. The transition between the crater floor and the delta is not well determined due to regolith and strongly degraded outcrops, and is currently under assessment. The ~20 m thick basal layers that are well-visible on orbital data consist of fine-grained sandstones and siltstones deposited in sub-horizontal planar beds with millimeter thick laminations. These deposits display a substantial alteration highlighted by the detection of both sulfates and phyllosilicates, with exception of local boulders of igneous texture lacking alteration. Texture and composition are both consistent with a quiet regime of deposition such as in lake deposits or distal delta slopes. These beds are considered of topmost importance for sample return and were cored in two locations. Pebbly sandstones and conglomerates with pebbles limited to a few centimeters are observed immediately above these strata. The texture is matrix-supported suggesting an emplacement through gravity sliding or turbidity flows below water rather than fluvial deposition. The composition is more variable than in underlying finer-grained beds and includes local carbonate detections. Uppermost deposits have not been reached by the rover yet, but have been analyzed remotely by RMI images, and VISIR for some of them. They consist of cross-bedded sandstones and conglomerates in all locations of the delta front. The diversity in texture of these deposits suggests a variability in depositional regimes including high-energy floods, either during the lacustrine phase, or subsequently. Boulders present within these layers are rounded suggesting a substantial abrasion by fluvial transport. These boulders are also interesting targets for sampling distant crustal rocks. The top of the delta will be analyzed and sampled along the traverse of the rover in 2023.

How to cite: Mangold, N., Caravaca, G., Dehouck, E., Beyssac, O., Beck, P., Clavé, E., Cousin, A., Dromart, G., Forni, O., Fouchet, T., Gasnault, O., Gupta, S., Le Mouélic, S., Mandon, L., Maurice, S., Meslin, P.-Y., Quantin-Nataf, C., Royer, C., and Wiens and SuperCam team, R.: Observations of the Perseverance rover at the Jezero crater delta front using the SuperCam instrument, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-4896, https://doi.org/10.5194/egusphere-egu23-4896, 2023.

EGU23-5885 | ECS | Orals | PS4.3

Seasonal evolution of near surface atmospheric temperatures at Jezero as measured by the MEDA instrument on Mars 2020 

Asier Munguira, Ricardo Hueso, Agustín Sánchez-Lavega, Manuel De la Torre-Juarez, Germán Martínez, Teresa del Río-Gaztelurrutia, Michael Smith, Mark Lemmon, Jose Antonio Rodríguez-Manfredi, Alain Lepinette, Eduardo Sebastián, and Donald Banfield

We use data from the MEDA instrument on Mars 2020 to study the evolution of atmospheric and surface temperatures at Jezero. The measurements correspond to four height levels from the surface to ~40 m and together they allow us to examine multiple aspects of the near-surface meteorology at Jezero. We extend the analysis of near-surface temperatures of Munguira et al. (JGR:Planets 2023), which covered the period from Ls 13º to Ls 203º, over a full Martian year. We show the seasonal evolution of temperatures, including temperature fluctuations and thermal gradients, which are affected by the properties of the terrain traversed by Perseverance. We will focus on a physical description of the thermal processes that take place in the Convective Boundary Layer at Jezero. We compare near-surface temperatures with the atmospheric opacity around-the-clock retrieved by Smith et al. (2022) and with daily averages of optical depth measured by MastCam-Z (Bell et al. 2022). After Ls 203º, atmospheric waves coming across Jezero predicted by atmospheric models are expected to contribute to shaping temperatures producing thermal oscillations on time-scales of a few sols. This effect is accompanied by an enhanced variability of atmospheric opacity and both effects contribute to produce a higher variability on temperatures.

 

References:

[1] Munguira, A. et al. (2023). Near Surface Atmospheric Temperatures at Jezero from Mars 2020 MEDA Measurements. JGR: Planets.

[2] Smith, M.D. et al. (2022). Diurnal and Seasonal Variations of Aerosol Optical Depth Observed by MEDA/TIRS at Jezero Crater, Mars. In Seventh international workshop on the Mars atmosphere: Modelling and observations (pp. 14-17).

[3] Bell, J.F. et al. (2022). Geological, multispectral, and meteorological imaging results from the mars 2020 perseverance rover in jezero crater. Science Advances, 8 (47), eabo4856. doi: 10.1126/sciadv.abo4856

How to cite: Munguira, A., Hueso, R., Sánchez-Lavega, A., De la Torre-Juarez, M., Martínez, G., del Río-Gaztelurrutia, T., Smith, M., Lemmon, M., Rodríguez-Manfredi, J. A., Lepinette, A., Sebastián, E., and Banfield, D.: Seasonal evolution of near surface atmospheric temperatures at Jezero as measured by the MEDA instrument on Mars 2020, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-5885, https://doi.org/10.5194/egusphere-egu23-5885, 2023.

EGU23-6062 | Orals | PS4.3

Vortices and Dust Devils at Jezero crater after one year of measurements with MEDA on Mars 2020 

Ricardo Hueso, Claire Newman, Teresa del Río-Gaztelurrutia, Munguira Aiser, Agustín Sánchez-Lavega, Daniel Toledo, Mark Lemmon, Germán Martínez, Ralph Lorenz, Manuel de la Torre-Juarez, Jose Antonio Rodríguez-Manfredi, Jorge Pla-García, Naomi Murdoch, and Baptiste Chide

After one year of surface operations at Jezero, the MEDA meteorological sensors have captured the signals produced by the close approach of hundreds of vortices and dust devils over different seasons and terrains. Here we update findings on the vortex and Dust Devils published in Hueso et al. (JGR: Planets, 2023). That work analyzed MEDA data from spring to early autumn identifying vortices as pressure drops and later characterizing them from the ensemble of MEDA measurements. In this updated analysis we show that, in winter, declining surface temperatures and smaller vertical gradients result in a wane of vortex activity. This decreased activity affects more the frequency of intense vortices (Δp >1.5 Pa) without showing a stiff decay in the total number of vortices (Δp>0.5 Pa). In this contribution we concentrate on the specific aspects of the thermodynamics of the vortices from temperature measurements obtained by MEDA that characterize the vertical thermal gradient at the time of the vortex passage. In addition, when vortices approach the rover closely in a favorable geometry (coming from the front of the vortex) we measure the increased temperatures inside the vortex. We also explore the increased nighttime vortex activity found on some sols, when pressure drops equivalent to those created by daytime vortices appear in the early morning before sunrise, with clusters of nighttime activity in winter and early spring.

How to cite: Hueso, R., Newman, C., del Río-Gaztelurrutia, T., Aiser, M., Sánchez-Lavega, A., Toledo, D., Lemmon, M., Martínez, G., Lorenz, R., de la Torre-Juarez, M., Rodríguez-Manfredi, J. A., Pla-García, J., Murdoch, N., and Chide, B.: Vortices and Dust Devils at Jezero crater after one year of measurements with MEDA on Mars 2020, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-6062, https://doi.org/10.5194/egusphere-egu23-6062, 2023.

The largest volcanos in our Solar System are part of a huge volcanic complex, named Tharsis Rise, which is located on the Martian surface several kilometers higher than the average topography. Moreover, the gravitational field of Mars shows a strong and large signal centered on top of the region, a positive anomaly (+300 mGal) surrounded by a negative ring (-300 mGal). Flexural theory is commonly used to understand the relationship between observed topography, crustal structure and gravity, revealing structures that support the volcanic complex.

The new information about the Martian lithosphere thanks to NASA’s Insight mission deserves a re-analysis of the lithosphere flexure models. The Martian lithosphere can be modeled by infinite plate and the thin shell flexure models. The latter takes into account the curvature effect responsible for supporting extra surface loads. We see that the need for compensation based on buoyancy is even lower at long wavelength than that of the classic infinite plate model. This has consequences for the interpretation of density structure underneath the volcanic regions.

After conducting spectral analysis on the topographic and gravity results from the flexural models, we found that the gravitational signal of Martian topography with thin shell compensation fits well with the observed free-air anomaly for degrees n≥2 . The best-fit elastic thickness (Te) is found to be 105 ±5 km and we observe a crustal density of 3050 ± 50 kg/m3. Despite the use of the thin shell flexure model, we notice a mismatch between modeled and observed gravity field between n=2-4 degrees, which suggests an active large-scale dynamic support of the Tharsis Rise. This could explain relatively the young geologic evidence for surface volcanism on Mars.

 

How to cite: Qin, W. and Root, B.: Is the lithospheric flexure strong enough to hold up the Tharsis Rise? A re-analysis of flexure on Mars, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-6454, https://doi.org/10.5194/egusphere-egu23-6454, 2023.

EGU23-6646 | ECS | Posters on site | PS4.3

Revisit the solar wind deceleration upstream of the Martian bow shock based on MAVEN observations 

Yuqi Liu, Kaijun Liu, Huang Hui, and Ducheng Lu

The solar wind deceleration upstream of the Martian bow shock is examined using particle and magnetic field measurements obtained by Mars Atmosphere and Volatile Evolution (MAVEN). Mars lacks a strong intrinsic magnetic field so its upper atmosphere extends beyond the Martian bow shock and interacts directly with the solar wind. Neutral atoms in the Martian upper atmosphere can be ionized through several physical processes and then start to move with the solar wind flow to form pickup ions. In return, the solar wind is expected to slow down due to the momentum transfer to the pickup ions. The present study surveys the MAVEN solar wind measurements between 2015 and 2019 to evaluate the solar wind deceleration upstream of the Martian bow shock. Different than the previous studies of solar wind deceleration, our analysis carefully excludes the solar wind deceleration in the shock magnetic foot region. The average solar wind deceleration calculated is about 0.7% of the upstream solar wind speed, much smaller than the values given by the previous studies. Further calculation using several reasonable Martian upper atmosphere profiles demonstrates that the deceleration observed is consistent with the pickup ion mass loading scenario.

How to cite: Liu, Y., Liu, K., Hui, H., and Lu, D.: Revisit the solar wind deceleration upstream of the Martian bow shock based on MAVEN observations, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-6646, https://doi.org/10.5194/egusphere-egu23-6646, 2023.

EGU23-7173 | Orals | PS4.3

Daily and Seasonal Behaviour of Fast Pressure Fluctuations at Jezero Crater 

Teresa del Río Gaztelurrutia, Agustin Sanchez-Lavega, Ricardo Hueso, Asier Munguira, Mark T. Lemmon, Michael D. Smith, German Martinez, Jorge Pla-Garcia, Claire Newman, Daniel Viudez, Manuel de la Torre-Juarez, and Jose Antonio Rodriguez-Manfredi

Pressure measurements by the MEDA sensor on board Perseverance Rover show oscillations in a wide range of temporal scales, from the seasonal evolution of average pressure to rapid fluctuations on the scale of a few seconds. In this work, we profit from an entire Martian Year of pressure measurements to analyse the seasonal and daily evolution of rapid fluctuations, a signature of atmospheric turbulence.  We find that during the full Martian year, fluctuations are enhanced at convective hours of the day, but the intensity of fluctuations is modulated through the seasons. At nighttime, the first half of the Martian years is characterized by an almost complete absence of fluctuations with an especially calm period in the early morning, while bursts of fluctuation become common in the dusty season. We also analyse the change of the daily pattern induced by regional dust storms at Jezero. We study the power spectra of the fluctuations to try to infer information about different turbulent regimes at the surface layer and their dependence on local time and season. Finally, we explore possible correlations with the dust load of the atmosphere and the temperature gradients, and we look at the origin of nighttime bursts of turbulence.

How to cite: del Río Gaztelurrutia, T., Sanchez-Lavega, A., Hueso, R., Munguira, A., Lemmon, M. T., Smith, M. D., Martinez, G., Pla-Garcia, J., Newman, C., Viudez, D., de la Torre-Juarez, M., and Rodriguez-Manfredi, J. A.: Daily and Seasonal Behaviour of Fast Pressure Fluctuations at Jezero Crater, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-7173, https://doi.org/10.5194/egusphere-egu23-7173, 2023.

EGU23-7189 | ECS | Posters on site | PS4.3

Retrieval of the Vertical Profile of Atmospheric Optical Depth using Thermal Emission Spectrometer Visible and Infrared Bolometer observations 

Emily L. Mason, Michael Smith, Michael Wolff, and Timothy McConnochie

The Mars Global Surveyor (MGS) mission carried a spectrometer and bolometer as part of the Thermal Emission Spectrometer (TES) instrument package. While the spectrometer ceased operations in early Mars Year (MY) 37 due to aging of the required neon lamp, the bolometers continued to operate for nearly a full Mars year. This time-period covered the MY 27 dust storm season and most of the MY 28 aphelion cloud belt season. TES consisted of a spectrometer with two additional broadband bolometers in the visible (0.3-3.0 µm) and infrared (5-100 µm). Observations were taken with both the spectrometer and bolometer simultaneously for nearly three Mars years prior to degradation of the neon lamp. The observational cadence during the bolometer-only extended mission alternated between one orbit of nadir observations and one orbit of limb observations. We will present results for the vertical distribution of atmospheric aerosol optical depth retrieved from the TES bolometer limb observations prior to the extended mission when spectrometer data (and previous retrievals) are available to inform the results. In addition, we will provide examples of retrieved vertical distribution of aerosol optical depth for observations taken in the bolometer-only extended mission for comparison.

How to cite: Mason, E. L., Smith, M., Wolff, M., and McConnochie, T.: Retrieval of the Vertical Profile of Atmospheric Optical Depth using Thermal Emission Spectrometer Visible and Infrared Bolometer observations, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-7189, https://doi.org/10.5194/egusphere-egu23-7189, 2023.

EGU23-8449 | Posters on site | PS4.3

Terrestrial analogues of the glaciers on Mars: possible test sites for FlyRadar survey 

Osip Kokin, Aino Kirillova, Akos Kereszturi, and Gian Gabriele Ori

FlyRadar is a project funded by the Horizon 2020 research and innovation program of the European Union. The project aims the production of a low-frequency dual-mode radar (synthetic aperture and ground penetrating) installed on board of a lightweight unmanned aerial vehicle (or drone) and their testing for future usage in Earth and planetary investigations.

Currently, one of the most important issues in the study of Mars is the understanding of the so-called viscous flow features, which, according to the modern hypothesis, are debris-covered glaciers (DCG) and consist of near-surface water ice and represent part of Martian cryosphere. These glaciers could be a source of water for future human exploration in-situ, as well as a source of hydrogen and oxygen for fuel.

Besides, ice of DCG contain historical records of climatic and geologic changes and can preserve ancient microbial life or even living organisms, if Mars ever harboured life. However, there are still no detailed studies on the thickness of the debris cover and the structure and thickness of DCG on Mars. The use of FlyRadar type probe on Mars could partially fill this gap. That is why one of the directions of the FlyRadar project is to test the use and capabilities of such an instrument in the study of DCG on Earth for further use on Mars.

Based on the synthesized information on the mid-latitude DCS of Mars and their terrestrial analogues previously proposed in the published literature, the following types of possible analogues of the Martian DCG on Earth are considered in this work as test sites for FlyRadar surveys:

1) Rock glaciers – very good external similarity of surface morphology, but low content of pure ice (up to 30%).

2) DCG with maximum covered area due to ablation and slope processes – high content of pure ice (more than 80-90%), possibility of conservation ice in permafrost, but not always very good external similarity of debris-covered areas and surface morphology due to processes associated with melting and melt waters, irregular accumulation of debris material (usually only the lower part of the glacier in the ablation zone is covered by debris).

3) Ice-cored moraines and parts of DCG with limited melting due to conservation of ice (partly relict) in permafrost – high content of pure ice and good preservation potential of relict ice, but the complete absence of external similarity.

4) Completely DCG due to volcanic sedimentation from atmosphere (ashfall) – high content of pure ice, good preservation potential of relict ice due to permafrost, completely debris coverage of the glacier surface except for newly formed ice in the accumulation zone. Possibly, it is the closest analogue to Martian DCG.

5) Pleistocene massive ground ice (possible glaciers) buried by marine and aeolian sedimentation: high content of pure ice, good preservation potential of relict ice due to permafrost, completely debris coverage of the glacier surface, but the complete absence of external similarity, since most often morphologically buried glacier is not expressed in land surface.

How to cite: Kokin, O., Kirillova, A., Kereszturi, A., and Ori, G. G.: Terrestrial analogues of the glaciers on Mars: possible test sites for FlyRadar survey, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-8449, https://doi.org/10.5194/egusphere-egu23-8449, 2023.

EGU23-8669 | Posters on site | PS4.3 | Highlight

Mars Express: Toward a 20-year scientific and technical success story 

Patrick Martin, Colin Wilson, James Godfrey, Alejandro Cardesin Moinelo, Rick Blake, Andrew Johnstone, Luke Lucas, Simon Wood, Sylvain Damiani, Donald Merritt, Julia Marin Yaseli de la Parra, Mar Sierra, Michel Breitfellner, Emmanuel Grotheer, David Heather, Carlos Muniz Solaz, Mars Express Science Ground Segment Team, and Mars Express Flight Control Team

Mars Express, ESA's first flagship for Mars exploration, will reach the momentous milestones of 20 years in space and at Mars on 2 June and 25 December this year, respectively. Its scientific record is unprecedented for a mission which was initially planned for one Martian year. Since end 2003 Mars Express has gathered a wealth of data from the subsurface, surface, atmosphere, plasma environment and moons of the red planet in a quasi-uninterrupted and routine way. Furthermore, Mars Express is currently as scientifically active and productive as at any time through its lifetime in space, thanks to several additions and improvements recently made to its spacecraft and payload capabilities (e.g., MARSIS radar new subsurface and Phobos operative modes, radio frequency occultation measurements between Mars Express and ESA’s Trace Gas Orbiter using an upgraded MELACOM communications system, plasma sounding by ASPERA during MARSIS measurements, occultation observations during egress). Mars Express is expected to maintain and even enhance its scientific return over the next few years, should the mission be extended. Technical feasibility of further mission extensions has been reviewed and confirmed. The mission is constrained by 3 lifetime-limiting elements which are the remaining gyro lifetime, remaining fuel and the battery lifetime. However, it has been demonstrated that none of those 3 constraints is likely to prevent Mars Express from continuing its routine operations until beyond 2030. Whether Mars Express is extended or not, nominal archiving is proceeding at pace and higher-level data sets being produced in collaboration with the PI teams to optimise the Mars Express archive legacy.

The mission and science operations teams, together with the mission scientists, are looking forward to several additional years of scientific productivity and discoveries. Successful joint science campaigns with the CNSA Tianwen/Zhurong orbiter and rover missions, UAE’s Hope orbiter mission, and especially the upcoming MMX mission to Phobos by JAXA should contribute to further augment Mars Express’ 20-year success story.

How to cite: Martin, P., Wilson, C., Godfrey, J., Cardesin Moinelo, A., Blake, R., Johnstone, A., Lucas, L., Wood, S., Damiani, S., Merritt, D., Marin Yaseli de la Parra, J., Sierra, M., Breitfellner, M., Grotheer, E., Heather, D., Muniz Solaz, C., Science Ground Segment Team, M. E., and Flight Control Team, M. E.: Mars Express: Toward a 20-year scientific and technical success story, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-8669, https://doi.org/10.5194/egusphere-egu23-8669, 2023.

EGU23-8764 | Orals | PS4.3 | Highlight

Mars Sample Return Science Management 

Gerhard Kminek and Michael A. Meyer

NASA and ESA intend to conduct a Mars Sample Return (MSR) Campaign to return martian samples safely to Earth for scientific research, based on the highest priority recommendations of the international science community. Returned samples will allow scientists to utilize advanced sample processing and scientific instrumentation unavailable on robotic spacecraft.

The journey of scientifically selected samples starts with the context development and acquisition of the samples by the Mars 2020 Perseverance rover, continues with the transit through the flight elements of the MSR Program and retrieval on Earth for curation and analysis by the world’s scientific community. The samples collected by Mars 2020 to date already show scientific potential beyond the pre-launch expectations of the scientific community for the first sample return from Mars.

Based on an already signed NASA-ESA MSR Science and Sample Management Memorandum of Understanding, a Joint Science Management Plan (JSMP) has been developed to provide the framework and processes to ensure the scientific potential of the samples is preserved during return to Earth, on Earth, and for future generations, and that the science objectives of MSR can be met.

This talk will inform the science community about the key science management elements described in the JSMP.

How to cite: Kminek, G. and Meyer, M. A.: Mars Sample Return Science Management, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-8764, https://doi.org/10.5194/egusphere-egu23-8764, 2023.

EGU23-9049 | ECS | Orals | PS4.3

The nighttime boundary layer of Mars as predicted by large-eddy simulations 

Orkun Temel, Cem Berk Senel, and Ozgur Karatekin

The Martian planetary boundary layer (PBL) drives the surface-atmosphere exchange processes such as the Martian dust cycle, which leads to strong atmospheric variations from diurnal to seasonal and inter-annual time scales [1]. The amount of dust lifted into the atmosphere and the vertical winds that balance the gravitational settling for the aerosols are affected by the turbulent mixing within the boundary layer. Several studies focused on the dynamics of the Martian PBL during daytime conditions [2,3]. During daytime conditions, the strong buoyancy caused by the vertical thermal gradient can generate turbulent mixing and initiate turbulence. On the other hand, the nighttime boundary layer is suggested to form under very weak turbulent mixing conditions. However, recent observations by the InSight lander showed unexpected turbulent signatures during nighttime conditions [4]. Nevertheless, lacking the observational datasets revealing the vertical variation of temperature and winds within the first kilometer of the Martian atmosphere, we do not fully understand the dynamics of the Martian boundary layer. To complement the limited observations on the Martian boundary-layer meteorology, high-resolution limited area models, so called large-eddy simulations (LES), are used. Here, we use the LES module of MarsWRF [3,5] to investigate the time and length scales of nighttime turbulence and possible large-scale atmospheric phenomena that can affect the near-surface nighttime meteorology. We present possible implications related to the Martian dust cycle.

[1] Senel, C.B., Temel, O., Lee, C., Newman, C.E., Mischna, M.A., Muñoz‐Esparza, D., Sert, H. and Karatekin, Ö., 2021. Interannual, Seasonal and Regional Variations in the Martian Convective Boundary Layer Derived From GCM Simulations With a Semi‐Interactive Dust Transport Model. Journal of Geophysical Research: Planets, 126(10), p.e2021JE006965.
[2] Spiga, A., Forget, F., Lewis, S.R. and Hinson, D.P., 2010. Structure and dynamics of the convective boundary layer on Mars as inferred from large‐eddy simulations and remote‐sensing measurements. Quarterly Journal of the Royal Meteorological Society: A journal of the atmospheric sciences, applied meteorology and physical oceanography, 136(647), pp.414-428.
[3] Temel, O., Senel, C.B., Porchetta, S., Muñoz-Esparza, D., Mischna, M.A., Van Hoolst, T., van Beeck, J. and Karatekin, Ö., 2021. Large eddy simulations of the Martian convective boundary layer: towards developing a new planetary boundary layer scheme. Atmospheric Research, 250, p.105381.
[4] Temel, O., Senel, C.B., Spiga, A., Murdoch, N., Banfield, D. and Karatekin, O., 2022. Spectral analysis of the Martian atmospheric turbulence: InSight observations. Geophysical Research Letters, 49(15), p.e2022GL099388.
[5] Wu, Z., Richardson, M.I., Zhang, X., Cui, J., Heavens, N.G., Lee, C., Li, T., Lian, Y., Newman, C.E., Soto, A. and Temel, O., 2021. Large eddy simulations of the dusty Martian convective boundary layer with MarsWRF. Journal of Geophysical Research: Planets, 126(9), p.e2020JE006752.

How to cite: Temel, O., Senel, C. B., and Karatekin, O.: The nighttime boundary layer of Mars as predicted by large-eddy simulations, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-9049, https://doi.org/10.5194/egusphere-egu23-9049, 2023.

EGU23-9921 | ECS | Orals | PS4.3

The Aeolian Activity at InSight Over Two Martian Years 

Constantinos Charalambous, Matt Golombek, Tom Pike, Mark Lemmon, Aymeric Spiga, Claire Newman, Veronique Ansan, Mariah Baker, Maria Banks, Ralph Lorenz, Alexander Stott, and Daniel Viudez-Moreiras

Aeolian activity, the movement of sand and dust by the wind, is common on Earth and has been observed on other planets [1]. Under the current climatic conditions on Mars, aeolian activity is the primary process of surface modification driven by winds, dust storms and wind vortices. Landed and orbiting cameras show that widespread aeolian activity occurs despite low measured and modelled winds, challenging Earth-based theories [2, 3]. Dust particles enter into long-term suspension forming global dust storms which drastically alter the Martian atmospheric dynamics and present hazards to robotic and human missions.

Several models have been proposed on the long-standing conundrum of sediment transport on Mars, however, none of these have been verified on the planet. The outstanding question of what wind shear velocities mobilize sediments on Mars has remained elusive despite multiple spacecrafts carrying wind sensors and studying aeolian activity on finer spatial and temporal scales than can be achieved in orbit. Quantitative examination of aeolian activity under natural Martian surface conditions is imperative in validating transport models.

The InSight lander has provided a unique opportunity for monitoring simultaneous coverage of aeolian activity on Mars by combining, for the first time, imaging with atmospheric, seismic and magnetic measurements. Previous studies spanned over just half of the first Martian year, from the end of northern winter to midsummer, and observed minor aeolian activity limited to sporadic grain motion and dust devil tracks [4, 5].

In this study, we extend observations of aeolian activity for two Martian years, allowing us to infer the seasonal evolution at the landing site. We report a series of remarkable daytime vortex-induced events with pressure excursions up to 10 Pa, including an investigation of the burst in daytime vortices and emergence of nighttime vortices in northern autumn. Despite our observations reinforcing the quiescent aeolian surface environment at InSight, we observe further evidence and constrain timings of surface track formation, saltation, dust lifting and surface creep of coarser particles both on the surface of Mars and lander elements. Such an investigation was previously impossible due to power constraints allowing only intermittent meteorological measurements in the second year and wind-sensor saturation from energetic close vortex encounters that cause surface changes. Here, we derive estimates of vortex-induced peak wind speeds responsible for grain motion based on strong correlations from the excitation of high-frequency lander resonances sensitive to wind forcing measured continuously by the seismometers [6]. This wealth of data allows us to obtain a unique catalogue of complete wind-induced surface activity at InSight over two Martian years. Our findings provide an insight into the long-standing paradox of aeolian transportation on Mars by quantifying the environmental variables responsible for sand motion which help constrain current threshold and transport models.

[1] Hayes (2018) Sci. [2] Kok et al. (2012) RPP [3] Newman et al. (2022) Auth. [4] Charalambous et al. (2021) JGR 126(6) e2020JE006538 [5] Baker et al., (2021) JGR [6] Charalambous et al. (2021) JGR 126(4) e2020JE006514.

How to cite: Charalambous, C., Golombek, M., Pike, T., Lemmon, M., Spiga, A., Newman, C., Ansan, V., Baker, M., Banks, M., Lorenz, R., Stott, A., and Viudez-Moreiras, D.: The Aeolian Activity at InSight Over Two Martian Years, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-9921, https://doi.org/10.5194/egusphere-egu23-9921, 2023.

EGU23-9961 | Posters on site | PS4.3

One Martian year of MEDA HS humidity sensor observations and comparisons with models 

Jouni Polkko and the One Martian year of MEDA HS humidity sensor observations and comparisons with models

The Mars 2020 mission rover “Perseverance”, launched on 30 July 2020 by NASA, landed successfully 18th Feb. 2021 at Jezero Crater, Mars (Lon. E 77.4509° Lat. N 18.4446°). The landing took place at Mars solar longitude Ls = 5.2°, close to start of the northern spring. Perseverance’s payload includes the relative humidity sensor MEDA HS (Mars Environmental Dynamics Analyzer Humidity Sensor), which almost one Martian year of observations are described here. The relative humidity measured by MEDA HS is reliable from late night hours to few tens of minutes after sunrise when the measured relative humidity is greater than 2% (referenced to sensor temperature). Observations show seasonal and diurnal trends and short term temporal fluctuations, which are discussed.

Nighttime observations are compared with the Finnish Meteorological Institute and Helsinki University adsorptive Single Column Model in various conditions and seasons. The model allows estimating daytime humidity levels. Model comparisons suggest water vapor nighttime adsorption into the soil.

Short period fluctuations in the surface humidity data may be due to turbulence caused by downslope winds and nighttime jets. These turbulences break nighttime boundary layer and bring humid air from above. Observed data is compared with the numerical simulations of turbulence over Jezero given by Mars Regional Atmospheric Modeling System (MRAMS).

Data is also compared with the Mars Science Laboratory rover Curiosity humidity instrument data.

 

How to cite: Polkko, J. and the One Martian year of MEDA HS humidity sensor observations and comparisons with models: One Martian year of MEDA HS humidity sensor observations and comparisons with models, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-9961, https://doi.org/10.5194/egusphere-egu23-9961, 2023.

EGU23-10117 | Orals | PS4.3

One Martian Year of MEDA/TIRS observations at the Mars 2020 landing site 

German Martinez, Eduardo Sebastian, Michael Smith, Hannu Savijärvi, Hartzel Gillespie, Alvaro Vicente-Retortillo, Asier Munguira, Ricardo Hueso, Daniel Toledo, Leslie Tamppari, Claire Newman, Agustin Sanchez-Lavega, Mark Lemmon, Victor Apestigue, Ignacio Arruego, Erik Fischer, Jorge Pla-Garcia, Luis Mora-Sotomayor, Manuel de la Torre Juarez, and Jose Antonio Rodriguez-Manfredi

The Thermal Infrared Sensor (TIRS; Sebastián et al., 2021; Martínez et al., 2023) is one of the six sensor packages of the Mars Environmental Dynamics Analyzer (MEDA; Rodríguez-Manfredi et al., 2021), which in turn is one of the seven science instruments on board Perseverance. Here we show a summary of TIRS scientific highlights during the first Martian year of operations. In particular, TIRS is providing the first in situ determination of the surface radiative budget, direct determination of broadband albedo and thermal inertia (Martínez et al., 2023; Savijärvi et al., 2022), and around-the-clock determination of aerosol opacities (Smith et al., 2023). In addition, TIRS is providing ground-truth to orbital retrievals of thermal inertia and albedo, as well as geophysical characterization of the uppermost surface of the regolith during Phobos and Deimos eclipses. In synergy with other instruments, TIRS is being used to determine vertical profiles of temperature (Munguira et al., 2023), to detect dust lifting from sudden changes in albedo (Vicente-Retortillo et al., 2023), and to assess changes in the water content of the Martian soil (Hausrath et al., 2023), including the potential formation of frost.

TIRS observations are critical to achieve MEDA’s first programmatic objective (validate global atmospheric models by measuring the radiative surface budget in preparation for future human exploration). Also, TIRS observations are important in support of flights of Ingenuity and therefore for the design and operations of future drones. 

References:

Hausrath, E. M. et al. (2023), The SuperCam team and the Regolith working group, An Examination of Soil Crusts on the Floor of Jezero crater, Mars, Journal of Geophysical Research: Planets (accepted).

Martínez, G. M. et al. (2023), Surface Energy Budget, Albedo and Thermal Inertia at Jezero Crater, Mars, as Observed from the Mars 2020 MEDA Instrument, Journal of Geophysical Research: Planets (accepted).

Munguira, A. et al. (2023), Near Surface Atmospheric Temperatures at Jezero from Mars 2020 MEDA measurements, Journal of Geophysical Research: Planets (under review).

Rodriguez-Manfredi, J.A. et al. (2021), The Mars Environmental Dynamics Analyzer, MEDA. A suite of environmental sensors for the Mars 2020 mission, Spa. Sci. Rev., 217(3), 1-86.

Savijärvi, H. I. et al. (2022), Surface energy fluxes and temperatures at Jezero crater, Mars, Journal of Geophysical Research: Planets: e2022JE007438.

Sebastián, E. et al. (2021), Thermal calibration of the MEDA-TIRS radiometer onboard NASA's Perseverance rover, Acta Astronautica, 182,144-159.

Smith, M. D. et al. (2023), Diurnal and Seasonal Variations of Aerosol Optical Depth Observed by MEDA/TIRS at Jezero Crater, Mars, Journal of Geophysical Research: Planets (accepted).

Vicente-Retortillo, A. et al. (2023), Dust Lifting Through Changes in Albedo at Jezero Crater, Mars, Journal of Geophysical Research: Planets (under review).

How to cite: Martinez, G., Sebastian, E., Smith, M., Savijärvi, H., Gillespie, H., Vicente-Retortillo, A., Munguira, A., Hueso, R., Toledo, D., Tamppari, L., Newman, C., Sanchez-Lavega, A., Lemmon, M., Apestigue, V., Arruego, I., Fischer, E., Pla-Garcia, J., Mora-Sotomayor, L., de la Torre Juarez, M., and Rodriguez-Manfredi, J. A.: One Martian Year of MEDA/TIRS observations at the Mars 2020 landing site, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-10117, https://doi.org/10.5194/egusphere-egu23-10117, 2023.

EGU23-10369 | ECS | Posters on site | PS4.3

Martian interactive dust and water cycle GCM simulations as compared with TGO/NOMAD and MCS observations 

Cem Berk Senel, Orkun Temel, and Ozgur Karatekin

The dust cycle is the key driver of the Martian climate, therefore capturing the time-evolving dust distribution correctly is vital for simulating a realistic climate. The proper modeling of the dust cycle is closely coupled with water cycle dynamics, as both affect the radiative state of the atmosphere as well as general circulations. A better understanding of the dust-water cycle feedback is key to advancing our knowledge of the Martian climate system, such as from polar cap evolution towards the dust storm-water escape interaction and the formation of elongated water ice clouds in the wake of a volcano. Recently, we presented decadal GCM simulations of the convective boundary layer until Mars Year 34, unraveling the feedback between Martian turbulence and dust during major storms. Those GCM simulations were carried out by developing an in-house dust transport model [1] constrained by column dust climatology observations [2]. Our model was validated by in-situ observations of NASA’s MSL rover and orbiter observations from Mars Climate Sounder (MCS) observations. Here, by coupling the fully-interactive water cycle model [3] with our semi-interactive dust transport model [1], we present new dust and water cycle GCM simulations within the ROB version of MarsWRF. We performed a year-long GCM simulation in Mars Year 34, in which the red planet experienced a global dust storm (GDS) that began shortly after the southern summer solstice lasting more than 100 sols. We compared model results with recent spacecraft observations, comprising (i) MCS observations onboard the Mars Reconnaissance Orbiter (MRO) and (ii) Nadir and Occultation for Mars Discovery (NOMAD) onboard the Trace Gas Orbiter (TGO) observations. Recently, from the latter observations, Liuzzi et al. (2020) [4] presented vertical distributions of water ice and dust, besides the large variabilities of water ice clouds within the perihelion season in MY 34. Furthermore, Vandaele et al. (2019) [5] reported rapid alterations in water vapor vertical distributions as driven by Martian dust storms. Here, we simulate vertical distributions of the dust, water ice and vapor on Mars, investigating the responses to the major dust storm events.

[1] Senel, C. B., Temel, O., Lee, C., Newman, C. E., Mischna, M. A., ... & Karatekin, O. (2021). Interannual, Seasonal and Regional Variations in the Martian Convective Boundary Layer Derived From GCM Simulations With a Semi‐Interactive Dust Transport Model. JGR: Planets, 126(10), e2021JE006965.

[2] Montabone, L., et al. (2020). Martian year 34 column dust climatology from Mars climate sounder observations: Reconstructed maps and model simulations. JGR: Planets, 125(8), e2019JE006111.

[3] Lee, C., Richardson, M. I., Newman, C. E., & Mischna, M. A. (2018). The sensitivity of solsticial pauses to atmospheric ice and dust in the MarsWRF General Circulation Model. Icarus, 311, 23-34.

[4] Liuzzi, G., et al. (2020). Strong variability of Martian water ice clouds during dust storms revealed from ExoMars Trace Gas Orbiter/NOMAD. Journal of Geophysical Research: Planets, 125(4), e2019JE006250.

[5] Vandaele, A. C., et al. (2019). Martian dust storm impact on atmospheric H2O and D/H observed by ExoMars Trace Gas Orbiter. Nature, 568(7753), 521-525.

How to cite: Senel, C. B., Temel, O., and Karatekin, O.: Martian interactive dust and water cycle GCM simulations as compared with TGO/NOMAD and MCS observations, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-10369, https://doi.org/10.5194/egusphere-egu23-10369, 2023.

EGU23-10444 | ECS | Orals | PS4.3

Trace Element Concentrations from the Mars Exploration Rover Alpha Particle X-Ray Spectrometers: Implications for the Geologic Histories of Meridiani Planum and Gusev Crater 

Abigail Knight, Scott VanBommel, Ralf Gellert, Jeff Berger, Jeffrey Catalano, and Juliane Gross

The Alpha Particle X-ray Spectrometers (APXS) onboard the Mars Exploration Rovers (MER) Spirit and Opportunity interrogated the bedrock, soil, and regolith at Gusev crater and Meridiani Planum, respectively. The APXS derives the composition of geologic materials through a combination of particle-induced X-ray emission (PIXE) and X-ray fluorescence (XRF) spectroscopy. Each measurement results in a histogram of energies with characteristic peak areas proportional to elemental concentrations. This spectrum reflects not only the composition of a target but also varies with experimental conditions (e.g., measurement duration, mission age, standoff, temperature), which must be accounted for to accurately quantify the elements present in a spectrum. Individual APXS measurements often provide sufficient counting statistics to resolve and quantify major, minor, and select trace elements (e.g., Ni, Zn, Br) while others (e.g., Ga, Ge) are more difficult to precisely quantify due to, in part, their typical low concentrations (e.g., sub-30 µg/g).

To combat the effect of statistical noise on trace element quantification, individual spectra are summed together to create a composite spectrum. We have assembled a database of target characteristics, such as target type (e.g., rock, soil), location, feature, target, formation, and degree of sample preparation (e.g., as-is, brushed, abraded), for each individual APXS spectrum. Spectra of targets with shared geological context and geochemical characteristics (e.g., ratio of Fe3+ to FeT) were summed to create meaningful combinations of individual spectra (i.e., composite spectrum). The composite spectra were fit with a simplified (i.e., Gaussian peaks with a linear background) nonlinear least squares fitting routine to identify promising composites for quantification with the fitting routine developed and utilized for the quantification of other elements within MER APXS spectra. Composite spectra were also assessed visually and quantitatively to confirm they were representative of trace element peaks within each of the individual spectra rather than outliers.

At both Meridiani Planum and Gusev crater, results indicate that the concentrations of Ga and Ge in outcrops are more than an order of magnitude higher than expected from meteoritic contribution alone. The ratios of Ga to Al and Ge to Si can also be used to infer the geologic history of a region due to their similar ionic radii and charges and therefore geochemical behavior. The Ga/Al molar ratio tends to be much more consistent at Meridiani Planum compared to that of Ge/Si, which shows more variation between formations. The divergence of the behaviors of Ge and Si could be explained by high temperature diagenetic fluids, as could the consistent behaviors of Ga and Al. We conclude that the elevated concentrations of trace elements such as Ga and Ge may be sourced in part from volcanic outgassing, and regional trends in the molar ratios of Ga/Al and Ge/Si are potentially due to high temperature diagenetic fluids.

How to cite: Knight, A., VanBommel, S., Gellert, R., Berger, J., Catalano, J., and Gross, J.: Trace Element Concentrations from the Mars Exploration Rover Alpha Particle X-Ray Spectrometers: Implications for the Geologic Histories of Meridiani Planum and Gusev Crater, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-10444, https://doi.org/10.5194/egusphere-egu23-10444, 2023.

EGU23-10622 | ECS | Posters on site | PS4.3

Martian Ionospheric Magnetic Fluctuations 

Teresa Esman, Jared Espley, Jacob Gruesbeck, Christopher Fowler, Shaosui Xu, Meredith Elrod, Yuki Harada, Joe Giacalone, Alexa Halford, and Anne Verbiscer

Understanding the properties and variability of the ionosphere is vital for understanding the atmosphere of Mars. The presence and property of waves provide insight into the plasma and magnetic environment. We conducted a search for 5 - 16 Hz signals below 400 km in magnetic field data from Mars Global Surveyor (MGS), the Mars Atmosphere and Volatile Evolution (MAVEN), and Interior Exploration using Seismic Investigations, Geodesy, and Heat Transport (InSight) missions. 

We discuss an analysis of 54 identified MAVEN events using multiple instruments and present a case study event. Nearly half the wave events occur near the cusps of strong crustal magnetic fields (CMFs). The stronger regions have fewer events and may be a result of stronger CMFs preventing draped field lines from reaching lower altitudes. A majority of the observed magnetic waves occur on the nightside, are associated with greater fluxes of electrons traveling downward along the local magnetic field compared to those traveling upward, and correspond to increases in thermal plasma density. These aspects indicate electron precipitation was present during these wave events. We conclude that these waves are observed under magnetic field conditions favorable for the penetration of electrons and waves into the lower ionosphere, but that the electron precipitation cannot solely account for the waves or plasma changes.

We then discuss our null results regarding Schumann resonances, which are electromagnetic signals generated by lightning that, if they exist on Mars, are expected to propagate at 7-14 Hz. Future studies specifically looking for Schumann resonances will require higher sensitivity instruments and would benefit from additional missions that reach into the ionosphere of Mars. Finally, we comment on the inconsistency between identifying MGS events purely via by-eye analysis versus using quantitative methods for guidance. 

 

How to cite: Esman, T., Espley, J., Gruesbeck, J., Fowler, C., Xu, S., Elrod, M., Harada, Y., Giacalone, J., Halford, A., and Verbiscer, A.: Martian Ionospheric Magnetic Fluctuations, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-10622, https://doi.org/10.5194/egusphere-egu23-10622, 2023.

EGU23-10757 | Orals | PS4.3 | Highlight

A varnish-like high-manganese rock coating in Jezero crater, Mars 

Nina Lanza, Patrick Gasda, Ann Ollila, Baptiste Chide, Bradley Garczynski, Jeffrey Johnson, Woodward Fischer, Allan Treiman, Amy Williams, Scott VanBommel, Abigail Knight, Joel Hurowitz, Sunanda Sharma, Hemani Kalucha, Pamela Conrad, Karim Benzerara, Elise Clave, Lucia Mandon, Roger Wiens, and Sylvestre Maurice

Manganese-rich phases have been detected in situ on Mars by the NASA Opportunity and Curiosity rovers, and in the martian meteorite NWA 7034 (and its pairs). Notably, instruments on Curiosity in Gale crater have detected Mn-rich materials in many geologic contexts, including fracture fills, coatings, nodules, and cements; this variety suggests a complex, long-term manganese cycle or cycles in the region. The origins of these materials is not well understood, but their existence points to strongly oxidizing aqueous environments in Mars’ distant past. On Earth today, manganese cycling is primarily mediated by microbes, making manganese minerals on Mars important targets for detailed study. On Earth, a significant geologic setting for Mn-rich materials is rock varnish, a dark, shiny coatings composed of Mn- and Fe-oxides and clays. Varnishes are ubiquitous in arid environments on Earth and have recently been shown to be produced and modified by microbial communities. Such varnishes have long been predicted for Mars (as an abiotic feature) but have not been observed until now. In Jezero crater, the SuperCam and Mastcam-Z instruments on the Perseverance rover have now documented a dark, shiny, Mn-rich coating on the rock Hogback Mountain, which is in the Hogwallow Flats region of Jezero Delta sediments. SuperCam laser-induced breakdown spectroscopy (LIBS) analyses of 30- and 150-shot depth profiles penetrated through a thin, Mn-rich layer with MnO as high as 30 wt% (avg 11 wt% MnO over all shots). Preliminary chemistry results suggest that Ni is positively correlated with Mn; this is consistent with a Mn-oxide mineral, which adsorb Ni, Co, and other metals when available. Acoustic data from the SuperCam microphone obtained concurrently with the LIBS depth profiles show that the high-Mn coating is relatively hard, and that material properties change beneath the coating at ~40 shots (~12 µm) depth, in good agreement with the LIBS chemistry data. SuperCam reflectance spectra (0.40-0.85 um, 1.3-2.6 µm) of the coating suggest contributions from phyllosilicates and likely Mn-bearing minerals, including but not limited to birnessite, [(Na,Ca)0.5(Mn4+,Mn3+)2O4·1.5H2O]), which is the most common Mn-oxide in terrestrial rock varnish. So far, Hogback Mountain is the only SuperCam target with such high Mn. However, Mastcam-Z multispectral observations suggest that similar Mn-rich coatings are present on rock surfaces throughout the area. On Earth, varnish formation (and Mn-mineral formation in general) is associated with organic materials. Notably, at the nearby Berry Hollow abrasion patch, high intensity fluorescence signals indicate that possible organics were found by the SHERLOC instrument. Further investigation of these signals and colocated Raman signals is ongoing. This observation of a varnish-like coating on Mars represents a new geologic context for Mn-bearing minerals on that planet that expands the range of environments known to produce these materials, and opens up new opportunities to answer questions about potential biosignatures on Mars.

How to cite: Lanza, N., Gasda, P., Ollila, A., Chide, B., Garczynski, B., Johnson, J., Fischer, W., Treiman, A., Williams, A., VanBommel, S., Knight, A., Hurowitz, J., Sharma, S., Kalucha, H., Conrad, P., Benzerara, K., Clave, E., Mandon, L., Wiens, R., and Maurice, S.: A varnish-like high-manganese rock coating in Jezero crater, Mars, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-10757, https://doi.org/10.5194/egusphere-egu23-10757, 2023.

EGU23-10794 | Orals | PS4.3

Analysis of Purple Coatings by the SuperCam Instrument on the Perseverance Rover in Jezero Crater, Mars 

Ann Ollila, Baptiste Chide, Nina Lanza, Brad Garczynski, Mariek Schmidt, Patrick Gasda, Olivier Forni, Agnes Cousin, Erwin Dehouck, Roger Wiens, Sylvestre Maurice, Marion Nachon, Jeff Johnson, and Sam Clegg and the SuperCam Team

The NASA Perseverance rover has encountered numerous instances of purplish colored surficial material on rocks and pebbles throughout its traverse across the Jezero crater floor and the delta front. These enigmatic materials are visible on many different rock types and can vary in apparent thickness, from being very thin (microns) to several mm thick, and potentially forming in more than one layer. On Earth, such thin layers may form from a variety of processes, e.g., as coatings deposited on rock surfaces, exposed fracture fills, and/or alteration rinds/case hardening. The purple materials observed at Jezero typically unconformably overlie eroded natural rock surfaces, suggesting these features are possibly surface coatings of externally derived material. On Earth, coatings arise due to interactions between rock surfaces and the atmosphere, liquid water, and life. As such, they represent important targets for study on Mars.

Using Laser-Induced Breakdown Spectroscopy (LIBS) and a microphone, SuperCam is able to analyze these coatings for chemical composition (LIBS) and material properties (recording the LIBS acoustic signal). By interrogating the same location with the LIBS laser multiple times, changes in composition and material properties with shot (depth) may be observed if the layer is thin enough. SuperCam has made 125-150 laser shot depth profiles on several of these coated rocks, at 4-5 locations on each. For each raster, we attempt to have at least one point on an uncoated area to compare with the coated surface profile. Whenever possible, SuperCam analyses of coatings were made at locations adjacent to a rover-made abrasion patch, where the upper ~mm is abraded off to expose the underlying rock. Here we focus on comparing compositions of depth profiles on purple coatings that are directly adjacent to abrasion patches; these targets are Cordoeil (sol 268), near the abrasion patch Dourbes, Chokecherry (sol 378) which is near the Alfalfa abrasion patch, and Pile_Bay (sol 582) located by the Novarupta patch. Coating compositions from these targets roughly matches that of the fine martian dust (e.g., Lasue et al., 2018, doi.org/10.1029/2018GL079210), potentially indicating a link between the two. Airfall dust is an important contributor to rock coating formation on Earth and may likewise play a role for coating formation on Mars.       

How to cite: Ollila, A., Chide, B., Lanza, N., Garczynski, B., Schmidt, M., Gasda, P., Forni, O., Cousin, A., Dehouck, E., Wiens, R., Maurice, S., Nachon, M., Johnson, J., and Clegg, S. and the SuperCam Team: Analysis of Purple Coatings by the SuperCam Instrument on the Perseverance Rover in Jezero Crater, Mars, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-10794, https://doi.org/10.5194/egusphere-egu23-10794, 2023.

EGU23-11004 | Orals | PS4.3

Mesospheric clouds in Jezero as observed by MEDA Radiation and Dust Sensor (RDS) at twilight 

Daniel Toledo, Laura Gomez, Victor Apéstigue, Ignacio Arruego, Mark Lemmon, Michael Smith, Priya Patel, Asier Munguira, Agustin Sanchez-Lavega, Margarita Yela, Daniel Viudez-Moreiras, German Martínez, Alvaro Vicente-Retortillo, Claire Newman, Manuel de la Torre Juarez, and Jose Antonio Rodríguez-Manfredi

Clouds on Mars are primary elements for understanding the past and present climate of the planet. Cloud particles can affect the energy balance of the planet, and so the atmospheric dynamic, as well as influence the vertical distribution of dust particles through dust scavenging. The dust scavenging by clouds has critical consequences in the water cycle of the planet; e.g. regions in the atmosphere with insufficient quantity of dust particles (or condensation nuclei) can inhibit the formation of H2O clouds and thus lead to the presence of water vapor in excess of saturation. The study of these interactions requires observations whose analysis allows us to infer simultaneously the properties of both the clouds and dust. To address these observations, the Radiation and Dust Sensor (RDS) is part of the Mars Environmental Dynamics Analyzer (MEDA) payload onboard of the Mars 2020 rover Perseverance.

In this work we analysed the RDS observations made during twilight in the period Ls 39-262 to characterize the clouds above ∼ 30 km over the Perseverance rover site. From the ratio between the irradiance measured at zenith at 450 nm and 750 nm, we inferred that from Ls= 39 to 150 (referred as the cloudy period), water ice is the main constituent of the detected high-altitude aerosol layers. For Ls 150-262 dust is the main aerosol present. A total of 161 twilights were analysed in the cloudy period with a radiative transfer code in spherical geometry. Among other results we found: i) signatures of clouds or hazes on the RDS signals in the 58 % of the twilights; ii) most of the clouds were at altitudes between 40 km and 50 km and with particle sizes between 0.6 μm and 2 μm (in effective radius); iii) the cloud activity at sunrise is slightly higher that at sunset (65 % against 52 %), likely due to the differences in temperature; iv) the cloudiest time in Perseverance site and with the greatest cloud opacities is in Ls 120-150; and v) a notable decrease in the cloud activity around the aphelion (Ls ∼ 70), along with lower cloud altitudes and opacities. The drop in cloud activity around Ls ∼ 70 indicates lower concentrations of water vapor or cloud nuclei (dust) around this period in the Martian mesosphere. In this presentation, we will discuss the implications of our results on the water cycle of the planet.

How to cite: Toledo, D., Gomez, L., Apéstigue, V., Arruego, I., Lemmon, M., Smith, M., Patel, P., Munguira, A., Sanchez-Lavega, A., Yela, M., Viudez-Moreiras, D., Martínez, G., Vicente-Retortillo, A., Newman, C., de la Torre Juarez, M., and Rodríguez-Manfredi, J. A.: Mesospheric clouds in Jezero as observed by MEDA Radiation and Dust Sensor (RDS) at twilight, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-11004, https://doi.org/10.5194/egusphere-egu23-11004, 2023.

EGU23-11186 | ECS | Posters on site | PS4.3

Helicopter Magnetic Field Surveys for Future Mars Missions 

Anna Mittelholz, Lindsey Heagy, Catherine L. Johnson, Abigail A. Fraeman, Benoit Langlais, Rob J. Lillis, and William Rapin

The recent successful flight demonstration of the Mars 2020 helicopter, Ingenuity, has opened doors for future Mars mission concepts that exploit modern technology, and promising investigations include low altitude magnetic field surveys.  The martian crustal magnetic field has been studied extensively from orbit and those data sets have allowed global studies of the magnetic field and resulted in a range of models for the crustal magnetic field which however lack short wavelength information that is not resolvable from orbital altitudes. The InSight lander and the Chinese Zhurong missions have recently acquired magnetic measurements of the local field at their respective landing sites. However, to-date no measurements at scales in between those of local surface and global orbital data have been collected.  Such measurements are key to understanding near-surface magnetizations, the processes by which they were acquired, and their interaction with magnetic fields generated above the planet’s surface. Here, we investigate data sets that a future helicopter-based magnetometer might be able to provide.

We construct forward models that resemble a range of plausible subsurface geological structures that allow us to experiment with survey design, e.g., the value of multiple measurement tracks horizontally and/or vertically and their trade-offs with regional data coverage. We simulate vector magnetic field data collected by a helicopter for different geological scenarios and aim to recover our model via an inverse problem. Because such inverse problems are inherently non-unique, we investigate several approaches to find solutions, including different types of regularization, as well as modification of the model parameterization.   As one example, we investigate recovery of a magnetization signature associated with a small (~200 m diameter) crater, from a few (e.g., 3) helicopter tracks over the crater.   We show that smooth and sparse inversion solutions result in detection of the signal, with improved localization of the structure in the latter case.  Parameterized solutions improve upon sparse solutions, but require some prior knowledge, or assumption, of the geometry (in this case a magnetized half sphere) of the source.

Our investigation allows us to assess the capabilities of helicopter-based magnetic field  studies in addressing some of the fundamental open questions in the field. These kinds of considerations will greatly aid in preparing for and designing future missions,  optimizing their science return and demonstrating their scientific value.

 

How to cite: Mittelholz, A., Heagy, L., Johnson, C. L., Fraeman, A. A., Langlais, B., Lillis, R. J., and Rapin, W.: Helicopter Magnetic Field Surveys for Future Mars Missions, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-11186, https://doi.org/10.5194/egusphere-egu23-11186, 2023.

EGU23-12953 | ECS | Posters on site | PS4.3

What Marsquakes Tell Us About Impact Rates on Mars 

Géraldine Zenhäusern, Natalia Wójcicka, Simon Stähler, Gareth Collins, Ingrid Daubar, Domenico Giardini, Martin Knapmeyer, John Clinton, and Savas Ceylan

The current Martian cratering rate has been determined either from repeated orbital imaging (e.g.[1][2]), or using lunar rates extended to Mars in combination with crater counting [3]. Eight seismic events detected by the NASA InSight seismometer have been confirmed as impacts by orbital imaging [4]. Six of those events are part of the Very High Frequency (VF) group of marsquakes, which consists of 70 events in total. The impact signals are very similar to other VF events, suggesting that more or all VF events could be impact related. The unique characteristics of VF events, such as a long seismic coda interpreted as a result of shallow source in a strongly scattering near-surface layer [5] and their temporal and spatial distributions, are consistent with impact origin.

Assuming all high quality VF events are impacts allows us to place a novel constraint on the impact rate on Mars, independent of the formation of easy-to-spot large blast zones, necessary to identify fresh craters in orbital images. We test the compatibility with the existing cratering rate estimates by using two approaches to derive a first seismically constrained impact rate for Mars. First, we use the Gutenberg-Richter law to determine the slope of the VF event magnitude-frequency distribution. The impact rate is derived by applying a relationship between seismic moment and crater diameter [6]. We refine our estimates by extrapolating the detectability of each event using a semi-empirical relationship between crater size and seismic amplitude [6]. We find that both approaches give similar rates, varying slightly depending on the detectability conditions assumed by each method. The cumulative rates N(D≥8m) = 1-4x10-6 /km2/yr are higher than those from previous imaging studies, but consistent with isochron rates [3].

The discrepancy with imaging-based rates could indicate that there are impacts which are missed in imagery due to absent blast zones or that are located in unfavourable terrain, unaccounted for in the imaging-based area correction.

 

References:

[1] Daubar et al. (2013). doi: 10.1016/j.icarus.2013.04.009

[2] Daubar et al. (2022). doi: 10.1029/2021JE007145

[3] Hartmann (2005). doi: 10.1016/j.icarus.2004.11.023

[4] Daubar et al. (2023). InSight Seismic Events Confirmed as Impacts Thus Far. Lunar and Planetary Science Conference 2023 abstract.

[5] van Driel et al. (2021). doi: 10.1029/2020JE006670

[6] Wójcicka et al. (2023). Impact Rate on Mars Implied by Seismic Observations. Lunar and Planetary Science Conference 2023 abstract.

How to cite: Zenhäusern, G., Wójcicka, N., Stähler, S., Collins, G., Daubar, I., Giardini, D., Knapmeyer, M., Clinton, J., and Ceylan, S.: What Marsquakes Tell Us About Impact Rates on Mars, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-12953, https://doi.org/10.5194/egusphere-egu23-12953, 2023.

EGU23-13871 | Posters on site | PS4.3

The changing gravity field due to a superplume under the Tharsis Region 

Cedric Thieulot, Marjolein Blasweiler, and Bart Root

The Tharsis Region has been an interest of study for many years due to its large impact on the long wavelength gravity field and topography of Mars. The leading theory on the origin of the volcanic region is a combination of both isostatic flexure of a thickened crust and a small contribution due to a (possible) large superplume residing in the upper mantle. The isostatic balance, on which previous studies have relied, does not adequately explain the long-wavelength gravity field spectra. These long-wavelength signals contribute to large scale features in the mantle. We consider the presence of a dynamic mass anomaly below the Tharsis Region. This could help explain the geological surveys of the relative young lava flows. By looking at mantle dynamic models we can explore the effect of a superplume that is actively rising in the mantle and changing the geoid over time.

We ran a series of instantaneous axisymmetric finite element models of Mars with varying plume and subsurface structural variables constrained by InSight. We run the model for 50 years, thereby accounting for the total duration of satellite data acquisition. The deformation in the model allows us to calculate the change in dynamic topography and gravity anomaly.

Our preliminary results show dynamic topography rates of a few centimetres per year and gravity rates in the order of 0.1 μGal per year. These gravity rates should fall within the precision of the Mars Reconnaissance Orbiter gravity field estimates, but are masked by other geological surface mass changes. Our results show that with longer and dedicated gravity observations, we should be able to observe the large scale mantle dynamics of Mars.

How to cite: Thieulot, C., Blasweiler, M., and Root, B.: The changing gravity field due to a superplume under the Tharsis Region, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-13871, https://doi.org/10.5194/egusphere-egu23-13871, 2023.

EGU23-14114 | Orals | PS4.3 | Highlight

Comparison of orbital and Supercam in situ investigation of the floor Units of Jezero crater 

Cathy Quantin-Nataf, Olivier Beyssac, Arya Udry, Lucia Mandon, Elise Clave, Karim Benzerara, Erwin Dehouck, François Poulet, Pierre Beck, Stephane LeMouelic, Nicolas Mangold, Agnes Cousin, Pierre Yves Meslin, Olivier Forni, Olivier Gasnault, Roger Wiens, and Sylvestre Maurice

On February 18, 2021, NASA’s Mars 2020 Perseverance rover landed successfully on the floor of Jezero crater. Two geological and compositional units had previously been identified from orbital data analysis within the floor of Jezero crater [1,2]: a dark pyroxene-bearing floor unit and an olivine-bearing unit exposed in erosional windows [3]. During the 420 first sols of the mission, the rover has completed an in situ exploration campaign of these two units.

The SuperCam instrument contains a suite of techniques including passive spectroscopy in the 0.40-0.85 (VIS) and 1.3-2.6 microns (IR) wavelength ranges, Raman spectroscopy, Laser Induced Breakdown Spectroscopy (LIBS) and a camera providing high resolution context images [4,5]. Since the landing, SuperCam has acquired more than 3 thousands of observations.

From orbit the two geological units in the floor of Jezero have distinctive morphology and spectral signature. The crater floor unit called Cf-fr (Crater floor fractured rough) has a pyroxene signature [2] with no clear evidence of alteration.  The unit is laying on the top of the olivine rich unit. The interpretations varied from lacustrine deposits to volcanic deposits. The underlying unit seems to be part of the regional olivine-rich deposits with parts altered into carbonates and clays [1,6]. Interestingly, this regional olivine rich unit has a unique spectral signature on Mars, an effect of either grain size or composition [7]. Many hypotheses have been suggested: Isidis impact related ejectas layer [8], pyroclastic deposits [i.e. 6] or clastics deposits [9].   

In situ, we discovered that the Cf-fr, composed of different sub-units is not layered, composed of grainy rocks, dominated by plagioclase and Fe-rich pyroxenes [10] with a restricted but pervasive multistage [10]. From in situ data, Maaz is interpreted lava flows [11, 12] emplaced before the last lacustrine activity associated with the main western delta fan. Below the cf-fr, Seitah occurs as layered Mg-olivine rich rocks generally flat but slightly plunging below Maaz on the edges. The rocks are dominated by mm grains of pristine Olivine and some pyroxenes [10, 13, 14] .  The various spectroscopic methods detected alteration phases such as Mg- phyllosilicate and Mg Carbonates. [15, 16]. The rock texture and petrology of Seitah were interpreted as an olivine cumulate with limited alteration.

Lessons learned from this in situ campaign will be presented such as how accurate are the orbital spectral analyses, the morphological analysis and how to transfer the results of Jezero to the other places on Mars investigate by orbital data only.  

References :  [1] Horgan et al., 2020 [2] Goudge et al., 2015  [3] Tarnas, et al., 2021. [4] Wiens, et al., 2021. ; [5]  Maurice et al., , 2021 ; [6] Mandon et al., 2020.  [7] Ody et al.,2013   [8] Mustard et al., 2006 [9] Rogers et al., 2018, [10] Wiens et al., 2021 ; [11] Udry et al., 2022, [12] Horgan et al., 2022, [13] Liu et al., 2022, [14] ; Beyssac et al., 2023 [15] Mandon et al., 2022 [16] Clave et  al., 2022.

How to cite: Quantin-Nataf, C., Beyssac, O., Udry, A., Mandon, L., Clave, E., Benzerara, K., Dehouck, E., Poulet, F., Beck, P., LeMouelic, S., Mangold, N., Cousin, A., Meslin, P. Y., Forni, O., Gasnault, O., Wiens, R., and Maurice, S.: Comparison of orbital and Supercam in situ investigation of the floor Units of Jezero crater, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-14114, https://doi.org/10.5194/egusphere-egu23-14114, 2023.

EGU23-14333 | Posters on site | PS4.3

Mars Sample Return Rock Sampling: Post-landing Extraction of Solid-core Samples.  

John Bridges and Fiona Thiessen and the NASA-ESA MSR Rock Sampling Team

A NASA-ESA Rock Sampling working group has been set up to determine plans for opening the Mars2020 sample tubes once they are returned to Earth. This team works under the oversight of the Mars Campaign Science Group (MCSG). The rocks sampled so far by the Perseverance Rover comprise igneous rocks like basalt and olivine cumulates that experienced various degrees of secondary water alteration; fluviolacustrine sedimentary rocks that show various levels of induration, and unconsolidated Mars regolith. Two main considerations weigh on the strategy that should be adopted for opening the sample tubes on Earth. These are (1) preservation of textural relationships and layering, and (2) minimizing metal and organic, magnetic contamination.

It is anticipated that the mechanical state of each sample, as received in the laboratory on Earth, will be assessed by computed tomography (CT) scanning techniques prior to opening.  The decision on how to open each sample tube can therefore be based on geological data collected by the Mars2020 team, tests done on analogue samples, as well as the penetrative imaging data obtained on Earth during basic characterization.

The Rock Sampling Team is considering radial and longitudinal cuts through the Ti alloy tubes but finds that a single approach will not be appropriate for all the various types of rock samples that are expected to be returned.  In the next stage of the MSR Rock Sampling Group’s work we will select appropriate Mars2020 analogues and test the proposed tube cutting protocols.

The decision to implement MSR will not be finalized until NASA’s completion of the National Environmental Policy Act (NEPA) process. 

How to cite: Bridges, J. and Thiessen, F. and the NASA-ESA MSR Rock Sampling Team: Mars Sample Return Rock Sampling: Post-landing Extraction of Solid-core Samples. , EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-14333, https://doi.org/10.5194/egusphere-egu23-14333, 2023.

EGU23-14614 | Orals | PS4.3

Study of Recurring Slope Lineae Activity in Hale Crater: Wind and Dust Deposition Triggers. 

Yann Leseigneur and Mathieu Vincendon

Recurring Slope Lineae (hereinafter RSL) are seasonal dark flows on Mars steep slopes. These movements of several meters long appear and grow downwards (more or less incrementally) and fade (partially or totally) more or less progressively. After investigating wet origins, dry processes involving dust are favoured (e.g., dust-removed features, dark sand movements, …) but are not yet precisely understood. One of the main common features between RSL and dust is seasonality, for example major formations are observed during the dust storm season at all latitudes. A specific RSL seasonality composed of three pulses of RSL apparition or lengthening has been found by Stillman et al. (2018) at Hale crater (323.48°E, 35.68°S). Here we assess whether this RSL timing could be related to the three pulses of the dust cycle. So, we reanalyse the observations of Hale to characterise the RSL activity with a dust removal/deposition point of view, trying to constrain the formation triggers (dust deposition, winds, …) and formation scenario for RSL.

 

We analyse consecutive high-resolution images (>0.25 m/pixel) of two Hale areas, taken by HiRISE onboard Mars Reconnaissance Orbiter, for Martian years 31, 32, and 33. We divided the characterisation into two parts: periods of apparition or lengthening of RSL-like features (i.e., when the extent of dark surfaces increases) and periods of RSL fading or disappearing (i.e., when the contrast between dark surfaces and adjacent bright surfaces decreases). In the framework of the “dust-removed” hypothesis for RSL, these two periods correspond respectively to dust removal and deposition periods. Each of those has three levels of intensity: low, intermediate and high. Then, we compare this RSL activity timeline to atmospheric dust optical depth variations over Hale.

 

With this new characterisation, we overall find again the three southern hemisphere spring/summer pulses and we also have identified an RSL formation event occurring near winter solstice (not already noticed). Then, we notice that there are dust depositions before each pulse, which correspond to a long decrease of atmospheric dust optical depth (1st pulse) or two local peaks (2nd and 3rd pulse). This may imply that dust deposition at RSL locations can occur as both progressive fallout or rapid transport associated with storms. This also implies that a certain surface dust deposition seems to be necessary to have a significant level of RSL formation, but it does not seem to be always sufficient to trigger RSL formation. Indeed, local increase in atmospheric dust, which could be related to increased wind activity, seems to be required (1stpulse) or seems to favour RSL formation (3rd pulse).

 

Thus, we can propose an RSL formation scenario consistent with these observations: if there is enough surface dust deposition, a dry avalanche-type formation can be observed (possibly initiated by winds); with less dust deposition or slope unfavourable conditions (not allowing avalanche) the RSL lengthen downward more incrementally (as for the 3rd pulse) under the action of winds. This proposed scenario elaborated using Hale observational constraints will be tested, improved, and confirmed with similar analyses performed at other RSL sites.

How to cite: Leseigneur, Y. and Vincendon, M.: Study of Recurring Slope Lineae Activity in Hale Crater: Wind and Dust Deposition Triggers., EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-14614, https://doi.org/10.5194/egusphere-egu23-14614, 2023.

EGU23-14629 | ECS | Posters virtual | PS4.3

Experimental Measurements of Electric and Magnetic Fields in Simulated Martian Dust Storms 

David Reid and Karen Aplin

Despite no direct observations of lightning on Mars, it is expected to occur. The planet is known to have large dust storms - which are believed to generate electric and magnetic fields. Magnetic fields are also expected in dust storms on Earth, though measurements are extremely limited. Understanding of electric and magnetic fields of this prevalent feature of the Martian landscape is vital to understanding and developing missions of Mars.

Two hypotheses were postulated. Firstly, the vertical separation of charge is responsible for the electric field, and, secondly, that the spiralling motion of the charged particles is responsible for the magnetic field. An experimental apparatus was designed to isolate the vertical and horizontal components of the motion in a dust storm in the lab with Martian analogue material by dropping or rotating the particulates respectively. In this rig electric fields are measured using a field mill (CS110) and magnetic fields with a search coil magnetometer (LEMI 133, the engineering model from the postponed ExoMars22 mission). The rig is carefully screened from background electrical and magnetic fields.

The equipment is currently being commissioned, and in the vertical separation mode, particulates such as polystyrene and glass beads were dropped onto a Faraday cup. By determination of the capacitance of the tank, the voltage signal can be converted into charge. In addition to this, the signals from the Faraday cup and field mill can be visualised across the time profile of a given drop. In the horizontal motion mode, the particulate is mixed with a paddle, akin to an ice-cream machine, to entrain the dust in a vortex. Results from these lab-based experiments are presented here.

How to cite: Reid, D. and Aplin, K.: Experimental Measurements of Electric and Magnetic Fields in Simulated Martian Dust Storms, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-14629, https://doi.org/10.5194/egusphere-egu23-14629, 2023.

EGU23-14721 | ECS | Posters on site | PS4.3

Synchrotron X-ray Diffraction for Early Characterisation of Sealed Mars2020 Samples 

Lukas Adam, John Bridges, Donald Bowden, John Holt, and Candice Bedford

NASA, ESA and the UK are collaborating on a Mars Sample Return (MSR) mission which aims to retrieve drill cores of Martian rock for terrestrial analysis, starting with the Mars2020 rover which landed successfully in Jezero Crater in Feb. 2021. Up to 30 samples, inside sealed titanium sample tubes, are planned to be returned to Earth in later missions. Due to the potential for back-contamination of Earth from possible extant life on Mars, strict contamination control measures must be taken for the purposes of planetary protection, as well as to prevent contamination of the samples by Earth’s environment. These measures place restrictions on the way measurements can be performed on the samples until they have been sterilised or judged safe. As the first step of scientific analysis, all samples will undergo a set of measurements called Pre-Basic Characterisation. Pre-BC will include weighing, X-ray CT, and magnetic measurements. These data along with Basic Characterisation data will be used to decide experimental plans for multi instrument analyses on the Mars samples. X-ray Diffraction (XRD) is currently planned for a later stage of sample analysis after the sample tubes have been opened due to limitations with conventional commercial X-ray diffractometers. [1, 2]

While a conventional X-ray tube cannot provide an appropriate X-ray beam, a synchrotron source is capable of much higher intensities and precise wavelength selectivity. Synchrotron facilities also allow more suitable diffraction geometries for the size and shape of sample expected from MSR. We have carried out experiments with the help of Diamond Light Source’s I12-JEEP beamline to test the feasibility of XRD analysis of samples in sealed Mars2020 sample tubes and suitable instrument parameters for XRD of these samples. Titanium tubes were prepared as analogues to Mars2020 sample tubes. Three different geological analogues were used in place of the Mars samples: an Icelandic basaltic sand, a calcareous mudstone from Watchet Bay, UK, and a Devonian Fine Grained Sandstone, UK. Two different methods for preventing unwanted diffraction signal from the sample tube walls have also been tested: subtracting the diffraction spectrum of an empty tube from the tube-with-sample spectrum, and using energy-dispersive X-ray diffraction to exclude tube wall signal. We show that quantitative XRD phase analysis can be successfully carried out on returned Mars samples in unopened sample tubes using a synchrotron X-ray source, and thus could be included in the Pre-BC phase of returned sample science. This would provide mineralogical data much earlier in the sample science process, improving decision-making around sample science, curation, and handling.

 

References:

1.       Meyer, M.A., et al., Final Report of the Mars Sample Return Science Planning Group 2 (MSPG2). Astrobiology, 2022. 22(S1): p. S-5-S-26.

2.       Tait, K.T., et al., Preliminary Planning for Mars Sample Return (MSR) Curation Activities in a Sample Receiving Facility (SRF). Astrobiology, 2022. 22(S1): p. S-57-S-80.

How to cite: Adam, L., Bridges, J., Bowden, D., Holt, J., and Bedford, C.: Synchrotron X-ray Diffraction for Early Characterisation of Sealed Mars2020 Samples, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-14721, https://doi.org/10.5194/egusphere-egu23-14721, 2023.

EGU23-15500 | ECS | Orals | PS4.3

Rock Properties of Shallow Martian Subsurface with the RIMFAX Ground Penetrating Radar 

Titus M. Casademont, Sigurd Eide, Emileigh Shoemaker, Tor Berger, Patrick Russell, and Svein-Erik Hamran

The RIMFAX ground penetrating radar instrument on board the Mars 2020 Perseverance Rover has been continuously sounding the subsurface along
the Rover traverse. In the data of the first 379 mission days on the Jezero Crater Floor we are able to identify hyperbolic patterns, likely caused by buried scatterers such as boulders or cavities in the upper 5 m of the subsurface. We present the first detailed estimates of radar wave propagation velocity by matching theoretical traveltime hyperbolas to the patterns generated by scatterers. The average dielectric permittivities are derived from these velocities and, consequently, the bulk rock densities for material above the scattering source. Simultaneously, we investigate the surface reflectivity to retrieve permittivity and density of the uppermost centimeter. Finally, we assess the radar attenuation by a constant-Q approach.
The results are consistent with a solid rock, mafic interpretation of the Jezero Crater subsurface. The talk is based on the respective two most recent publications as well as work in progress.

How to cite: Casademont, T. M., Eide, S., Shoemaker, E., Berger, T., Russell, P., and Hamran, S.-E.: Rock Properties of Shallow Martian Subsurface with the RIMFAX Ground Penetrating Radar, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-15500, https://doi.org/10.5194/egusphere-egu23-15500, 2023.

EGU23-15704 | Orals | PS4.3

On the plausibility of methane detections on Mars 

Sébastien Viscardy, Séverine Robert, Justin T. Erwin, Ian R. Thomas, Frank Daerden, Loïc Trompet, Yannick Willame, and Ann Carine Vandaele

As a potential biomarker, Martian methane has attracted attention through several reports of its detection over the last 20 years. However, the very existence of this gas has been continuously questioned, in particular because the observed lifetime should be several orders of magnitude shorter than the 300 years predicted by photochemical models. Although several fast removal processes have been hypothesized to explain the observations, none of them has met a large consensus.

It is in this context that the ESA-Roscomos ExoMars Trace Gas Orbiter (TGO) mission started its science operations in April 2018. ACS and NOMAD, two instruments onboard the TGO, have been collecting hundreds of highly sensitive measurements in solar occultation. No methane has been detected so far and an upper limit of 0.02 ppbv has been derived. The implications of this result on the methane problem on Mars will be addressed in this work.

This upper limit is a strong constraint on the background level and, in turn, on the potential emission scenarios making the reported methane detections consistent with the TGO results. While several model studies aimed at identifying them, we will here adopt a probabilistic approach to the problem in order to question the plausibility of those detections and estimate the lifetime required to make them plausible from a probabilistic standpoint.

How to cite: Viscardy, S., Robert, S., Erwin, J. T., Thomas, I. R., Daerden, F., Trompet, L., Willame, Y., and Vandaele, A. C.: On the plausibility of methane detections on Mars, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-15704, https://doi.org/10.5194/egusphere-egu23-15704, 2023.

EGU23-16154 | ECS | Orals | PS4.3

The chlorine cycle on Mars: What do we know after three Mars years of observation with ACS on TGO? 

Kevin S. Olsen, Alexander Trokhimovskiy, Anna A. Fedorova, Armin Kleinbohl, Franck Lefèvre, Franck Montmessin, Oleg I. Korablev, Juan Alday, Lucio Baggio, Denis A. Belyaev, Andrey S. Patrakeev, Alexey Shakun, and Manish Patel

 

The Atmospheric Chemistry Suite (ACS) on the ExoMars Trace Gas Orbiter (TGO) took its first science observation in April 2018, right before the onset of the Mars Year (MY) 34 global dust storm. One of the main objectives of the TGO mission is to search for as-yet undetected trace gases that can tell us about contemporary volcanism on Mars, or its present and past habitability. In the data collected those first months, heavily impacted by dust activity, the first novel trace gas was discovered: hydrogen chloride. MY 37 has just begun and we have recently finished observing our third full dusty season on Mars with TGO and ACS (around perihelion, spring and summer in the southern hemisphere). HCl in the atmosphere of Mars is a seasonal phenomenon, having appeared coincidentally with the start of dust activity in each MY. HCl was thought to be an indication of contemporary volcanism, but its widespread distribution across both hemispheres and recurring seasonality are suggestive of a photochemical source. Here, we present the climatology of HCl after three Martian perihelion periods, as well as a comparison with other parameters measured with ACS, such as water, temperature, and aerosols. From coincident measurements made with the Mars Climate Sounder (MCS) on Mars Reconnaissance Orbiter (MRO), we can also compare the climatology of HCl with those of dust and water ice. HCl is strongly correlated to water vapour, which is itself correlated to atmospheric temperatures. While HCl only appears in the presence of suspended dust aerosols, the measured abundances of these two quantities are poorly correlated. The disappearance of HCl towards the autumnal equinox may be related to changes in temperature. The cooling atmosphere removes water vapour from the gas phase, necessary for formation of HCl, and promotes ice formation, which HCl may adhere to. We will show the evolution of HCl abundance over three Martian years in both hemispheres, and show how they fit into the seasonality of Martian dust, the water cycle, and ice formation, and discuss the possible mechanisms of its formation and destruction.

How to cite: Olsen, K. S., Trokhimovskiy, A., Fedorova, A. A., Kleinbohl, A., Lefèvre, F., Montmessin, F., Korablev, O. I., Alday, J., Baggio, L., Belyaev, D. A., Patrakeev, A. S., Shakun, A., and Patel, M.: The chlorine cycle on Mars: What do we know after three Mars years of observation with ACS on TGO?, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-16154, https://doi.org/10.5194/egusphere-egu23-16154, 2023.

EGU23-16175 | Posters on site | PS4.3

Exploration of microbial-mineral interactions with the Noachian Martian breccia composed of ~4.5 Gyr old crustal materials from Mars 

Tetyana Milojevic, Denise Koelbl, Robert Bruner, and Matthew L. Morgan

In the past year we have been witnessing several important missions to Mars, including Mars 2020 Perseverance rover that landed to Jezero Crater to search for signs of ancient life. Multiple lines of evidence indicate an active hydrogeological history of Mars and chemolithoautotrophy-suited environments within its Noachian terrains. As a result, one of the primary aims of Mars missions is to search for signs of ancient life and collect a suite of samples to be returned to Earth via a Mars Sample Return mission. Being a few steps away from retrieving and returning the first Mars samples, we need to gain extensive knowledge how to access their potential biogenicity. In this connection, a valuable source of information can be extracted from microbial fingerprints of chemolithotrophic life based on Martian materials. Chemolithoautotrophy is the most ancient microbial form of life, which enables the transition of energy from a stone to the energy of a living entity. In our project, we investigate interactions of a wide variety of chemolithoautotrophs with Martian mineral materials (Martian meteorites and regolith simulants). Our recent research on the genuine Noachian Martian breccia “Black Beauty” permitted visualization and nanometer-scale imaging of microbial life designed and cultivated on Martian materials(1). Here we report on laboratory-scaled microbially assisted chemolithoautotrophic biotransformation(1) of the Noachian Martian breccia Northwest Africa (NWA) 7034 composed of ancient (~4.5 Gyr old) crustal materials from Mars. Nanoanalytical hyperspectral analysis provides clues for the trafficking and distribution of meteorite inorganic constituents in the microbial cell(1). We decipher biomineralization patterns associated with the biotransformation and reveal microbial nanometer-sized lithologies located inside the cell and on its outer surface layer(1). These investigations provide an opportunity to trace the putative bioalteration processes of the Martian crust and to assess the potential biogenicity of Martian materials. Our study on the Noachian Martian breccia composed of ~4.5 Gyr old crustal materials from Mars, delivered a prototype of microbial life experimentally designed on a real Martian material(1). This life of a pure Martian design is a rich source of Mars relevant biosignatures.

 

1. Milojevic, T., Albu, M., Kölbl, D. et al. Chemolithotrophy on the Noachian Martian breccia NWA 7034 via experimental microbial biotransformation. Commun Earth Environ 2, 39 (2021). https://doi.org/10.1038/s43247-021-00105-x

How to cite: Milojevic, T., Koelbl, D., Bruner, R., and Morgan, M. L.: Exploration of microbial-mineral interactions with the Noachian Martian breccia composed of ~4.5 Gyr old crustal materials from Mars, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-16175, https://doi.org/10.5194/egusphere-egu23-16175, 2023.

EGU23-16376 | Posters on site | PS4.3

ExoMars – WISDOM Field-Test Data Processed with Automatic Pipeline 

Dirk Plettemeier, Wolf-Stefan Benedix, Sebastian Hegler, Ronny Hahnel, Christoph Statz, Yun Lu, Valérie Ciarletti, Emile Brighi, Alice Le Gall, Issa Sall, Esther Mas, and Aleksey Shestov

The ExoMars Rover instrument WISDOM (“Water Ice and Subsurface Deposit Observations on Mars”) is a ground penetrating radar (GPR) designed to investigate the shallow subsurface of Oxia Planum, the ExoMars mission’s designated landing site. Using a frequency range from 0.5 GHz to 3.0 GHz the electromagnetic waves penetrate the subsurface via a wideband antenna assembly. The achieved penetration depth is at least three meters, with a depth resolution of a few centimeters. The dual-polarimetric design of the antenna allows to measure four different channels during probing the Mars soil.

The WISDOM radar will give access to the geological structure, electromagnetic nature, and possibly hydrological state of the shallow subsurface by retrieving the layering and properties of the buried reflectors. A short-term subsurface analysis will support the tight schedules of the rover operations both for science and drill operations in finding places of high scientific interest and low risk.

In order to achieve these short times for decision making the incoming data at the remote operation control center (ROCC) will be automatically processed through a predefined pipeline. The processing is written in Python, which uses a self-developed framework. The basic process consists of a chain of filters that produces several radargrams at different states of processing. Further, it prepares the data for storage in PDS4 format for long-term archiving.

In this work, automatic processing is introduced and results of processed measurement data acquired during a WISDOM field test in Svalbard are presented.

How to cite: Plettemeier, D., Benedix, W.-S., Hegler, S., Hahnel, R., Statz, C., Lu, Y., Ciarletti, V., Brighi, E., Le Gall, A., Sall, I., Mas, E., and Shestov, A.: ExoMars – WISDOM Field-Test Data Processed with Automatic Pipeline, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-16376, https://doi.org/10.5194/egusphere-egu23-16376, 2023.

EGU23-16586 | Posters on site | PS4.3

Introducing the concept of “astrobiological time-analogs”: Ecological successions throughout the desiccation of hypersaline lagoons on Earth and the wet-to-dry transition on early Mars 

Alberto G. Fairén, Nuria Rodriguez, Laura Sanchez-Garcia, Esther Uceda, Daniel Carrizo, Patricia Rojas, Ricardo Amils, and Jose Luis Sanz

Early Mars most likely had a diversity of environments in terms of pH, redox conditions, temperature, geochemistry, and mineralogy. Field research in terrestrial analog environments contribute to understand the habitability of this diversity of environments on Mars in the past, because terrestrial analogues are places on Earth characterized by environmental, mineralogical, geomorphological, or geochemical conditions similar to those observed on present or past Mars. So far, analogs have been referred to terrestrial locations closely similar to any of the geochemical environments that have been inferred on Mars, i.e., they are “place-analogs” that represent snapshots in time: one specific environmental condition at a very specific place and a very specific time. Because of this, each individual field analog site cannot be considered an adequate representation of the changing martian environmental conditions through time. Here we introduce the concept of “astrobiological time-analog”, referred to terrestrial analogs that may help understand environmental transitions and the related possible ecological successions on early Mars. As Mars lost most of its surface water at the end of the Hesperian, this wet-to-dry global transition can be considered the major environmental perturbation in the geological history of Mars, and therefore merits to be the first one to be assigned a “time-analog” for its better understanding and characterization. 
At the end of the Hesperian, several paleolakes on Mars were characterized by episodic inundation by shallow surface waters with varying salinity, evaporation, and full desiccation repeatedly over time, until the final disappearance of most surface water after the wet-to-dry transition. We show here that similar conditions can be tested through time in the terrestrial analog Tirez lagoon. Tirez was a small and seasonal endorheic athalassohaline lagoon that was located in central Spain. In recent years, the lagoon has totally dried out, offering for the first time the opportunity to analyze its desiccation process as a “time-analog” to similar events occurred during the wet-to-dry transition on early Mars. To do so, here we describe (i) the microbial ecology of Tirez when the lagoon was still active 20 years ago, with prokaryotes adapted to extreme saline conditions; (ii) the composition of the microbial community in the dried lake sediments today, in many case groups that thrive in sediments of extreme environments; and (iii) the molecular and isotopic analysis of the lipid biomarkers that can be recovered from the sediments today. We conclude that Tirez was habitable for a wide range of prokaryotes before and after its complete desiccation, in spite of the repeated seasonal dryness; and our results may inform about research strategies to search for possible biomarkers in Mars after all the water was lost. Our 25 yearlong analyses of the ecological transitions in the Tirez lagoon represent the first terrestrial astrobiological “time-analog” for desiccating saline lakes on early Mars

How to cite: G. Fairén, A., Rodriguez, N., Sanchez-Garcia, L., Uceda, E., Carrizo, D., Rojas, P., Amils, R., and Sanz, J. L.: Introducing the concept of “astrobiological time-analogs”: Ecological successions throughout the desiccation of hypersaline lagoons on Earth and the wet-to-dry transition on early Mars, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-16586, https://doi.org/10.5194/egusphere-egu23-16586, 2023.

EGU23-16660 | Orals | PS4.3

Martian Atmospheric Pressure Measurement from Space 

Joel Campbell, Zhaoyan Liu, Bing Lin, Jirong Yu, and Shibin Jiang

In order to facilitate human exploration on Mars, a need exists to study weather patterns and atmospheric conditions on Mars. Mars has colder weather than Earth, is known for its dust storms, and has a very thin atmosphere, yet its atmosphere and climate are more like Earth's than any other planet in our solar system. Despite these challenges, NASA scientists believe that Mars is the most promising planet for exploration and habitation. We are developing a new measurement concept that uses differential absorption Lidar system in the 2-μm CO2 absorption band to measure atmospheric CO2 and pressure on Mars. By selecting two or more closely spaced wavelengths, one can eliminate the effects of other gases and surface reflections, allowing us to accurately measure CO2 absorption and determine CO2 levels and air pressure on Mars. Our simulations show that this system will be able to measure air pressure with 1 Pa precision up to 5 km away, even in the presence of moderate dust, and measure CO2 and pressure profiles from the surface up to 13 km with a horizontal resolution of 100 km and a vertical resolution of 100 m (400 m during the day). These measurements will improve weather and climate modeling and prediction on Mars.

How to cite: Campbell, J., Liu, Z., Lin, B., Yu, J., and Jiang, S.: Martian Atmospheric Pressure Measurement from Space, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-16660, https://doi.org/10.5194/egusphere-egu23-16660, 2023.

EGU23-16728 | ECS | Orals | PS4.3

Updated orbital perspective of the Mt. Sharp upper sulfates in preparation for in situ exploration 

Rachel Sheppard, William Rapin, Valerie Tu, Lucy Lim, Travis Gabriel, Madison Hughes, Abigail Fraeman, and David Vaniman

Mg sulfate (MGS) is one of the most common secondary minerals on Mars, with orbital detections spread across the planet and multiple occurrences and elevations within Gale crater. The mineralogy of MGS (including its crystallinity and hydration state) and its geologic setting can be used to place precise limits on aqueous conditions during formation and diagenesis. Both monohydrated Mg-sulfate and polyhydrated Mg-sulfate have been observed in Gale crater from orbit, and the MSL mission is now within the area where MGS-rich strata are identified from orbit, presenting an opportunity to examine these common martian minerals in situ. We map MGS-rich outcrops along the planned rover traverse route and similar stratigraphic range around all of Mt. Sharp. By comparing CRISM and HiRISE data in a restricted stratigraphic range, we identify small features of interest such as potential thin monohydrated MGS layers. As monohydrated MGS cannot have been exposed to liquid water or frost since formation, these are important outcrops for the rover to conduct contact science and gather high-resolution textural observations which can be used to test formation hypotheses.

How to cite: Sheppard, R., Rapin, W., Tu, V., Lim, L., Gabriel, T., Hughes, M., Fraeman, A., and Vaniman, D.: Updated orbital perspective of the Mt. Sharp upper sulfates in preparation for in situ exploration, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-16728, https://doi.org/10.5194/egusphere-egu23-16728, 2023.

EGU23-17025 | ECS | Posters on site | PS4.3

High-resolution nesting simulations for the EDL stage of China’s first Mars exploration mission (Tianwen-1) 

Jing Xiao, Kim-Chiu Chow, Shaojie Qu, Yanqi Hu, Haogong Wei, Yemeng Wang, and Kun Zhang

China’s first Mars rover “Zhurong” successfully landed (on July 15, 2021,07:18 CST) at the pre-selected landing area on Utopia Planitia of Mars. The “Entrance, Descending, and Landing (EDL)” process was the most challenging and highly dependent on the accurate prediction of the atmospheric conditions all along the descending trajectory and around the landing site.

In this study, a series of five-domain nested simulations were conducted using MarsWRF GCM, with the top of the domains at ~90 km and the highest horizontal resolution of ~3.6 km. Especially, modified fully-interactive dust lifting and radiation feedback (hereafter “inter-active dust”) schemes were used in all nested domains as a “control” experiment. The results can reasonably represent the Martian atmospheric features based on MCS-MRO observations and MCD5.3 re-analysis data (e.g., the “thermal tide”, meridional circulations, semi-spherical and local topographic flows, and mesoscale structures around landing site). The advantages of our nesting simulation compared to MCD5.3 data included: 1) the suspended dust was more “elevated” at some regions; 2) it can resolve the topographic gravity waves and even convection-like structures in the boundary layer.

In consideration of the uncertainties caused by the dust and radiation processes, besides the control experiment, three more nesting simulations with different dust distributions and radiation feedback schemes were also conducted to give an ensemble prediction with a certain spread, which confirmed the engineering meteorological thresholds provided by CAST. Finally, the model predictions were validated by the EDL retrieved profiles, showing that the temperature and wind speed profiles were well predicted. Especially, only the “inter-active dust” experiments showed the easterlies between 20~30km altitudes as reported by the EDL data. However, the density profiles of both the model and MCD5.3 re-analysis were underestimated below 30 km altitude.

How to cite: Xiao, J., Chow, K.-C., Qu, S., Hu, Y., Wei, H., Wang, Y., and Zhang, K.: High-resolution nesting simulations for the EDL stage of China’s first Mars exploration mission (Tianwen-1), EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-17025, https://doi.org/10.5194/egusphere-egu23-17025, 2023.

EGU23-17592 | ECS | Orals | PS4.3

Martian atmospheric chemistry of HCl: implications for the lifetime of atmospheric methane 

Benjamin M. Taysum, Paul I. Palmer, Mikhail Luginin, Nikolay Ignatiev, Alexander Trokhimovskiy, Alexey Shakun, Alexey Grigoriev, Franck Montmessin, Oleg Korablev, and Kevin Olsen

We develop a 1-D atmospheric photochemistry model for Mars to interpret hydrogen chloride (HCl) profile measurements collected by the ACS MIR spectrometer aboard the ExoMars Trace Gas Orbiter (TGO) in Mars Year (MY) 34. We include a gas-phase chlorine chemistry scheme and study 1) surface chemistry, 2) hydrolysis, 3) photolysis, and 4) hydration and photolysis of dust grains as possible sources of gas-phase chlorine chemistry. Heterogeneous uptake of chlorine species onto water ice and minerals in Martian dust are loss processes common to all mechanisms. We drive the 1-D model using TGO profile measurements of aerosols and water vapour. We find that mechanism four can reproduce observed HCl profile tendencies during MY34. It reproduces the HCl cut-off at high southern latitudes (<60° S) at ≈35 km, and forms layers of HCl between 20-35km at the tropics. Mechanisms one, two, and three result in significant model biases.

Seasonal variations of Martian HCl are reproduced by mechanism four, yielding low HCl abundances (< 1 ppb) prior to the dust season that rise to 2--6 ppb in southern latitudes during the dust season. We find that the additional Cl atoms released via mechanism four shortens the atmospheric lifetime of methane by a magnitude of 102. This suggests the production of Cl via the UV (or other electromagnetic radiation) induced breakdown of hydrated perchlorate in airborne Martian dust, consistent with observed profiles of HCl, helps reconcile observed variations of methane with photochemical models.

How to cite: Taysum, B. M., Palmer, P. I., Luginin, M., Ignatiev, N., Trokhimovskiy, A., Shakun, A., Grigoriev, A., Montmessin, F., Korablev, O., and Olsen, K.: Martian atmospheric chemistry of HCl: implications for the lifetime of atmospheric methane, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-17592, https://doi.org/10.5194/egusphere-egu23-17592, 2023.

EGU23-1815 | Orals | PS4.4

One Martian Year of Observations by the Emirates eXploration Imager (EXI): Operations Summary, Current Status, and Seasonal Trends in the Diurnal Behavior of Water Ice Clouds 

Michael Wolff, Andrew Jones, Mikki Osterloo, Ralph Shuping, Christopher Edwards, Mariam Al Shamsi, Joey Espejo, Charles Fisher, Christopher Jeppesen, and Justin Knavel

The EXI instrument onboard the Emirates Mars Mission (EMM) spacecraft has been operating for a full Martian year.  Using the elliptical orbit, EXI has observed the atmosphere and surface of Mars at both regional and global scales while providing a unique diurnal sampling.  This diurnal coverage is available over much of the planet on a time scale of approximately ten days.  The observations are typically taken in both the ultraviolet and visible: 260, 320, 437, 546, and 635 nm, with an effective spatial resolution of 2–4 km per native pixel.  This presentation will provide an overview of EXI’s on-orbit activities and performance during the first Mars year of science operations, a summary of the diurnal behavior of seasonal trends in water ice clouds, and some examples of the combined analysis of EXI and Emirates Mars InfraRed Spectrometer (EMIRS) observations.  More specifically, we will cover the following:

 

  • The multiple types of observational modes employed, statistics of the images obtained and available in the EMM Science Data Center, and the radiometric performance of the camera as measured by the standard star observation program.

 

  • The diurnal trends are associated with the seasonal behavior of water ice clouds through a Martian year, including the aphelion and perihelion seasons.

 

  • The advantages and challenges of combining the EXI and EMIRS observations for atmospheric and surface studies, where the Instantaneous Field of View differs by one-to-two orders of magnitude.

 

Funding for the development of the EMM mission was provided by the UAE government and to co-authors outside of the UAE by the Mohammed bin Rashid Space Center (MBRSC).

How to cite: Wolff, M., Jones, A., Osterloo, M., Shuping, R., Edwards, C., Al Shamsi, M., Espejo, J., Fisher, C., Jeppesen, C., and Knavel, J.: One Martian Year of Observations by the Emirates eXploration Imager (EXI): Operations Summary, Current Status, and Seasonal Trends in the Diurnal Behavior of Water Ice Clouds, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-1815, https://doi.org/10.5194/egusphere-egu23-1815, 2023.

EGU23-2149 | Orals | PS4.4

Auroral currents from EMM and InSight: A comparison of EMM-EMUS auroral observations and InSight-IFG magnetic field fluctuations 

Matthew Fillingim, Robert Lillis, Anna Mittelholz, Hessa AlMatroushi, Hoor AlMazmi, Michael Chaffin, Peter Chi, Krishnaprasad Chirakkil, John Corriera, Justin Deighan, Scott England, Scott Evans, Heidi Haviland, Greg Holsclaw, Sonal Jain, Catherine Johnson, Steven Joy, Benoit Langlais, Fatma Lootah, and Susarla Raghuram

The Emirates Mars Ultraviolet Spectrometer (EMUS) onboard the Emirates Mars Mission spacecraft, which observes ultraviolet emission between approximately 100 and 170 nm, has observed multiple instances of nightside aurora at Mars. Variations in the auroral brightness and morphology have been observed to change on timescales of tens of minutes. The brightest aurorae are typically seen following space weather events, i.e., coronal mass ejection and stream interaction region impacts. The InSight Fluxgate Magnetometer (IFG) on the Interior Explorations using Seismic Investigations, Geodesy and Heat Transport (InSight) lander measured the magnetic field at the surface of Mars. IFG has measured variations in the nightside surface magnetic field, presumably due to variations in ionospheric and magnetospheric currents. Periodic and aperiodic variations in the surface field have been observed, including with timescales of a few minutes to tens of minutes. The magnitude of the fluctuations is often larger following space weather events. We examine the connection between the presence of aurora as observed by EMUS and surface magnetic field fluctuations as measured by IFG. Coincident EMUS and IFG observations show enhanced surface magnetic field fluctuations during times when aurorae were present. Additionally, the timescale of fluctuations in the auroral brightness are similar to the timescale of surface magnetic field fluctuations for non-coincident observations. These results suggest that IFG measured the surface magnetic field effect of time varying ionospheric auroral currents.

How to cite: Fillingim, M., Lillis, R., Mittelholz, A., AlMatroushi, H., AlMazmi, H., Chaffin, M., Chi, P., Chirakkil, K., Corriera, J., Deighan, J., England, S., Evans, S., Haviland, H., Holsclaw, G., Jain, S., Johnson, C., Joy, S., Langlais, B., Lootah, F., and Raghuram, S.: Auroral currents from EMM and InSight: A comparison of EMM-EMUS auroral observations and InSight-IFG magnetic field fluctuations, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-2149, https://doi.org/10.5194/egusphere-egu23-2149, 2023.

EGU23-2424 | Orals | PS4.4

EMIRS observations of temperature and dust aerosols: Seasonal and diurnal variability 

Syed A. Haider, Tariq Majeed, and Siddhi Shah

Recently, Emirates Mars Mission (EMM) arrived at Mars on 9 February 2021. It carried three instruments: (1) Emirates eXploration Imager (EXI), (2) Emirates Mars Infrared Spectrometer (EMIRS), and (3) Emirates Mars Ultraviolet Spectrometer (EMUS). In this paper we have used EMIRS data. The EMIRS instrument is measuring atmospheric temperature (at 0.5 mbar) and the column abundance of dust aerosols (referenced to 9 μm), water ice clouds (referenced to 12 μm), and water vapour (pr-μm). These observations were taken between 24 May, 2021 (MY 36, Ls= ~ 50o) and 24 February, 2022 (MY36, Ls = 180o). There is a gap in these data between Ls = 100o and 120o due to the solar conjunction and the spacecraft entering into safe mode. We have studied the seasonal and diurnal variability of surface temperature and dust aerosols in the Martian atmosphere. These observations are reported at Ls= 5o interval and 2o interval in latitude. The data are averaged over longitude. Our results show that Mars was relatively cool with little dust. The growth and decay of regional dust storms were observed by EMIRS instrument. Based on our analysis we conclude that EMIRS instrument is well suited for the study of temporal and seasonal variability of atmospheric temperature and column integrated quantities of dust. Detailed analysis of these observations will improve our understanding of the underlying physical processes. It will also help to validate and tune GCM models. The EMIRS observations are always providing an exciting new information as we enter the dust perihelion season.  

How to cite: Haider, S. A., Majeed, T., and Shah, S.: EMIRS observations of temperature and dust aerosols: Seasonal and diurnal variability, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-2424, https://doi.org/10.5194/egusphere-egu23-2424, 2023.

EGU23-2640 | ECS | Orals | PS4.4

Dust storm statistics based on the EMM camera EXI for a complete Martian Year period 

Bijay Kumar Guha, Claus Gebhardt, Roland M. B. Young, and Michael J. Wolff

Abstract: The Emirates eXploration Imager (EXI) onboard EMM is a multi-wavelength double lens camera suitable for observing the Martian lower atmospheric phenomena such as dust storms [3, 5]. The spacecraft’s unique orbit allows the EXI camera a full disk view of Mars at a time step of hours or less through its visible and UV channels (at ~2-4 km per pixel resolution). Therefore, we have used these unprecedented observations to characterize the dust storms for a one Martian-year period [4, 6]. Our dust storm research is directly aligned with the EMM science objective on the lower atmosphere and also with the objective of correlating the lower and upper atmosphere [1, 2]. In this study, we have prepared a one Martian year of dust storm database from EMM-EXI images. The dust storm database includes the start and end time of dust storms, their area, and the centroid latitude and longitude. Here, we also focused on characterizing the dust storms at a sub-daily time scale (which has not been emphasized before) by tracking their evolution at multiple local times. In addition, we consider the origination region, the pathway, and the morphological characteristics of dust storms. Our presentation includes accompanying simulations by a planetary climate model.

References: [1] Almatroushi, H., et al. (2021). Space Science Reviews, 217(8), 1-31. [2] Amiri, H. E. S., et al. (2022). Space Science Reviews, 218, 4 (2022). [3] Gebhardt, C., et al. (2022). Geophysical Research Letters. 49, e2022GL099528. [4] Guha, B. K., et al. (2021). Planetary and Space Science, 209, 105357. [5] Jones, A.R., et al. (2021). Space Science Reviews, 217, 81. [6] Wang, H., & Richardson, M. I. (2015). Icarus, 251, 112-127.

How to cite: Guha, B. K., Gebhardt, C., Young, R. M. B., and Wolff, M. J.: Dust storm statistics based on the EMM camera EXI for a complete Martian Year period, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-2640, https://doi.org/10.5194/egusphere-egu23-2640, 2023.

EGU23-3053 | Posters on site | PS4.4

The physics and dynamics of selected dust storms in the EMM primary mission 

Claus Gebhardt, Bijay K. Guha, Roland M. B. Young, Michael J. Wolff, and Christopher S. Edwards

Mars dust storms are an interdisciplinary field of research. They impact the entry-descent-landing operations of spacecraft, the energy production by the solar panels of Mars rovers and landers, and others. As can be foreseen, dust storms are also critical for the future human exploration of Mars. Dust storm research is directly aligned with the Emirates Mars Mission (EMM) science objective on the lower atmosphere, and with the science objective of correlating the lower and upper atmosphere [1,2]. First results of EMM dust storm research were reported in [3].

EMM has a high-altitude orbit and provides data products for studies of the Mars atmosphere and surface with a near-hemispheric view. Moreover, EMM can provide information on dust storm activity every few hours or less. EMM observed multiple dust storms during the primary mission, including a large regional dust storm in Sep. and Oct. 2022.

The focus of this presentation are unique dust storm observations by the EMM camera EXI [4]. We study a subset of dust storms, which is of particular interest to our research. The formation and growth of dust storms is followed at a (sub-)hourly time scale. This includes results on the dust storm morphology, wind direction, wind speed, surface dust lifting, etc.. Based on that, the implications for the physics and dynamics of dust storms are considered.

[1] Amiri, H.E.S., Brain, D., Sharaf, O. et al. The Emirates Mars Mission. Space Sci Rev 218, 4 (2022). https://doi.org/10.1007/s11214-021-00868-x

[2] Almatroushi, H., AlMazmi, H., AlMheiri, N. et al. Emirates Mars Mission Characterization of Mars Atmosphere Dynamics and Processes. Space Sci Rev 217, 89 (2021). https://doi.org/10.1007/s11214-021-00851-6

[3] Gebhardt, C., Guha, B. K., Young, R. M. B., & Wolff, M. J. (2022). A frontal dust storm in the northern hemisphere at solar longitude 97—An unusual observation by the Emirates Mars mission. Geophysical Research Letters, 49, e2022GL099528. https://doi.org/10.1029/2022GL099528

[4] Jones, A.R., Wolff, M., Alshamsi, M. et al. The Emirates Exploration Imager (EXI) Instrument on the Emirates Mars Mission (EMM) Hope Mission. Space Sci Rev 217, 81 (2021). https://doi.org/10.1007/s11214-021-00852-5

How to cite: Gebhardt, C., Guha, B. K., Young, R. M. B., Wolff, M. J., and Edwards, C. S.: The physics and dynamics of selected dust storms in the EMM primary mission, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-3053, https://doi.org/10.5194/egusphere-egu23-3053, 2023.

EGU23-3092 | Orals | PS4.4

The Spatial and Diurnal Distribution of Lower Atmospheric Dust as Revealed by the Emirates Mars Infrared Spectrometer 

Khalid Badri, Michael Smith, Christopher Edwards, Eman AlTunaiji, and Philip Christensen

The Emirates Mars Mission (EMM) is on its way to achieving 1 Martian year of Scientific Observations by the end of April 2023 to explore the dynamics of the Martian atmosphere on a global scale. The Emirates Mars Infrared Spectrometer (EMIRS) instrument onboard EMM, is an interferometric thermal infrared spectrometer designed to characterize the geographic, seasonal, and diurnal variability of key characteristics of Mars such as atmospheric dust, which will be the focus of this talk, and other constituents such as water ice optical depth, water vapor abundance, surface temperature, and atmospheric temperature profiles on sub-seasonal timescales.  

EMIRS observations provide full local solar time coverage at multiple emission angles providing data on these constituents over the entire Martian disk. Here, we present initial results of the spatial, seasonal and diurnal variation of dust on a global scale with particular attention to the diurnal variations of dust and the evolution of dust storms. Preliminary results show more diurnal variations during dust storm seasons. In addition, results on the biggest storm of the year will be presented which occurred after solar longitude of 300.  These new observations will continue to enhance our understanding of the dust cycle on Mars and how dust influences the current climate and atmospheric dynamics on Mars by relating the effect of dust to other EMIRS constituents mentioned above.

How to cite: Badri, K., Smith, M., Edwards, C., AlTunaiji, E., and Christensen, P.: The Spatial and Diurnal Distribution of Lower Atmospheric Dust as Revealed by the Emirates Mars Infrared Spectrometer, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-3092, https://doi.org/10.5194/egusphere-egu23-3092, 2023.

EGU23-3162 | Posters virtual | PS4.4

Production and radiative transfert of the OI 130.4 and 135.6 nm emissions in the Mars aurora 

Lauriane Soret, Jean-Claude Gérard, Benoît Hubert, and Sonal Jain

The presence of a weak oxygen emission at 130.4-nm resulting from the O 3P-3S transition was first detected in limb observations of the Martian aurora with SPICAM/Mars Express (Soret et al., 2016). It is mostly excited by direct impact of energetic electrons on ground-based O(3P) atoms, but the 130.4-nm radiation is affected by multiple scattering and absorption by CO2. In April 2021, the Emirates Mars Ultraviolet Spectrometer (EMUS) instrument (Holsclaw et al., 2021) on board the HOPE Emirates orbiter started collecting spectral images in the 110-180 nm range with a much increased sensitivity. The OI 135.6-nm emission corresponding to the 3P-5S forbidden transition has also been observed (Jain et al., 2022). In addition, EMUS is taking images of the discrete and sinuous aurora at 130.4 nm. We present Monte Carlo model simulations of the production of the O 3S and 5S excited states for different initial electron energies and discuss possible seasonal variations. We solve the radiative transfer equation for the 130.4-nm triplet and show that the I(130.4 nm/I(135.6 nm) nadir intensity ratio is expected to widely vary with the initial electron energy. These variations result from two effects:

  • The different shapes of the two emission cross sections since the optically thick 3P-3S resonance transition is permitted while 3P-5S is forbidden
  • the radiation entrapment of the 130.4 nm triplet by atmospheric atomic oxygen coupled with absorption by CO2.

We also discuss the sensitivity of the 130.4-nm nadir brightness to the energy distribution of the incoming auroral electrons.

 

References

Jain, S. et al. (2022), poster presented at AGU fall meeting.

Holsclaw, G. et al. (2021), Space Science Reviews217, 1-49.

Lillis, R. J. et al. (2022), Geophysical Research Letters49, e2022GL099820.

Soret, L. et al. (2016), Icarus264, 398-406.

How to cite: Soret, L., Gérard, J.-C., Hubert, B., and Jain, S.: Production and radiative transfert of the OI 130.4 and 135.6 nm emissions in the Mars aurora, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-3162, https://doi.org/10.5194/egusphere-egu23-3162, 2023.

EGU23-3198 | ECS | Orals | PS4.4

Diurnal Temperature Variations and Thermal Tides in the Martian Atmosphere Observed by EMIRS during EMM Primary Mission 

Siteng Fan, Francois Forget, Michael Smith, Sandrine Guerlet, Khalid Badri, Samuel Atwood, Roland Young, Christopher Edwards, Philip Christensen, Justin Deighan, Hessa Al Matroushi, Antoine Bierjon, Jiandong Liu, and Ehouarn Millour

We present results of diurnal temperature variations and thermal tides in the Martian atmosphere using observations obtained by the Emirates Mars InfraRed Spectrometer (EMIRS) onboard the Emirates Mars Mission (EMM) Hope probe during its primary mission. The novel orbit design of the spacecraft allows a full geography and local time to be covered every 10 Martian days, approximately ~5° of solar longitude (LS). Diurnal temperature variations are derived for the first time on a planetary scale without any significant gaps in local time or interference from seasonal changes. Contributions of thermal tides are then analyzed. The dataset of the EMM primary mission covers one Martian Year (MY) starting from MY 36 LS=49°. Seasonal changes of the diurnal temperature variations and thermal tides are investigated. The results show good agreements with predictions provided by the Mars Planetary Climate Model (PCM), but with noticeable differences in the phases and wavelengths of the thermal tides. This work provides valuable information on understanding the diurnal climate of Mars, and inspires future advances of Mars GCMs.

How to cite: Fan, S., Forget, F., Smith, M., Guerlet, S., Badri, K., Atwood, S., Young, R., Edwards, C., Christensen, P., Deighan, J., Al Matroushi, H., Bierjon, A., Liu, J., and Millour, E.: Diurnal Temperature Variations and Thermal Tides in the Martian Atmosphere Observed by EMIRS during EMM Primary Mission, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-3198, https://doi.org/10.5194/egusphere-egu23-3198, 2023.

EGU23-3932 | ECS | Posters virtual | PS4.4

Seasonal and Diurnal Variations of Orographic Clouds on Mars with EMM/EXI observations and the Mars Planetary Climate Model 

Anton Fernando, Mike Wolff, and Francois Forget

The formation of water ice clouds can significantly influence the Martian climate, although the Martian atmosphere contains low water vapor concentrations compared to terrestrial levels. The lower Martian atmosphere exhibits three global water ice cloud systems: Aphelion cloud belt (ACB), polar hoods (PHs), and orographic clouds. These clouds are associated with topography, solar heating, global atmospheric circulation, wave activity, and local convection. An appreciable amount of research has been conducted on the first two regimes (ACB and PHs) and very little attention has been given to the third regime (orographic clouds). In general, orographic clouds are observed in northern Spring and summer since they are associated with the major Martian volcanoes. Water ice optical depths provided by the Emirates Exploration Imager (EXI) of the Emirate Mars Mission (EMM) will be used to investigate seasonal and diurnal variations of such clouds in the Tharsis volcanic region: Ascraeus Mons, Pavonis Mons, Arsia Mons, and Olympus Mons. Additionally, context will be provided using the meteorological fields from the Mars PCM (Mars Planetary Climate Model led by Laboratoire de Meteorologie Dynamique Paris, France). This study provides a general picture of how Martian water ice clouds correlate with Mars PCM's meteorological variables: water ice optical depth, atmospheric temperature, meteorological winds, and water vapor mixing ratio. 

How to cite: Fernando, A., Wolff, M., and Forget, F.: Seasonal and Diurnal Variations of Orographic Clouds on Mars with EMM/EXI observations and the Mars Planetary Climate Model, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-3932, https://doi.org/10.5194/egusphere-egu23-3932, 2023.

EGU23-4712 | Posters on site | PS4.4

Seasonal Variation of the Martian Inner Hot Oxygen Exosphere Observed by EMM/EMUS 

Justin Deighan, Michael Chaffin, Krishnaprasad Chirakkil, Hessa Al Matroushi, Robert Lillis, Matthew Fillingim, Scott England, Sonal Jain, Greg Holsclaw, Fatma Lootah, Hoor Al Mazmi, Susarla Raghuram, Frank Eparvier, Ed Thiemann, Phil Chamberlin, and Shannon Curry

One of the primary objectives of the Emirates Mars Mission (EMM) is to study the seasonal variation of the upper atmosphere of Mars and associated changes in the escape of atmosphere to space. Here we present a preliminary analysis of the oxygen population in the inner exosphere (1.06-1.6 Martian radii) with nearly-contiguous sampling across all Martian seasons from early MY 36 to early MY 37. This oxygen is thought to be a non-thermal photochemically generated population driven by solar EUV, which can produce energetic atoms with sufficient velocity to escape Mars’ gravity. The observations are made by measuring the atomic oxygen emission at 130.4 nm using the Emirates Mars Ultraviolet Spectrometer (EMUS). We compare the brightness of the exospheric oxygen population with the thermospheric population ( < 1.06 Mars radii, or < 200 km) and find that the exosphere is much more responsive to seasonal variations in solar energy input. The seasonal variations cannot be explained by modulations in solar irradiance at 130.4 nm alone, and are consistent with the expectation that the extended oxygen exosphere at Mars is generated by a photochemical source.

How to cite: Deighan, J., Chaffin, M., Chirakkil, K., Al Matroushi, H., Lillis, R., Fillingim, M., England, S., Jain, S., Holsclaw, G., Lootah, F., Al Mazmi, H., Raghuram, S., Eparvier, F., Thiemann, E., Chamberlin, P., and Curry, S.: Seasonal Variation of the Martian Inner Hot Oxygen Exosphere Observed by EMM/EMUS, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-4712, https://doi.org/10.5194/egusphere-egu23-4712, 2023.

EGU23-4883 * | ECS | Orals | PS4.4 | Highlight

Emirates Mars Mission - Hope Probe - in a Martian Year 

Hessa Almatroushi, Justin Deighan, Greg Holsclaw, Christopher Edwards, and Michael Wolff and the EMM Science Team

In April 2023, the Emirates Mars Mission (EMM) completes its primary science mission observing the Martian atmosphere with global coverage examining the diurnal and seasonal variations throughout one full Martian year. The mission has disseminated publicly more than 1 TB of scientific data combined from three scientific instruments studying the atmosphere of Mars from ultraviolet, visible, and infrared bands. The measurements are taken from a highly elliptical orbit (20,000 km periapse and 43,000 km apoapse) providing unprecedented local and seasonal time coverage over most of the planet. Here we summarize the discoveries and key results from the primary science mission of EMM revealing atmospheric behavior and connections that challenge existing models and assumptions that we have of the Martian atmosphere and form new global perspective of the planet. We will also highlight the status of the mission and recent updates on its extended science phase.

How to cite: Almatroushi, H., Deighan, J., Holsclaw, G., Edwards, C., and Wolff, M. and the EMM Science Team: Emirates Mars Mission - Hope Probe - in a Martian Year, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-4883, https://doi.org/10.5194/egusphere-egu23-4883, 2023.

EGU23-5359 | ECS | Posters on site | PS4.4

Diurnal and seasonal variations of clouds in the Tharsis Montes region of Mars using the Emirates eXploration Imager (EXI) observations 

Maryam Yousuf, Mikki Osterloo, and Christopher Edwards

Observations of clouds on Mars have long been studied to understand activity and the Martian water cycle. The Martian volcanoes have been shown to have associated cloud formations such as the Aphelion Cloud Belt (ACB) (Wolff et al., 2022), Orographic Clouds (Benson et al., 2006), and Perihelion Cloud Trails (Clancy et al., 2021). Previous studies provide insights into how these clouds appear and contribute to the atmosphere. The objective of this study is to provide a catalog of the life cycle of clouds observed by Emirates eXploration Imager (EXI) spatially (longitude, latitude) and temporally (Solar Longitude (Ls), local time) using the following wavelength channels 635nm (red), 546nm (green), 437nm (blue) and 320nm (ultraviolet which can be used to retrieve the water ice optical depth). To undertake this study, we identified the volcanic region (Olympus Mons and Arsia Mons) as the study region due to cloud presence in the area throughout the Martian year.  EXI is a camera on board the Emirates Mars Mission (EMM) – Hope Probe. EXI acquires 12-megapixel images and has sufficient radiometric calibration for detailed scientific analysis (Jones et al., 2021). It was developed to better understand several critical constituents (e.g., dust, water ice clouds, etc) geographic and diurnal distribution in the lower atmosphere (Jones et al., 2021). We will present the results of our database for clouds for Mars year 36.

 

Benson, J., James, P., Cantor, B., & Remigio, R. (2006). Interannual variability of water ice clouds over major martian volcanoes observed by MOC. Icarus, 184(2), 365–371. https://doi.org/10.1016/j.icarus.2006.03.014

Clancy, R. T., Wolff, M. J., Heavens, N. G., James, P. B., Lee, S. W., Sandor, B. J., Cantor, B. A., Malin, M. C., Tyler, D., & Spiga, A. (2021). Mars perihelion cloud trails as revealed by MARCI: Mesoscale topographically focused updrafts and gravity wave forcing of high altitude clouds. Icarus, 362, 114411. https://doi.org/10.1016/j.icarus.2021.114411

Jones, A. R., Wolff, M., Alshamsi, M., Osterloo, M., Bay, P., Brennan, N., Bryant, K., Castleman, Z., Curtin, A., DeVito, E., Drake, V. A., Ebuen, D., Espejo, J., Farren, J., Fenton, B., Fisher, C., Fisher, M., Fortier, K., Gerwig, S., . . . Yaptengco, J. L. (2021). The Emirates Exploration Imager (EXI) Instrument on the Emirates Mars Mission (EMM) Hope Mission. Space Science Reviews, 217(8). https://doi.org/10.1007/s11214-021-00852-5

Wolff, M. J., Fernando, A., Smith, M. D., Forget, F., Millour, E., Atwood, S. A., Jones, A. R., Osterloo, M. M., Shuping, R., Al Shamsi, M., Jeppesen, C., & Fisher, C. (2022). Diurnal Variations in the Aphelion Cloud Belt as Observed by the Emirates Exploration Imager (EXI). Geophysical Research Letters, 49(18). https://doi.org/10.1029/2022gl100477

How to cite: Yousuf, M., Osterloo, M., and Edwards, C.: Diurnal and seasonal variations of clouds in the Tharsis Montes region of Mars using the Emirates eXploration Imager (EXI) observations, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-5359, https://doi.org/10.5194/egusphere-egu23-5359, 2023.

EGU23-8470 | Orals | PS4.4

Sinuous Aurora at Mars: exploring a new phenomenon with data and models 

Robert Lillis, Abigail Azari, Yingjuan Ma, Krishnaprasad Chirakkil, Justin Deighan, Michael Chaffin, Sonal Jain, Gregory Holsclaw, David Brain, Hessa Al Matroushi, Scott England, Nick Schneider, Shaosui Xu, Hoor Al Mazmi, Jasper Halekas, Robin Ramstad, Jared Espley, Jacob Gruesbeck, and Shannon Curry

Benefiting from a large orbit and high sensitivity, the Emirates Mars mission EMUS instrument has provided the first opportunity to regularly image Mars’ discrete FUV aurora synoptically.  EMUS has collected nearly 1000 synoptic observations of the Mars nightside have revealed at least three distinct types of discrete Aurora: 1) crustal field aurora, appearing in regions of mostly radial crustal magnetic fields, 2) patchy discrete aurora, observed away from strong crustal fields, and 3) sinuous discrete aurora, extending from the terminator typically thousands of kilometers onto the nightside, away from crustal fields.

Sinuous Discrete Aurora (SDA) is observed in approximately 5% of observations and is characterized by 2 primary attributes: morphology and the local time of its intersection with the terminator. Morphologies include serpentine, approximately linear, and short/lumpy. Dusk-side SDA does not occur preferentially for any particular interplanetary magnetic field (IMF) orientation, while Dawn and Midnight SDA appear to show a preference for northeastward IMF directions measured in situ by the MAVEN spacecraft. Dusk SDA observed about twice as often as Dawn or Midnight SDA. 

SDA reflect conditions whereby particular magnetic topologies connect the nightside atmosphere to a source of abundant electrons, whether dayside photoelectrons or sufficiently energetic magnetotail/sheath electrons.  In particular, midnight sinuous discrete aurora appear to be a projection of the tail current sheet, a persistent but highly variable feature of Mars’ double-lobed magnetotail resulting from the draping of the IMF around the conducting obstacle of Mars’ dayside ionosphere.  This interpretation is supported by magnetohydrodynamic (MHD) simulations, showing that the orientation of the tail current sheet approximately matches the orientation of midnight SDA.

EMM EMUS promises to be an invaluable tool in helping to understand the drivers of Martian Aurora.

How to cite: Lillis, R., Azari, A., Ma, Y., Chirakkil, K., Deighan, J., Chaffin, M., Jain, S., Holsclaw, G., Brain, D., Al Matroushi, H., England, S., Schneider, N., Xu, S., Al Mazmi, H., Halekas, J., Ramstad, R., Espley, J., Gruesbeck, J., and Curry, S.: Sinuous Aurora at Mars: exploring a new phenomenon with data and models, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-8470, https://doi.org/10.5194/egusphere-egu23-8470, 2023.

EGU23-8656 | Posters on site | PS4.4

Dayside auroral emission induced by proton deposition observed by EMM EMUS 

J. Scott Evans, Michael Chaffin, Justin Deighan, Sonal Jain, John Correira, Emmaris Soto, Hessa Al Matroushi, Hoor Al Mazmi, Scott England, Matthew Fillingim, Greg Holsclaw, Rob Lillis, and Fatma Lootah and the MAVEN Team Members

The Emirates Mars Ultraviolet Spectrometer (EMUS) onboard the Emirates Mars Mission (EMM) observes the Martian dayglow at ultraviolet wavelengths (100-170 nm). EMUS disk observations show unexpected variations in atomic hydrogen, atomic oxygen, and carbon monoxide disk emissions. These variations display local time and hemispheric asymmetry and are observed in approximately 25% of the disk images. England et al. (2022; doi:10.1029/2022GL099611) suggested that the spatial structure, occurrence, and spectral characteristics of these variations are associated with changes in composition and photoelectron flux. Using a similar EMUS data set, Chaffin et al. (2022; doi:10.1029/2022GL099881) reported the first observations of neutral atmosphere auroral emission on the Martian dayside, which is not a new type of aurora but another observable form of proton aurora, and suggested that solar wind deposition is responsible for exciting the auroral emission. We further investigate these two potential drivers of the unexpected variations in EMUS disk observations using data from the Imaging Ultraviolet Spectrograph (IUVS), the Solar Wind Ion Analyzer (SWIA), the SupraThermal And Thermal Ion Composition (STATIC) instrument, and a magnetometer (MAG), all onboard NASA’s Mars Atmosphere and Volatile EvolutioN (MAVEN) mission. We use vertical profiles of densities and temperatures retrieved from limb scan observations by IUVS to identify signatures of dynamics that correlate with unexpected variations in EMUS disk observations. We use measurements from all of the instruments to categorize and characterize EMUS observations in order to determine how changes in composition and solar wind deposition produce unexpected variations in the Martian ultraviolet dayglow.

How to cite: Evans, J. S., Chaffin, M., Deighan, J., Jain, S., Correira, J., Soto, E., Al Matroushi, H., Al Mazmi, H., England, S., Fillingim, M., Holsclaw, G., Lillis, R., and Lootah, F. and the MAVEN Team Members: Dayside auroral emission induced by proton deposition observed by EMM EMUS, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-8656, https://doi.org/10.5194/egusphere-egu23-8656, 2023.

EGU23-9200 | Orals | PS4.4

Hydrogen Escape Rates 2021-2023 Retrieved from Emirates Mars Mission Observations 

Michael Chaffin, Justin Deighan, Sonal Jain, Greg Holsclaw, Raghuram Susarla, Hoor AlMazmi, Krishnaprasad Chirakkil, John Correira, Scott England, Frank Eparvier, J. Scott Evans, Matt Fillingim, Rob Lillis, Fatma Lootah, Ed Thiemann, Shannon Curry, and Hessa AlMatroushi

The surface of the planet Mars exhibits a record of dessiccation and oxidation, the legacy of significant water escape to space as hydrogen and oxygen. This H escape can be constrained using ultraviolet observations of the planet's upper atmosphere, where neutral atomic hydrogen scatters UV sunlight. In the time since its orbit insertion in early 2021, the Emirates Mars Ultraviolet Spectrometer (EMUS) on the Emirates Mars Mission (EMM) has been observing this hydrogen at 102.6 nm and 121.6 nm, H Lyman beta and Lyman alpha. Here we present H escape rates retrieved from these observations, obtained using a 3D radiative transfer model that simulates the brightness of both spectral lines, combining their information content to constrain the atmospheric state. In agreement with past results, we find that H escape peaks around Southern Summer solstice, after perihelion, exhibiting a more than 10x increase relative to Northern Summer conditions. Importantly, our retrievals extract information about both the hydrogen density and temperature, and do not require independent assumptions about the upper atmosphere temperature. We will discuss prospects for extending these retrievals beyond the current EMM dataset as well as implications for the long-term evolution of the Mars atmosphere.

How to cite: Chaffin, M., Deighan, J., Jain, S., Holsclaw, G., Susarla, R., AlMazmi, H., Chirakkil, K., Correira, J., England, S., Eparvier, F., Evans, J. S., Fillingim, M., Lillis, R., Lootah, F., Thiemann, E., Curry, S., and AlMatroushi, H.: Hydrogen Escape Rates 2021-2023 Retrieved from Emirates Mars Mission Observations, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-9200, https://doi.org/10.5194/egusphere-egu23-9200, 2023.

EGU23-9313 | Posters on site | PS4.4

First observations of Deimos from the Emirates eXploration Imager (EXI) 

Mikki Osterloo, Christopher Edwards, Charles Fisher, Chris Jeppesen, Michael Wolff, Andrew Jones, Justin Knavel, Emily Pilinski, Christopher Tomso, Ralph Shuping, Justin Deighan, and Hessa Al Matroushi

The Emirates Mars Mission (EMM) has a unique opportunity to observe the surface of Deimos, the smaller and outermost of the two moons of Mars. The origins of both Phobos and Deimos remain debated largely due to lack of available observations. The elliptical orbit of the EMM spacecraft, designed to provide comprehensive coverage of the martian atmosphere, allows for campaigns to periodically observe the moon. The slight adjustment of the orbit to move into a resonance with Deimos permits nominal science to continue. The campaign began in August of 2022 by undertaking a series of maneuvers to enable several flybys each stepping in and progressively attaining a closer distance to Deimos. Here, we will present the images collected by EXI of the targeted flyby (e.g., the flyby wherein the spacecraft achieves its closest distance to the moon). Observations for each flyby will include an initial image set at the start of the approach (red/green/blue/320 nm/260 nm), red images will be acquired at 1 min intervals during the approach, and when the spacecraft is at the closest point to Deimos a red/green/blue image set at full resolution, as well as a 320 nm image binned at 2×2 pixels, will be acquired. As the spacecraft leaves Deimos, the reverse observation strategy will be employed. These observations will help constrain the short-wavelength spectral properties and further characterize the geomorphology of this relatively understudied martian moon.

How to cite: Osterloo, M., Edwards, C., Fisher, C., Jeppesen, C., Wolff, M., Jones, A., Knavel, J., Pilinski, E., Tomso, C., Shuping, R., Deighan, J., and Al Matroushi, H.: First observations of Deimos from the Emirates eXploration Imager (EXI), EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-9313, https://doi.org/10.5194/egusphere-egu23-9313, 2023.

EGU23-9770 | ECS | Orals | PS4.4

Diurnal and Seasonal Mapping of Martian Ices with EMM/EMIRS 

Aurélien Stcherbinine, Christopher Edwards, Michael Wolff, Eman Altunaiji, Christopher Haberle, Michael Smith, and Philip Christensen

Condensation and sublimation of ices at the surface of the planet is a key part of both the Martian H2O and CO2 cycles, either from a seasonal or diurnal aspect. If most of the ices are located within the polar caps, surface frost is known to be formed during nighttime down to equatorial latitudes. The Emirate Mars InfraRed Spectrometer (EMIRS) instrument onboard the Emirates Mars Mission (EMM) "Hope" probe is a Fourier Transform Infrared spectrometer that is observing the Martian surface and atmosphere between 6 and 100 μm from February 2022. The unique orbit of EMM allows EMIRS to observe the entire Martian disk at each observation, covering all the surface of the planet across all local times in ~ 4 orbits, which corresponds to ~ 5° of Ls.

Here we use the surface temperature data retrieved from the EMIRS spectra (Smith et al. 2022) to detect and map the ice at the surface of the Red Planet. We compute the amplitude of the diurnal temperature variations to derive maps of the presence of ices (either H2O or CO2) at the surface of the planet over the day, which allows us to monitor the seasonal evolution of the polar caps. And, based on the methodology used in Piqueux et al. (2016), we also compute for each EMIRS pixel the corresponding freezing temperature of CO2, according to Clapeyron’s law, and we consider that CO2 ice is present at the surface if the retrieved temperature is below TCO2, ice. This allows us to monitor the timing of the formation and disappearance of the surface CO2 frost under midlatitudes over the Martian night, and its seasonal evolution.

How to cite: Stcherbinine, A., Edwards, C., Wolff, M., Altunaiji, E., Haberle, C., Smith, M., and Christensen, P.: Diurnal and Seasonal Mapping of Martian Ices with EMM/EMIRS, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-9770, https://doi.org/10.5194/egusphere-egu23-9770, 2023.

EGU23-9807 | Orals | PS4.4

The First Observations of Deimos from the Emirates Mars Mission (EMM) Flybys 

Christopher Edwards, Mikki Osterloo, Charles Fisher, Chris Jeppesen, Nathan Smith, Greg Holsclaw, Michael Wolff, Andrew Jonees, Justin Knavel, Emily Pilinski, Daniel Kubitschek, Thibaud Teil, Justin Deighan, Hessa Al Matroushi, Jeff Parker, Philip Christensen, Saadat Anwar, Heather Reed, Pete Withnell, and Omran Sharaf

The origins of the martian moons Phobos and Deimos remain enigmatic. Over the past decades a range of spacecraft have observed Phobos and Deimos in order to constrain their origin and evolutionary history, with proposals for their origins ranging from captured asteroids, to coalesced material from a giant impact on Mars. However, given the orbits these spacecraft and the orbits of Phobos and Deimos, Phobos has garnered the majority of the attention. Now thanks to the unique orbit of the Emirates Mars Mission (EMM) Hope spacecraft and a minor correction to its nominal science orbit, EMM has a unique opportunity to examine Deimos in great detail while fully retaining the originally designed mission to capture the variability in the martian atmosphere and exosphere.

Following a minor orbital adjustment maneuver campaign beginning in August 2022, EMM will encounter Deimos multiple times, progressively observing the martian moon at lower and lower distances beginning in early 2023. These flybys culminate in the closest approach of ~150 km, observing the mostly illuminated, far side of Deimos. All three EMM instruments, the Emirates eXploration Imager (EXI), the Emirates Mars Infrared Spectrometer (EMIRS), and the Emirates Ultraviolet Spectrometer (EMUS) have observation sequences tailored to these flybys, collecting the highest resolution multispectral visible imaging data, thermal infrared surface temperatures and emission spectra, and ultraviolet spectra.  When combined these instrument observations will provide key insights into the composition, morphology, and surface physical properties of the least studied martian moon, Deimos.

How to cite: Edwards, C., Osterloo, M., Fisher, C., Jeppesen, C., Smith, N., Holsclaw, G., Wolff, M., Jonees, A., Knavel, J., Pilinski, E., Kubitschek, D., Teil, T., Deighan, J., Al Matroushi, H., Parker, J., Christensen, P., Anwar, S., Reed, H., Withnell, P., and Sharaf, O.: The First Observations of Deimos from the Emirates Mars Mission (EMM) Flybys, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-9807, https://doi.org/10.5194/egusphere-egu23-9807, 2023.

EGU23-10186 | Posters on site | PS4.4

The First Observations of Deimos by the Emirates Mars Ultraviolet Spectrometer (EMUS) 

Gregory Holsclaw, Justin Deighan, Michael Chaffin, Hessa Al Matroushi, Robert Lillis, Matthew Fillingim, Scott England, Sonal Jain, Fatma Lootah, Hoor Al Mazmi, Gabriel Bershenyi, Emily Pilinski, Thibaud Teil, Jeff Parker, and Omran Sharaf

The Emirates Mars Mission (EMM) Hope probe launched on 20 Jul 2020 and entered Mars orbit on 9 Feb 2021, carrying a payload of 3 complementary instruments to characterize the global atmosphere across the full range of altitudes (surface to exosphere) at diurnal and seasonal timescales.  The unique, high-altitude orbit of the Hope probe (19,970 km periapse, 42,650 km apoapse altitude, 25 deg inclination, 54.5-hour period) that enables its synoptic view of the red planet also brings the spacecraft across the orbit of Mars’ outermost moon, Deimos.  The Hope trajectory was slightly modified by two maneuvers in Aug 2022 and Jan 2023 that will allow the surface of Deimos to be observed in a series of flybys in Feb-Mar 2023.  Here we present preliminary results from the Emirates Mars Ultraviolet Spectrometer (EMUS), an imaging spectrograph with a wavelength range of 100-170 nm and a field of view of 10.75 x 0.18 deg (using the high-resolution slit position).  We will derive the absolute reflectance of the surface, search for any compositionally distinct spectral features (e.g. carbon, polycyclic aromatic hydrocarbons, water ice), and examine any spatial heterogeneity across the surface.

How to cite: Holsclaw, G., Deighan, J., Chaffin, M., Al Matroushi, H., Lillis, R., Fillingim, M., England, S., Jain, S., Lootah, F., Al Mazmi, H., Bershenyi, G., Pilinski, E., Teil, T., Parker, J., and Sharaf, O.: The First Observations of Deimos by the Emirates Mars Ultraviolet Spectrometer (EMUS), EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-10186, https://doi.org/10.5194/egusphere-egu23-10186, 2023.

EGU23-10291 | ECS | Posters on site | PS4.4

The Observations of Deimos from the Emirates Mars Infrared Spectrometer (EMIRS) 

Nathan Smith, Christopher Edwards, Mikki Osterloo, Philip Christensen, Saadat Anwar, Emily Pilinski, Paul Wren, Dale Noss, Ken Rios, Scott Dickenshied, Hessa Al Matroushi, Justin Deighan, Jeffrey Parker, and Omran Sharaf

We present the initial views of the surface of Mars’ outer moon Deimos as observed by the Emirates Mars InfraRed Spectrometer (EMIRS), a Fourier transform infrared spectrometer observing from 6-50 µm with a spectral sampling of up to 5 cm-1. The primary science goal of the Emirates Mars Mission (EMM) is to study the variability in Mars’ atmosphere. As part of a coordinated campaign, the EMM spacecraft has adjusted its orbit into a resonance with Deimos, where it will periodically fly by the moon. Beginning the spring of 2023, EMIRS will collect numerous thermal infrared spectra of Deimos’ surface with a spatial resolution ranging from ~1-10 km. These observations will be the best-resolved infrared views of Deimos to date. Our planned observations achieve nearly complete global coverage of the surface, and span a range of local solar times, enabling investigations of both compositional and thermophysical properties. We will discuss these observations and initial findings. 

How to cite: Smith, N., Edwards, C., Osterloo, M., Christensen, P., Anwar, S., Pilinski, E., Wren, P., Noss, D., Rios, K., Dickenshied, S., Al Matroushi, H., Deighan, J., Parker, J., and Sharaf, O.: The Observations of Deimos from the Emirates Mars Infrared Spectrometer (EMIRS), EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-10291, https://doi.org/10.5194/egusphere-egu23-10291, 2023.

EGU23-10341 | Posters on site | PS4.4

Reconstructing Martian Year 36 column dust optical depth maps using EMM/EMIRS and MRO/MCS 

Luca Montabone, Armin Kleinboehl, Michael Smith, Christopher Edwards, François Forget, David Kass, Ehouarn Millour, and Aurélien Stcherbinine

Montabone et al., 2015 and 2020, [1, 2] have developed an iterative, weighted, running mean methodology to grid the available retrievals of atmospheric column dust optical depth (CDOD) from multi-annual and multi-instrument spacecraft observations at Mars. The application of this methodology has produced daily gridded maps of CDOD from Martian Year (MY) 24 through 35, using Mars Global Surveyor/Thermal Emission Spectrometer and Mars Odyssey/Thermal Emission Imaging System nadir observations, as well as the estimates of this quantity from Mars Reconnaissance Orbiter/Mars Climate sounder (MRO/MCS) limb observations. Given the lack of dust observations at certain times and locations, the daily gridded maps have missing values at some grid points. Kriging spatial interpolation has been used to produce regular maps that are useful as multiannual dust scenarios for model simulations, and for the Mars Climate Database (MCD) statistics [3].

We have now adapted this methodology to include CDOD retrievals from Emirates Mars Mission/Emirates Mars Infrared Spectrometer (EMM/EMIRS) nadir observations in MY 36 [4]. The specificity of EMIRS spatial and temporal coverage as well as the extended nature of its footprint are taken into account when carrying out the gridding. We will present a cross-comparison of maps obtained using only EMIRS retrievals and maps obtained using only MCS retrievals, in the attempt to understand what is the best approach to produce a MY 36 dust scenario that makes the best use of both instruments. We will particularly focus on the evolution of large-scale dust storms in MY 36.

References: [1] Montabone, L., et al. (2015) Icarus 251, pp. 65-95, doi: 10.1016/j.icarus.2014.12.034 ; [2] Montabone, L., et al. (2020) J. Geophys. Res. - Planets, doi: 10.1029/2019JE006111 ; [3] http://www-mars.lmd.jussieu.fr (Publicly available dust gridded maps can be currently found up to MY 35 by clicking on the “climatologies of Martian atmospheric dust” link under “Martian dust Climatology”) ; [4] Smith, M.D., et al. (2022) Geophys. Res. Lett. 49, Issue 15, doi: 10.1029/2022GL099636

How to cite: Montabone, L., Kleinboehl, A., Smith, M., Edwards, C., Forget, F., Kass, D., Millour, E., and Stcherbinine, A.: Reconstructing Martian Year 36 column dust optical depth maps using EMM/EMIRS and MRO/MCS, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-10341, https://doi.org/10.5194/egusphere-egu23-10341, 2023.

EGU23-10598 | Orals | PS4.4

The first EMM/EMUS stellar occultation measurements of the Martian atmosphere in both extreme and far ultraviolet wavelengths 

Sonal Jain, Justin Deighan, Michale Chaffin, Greg Holsclaw, Rob Lillis, Matthew Fillingim, Scott England, Hoor Al Mazmi, Fatma Lootah, Roger Yelle, Sumedha Gupta, Nick Schneider, and Hessa Al Matroushi
The major scientific objective of the Emirates Mars Mission (EMM) is to explore the global atmospheric dynamics of the Martian atmosphere both in short term (diurnal) and long term (seasonal). The Emirates Mars Ultraviolet Spectrometer (EMUS) instrument on board the EMM makes two-dimensional images ( in extreme and far ultraviolet wavelengths: 90-170 nm) of the Martian disk and exosphere to characterize the neutral densities in the thermosphere and exosphere of Mars. In this paper, we will present the first results from the stellar occultation measurements made by the EMUS instruments in October 2022. These occultation observations were not part of the original science planning and were added as a bonus EMM science. A total of seven stellar occultations were performed during the two EMM orbits spanning between 24 to 27 October. These measurements were the first stellar occultation of Mars in the EUV wavelengths (90-110 nm). Due to the higher sensitivity of the EMUS instrument, the occultation measurements were able to probe the atmosphere with an altitude sampling of 2 km or lower. The occultation measurements by SPICAM/MEx and IUVS/MAVEN were limited to 160 km due to wavelengths limited to a longward of 110 nm.  However, the use of EUV wavelengths in the EMUS stellar occultation provided atmospheric probing up to 190 km thus enabling neutral density retrieval up to the exobase region of Mars. The CO2 densities are retrieved from 90-185 km and the temperature profiles were retrieved using the constraint of hydrostatic equilibrium to the CO2 densities. We shall discuss results from the EMUS occultation campaign specifically the observed variability in the CO2 density and temperature during the occultation campaign.

How to cite: Jain, S., Deighan, J., Chaffin, M., Holsclaw, G., Lillis, R., Fillingim, M., England, S., Al Mazmi, H., Lootah, F., Yelle, R., Gupta, S., Schneider, N., and Al Matroushi, H.: The first EMM/EMUS stellar occultation measurements of the Martian atmosphere in both extreme and far ultraviolet wavelengths, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-10598, https://doi.org/10.5194/egusphere-egu23-10598, 2023.

EGU23-10766 | ECS | Posters on site | PS4.4

Automated Detection of Limb Clouds and Hazes by the Emirates Mars Mission (EMM) Emirates eXploration Imager (EXI) 

Michael Rothman, Alia Almansoori, David Brain, and Michael Wolff

The Emirates Mars Mission (EMM) has returned an abundance of whole disk images of Mars at visible wavelengths. Clouds and hazes are evident at the limb of the planet in many of these images, offering an opportunity to determine the vertical distribution of clouds on Mars over the course of a Martian year. However, there are challenges in determining the height of limb clouds due to uncertainty in the location of the Martian surface in the images. This uncertainty comes primarily from small uncertainties in the pointing of the instrument, coupled with the fact that the surface can be difficult to identify in the images due to the opacity of the atmosphere at low altitudes. With a typical pixel spanning roughly 5 km on the limb, the uncertainties in cloud height can be large.

 

Here we present an algorithm for automatically detecting limb clouds and hazes in Emirates eXploration Imager (EXI) observations, while simultaneously detecting the location of the surface. The algorithm considers straight line ‘transects’ through the images that extend from space to the disk of the planet. The inflection point in the recorded intensity along the transect (i.e. from ‘space’ where the intensity is small, to ‘Mars’ where the intensity is large) is used to determine the location of the surface. The transect is also used to infer the presence of detached clouds, as well as surface hazes. The heights and thicknesses of clouds and hazes can be extracted from the transects. We will present the algorithm, as well as a comparison of how the results of the algorithm compare to manual analysis of EXI images. We will highlight where the algorithm does well and where it has difficulty, and how the algorithm might be used to analyze other planetary datasets.

How to cite: Rothman, M., Almansoori, A., Brain, D., and Wolff, M.: Automated Detection of Limb Clouds and Hazes by the Emirates Mars Mission (EMM) Emirates eXploration Imager (EXI), EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-10766, https://doi.org/10.5194/egusphere-egu23-10766, 2023.

EGU23-11074 | Orals | PS4.4

Surface temperature of Mars: Exploring diurnal and seasonal variations with the Emirates Mars Mission 

Dimitra Atri, Nour Abdelmoneim, Dattaraj Dhuri, and Mathilde Simoni
The ~55 hour orbit of the Emirates Mars Mission (EMM) or the “Hope'" orbiter enables it to achieve a near-global coverage of the planet every 4 orbits, or ~9 sols. The Emirates Mars Infrared Spectrometer (EMIRS) instrument on board EMM is used to retrieve surface temperatures. We study the geographical and temporal variation of surface temperature on diurnal and seasonal timescales. We compare these measurements with NASA’s rover measurements —  from the Rover Environmental Monitoring Station (REMS) suite on board the Mars Science Laboratory (MSL) "Curiosity" rover, and the Mars Environmental Dynamics Analyzer (MEDA) suite on board the Mars 2020 "Perseverance” rover. We also compare these measurements with the Mars Climate Database (MCD), identify anomalies in surface temperature and discuss the role of thermal inertia. We discuss other implications of these findings leading to a better understanding of temperature variation on Mars and its impact on weather and climate.  

 

How to cite: Atri, D., Abdelmoneim, N., Dhuri, D., and Simoni, M.: Surface temperature of Mars: Exploring diurnal and seasonal variations with the Emirates Mars Mission, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-11074, https://doi.org/10.5194/egusphere-egu23-11074, 2023.

EGU23-11146 | ECS | Posters on site | PS4.4

Expanding the Emirates Mars Infrared Spectrometer (EMIRS) Science Dataset using EMIRS off-axis detectors 

George H. Cann, Roland M. B. Young, Christopher S. Edwards, Michael D. Smith, and Michael J. Wolff

Keywords: Mars, Atmosphere, EMM, Emirates Mars Infrared Spectrometer, Off-axis Detectors.

Introduction: The Emirates Mars Mission (EMM) Emirates Mars InfraRed Spectrometer (EMIRS) instrument is a Fourier Transform Infrared (FTIR) spectrometer designed to observe the Martian disk, with the primary scientific objective of determining the three-dimensional thermal state of the lower atmosphere and its diurnal variability on sub-seasonal timescales [1].

EMIRS uses a 3x3 array of deuterated L-alanine doped triglycine sulfate (DLaTGS) pyroelectric detectors [1], however, following the integration of the EMIRS electronics with the optical and mechanical hardware it was observed that the performance of the off-axis (non-central) detectors of the array were lower than expected [1]. Investigations into the performance of these off-axis detectors has so far yielded inconclusive root causes. As EMIRS could meet its primary science objective with the on-axis (central) detector and was subject to a pressing instrument schedule, a project level decision was made to forgo any additional investigation and instead rely on the on-axis detector [1][2].

Method: In this study we present a comparison of observations captured by EMIRS from the off-axis detectors against the on-axis detector. The comparison is performed via a top-down and bottom-up pathway approach using the EMM Science Team processing pipeline. The top-down pathway focuses on the effects of the pre-processing steps on the detector interferograms, whereas the bottom-up approach compares calibrated radiances derived from the pipeline with and without applying the pre-processing steps [3] [4]. Correction of these issues will expand the retrieval derived products by a factor of five.

Results: The top-down comparison shows differences in terms interferogram amplitude and phase error between on and off-axis detectors. We assess the feasibility of correction, then apply correction methods to a subset of EMIRS observations, and propose the root cause of the issues. This study is presented along with the generation of a joint dataset of near-mutual EMIRS and EXI (Emirates eXploration Imager) observations [5].

Acknowledgements: The authors would like to acknowledge support by a Joint Research Agreement between the Mohammed Bin Rashid Space Centre (MBRSC) and the National Space Science and Technology Center (NSSTC), UAE University (UAEU).

References:

[1] Edwards, C. S., et al. (2021). Space Science Reviews (2021) 217:77.

[2] Amiri, H.E. S., et al. (2022). Space Science Reviews (2022) 218:4.

[3] Forman, M. L., et al. (1966). J. Opt. Soc. Am. 56(1), 59–63.

[4] Christensen, V.E., et al. (2018). Space Science Reviews (2018), 215:87.

[5] Jones, A. R., et al. (2021). Space Science Reviews (2021) 217:81.

How to cite: Cann, G. H., Young, R. M. B., Edwards, C. S., Smith, M. D., and Wolff, M. J.: Expanding the Emirates Mars Infrared Spectrometer (EMIRS) Science Dataset using EMIRS off-axis detectors, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-11146, https://doi.org/10.5194/egusphere-egu23-11146, 2023.

EGU23-11360 | ECS | Posters on site | PS4.4

Seasonal and Local Time Dependence of Martian FUV Discrete Aurora Observed by EMM EMUS 

Krishnaprasad Chirakkil, Robert Lillis, Justin Deighan, Michael Chaffin, Sonal Jain, David Brain, Matthew Fillingim, Susarla Raghuram, Scott Evans, Gregory Holsclaw, Hessa Al Matroushi, Scott England, Hoor Al Mazmi, Robin Ramstad, Jasper Halekas, Jared Espley, Shaosui Xu, Xiaohua Fang, Nick Schneider, and Shannon Curry

Discrete aurorae are produced by charged particle precipitation (mostly electrons) into the upper atmosphere. Electron impact causes electronic excitations of atoms and molecules in the atmosphere, whose deexcitation releases ultraviolet photons. Discrete aurora was first discovered as an ultraviolet glow coming from “magnetic umbrellas” in the southern hemisphere. These are strong crustal magnetic field regions on Mars, which are remnants of a global field that decayed billions of years ago. Both Mars Express (Bertaux et al., 2005) and MAVEN (Schneider et al., 2021) have observed cases of discrete aurora events using their limb viewing observations. Emirates Mars Mission (EMM) provides the first synoptic (or disk) images of discrete aurora at Mars (Lillis et al., 2022), thanks to its large orbit and high sensitivity UV spectrograph.

Using observations from Emirates Mars Ultraviolet Spectrometer (EMUS) onboard EMM, the geographic, local time and seasonal distributions of FUV discrete aurora in oxygen auroral emissions (130.4 nm and 135.6 nm) are investigated. Interesting local time asymmetry is observed in the aurora occurrence rates, brightnesses and emission line ratios. More aurora occurrence is observed during pre-midnight (dusk) as compared to post-midnight (dawn). Strong radial crustal field regions (SCFR) have aurora mostly during dusk, and not during dawn. Aurora also tend to occur more in open magnetic field regions away from SCFR. Brighter aurora is observed in the southern hemisphere during dusk, while in the northern hemisphere during dawn. Low brightness ratio [O I 130.4 nm/O I 135.6 nm] is observed in SCFR, but higher ratio in regions away from SCFR in the southern hemisphere. Also, the occurrence rate is found to be enhanced during the perihelion season as compared to the aphelion season. Statistical analysis of the dependence of discrete aurora on observation geometry, upstream solar wind and interplanetary magnetic field conditions will also be presented.

References:

[1] Bertaux, JL., Leblanc, F., Witasse, O. et al. (2005). Discovery of an aurora on Mars. Nature, 435, 790–794, https://doi.org/10.1038/nature03603.

[2] Schneider, N. M., Milby, Z., Jain, S. K., Gérard, J.-C., Soret, L., Brain, D. A., et al. (2021). Discrete aurora on Mars: Insights into their distribution and activity from MAVEN/IUVS observations. Journal of Geophysical Research: Space Physics, 126, https://doi.org/10.1029/2021JA029428.

[3] Lillis, R. J., Deighan, J., Brain, D., Fillingim, M., Jain, S., Chaffin, M., et al. (2022). First synoptic images of FUV discrete aurora and discovery of sinuous aurora at Mars by EMM EMUS. Geophysical Research Letters, 49, https://doi.org/10.1029/2022GL099820.

How to cite: Chirakkil, K., Lillis, R., Deighan, J., Chaffin, M., Jain, S., Brain, D., Fillingim, M., Raghuram, S., Evans, S., Holsclaw, G., Al Matroushi, H., England, S., Al Mazmi, H., Ramstad, R., Halekas, J., Espley, J., Xu, S., Fang, X., Schneider, N., and Curry, S.: Seasonal and Local Time Dependence of Martian FUV Discrete Aurora Observed by EMM EMUS, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-11360, https://doi.org/10.5194/egusphere-egu23-11360, 2023.

EGU23-13029 | ECS | Posters on site | PS4.4

Comprehensive statistical analyses and data-driven modeling of electron and proton auroras on Mars using EMM and MAVEN observations 

Dattaraj Dhuri, Mathilde Simoni, Dimitra Atri, and Ahmed Alhantoobi

Auroras are an important probe for characterizing the interaction of solar wind with the induced magnetosphere of Mars and understanding the evolution of Mars’s atmosphere. Since their first discovery in 2005, Mars auroras have been studied extensively, particularly using the observations from NASA’s Mars Atmosphere and Volatile Evolution (MAVEN). Electron auroras with discrete and diffuse morphology are observed on the nightside of Mars whereas proton auroras are observed mainly on the dayside of Mars. Recently the Emirates Mars UV Spectrometer (EMUS) onboard the Emirates Mars Mission (EMM) has discovered new morphologies of sinuous electron auroras and patchy proton auroras on Mars. In this work, we perform comprehensive statistical analyses of aurora observations to understand the processes responsible for the varied auroral activity on Mars. We systematically isolate electron aurora regions from the nightside EMUS observations and characterize their occurrences and emissions with respect to the crustal magnetic fields, IMF, and electron energies measured by MAVEN. We also develop a purely data-driven model of proton auroras on Mars using MAVEN in-situ observations and UV limb scans between 2014-2022 to train an artificial neural network (ANN). We show that the ANN faithfully reconstructs the observed proton aurora limb scans profiles. We use the trained ANN to analyze the influence of Mars’ crustal magnetic field and IMF on the occurrence rates of the proton auroras using gradient-based attribution maps. 

How to cite: Dhuri, D., Simoni, M., Atri, D., and Alhantoobi, A.: Comprehensive statistical analyses and data-driven modeling of electron and proton auroras on Mars using EMM and MAVEN observations, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-13029, https://doi.org/10.5194/egusphere-egu23-13029, 2023.

EGU23-13324 | Posters on site | PS4.4

Seasonal variability of atomic hydrogen and oxygen in the EMM/EMUS cross-exospheric observations during Mars year 36 

Susarla Raghuram, Krishnaprasad Chirakkil, Justin Deighan, Michael Chaffin, Sonal Jain, Robert Lillis, Marko Gacesa, Matthew O. Fillingim, David Brain, Ed Thiemann, Frank Eparvier, Greg Holsclaw, Scott England, Scott Evans, Fatma Hussain Lootah, Hoor Abdelrahman Al Mazmi, Shannon Curry, and Hessa Rashid Al Matroushi

Atomic hydrogen and oxygen are the dominant species in the Martian exosphere. Atomic hydrogen is essentially produced from the dissociation of H2O, whereas, hot oxygen atoms are populated by non-thermal processes such as the dissociative recombination of O2+ with electrons in the Martian ionosphere. The study of these species helps to understand the evolution of the Martian atmosphere and more specifically the history of water on Mars.  The Emirates Mars Ultraviolet Spectrometer (EMUS), one of the primary instruments onboard the Emirates Mars Mission (EMM), has been observing atomic hydrogen and oxygen in the Martian exosphere over the Mars Year 36. We present the analysis of the cross-exospheric observations by the EMUS for hydrogen Lyman series and oxygen 130.4 nm emissions and their seasonal variability. The EMUS cross-exospheric observations cover the tangent altitude starting from 130 km to more than 35,000 km above the disk (see Fig. 1), with most of the observations below 25,000 km. The observations show that when Mars moved from perihelion to aphelion, the hydrogen emission line intensities increase by an order of magnitude or more whereas, for oxygen, it is an increment by a factor of about 2 at larger altitudes. Based on these observations, we also discuss the retrieval of densities, temperature, and the estimation of escape fluxes of hydrogen and oxygen species by applying 3D hydrogen ballistic corona and 3D Monte Carlo particle transport models, respectively.

Figure 1: The EMM-observed cross-exosphere emission intensity profiles of atomic hydrogen and oxygen during Mars Year 36

How to cite: Raghuram, S., Chirakkil, K., Deighan, J., Chaffin, M., Jain, S., Lillis, R., Gacesa, M., Fillingim, M. O., Brain, D., Thiemann, E., Eparvier, F., Holsclaw, G., England, S., Evans, S., Lootah, F. H., Al Mazmi, H. A., Curry, S., and Al Matroushi, H. R.: Seasonal variability of atomic hydrogen and oxygen in the EMM/EMUS cross-exospheric observations during Mars year 36, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-13324, https://doi.org/10.5194/egusphere-egu23-13324, 2023.

EGU23-13860 | Posters on site | PS4.4

Scattering cross sections for O(3P), C(3P), and H colliding with a CO2 molecule for planetary aeronomy 

Marko Gacesa, Balasubramoniam Murali Krishnan, Saheer Velluvakandi Chaluvalappil, and Mariam Alraie

We present scattering cross sections for O(3P), C(3P), and H colliding with a CO2 molecule at collision energies between 0.1 and 5 eV. The kinetics, transport, and energy relaxation associated with collisions between fast atoms and thermal background atomic and molecular species are of fundamental interest for escape processes in the Martian atmosphere. Two of three primary objectives of the Emirates Mars Mission are related to hydrogen and oxygen escape processes and the collision cross sections are used in the models needed to interpret the observations by the EMUS and EMIRS instruments.

In this work, the collision cross sections have been computed using first principles electronic potential energy surfaces constructed in reduced dimensionality for the lowest-energy asymptotes corresponding to the ground states of the interacting pairs. For the three systems, namely C(3P)-CO2, O(3P)-CO2, and H-CO2, velocity-dependent elastic, rotationally inelastic, and corresponding differential cross sections and derived quantities, including the momentum-transfer cross sections, were constructed. In all cases, the CO2 molecule was modeled using the rigid-rotor approximation, and the collisions were treated as non-reactive. The cross sections were calculated from the first principles (no external parameters) by solving quantum-mechanical coupled channel equations following the approach of Arthurs-Dalgarno, with the coupled-state approximation1,2.

We estimate the impact of the collision cross sections impact on the O, C, and H escape rates at Mars using simple 1D transport models and find significant differences compared to the values in the literature. In the transport model, we used the altitude density profiles taken from NASA’s MAVEN mission. In case of all three energetic atoms, the inelastic cross sections are found to be a significant part of the total cross sections. In case of O escape, we obtain a larger escape flux closer to the estimates based on the MAVEN measurements. We find that that O+CO flux affects the O escape more significantly than expected3, due to its effects on the available energetic O flux. We expect a similar effect to be present not only at Mars but at all CO2-rich planets due to the O-CO-CO2 photochemistry. The impact on C escape is inconclusive, suggesting that the accounted mechanisms of photochemical escape of C are not sufficient to explain the missing carbon at Mars4,5. Please insert your abstract HTML here.

How to cite: Gacesa, M., Krishnan, B. M., Chaluvalappil, S. V., and Alraie, M.: Scattering cross sections for O(3P), C(3P), and H colliding with a CO2 molecule for planetary aeronomy, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-13860, https://doi.org/10.5194/egusphere-egu23-13860, 2023.

EGU23-15008 | ECS | Orals | PS4.4

Properties of Limb Clouds at Mars determined from the Emirates Mars Mission (EMM) eXploration Imager (EXI) 

Alia Almansoori, Michael Rothman, Dave Brain, Michael Wolff, Aurélien Stcherbinine, and Justin Deighan

Observations of clouds in planetary atmospheres can provide insight about atmospheric characteristics such as vertical temperature structure and dynamics. Clouds observed at the limb of a planet (from the perspective of the telescope or spacecraft observing them) can be particularly useful tools, in part because their height above the surface can be measured directly.

The Emirates Mars Mission (EMM) has been recording visible light images of the Martian disk since early 2021, using the Emirates eXploration Imager (EXI). We present an analysis of limb clouds evident in EXI images taken using its red filter (centered on 635 nm) over the course of a Martian year. We present statistics on their height, thickness, spatial extent, and geographic and local time distribution – as well as correlations between these parameters. We place our results in context with previous work, and explore reasons for observed trends.

How to cite: Almansoori, A., Rothman, M., Brain, D., Wolff, M., Stcherbinine, A., and Deighan, J.: Properties of Limb Clouds at Mars determined from the Emirates Mars Mission (EMM) eXploration Imager (EXI), EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-15008, https://doi.org/10.5194/egusphere-egu23-15008, 2023.

The Martian atmosphere has undergone significant decay over time, with several factors contributing to this process. It is believed that thermal (Jeans) escape is a significant contributor to hydrogen loss on Mars (Chaufray, 2021). In this research, the role of thermal (Jeans) escape in the uplifting of hydrogen molecules to the exosphere, driven by solar wind forcing, is investigated on seasonal bases. Studying hydrogen escape seasonally can provide insights into the role of solar forcing in atmospheric processes. This research utilizes observations from the Emirates Mars Ultraviolet Spectrometer (EMUS) onboard the Emirates Mars Mission (EMM) To study the atmospheric Hydrogen Lyman Alpha emission on seasonal timescales. The data for this study focuses on the perihelion (greater than Ls 225) and aphelion (between 60-90 Ls)  periods, during which variations in the escape flux due to exobase temperature changes are expected. Level 2b/2a data is specifically chosen because it includes calibrated brightness and added geometric data, a combination of different EMUS observation modes is used in the study. The Lyman Alpha brightness measurements are used to derive the density profile of hydrogen in the Martian atmosphere using the same approach described in (Chaufray, 2008). The atmospheric model is divided into two parts, below the exobase the hydrogen density is described by a diffusive model, while above it uses Chamberlain’s model without satellite particles (Chamberlain, 1963). Deriving atmospheric hydrogen density profile is done by assuming the exobase temperature and solving radiative transfer equations to compute theoretical intensities which are then fitted with observational data to determine exobase temperature and density, a reasonable fit of observations is done assuming the parameters are in ranges that are in line with photochemical models (Krasnopolsky, 2002). This approach has been used to analyze the Mariner 6, 7 exospheric Lyman-α data during the late 1960s (Anderson and Hord, 1971), and the same approach has been used to analyze SPICAM Lyman-α data on Mrs express (Chaufray, 2008), this research attempts to use the same approach to analyze EMUS Lyman-α observations. It is expected that the (Jeans) escape flux of Hydrogen will vary on seasonal timescales, with higher escape fluxes observed around the perihelion period when the exobase temperature is the highest. This is due to the fact that the (Jeans) escape mechanism is driven by the temperature of the exobase, with higher temperatures resulting in higher escape rates. On the other hand, it is expected that lower escape fluxes will be observed during the aphelion period when the exobase temperature is lower.

How to cite: Marwan, M., Yousuf, M., Mohammad, B., and AlHammadi, H.: Investigating Seasonal Variations in Mars' Hydrogen Escape Flux derived by model fitting Lyman Alpha observations from Emirates Mars Ultraviolet Spectrometer (EMUS) onboard the Emirates Mars Mission (EMM)., EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-15440, https://doi.org/10.5194/egusphere-egu23-15440, 2023.

EGU23-15830 | Orals | PS4.4

One Martian Year of data assimilation with the Emirates Mars Mission 

Roland Young, Ehouarn Millour, François Forget, Christopher Edwards, Nathan Smith, Michael Smith, Saadat Anwar, Philip Christensen, and Luca Montabone

The Emirates Mars Mission (EMM) will have spent just over one Martian Year (MY) of science operations by the time the EGU General Assembly begins in late April 2023, having begun its primary science phase in May 2021 or MY36 Ls = 49o. Over this primary phase of the mission, we have been assimilating observations from EMM into the Mars Planetary Climate Model (PCM), using the Local Ensemble Transform Kalman Filter (LETKF), to understand various aspects of Mars' climate. EMM's unique high orbit and viewing geometry make it an extremely valuable source of data for assimilation, as it can observe nearly a whole hemisphere at once, monitor synoptic-scale features for several hours, and sample the whole diurnal cycle over 10 sols. This presentation will focus on the assimilation of atmospheric temperature profiles and column dust optical depth measurements, retrieved from spectral observations made by the Emirates Mars InfraRed Spectrometer (EMIRS), a thermal infrared spectrometer sensitive to 6-50 μm wavelengths on board EMM. We may also include EMIRS surface temperature measurements, and observations from Mars Climate Sounder (MCS) on board Mars Reconnaissance Orbiter (MRO) to fill in gaps in the data record. The assimilation combines EMIRS observations with a climate model in a statistically rigorous way to produce a data product consistent with the uncertainties in both. By measuring the quality of these analyses against assimilated and independent observations, we will highlight how assimilation can be used to inform the future development of our climate simulations.

How to cite: Young, R., Millour, E., Forget, F., Edwards, C., Smith, N., Smith, M., Anwar, S., Christensen, P., and Montabone, L.: One Martian Year of data assimilation with the Emirates Mars Mission, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-15830, https://doi.org/10.5194/egusphere-egu23-15830, 2023.

EGU23-708 | ECS | Posters on site | TS13.1

Mapping linear surface features on Europa using a deep learning framework 

Caroline Haslebacher and Nicolas Thomas

The surface of Jupiter's icy moon Europa shows curvilinear geological features, so called lineaments. Some of them span over a hemisphere, while others appear only on a regional scale. These curvilinear surface features that potentially stem from cracks in the ice shell are of keen interest because they might provide a direct or indirect connection to Europa's subsurface ocean, allowing a remote sensing study of the subsurface ocean.
The solid-state imager onboard the Galileo mission observed Europa between 1996 and 2002 during 11 flybys and sent back data of almost 2 gigabyte. Based on a global map mosaicked from Galileo and Voyager images at a scale of 1:15M, Leonard et al. (2019) created a global map of the surface of Europa. Their mapping shows that ridged plains make up a major part of the surface area. Ridged plains are seemingly smooth but contain a high amount of undifferentiated lineae visible at higher resolution. 

We attempt to create a global map of lineaments at a higher resolution than the global geologic map. Although for the Galileo dataset, this mapping could be done manually, we need to prepare for a bigger data return by NASA's Europa Clipper mission. For this purpose, we introduce a deep learning framework that can map linear surface features in Galileo images on Europa autonomously and apply it on a global scale. More specifically, we train a Mask R-CNN that can detect, classify and segment lineaments. The current status of the work is presented.

References:
[1] Leonard, E. J., Senske, D. A., Patthoff, D. A., Global and Regional scale Geologic Mapping of Europa, EPSC-DPS2019-57-1, Vol. 13, 2019

How to cite: Haslebacher, C. and Thomas, N.: Mapping linear surface features on Europa using a deep learning framework, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-708, https://doi.org/10.5194/egusphere-egu23-708, 2023.

Meteorite impact is recognized as a fundamental geological process of the solar system. Although mechanisms of large impact cratering have been studied intensely, mostly by numerical modelling, an outstanding problem concerns long-term crater modification, which operates on time scales of tens of thousands of years after impact. Localized deformation in the form of radial and concentric floor fractures (FFCs) are known from large craters on all terrestrial planets. On Earth, we can observe the occurrence of radial and concentric impact melt rock dikes in the eroded basement of large impact structures, such as Sudbury (Canada) and Vredefort (South Africa). Two mechanisms were proposed in the past to explain the formation of FFCs: the intrusion and inflation of igneous bodies below the crater floor and long-term isostatic re-equilibration of impacted target rocks. Using two-layer analogue experiments scaled to physical conditions on Earth, we explore to what extent isostatic re-equilibration of crust may account for the observed dike and fracture patterns of FFCs.

The structural evolution of model upper crust was examined for a variety of initial depths and diameters of crater floors. The crater diameter-to-depth ratio was scaled according to numerical models for average continental crust. Specifically, a tank, 80cm by 80cm in size, was filled with PDMS, representing the viscous middle and lower crust and granular material, simulating the brittle upper crust. Moreover, we introduce a method, which allowed us to generate any shapes of model impact crater floors.

The experiment surfaces were monitored with a 3D digital image correlation system allowing us to quantify key parameters, such as surface motion as well as the distribution and evolution of surface strain. The results of our scale models enabled us to quantify the duration, geometry and distribution of brittle deformation of upper crust. Most importantly, the analogue experiments provided, for the first time, a quantitative relationship between diameter, depth and fracture geometry of crater floors.

Our results indicate that FFCs are caused by long-term uplift of the crater floor, compensated by crustal flow toward the crater center. Such radial convergent flow generated radial and concentric dilation fractures. Crater floor uplift is accompanied by long-wavelength subsidence of the crater periphery on the order of 50 minutes, amounting to some 3000 years in nature. The formation of radial versus concentric fractures depends on the ratio between crater diameter and crater depth and, hence, is controlled by isostacy and crustal strength. The geometry and distribution of fractures in analogue experiments are strikingly similar to the geometry of impact melt rock dikes at Sudbury and Vredefort.

How to cite: Eisermann, J. O. and Riller, U.: Long-term crustal modification of large terrestrial meteorite impact structures: insights from scaled analogue experiments, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-1295, https://doi.org/10.5194/egusphere-egu23-1295, 2023.

EGU23-3108 | ECS | Orals | TS13.1 | Highlight

A comparative study of magma ascent and storage below impact craters on terrestrial planets 

Alexandra Le Contellec, Chloé Michaut, Francesco Maccaferri, and Virginie Pinel

On terrestrial bodies other than Earth, volcanism and magmatism are often related to impact craters. On Venus, RADAR observations of the surface have revealed two categories of craters: bright-floored and dark-floored craters, the latter being interpreted as partial filling of the crater by lava. On the Moon, volcanic deposits and evidence of pyroclastic activities are also frequently located within impact craters, especially within floor-fractured craters. These craters are characterized by uplifted, fractured floors resulting from underlying shallow magmatic intrusions. 

The elastic stress induced within the crust by a crater excavation indeed has two competitive effects. It induces a depressurization of the encasing elastic medium, which provides a driving pressure to the magma. This allows its ascent through the crust despite the magma’s negative buoyancy and explains why the magma tends to erupt preferentially within impact craters (Michaut and Pinel, 2018). However, the state of stress below the unloading is such that the minimum compressive stress is vertical at the unloading axis, which tends to horizontalize the dyke intrusion, therefore favoring magma storage below a crater at the expense of eruption.

We calculated the stress fields generated by surface unloadings of different radius on top of a semi-infinite half-space and use them in numerical mechanical models of magma ascent (Maccaferri et al, 2011) to evaluate the path followed by a dyke below a crater. We identify several types of behavior (ascent to the crater floor, horizontalization of the intrusion, storage at depth, ascent to the planet surface) depending on the physical properties of the magma and crust, as well as on the dyke and crater unloading characteristics. We draw a regime diagram for magma ascent below craters as a function of two characteristic dimensionless numbers depending on these different physical parameters.

Our results show that magma ascent to the crater interior requires relatively small density contrasts between the crust and magma and rather small crustal thicknesses as opposed to dyke horizontalization that results from larger crust-magma density contrasts and crustal thicknesses. Furthermore, on the Moon, craters are considerably deeper than on Venus, leading to a larger dimensionless deviatoric stress below a crater of a given radius, favoring dyke horizontalization and storage. This well explains why the magma tends to store as horizontal intrusions below floor-fractured craters on the Moon while it tends to erupt on the floor of dark-floored craters on Venus.

ACKNOWLEDGMENT: This project has received funding from the European Research Council (ERC) under the European Union's Horizon 2020 research and innovation program (grant agreement No. 101001689).

How to cite: Le Contellec, A., Michaut, C., Maccaferri, F., and Pinel, V.: A comparative study of magma ascent and storage below impact craters on terrestrial planets, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-3108, https://doi.org/10.5194/egusphere-egu23-3108, 2023.

EGU23-3625 | Orals | TS13.1

Locating a new emission source in Io’s Bosphorus Regio 

Albert Conrad, Steve Ertel, Imke de Pater, Ned Molter, Deepashri Thatte, Joel Sanchez-Bermudez, Anand Sivaramakrishnan, Joseph Shields, Katherine de Kleer, Rachel Cooper, and Jarron Leisenring

During late spring 2022, using JWST aperture masking interferometry (ERS program #1373) and ground-based adaptive optics at the Keck telescope, we detected a new emission feature in Io’s Bosphorus Regio.  To pinpoint the location more accurately we followed up with the Large Binocular Telescope (LBT).  An accurate location will help determine if this feature is part of the Emakong Patera, is part of the Seth Patera, or is an independent volcano emitting lava from its own magma source.  Here we report on the LBT observation and data analysis.

On UT November 8th, 2022, we observed Io with the Large Binocular Telescope Interferometer (LBTI).  We acquired over 30,000 14ms frames over a period of 4 hours and parallactic angle coverage of approximately 70 degrees.  Data were acquired at both M-band (4.8 microns) and a wide band-pass spanning 2.2 to 5.0 microns.  As in past LBTI observations of Io (Conrad et al., 2015), we employed lucky fringing and frame selection to assemble a data set in which all frames are co-phased.  From these data (taken with a 23-meter baseline), we expect to determine the location of the feature to a degree of accuracy approximately three times greater than is possible with adaptive optics on 8-10 meter ground-based telescopes.

Image reconstruction is the preferred method for combining interferometer data for most science programs.  However, for science programs that a) require only accurate astrometry of point sources (all volcanoes in our data are unresolved at the observed wavelengths) and b) utilize data taken with a Fizeau interferometer like LBTI, we have developed a simpler method.  This method has two advantages.  First, the method preserves the spatial information available in the raw data.  Image reconstruction can sometimes shift the location of a measured source.  Second, with our method data taken at different wavelengths can still be combined to yield a single measurement.  Image reconstruction methods can only combine images which were all taken with the same filter.

The method is quite simple.  Because a Fizeau interferometer like LBTI provides complete images (i.e., the image is not reconstructed from visibilities and closure phases), we can take a one-dimensional cut through each fringe pattern as it appears in the raw data.  From each cut we compute a one-dimensional centroid to get a sub-pixel location along that baseline.  These results, taken at different baseline angles (the LBTI baseline rotates with parallactic angle) are statistically combined to produce a single location measurement.  This location is then mapped from detector space to a latitude and longitude on the sphere of Io.  The uncertainty in the measurement is reflected as two orthogonal error bars, one for latitude and one for longitude, computed by statistically combining the individual uncertainties of each cut.

This same method can be used to locate other volcanoes visible in our data set, which will be the subject of a future work.

How to cite: Conrad, A., Ertel, S., de Pater, I., Molter, N., Thatte, D., Sanchez-Bermudez, J., Sivaramakrishnan, A., Shields, J., de Kleer, K., Cooper, R., and Leisenring, J.: Locating a new emission source in Io’s Bosphorus Regio, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-3625, https://doi.org/10.5194/egusphere-egu23-3625, 2023.

EGU23-3719 | ECS | Posters on site | TS13.1

Newly discovered moonquakes from Apollo short-period seismometer data 

Keisuke Onodera, Yuki Imagawa, and Satoshi Tanaka

The beginning of planetary seismology dates back to the Apollo lunar seismic observations (1969 – 1977), where two types of seismometers were deployed at four places on the nearside of the Moon. The seismic observation package consisted of (i) two horizontal and one vertical long-period (LP) sensors and (ii) one vertical short-period (SP) sensor. About 8 years of observation brought us 13000 seismic events and contributed to the understanding of the internal structure and the seismicity of the Moon (see Nunn et al., 2020 and Garcia et al., 2019 for the recent review).

On the other hand, because the existing moonquake catalog by Nakamura et al. (1981) builds on the LP data, it has been expected that there are potential events only observable in the SP data (Nakamura, 2021, pers. comm.). Referring to the already cataloged events, shallow moonquakes and thermal moonquakes excite the energy at a high-frequency range more sensible with the SP sensor (> 1-2 Hz). Especially, shallow moonquakes being used to define the lunar seismicity (Banerdt et al., 2020), it is of great importance to investigate the SP data for re-evaluating the current seismic activities on the Moon.

In this study, utilizing the re-archived Apollo lunar seismic data by Nunn et al. (2022), we searched for undetected moonquakes by looking into the coherence between the reference moonquakes and the SP time series. As a result, we succeeded in discovering seismic events that were not cataloged before. A new SP event catalog will be released with our future publication. 

In the presentation, we will show the newly detected moonquakes and describe their characteristics.

 

References

  • Banerdt et al. (2020), Nat. Geosci.,13, 183–189.
  • Garcia et al. (2019), Space Sci. Rev., 215, 50.
  • Nakamura et al. (1981), UTIG Technical Report, 18.
  • Nunn et al. (2020), Space Sci. Rev., 216, 89.
  • Nunn et al. (2022), Planet. Sci. J., 3 219.

 

How to cite: Onodera, K., Imagawa, Y., and Tanaka, S.: Newly discovered moonquakes from Apollo short-period seismometer data, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-3719, https://doi.org/10.5194/egusphere-egu23-3719, 2023.

EGU23-5378 | ECS | Orals | TS13.1

Geological mapping and structural analysis of the Michelangelo (H-12) quadrangle of Mercury 

Salvatore Buoninfante, Valentina Galluzzi, Luigi Ferranti, Maurizio Milano, and Pasquale Palumbo

Geological cartography and structural analysis are essential for understanding Mercury’s geological history and tectonic processes. This work focuses on the Michelangelo quadrangle (H-12), located at latitudes 22.5°S-65°S and longitudes 180°E-270°E. We present the preliminary results derived from the photointerpretation of the MErcury Surface, Space ENvironment, GEochemistry, and Ranging (MESSENGER) Mercury Dual Imaging System (MDIS) imagery. The first geological map of this quadrangle was produced by [1] at 1:5M scale using Mariner 10 data. The Authors identified and mapped five classes of craters and four main plain units. The present study is a contribution to the 1:3M geological map series, planned to identify targets to be observed at high resolution during the ESA-JAXA BepiColombo mission [2]. Geologic contacts and linear features were drawn at a mapping scale between 1:300,000 and 1:600,000.

We mapped tectonic structures and geological contacts using the MDIS derived basemaps, with an average resolution of 166 m/pixel. Linear features are subdivided into large craters (crater rim diameter > 20 km), small craters (5 km < crater rim diameter < 20 km), subdued or buried craters, certain or uncertain thrusts, certain or uncertain faults, wrinkle ridges and irregular pits. Geological contacts, mapped as certain or approximate, delimit the geological units grouped into three classes of crater materials (c1-c3) based on degradation degree, and plains (smooth, intermediate and intercrater plains).

We identified two main regional thrust systems with a NW-SE strike. The presence of old impact basins influenced the arrangement of faults because of the frequent reactivation of crater rims. Beethoven basin (20.8°S–236.1°E) and Vincente-Yakovlev basin (52.6°S–197.9°E) represent clear examples of tectonic inversion. The reactivation structures [3] are the result of previous impact-related normal faults that were reactivated due to the compressive tectonic regime deriving from the global contraction. Similarly to the Victoria quadrangle (H-02) [4], in the Michelangelo quadrangle the NW-SE system borders the southwestern edge of the high-Mg region, although the accuracy of XRS data at these latitudes is much lower than the accuracy of data acquired in the Northern hemisphere. We noted the frequent interaction between volcanic vents and thrusts, as already suggested by [5]. These vents are often located along lobate scarps or in soft-linkage zones between thrust segments. Indeed, as also observed on Earth, curved thrust surfaces or linkage areas between fault segments represent weakness zones acting as preferential pathways for magma uprising.

 

Acknowledgements: We gratefully acknowledge funding from the Italian Space Agency (ASI) under ASI-INAF agreement 2017-47-H.0.

 

References:

[1] Spudis P. D. and Prosser J. G., (1984). U.S. Geological Survey, IMAP 1659.

[2] Galluzzi et al. (2021). LPI Contrib., 2610.

[3] Fegan E. R. et al., (2017). Icarus, 288, 226-234.

[4] Galluzzi et al. (2019). Journal of Geophysical Research Planets, 124, 2543-2562.

[5] Thomas R. J. et al., (2014). Journal of Geophysical Research Planets, 119, 2239-2254.

How to cite: Buoninfante, S., Galluzzi, V., Ferranti, L., Milano, M., and Palumbo, P.: Geological mapping and structural analysis of the Michelangelo (H-12) quadrangle of Mercury, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-5378, https://doi.org/10.5194/egusphere-egu23-5378, 2023.

EGU23-6827 | Orals | TS13.1 | Highlight

The complexity of water freezing under reduced atmospheric pressure – insights on effusive cryovolcanism from laboratory experiments 

Petr Brož, Vojtěch Patočka, Marie Běhounková, Matthew Sylvest, and Manish Patel

Exploration of the Solar System has revealed that the surfaces of many icy bodies have been resurfaced by cryovolcanism: a process during which liquid and vapour are released from the surface into extremely cold and low pressure conditions. Water is one of the most commonly released liquids, and its stability and behavior under such conditions are thus of special interest. When exposed to low pressure, water boils, but it may also start freezing at the phase boundary due to evaporative cooling, as indicated by previous studies. There is only limited insight into how exactly the multiple phase transitions interact and what parameters control the dynamics of the system. To overcome this knowledge gap, we performed experiments in which we simulated the release of water at low pressure and low temperatures, such as could be encountered at local conditions at the  surface of an icy moon.

We used the Mars Simulation Chamber at The Open University (UK), in which a 60 x 40 cm container containing 5 and 17 litres of water was exposed to a reduced atmospheric pressure of ~4.5 mbar. Deionised water was mixed with a small amount of NaCl to achieve a salinity of 0.5% and was precooled to ~3.8°C to be close to the freezing point. Experiments were documented by video cameras situated around the container and the temperature inside the chamber and of the water was recorded by thermocouples.

At the beginning of each experiment, the atmospheric pressure was gradually reduced from ambient, which triggered boiling within the entire volume of water and evaporative cooling in its uppermost layer. This caused a gradual drop in the water temperature down to the freezing point, forming pieces of floating ice. The area where ice was present slowly grew and within timescales of a few minutes the entire surface of the container was covered with ice. However, the ice layer was broken into blocks with uneven surfaces. This was due to active boiling below the freezing layer of the water, with the intense formation of vapour bubbles which were capable of breaking and/or uplifting the ice. Once the fracture(s) developed, trapped vapour was released and deflation followed. Experimental results show that the process was more intense when larger amounts of water were used within the container, which significantly disrupted the freezing of water in those experiments and affected the final topography of the ice layer.

Our experiments show that water phase transition during effusive cryovolcanic eruptions are likely to be a highly complex process due to boiling causing major ice fracturing and the formation of topographical anomalies on the frozen surface.

How to cite: Brož, P., Patočka, V., Běhounková, M., Sylvest, M., and Patel, M.: The complexity of water freezing under reduced atmospheric pressure – insights on effusive cryovolcanism from laboratory experiments, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-6827, https://doi.org/10.5194/egusphere-egu23-6827, 2023.

EGU23-7383 | Orals | TS13.1

Review of the seismicity on Mars 

Simon C. Stähler, Savas Ceylan, Domenico Giardini, John Clinton, Doyeon Kim, Amir Khan, Géraldine Zenhäusern, Nikolaj Dahmen, Cecilia Duran, Anna Horleston, Taichi Kawamura, Constantinos Charalambous, Martin Knapmeyer, Raphaël Garcia, Philippe Lognonné, Mark Panning, W. Thomas Pike, and W. Bruce Banerdt

The InSight mission collected an astounding seismic dataset from Mars during more than four years (1450 sols) of operation until it was retired on 21 December 2022.

The Marsquake Service MQS detected more than 1300 events of seismic origins. Two of these events (S1000a and S1094b) were later confirmed as distant impacts (Figure 1), with magnitudes of MWMa=4.0 and 4.2 and crater diameters of 130 and 150 m, respectively. Finally, the largest marsquake (S1222a, MWMa=4.6) that occurred during InSight's lifetime was recorded on May 4, 2022.

Here, we present the current understanding of the Martian seismicity and the different types of events we observed on Mars, based on the data collected over the whole mission.

Low-frequency (LF) and broadband (BB)
The LF family of events include energy predominantly below 1 Hz. They are similar to teleseismic events observed on Earth, and clear P and S waves are often identified. The hypocenter is known for about half of the recorded LF-BB events, owing to the difficulty of determining back-azimuth and in some cases also distance for the smaller events. The following elements are now understood:

  • Seismicity appears to be located only in few spots around Mars (Figure 2) and no tectonic events were located within 25° from the InSight station.
  • A large number of LF-BB events are located 26–30° from the station, interpreted to be associated with the active dynamics of the volcanic Cerberus Fossae area.
  • A group of events show only a weak S-wave energy and are aligned using the P-wave and length of its coda to around 46°. Their tectonic origin is yet unknown.
  • A few events are located around 60° with relatively emergent P- and S-wave energy.
  • Two large events (S0976a and S1000a) lie beyond the core shadow and have PP and SS phases; S0976a in the Valles Marineris region 146° away from InSight, and S1000a as the result of a meteoritic impact.
  • A number of events of uncertain location are clustered in the same distance, around 100-120° distance.
  • LF events have the largest magnitudes with S1222a reaching MWMa=4.6 and a few others at or above MWMa=3.5.

High-frequency (HF)
The HF family of events are predominantly at and above the 2.4 Hz, local subsurface resonance. The HF events have magnitudes below MWMa 2.5 and originate from a distance range of 25–30°, likely a single area in the central Cerberus Fossae region, as very shallow events associated to active volcanic dykes. 

Very high frequency (VF):
A small number of HF events are characterized by higher frequency content, up to 20–30 Hz with a notable amplification on the horizontal components at very high frequency, and are termed VF events. The amplification is plausibly explained by the local subsurface structure. These events are observed only close to the lander. Remote imaging of recent craters and the presence of a distinctive acoustic signal confirmed that the closest events were produced by meteoric impacts. Investigations are being conducted to understand if other VF events can be confirmed as impacts, too.

How to cite: Stähler, S. C., Ceylan, S., Giardini, D., Clinton, J., Kim, D., Khan, A., Zenhäusern, G., Dahmen, N., Duran, C., Horleston, A., Kawamura, T., Charalambous, C., Knapmeyer, M., Garcia, R., Lognonné, P., Panning, M., Pike, W. T., and Banerdt, W. B.: Review of the seismicity on Mars, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-7383, https://doi.org/10.5194/egusphere-egu23-7383, 2023.

EGU23-10833 | ECS | Posters on site | TS13.1

Ground motion amplification due to lunar topography 

Meenakshi Yellapragada and Raghukanth stg

In recent years, estimating the possible ground motion on the Moon became quite essential as various researchers are exploring safe extra-terrestrial habitats close to the Earth. From the high-resolution imageries, it is observed that seismic sources like lobate scarps and wrinkle ridges are identified representing that there is seismic activity on the Moon which is considered a hazard to the lunar base. Therefore, it is essential to include topographic amplification factors in the ground motion predictions on the Moon which are in turn used in the seismic hazard analysis. It is well known that there is a wide variation of topographical features in the lunar south pole region (LSPR). Hence in this study, the spectral element method is preferred to model the seismic wave propagation in such complex topographic regions. The main objective of this study is to estimate the ground motion amplification on the Artemis landing sites that are present in the LSPR region. The topography for the study region is extracted from the entire South-pole topographic map which is obtained from the LRO-LOLA. A grid elevation data is incorporated with a resolution of 30m. The shallow moonquake event that occurred on March 13, 1973, is considered a seismic source, located at [84⁰ S, 134⁰ W] and has a focal depth of 5 km. The seismic wave simulations can generate up to a frequency of up to 2Hz from the developed model. The simulations have been performed with and without topography. The amplification ratio i.e., Peak ground displacement with topography/ Peak ground displacement without topography is calculated for the considered landing sites. In addition, an amplification map of the shake intensity maps is also generated for the considered study region. Results show that there is amplification on ridges and de-amplification in the valleys.

How to cite: Yellapragada, M. and stg, R.: Ground motion amplification due to lunar topography, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-10833, https://doi.org/10.5194/egusphere-egu23-10833, 2023.

EGU23-11093 | ECS | Posters on site | TS13.1

Low-voluminous, mafic-dominated volcanism in Claritas Fossae, Thaumasia region on Mars 

Bartosz Pieterek, Petr Brož, and Ernst Hauber

The majority of Tharsis is covered by relatively young and low-viscous widespread lava plains, being of basaltic composition. They likely buried older volcanic landforms which could have provided important data about ancient eruptive style and magma composition. However, several fractured regions forming topographic raises survived regional resurfacing, and they are providing an insight into the volcanic history of the planet. To date, these Noachian/Hesperian-aged fractured terrains revealed the presence of putative scoria cones in Ulysses (Brož and Hauber, 2012) and Noctis Fossaes (Pieterek et al., 2022) supporting a hypothesis that the volcanic activity differed in the past from waste eruptions of young low-viscous lavas. Here, we present results of mapping that focused on the edifices superimposed on the Noachian-age fractured crust within the Claritas Fossae region. The aim was to decipher their origin and provide additional constraints on the volcanism emplaced on the ancient terrains.

In the studied region, we mapped 39 topographically positive edifices of constructional character. They are spread on the ancient crust showing NW-SE trending alignment over an area of 170 x 500 km. Based on the CTX observations, we noted that their majority is characterized by elongated (WNW-trending) to irregular or circular outlines and relatively steep-appearing flanks without associated flow-like units. Among these edifices, one circular-shaped edifice located in the easternmost part of the studied area is associated with short-distance flow-like units and rimmed by a caldera-like structure. We also determined the mineralogical composition for several edifices with available CRISM spectral data. This showed that edifices are spatially associated with high concentrations of igneous-origin low-calcium pyroxenes (LCP). Based on the relative stratigraphy, we showed that volcanic activity postdates the fracturing, the age of which has been estimated to space between ~3.4 to ~2.6 Ga and likely predates the formation of Thaumasia graben (Late Hesperian/Early Amazonian).

The shapes, sizes, distribution pattern, and mineralogical composition of the mapped edifices are consistent with putative volcanic origin. Therefore, we argue that Claritas Fossae’s field mainly experienced effusive eruptions characterized by highly viscous, volatile-poor magma(s). Such composition limited the ability of the effused lavas to spread from the site into the surroundings. The elongation and spatial distribution of the edifices together with their LCP-rich composition indicate volcanic eruptions might be controlled by the migration of subsurface dike(s) from the shallow magma chamber(s). Altogether the comprehensive study of the volcanic evolution of the Thaumasia region showed that the studied edifices might express the late-stage dike migration of LCP-rich magmas that used the reactivated WNW-ESE tectonic pathways.

Besides the effusive-origin edifices, the area might contain one of the best-preserved kilometer-sized, explosive-type volcanic edifice emplaced within the putative caldera-like rim known from Mars.

This research was funded by the “GEO-INTER-APLIKACJE” project no. POWR.03.02.00-00-I027/17.

References

Brož, P., Hauber, E., 2012. A unique volcanic field in Tharsis, Mars: Pyroclastic cones as evidence for explosive eruptions. Icarus 218, 88–99. https://doi.org/10.1016/j.icarus.2011.11.030

Pieterek, B., Laban, M., Ciążela, J., Muszyński, A., 2022. Explosive volcanism in Noctis Fossae on Mars. Icarus 375, 114851. https://doi.org/doi.org/10.1016/j.icarus.2021.114851

How to cite: Pieterek, B., Brož, P., and Hauber, E.: Low-voluminous, mafic-dominated volcanism in Claritas Fossae, Thaumasia region on Mars, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-11093, https://doi.org/10.5194/egusphere-egu23-11093, 2023.

Many scientists who study the tectonic inventory of planetary bodies were initially trained as Earth-based structural geologists. In this context, a comparative approach of methodology in planetary and terrestrial tectonics is helpful with regards to what works and what does not. The methodological approaches are subdivided into (i) nature, (ii) experiment, (iii) modeling.

(i) Acquisition of data in the field, which provides the ground truth for the Earth geologist, is still largely impossible on planetary bodies, at least nowadays, or limited to small regions with the help of rovers. Likewise, microstructural analysis – an important branch in structural geology - is not possible, or is limited to meteorites and the few mission return samples. Those deficits are compensated by remote sensing data. Their quality, spatial resolution and coverage varies greatly, but is steadily improving, and sometimes reaches decimeter resolution (Mars). Most data are sufficient for tectonic work, and sometimes allow the measurement of strike and dip of layers and faults and even enable the construction of cross-sections. The outcrop conditions are usually better on planetary surfaces and the context between geomorphology and tectonics is apparent and similar to neotectonics on Earth due to lower resurfacing rates. Determination of surface ages using crater size-frequency-distributions also allows dating of tectonic processes, although this approach is much less sensitive than Earth-based methods. The exploration of the subsurface by drilling and geophysical surveying is strongly limited in planetary tectonics (e.g., GPR). Detailed seismic surveys cannot be performed yet. However, geophysical measurements (gravity and magnetic field) are often available, which at least allow to decipher crustal-scale processes.

(ii) Rock-mechanical experiments are key for determining the rheology of crustal rocks in planetary and terrestrial tectonics. However, some of the physical boundary conditions to be considered in planetary tectonics are less well constrained and cover a larger range of temperatures. In planetary tectonics, basalts and various types of ices play a central role, which receive little attention in terrestrial structural geology. In tectonic analogue modeling, the parameter gravity poses a challenge. Gravity affects the scaling relationships of faults (displacement–length–width) but gravity can only be modified in centrifuges, space, or parabola flights.

(iii) The mathematical simulation of deformation processes on planetary bodies works in the same way as for terrestrial processes by discretization of the continuum. It is easily adaptable but the systems to be modeled are sometimes underdetermined with regard to the parameter space.

To conclude the methodological tools in planetary tectonics are somewhat limited compared to those applied in terrestrial structural geology. Analogue field studies in specific terrestrial environments (e.g., Svalbard, Iceland) are aimed to compensate the missing field acquisition in planetary tectonics. Despite these limitations, planetary tectonics is a fascinating endeavor that allows us to better understand the dynamic geological processes and narrow down the physical boundary conditions of planetary bodies. With the ever improving remote sensing data by recent and upcoming missions (e.g., BepiColombo, EnVision, Veritas, Juice) the field of planetary tectonics will continue to gain importance.

How to cite: Kenkmann, T.: Planetary tectonics versus Earth tectonics: a comparative approach of working principles, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-11631, https://doi.org/10.5194/egusphere-egu23-11631, 2023.

EGU23-12423 | ECS | Posters on site | TS13.1

UPSIDES - Unravelling icy Planetary Surfaces: Insights on their tectonic DEformation from field Survey 

Costanza Rossi, Paola Cianfarra, Alice Lucchetti, Riccardo Pozzobon, Luca Penasa, Giovanni Munaretto, and Maurizio Pajola

The icy satellites of the Solar System, such as Europa and Ganymede, show widespread evidence for tectonic structures that provide insights to infer the kinematics and the mechanical properties of their crusts. Their investigation is pivotal for the understanding of the regimes responsible for their formation and the connection with subsurface layers. Icy satellite tectonics is dominated by extension and shear regimes, while paucity evidence for compression represents an open issue. Structural investigation is constrained at regional-scale coverage of the remote sensing imagery. The research of analogues on Earth represents a strong support for the geologic analysis of the icy satellites. Glaciers represent optimal terrestrial analogues, showing deformation styles similar to those in the icy satellites, and being the excellent sites to further explore, verify and confirm what observed through remote sensing on the icy satellite geology. Although the formation processes differ, the similarity of their structures at surface allows quantifying and predicting the state of deformation in the icy satellites at different scales of investigation. Moreover, glacier deformation shows corridor-like pattern, analogous to the main tectonic setting recognized in the icy satellites. The UPSIDES project aims to investigate and compare the tectonic structures of the glaciers with those on the icy satellites, by means of multi-scale approach of both remote-sensing and field survey. We propose a structural investigation in the Russell and Isunguata Sermia glaciers, located at the western margin of the Greenland Ice Sheet, where field campaign has been conducted under the Europlanet 2024 RI's Transnational Access field analogue in Kangerlussuaq. This project aims i) to achieve knowledge of the tectonic setting at local-scale, ii) to compare with that at regional-scale, and in turn iii) to better understand the tectonic process and to characterize structures that are exclusively identified at regional-scale (such as in the icy satellites). Field measurements of brittle structures (fractures/faults), concerning the quantification of their azimuth, dip, length, width, throw and spacing, have been performed. In parallel, remote sensing analysis, concerning structural mapping on areas covering the locations of the investigated outcrops, allowed to derive the same quantities at regional-scale. In this way, both local- and regional-scale tectonic setting has been investigated, and the stress analysis has been performed. Obtained results have been compared and in turn related with areas that show similar tectonic setting on Ganymede. In particular, the lack of detection of the regional-scale counterpart of the compressional structures that have been recognized at local-scale in the investigated glaciers, has been related to the lack of evidence of such structures in the icy satellite’s surfaces. Such comparison allows us to prepare a tectonic model that suggests deep zones of existence of compressional structures and explains their limited detection at surface and regional-scale investigations.

Acknowledgments: This project has received funding from the European Union's Horizon 2020 research and innovation programme under grant agreement No 871149. The activity has been realized under the ASI-INAF contract 2018-25-HH.0.

How to cite: Rossi, C., Cianfarra, P., Lucchetti, A., Pozzobon, R., Penasa, L., Munaretto, G., and Pajola, M.: UPSIDES - Unravelling icy Planetary Surfaces: Insights on their tectonic DEformation from field Survey, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-12423, https://doi.org/10.5194/egusphere-egu23-12423, 2023.

EGU23-12524 | ECS | Orals | TS13.1

Crustal structure observed by the InSight mission to Mars 

Doyeon Kim, Simon Stähler, Christian Boehm, Ved Lekic, Domenico Giardini, Savas Ceylan, John Clinton, Paul Davis, Cecilia Duran, Amir Khan, Brigitte Knapmeyer-Endrun, Ross Maguire, Mark Panning, Ana-Catalina Plesa, Nicholas Schmerr, Mark Wieczorek, Géraldine Zenhäusern, Philippe Lognonné, and William Banerdt

After more than 4 Earth years of operation on the martian surface monitoring the planet’s ground vibrations, the InSight’s seismometer is now retired. Throughout the mission, analyses of body waves from marsquakes and impacts have led to important discoveries about the martian interior structure of the crust, mantle, and core. Recent detection of surface waves, together with gravimetric modeling enabled the characterization of crustal structure variations away from the InSight landing site and showed that average crustal velocity and density structure is similar between the northern lowlands and the southern highlands. Especially for the observed overtones and multi-orbiting surface waves in S1222a, we find the depth sensitivity expands down to the uppermost mantle close to 90 km. Furthermore, our 3D wavefield simulations show significantly broadened volumetric sensitivity of the higher-orbit surface waves. These new constraints obtained by our surface wave analyses provide an important opportunity not only to refine and verify our previous radially symmetric models of the planet’s interior structure but also to improve understanding of seismo-tectonic environments on Mars. Here, we summarize our recent effort in the analyses of surface waves on Mars and discuss the inferred crustal property and its global implications.

How to cite: Kim, D., Stähler, S., Boehm, C., Lekic, V., Giardini, D., Ceylan, S., Clinton, J., Davis, P., Duran, C., Khan, A., Knapmeyer-Endrun, B., Maguire, R., Panning, M., Plesa, A.-C., Schmerr, N., Wieczorek, M., Zenhäusern, G., Lognonné, P., and Banerdt, W.: Crustal structure observed by the InSight mission to Mars, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-12524, https://doi.org/10.5194/egusphere-egu23-12524, 2023.

EGU23-14136 | Posters on site | TS13.1

High-resolution magnetic investigation of hydrothermal circulation in the Danakil Depression 

Hanjin Choe, Daniel Mege, and Jerome Dyment

The Danakil Depression is an active divergent boundary opening between the southern Red Sea rift and the Afar triple junction at a rate of ~1 cm/yr. Despite its geological interest, it is becoming increasingly difficult to study due to regional political instability and extreme environment. Our study area, located between the Erta ‘Ale volcano and Dallol, exhibits thick salt layers and iron-rich clay intercalations locally covered by mud volcanism deposits. The heat from the volcanic rift segment and the occasional influx of saltwater from Lake Karum create a unique hydrothermal system on land. In 2019 we collected ground magnetic field data around the main active hydrothermal fissure to investigate the magnetic signature of this hydrothermal system.  Our data show a clear linear magnetic anomaly low associated with the fissure, indicating a loss of magnetization due to the active hydrothermal activity. Local anomaly lows are observed at hydrothermal pools and in areas of subsurface bubbling. Apart from the hydrothermal areas, a relatively uniform magnetic anomaly is observed above the resurfaced reddish mud. Its slow decay away from the fissure may correspond to the progressive attenuation of the superficial iron-rich mud layer considered the most likely coherent magnetized source in the area. Our inference of the iron-rich mud layer as the bearer of a coherent magnetization that is altered by the hydrothermal activity needs however to be confirmed by sample analyses.

How to cite: Choe, H., Mege, D., and Dyment, J.: High-resolution magnetic investigation of hydrothermal circulation in the Danakil Depression, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-14136, https://doi.org/10.5194/egusphere-egu23-14136, 2023.

EGU23-14918 | ECS | Posters on site | TS13.1 | Highlight

The Marsquake Service since the InSight mission to Mars 

Doyeon Kim, John Clinton, Savas Ceylan, Anna Horleston, Simon Stähler, Taichi Kawamura, Constantinos Charalambous, Nikolaj Dahmen, Cecilia Duran, Matthieu Plasman, Géraldine Zenhäusern, Fabian Euchner, Martin Knapmeyer, Domenico Giardini, Philippe Lognonné, Tom Pike, Mark Panning, and William Banerdt

After ~4 years of deployment on the martian surface monitoring the planet’s ground motion, the InSight seismometer is now retired. Here, we review the procedures and methods the Marsquake Service (MQS) used to curate the seismic event catalog and describe the content of the catalog. The marsquake catalogue is different from normal catalogues on Earth as it aims to provide the authoritative catalog for the mission, covering the entire planet, using only a single station. As of January 1st, 2023, the MQS catalog contains 1319 seismic events of which 6 are known meteorite impacts. We have also identified 1383 superhigh frequency events that are interpreted as thermal cracking nearby the InSight lander. Late in the project large distant events occurred that allowed MQS to detect surface waves. Multiple events have been associated as impacts using orbital imaging, confirming the MQS single station location procedures. All of these new seismic phases have contributed to advance our understanding of the internal structure of Mars. The marsquake S1222a, the largest event recorded during the mission (MW 4.7) occurred in March 2022 and is also documented in our latest MQS catalog, V13, with many associated seismic phases including both Rayleigh and Love waves, their first-order overtones, and multi-orbiting surface waves that have not been identified in other marsquake records from our previous catalogues. The InSight mission is now closed but the MQS operation continues to analyze the ~4 years of seismic recordings on Mars and a final catalog, including event-specific products such as filter banks, and spectra, is in preparation. This final catalog will inform capabilities and field strategies in geophysical explorations for future martian science missions.

How to cite: Kim, D., Clinton, J., Ceylan, S., Horleston, A., Stähler, S., Kawamura, T., Charalambous, C., Dahmen, N., Duran, C., Plasman, M., Zenhäusern, G., Euchner, F., Knapmeyer, M., Giardini, D., Lognonné, P., Pike, T., Panning, M., and Banerdt, W.: The Marsquake Service since the InSight mission to Mars, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-14918, https://doi.org/10.5194/egusphere-egu23-14918, 2023.

EGU23-15069 | Orals | TS13.1

Constraints on Martian Crustal Lithology from Seismic Velocities by InSight 

Brigitte Knapmeyer-Endrun, Jiaqi Li, Doyeon Kim, Ana-Catalina Plesa, Scott McLennan, Ernst Hauber, Rakshit Joshi, Jing Shi, Caroline Beghein, Mark Wieczorek, Mark P. Panning, Philippe Lognonne, and W. Bruce Banerdt

Analysis of data from the seismometer SEIS on NASA’s InSight mission has by now provided a wealth of information on the crustal structure of Mars, both beneath the lander and at other locations on the planet. Here, we collect the P- and S-wave velocity information for kilometer-scale crustal layers available up to now and compare it to predictions by rock physics models to guide the interpretation in terms of crustal lithology.

Modeling is performed based on the Hertz-Mindlin model for un- or poorly consolidated sediments, Dvorkin and Nur’s cemented-sand model for consolidated sediments and Berryman’s self-consistent approximation to simulate cracked rocks. Considered lithologies include basalt, andesite, dacite, kaolinite, and plagioclase, and cementation due to calcite, gypsum, halite and ice. We use Gassmann fluid substitution to study the effect of liquid water instead of atmosphere filling the pores or cracks.

Below the lander, available constraints are based on Ps-receiver functions and vertical component autocorrelations for SV- and P-wave velocities, whereas SH-reflections and SsPp phases provide additional information on SH- and P-wave velocities in the uppermost 8-10 km, respectively. SS and PP precursors at the bouncing point of the most distant marsquake contain information on crustal velocities at a near-equatorial location far from InSight. Surface wave observations from two large impacts as well as the largest marsquake recorded by InSight provide average crustal velocities along their raypaths, which are distinct from the body wave results.

The subsurface structure beneath the lander can be explained by 2 km of either unconsolidated basaltic sands, clay with a low amount (2%) of cementation, or cracked rocks (e.g. basalts with at least 12% porosity). Within the range of lithologies considered, the seismic velocities can neither be explained by intact rocks, nor rocks with completely filled pores, e.g. by ice, nor by fluid-saturated rocks. Below, down to a depth of about 10 km beneath InSight, both P- and SV-wave velocities are consistent with fractured basaltic rocks or plagioclase of at least 5% porosity, depending on crack aspect ratios. About 10% of that porosity needs to have a preferred orientation to explain the observed anisotropy. For porosities exceeding 12%, the measured velocities would also be consistent with water-saturated rocks. The transition to higher velocities at about 10 km depth beneath InSight can be modeled by more intact material, i.e. a porosity reduction by 50% compared to the layer above, which can be achieved by either cementation or a lower initial porosity.

The SV-velocities derived by surface waves down to 25-30 km depth, averaging over a large part of Mars, are consistent with basalts of a porosity of less than 5% or nearly intact plagioclase. They could also be explained by rocks with a higher porosity if pores are filled by ice, but that is unlikely for the whole depth range considered. The velocities at larger depth, i.e. below about 20 km beneath InSight and 25-30 km along the surface wave paths, are consistent with intact basalt.

How to cite: Knapmeyer-Endrun, B., Li, J., Kim, D., Plesa, A.-C., McLennan, S., Hauber, E., Joshi, R., Shi, J., Beghein, C., Wieczorek, M., Panning, M. P., Lognonne, P., and Banerdt, W. B.: Constraints on Martian Crustal Lithology from Seismic Velocities by InSight, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-15069, https://doi.org/10.5194/egusphere-egu23-15069, 2023.

Long-lasting widespread volcanism contributed to heavily shaping the surface of Mars. In fact, the Tharsis volcanic province is one of the largest volcanic provinces with the largest shield volcanoes of the Solar System, Mount Olympus and the NE-SE trending Tharsis Montes, namely Ascareaus, Pavonis and Arsia Mons.

However, volcanism on Mars is characterized also by the presence of wide volcanic fields, either in form of small shields or monogenic cones. The region of Syria Planum (SP), located eastern to the Tharsis province and encompassed between Noctis Labyrinthus on the North and Claritas Fossae on the southwest, is an example of diffuse volcanism. SP presents hundreds of small edifices which insist on top of a large bulge roughly 300x200 km in size.

New chronological results pointed out a complex magmatic history and volcano-tectonic evolution of the whole Tharsis and SP area spanning from the early-Noachian to the more recent times such as the 130 Ma of the Arsia Mons’ single caldera and the 140 Ma for the Pavonis Mons’ composite calderas. Although through the years SP has been considered the by-product of the enormous volcano-tectonic activity forming the Tharsis, it has been shown that this magmatic complex could be related to large multiple episodes of mantle upwelling forming minor edifices that do not necessarily overlap with the major volcanic centres. Moreover, the NW-SE elongated SP volcanic field grew just south of the Noctis Labyrinthus canyon systems that form a dissected highland and is located at the western tip of the Valles Marineris.

In this work, we investigate the geometry of the plumbing system of the SP volcanic field as well as the structures (vent elongation and vent alignment) that fed the magma to forward a possible tectonic and volcanic evolution of the area. The spatial distribution of vents and the overall shape of the volcanic field have been studied in terms of vent clustering and spatial distribution. Moreover, analyzing the lineament pattern on SP and surrounding areas possible links with the formation and evolution of the Noctis Labyrinthus graben, the Valles Marineris and the Tharsis province are forwarded.

How to cite: Pozzobon, R., Mazzarini, F., and Isola, I.: Syria Planum volcanic province, an example of diffuse volcanism on Mars: insights from vents distribution analysis and spatial clustering, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-15312, https://doi.org/10.5194/egusphere-egu23-15312, 2023.

EGU23-16365 | ECS | Orals | TS13.1

Modeling of surface displacement and dynamic fracturing during magma emplacement at floor-fractured craters on the Moon and Mars 

Sam Poppe, Alexandra Morand, Anne Cornillon, and Claire Harnett

Floors of impact craters on rocky planetary bodies in our Solar System are often fractured and bulged. Such deformation features are thought to form by the ascent of impact-generated magma and the inflation of laccolith-shaped magma bodies at a shallow depth below the crater floor. Only the final surface deformation features can be observed from space, and so modeling is the only manner to understand controls on magma emplacement depth and volume, and deformation of the overlying rock. The existing models of crater floor fracturing mostly assume linearly elastic deformation of the shallow planetary crust and are not capable of simulating dynamic opening and propagation of fractures. In contrast, magma-induced deformation on Earth often displays non-elastic deformation features. This mismatch between the realistic mechanical response of planetary crust to magma intrusion and the one assumed by numerical models leads to significant inaccuracies in the modeled magma intrusion characteristics. This has important consequences for volcanic unrest monitoring on Earth and our understanding of structural deformation generated by volcanism throughout the Solar System.

We propose a new two-dimensional (2D) Discrete Element Method (DEM) approach to model dynamic fracturing and displacement in a particle-based host medium during the simulated inflation of a laccolith intrusion. The model indicates highly discontinuous deformation and dynamic fracturing and visualizes the localization of subsurface strain. We explored the effect of different gravitational conditions on the Moon, Mars and Earth on the spatial distribution of strain, stress, and fracturing above an inflating laccolith. Moreover, by systematically exploring a range of numerical parameters that govern host rock strength (bond cohesion, bond tensile strength, bond elastic modulus), and intrusion depth, we find complex controls of mechanical properties of planetary crust on the magma intrusion characteristics. Our models help understand fracture distribution patterns above laccolith intrusions in the shallow crust of rocky planetary bodies. We demonstrate that considering dynamic deformation and fracturing mechanisms in numerical models of magma-induced deformation is essential to better understand the formation of floor-fractured craters and the magmatic intrusions that lie beneath.

How to cite: Poppe, S., Morand, A., Cornillon, A., and Harnett, C.: Modeling of surface displacement and dynamic fracturing during magma emplacement at floor-fractured craters on the Moon and Mars, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-16365, https://doi.org/10.5194/egusphere-egu23-16365, 2023.

EGU23-326 | ECS | PICO | GD3.2

Thermal constraints on the ureilite parent body (UPB): Evidence from the refractory spinel in polymict ureilite EET 87720 using in situ SIMS 

Yaozhu Li, Phil J. A. McCausland, Roberta L. Flemming, and Noriko T. Kita

Ureilites are ultramafic achondrite meteorites that likely represent a large parent body. Large olivine and pyroxene grains display a high degree of textural equilibrium, forming “triple-junction” contacts at their grain boundaries. However, ureilites also have primitive characteristics, for example high siderophile and carbon content, high noble gas content, and unequilibrated olivine and pyroxene compositions. So far, the origin of ureilites and their parent body are still debated as it is difficult to explain the observation of textural equilibrium juxtaposed with such primitive properties. Conventionally, ureilites are considered to be mantle residues from within an unknown, large rocky body. Because feldspar is completely depleted from most ureilite samples, it has been thought that the parent body accreted early and experienced extensive igneous differentiation processes, with primary heating attributed to short-lived 26Al decay in the early solar system. Here we report on polymict ureilite breccia Elephant Moraine 87720. We found that the sample has several unusually magnesian-rich olivine clasts with mg# (Mg/(Mg+Fe)) up to 98.7 and calcium-poor pyroxene with Wo as low as to 1.0. Moreover, we discovered two coarse-grained aluminous spinel grains with over 56.4-58.7 wt% Al2O3 and 11.3-11.8wt% Cr2O3, in contact with olivine and pyroxene grains. These aluminous spinel clasts are unique among ureilite samples. To determine the provenance of the spinel grains and other clasts (e.g., high magnesian olivine and low calcium pyroxene) in this sample, we conducted in situ oxygen 3-isotope analyses by Secondary Ion Mass Spectrometry SIMS (IMS 1280), University of Wisconsin-Madison. SIMS mineral data plot along the slope ~1 line in the oxygen 3-isotope diagram, similar to those of bulk ureilites (Greenwood et al., 2017, Chemie der Erde 77, 1-43) including ureilitic samples found in Almahata Sitta, with the same range of ∆17O (from –2.3‰ to –0.2‰). These grains follow the Fe-loss/addition trend defined by a molar plot of Fe/Mn versus molar Fe/Mg, showing a near constant and chondritic Mn/Mg ratio, falling in among common ureilitic compositions. We conclude that the origin of these clasts, including the aluminous spinel, is primarily ureilitic, but they extend the δ18O measurement for ureilites up to 9.7 ‰. We hypothesize a magmatic origin for these clasts that they were formed under low-oxygen fugacity, in a high Al/Si ratio hot melt, favouring the crystallization of Al-spinel instead of a Cr-rich endmember. The clasts in this EET 87720 specimen may possibly represent a new type of high Al, low Ca, low Cr lithic material within the ureilite parent body. Finally, we calculated a possible crystallization temperature of 1379 K using spinel-olivine equilibrium crystallization (Roeder et al 1979, Contrib. Min. Petrol. 6, 325-334). Our estimate corresponds well with the theoretical model proposed by Goodrich et al. (2004, Chemie der Erde 64, 283-327) that the UPB was hot, with a temperature above 1100 °C (1373 K). Our results are consistent with other petrological evidence and olivine-pigeonite-melt thermometry (Singletary and Grove, 2003, Met. Planet. Sci. 38, 95-108) which constrain smelting temperatures within the ureilite parent body.

How to cite: Li, Y., McCausland, P. J. A., Flemming, R. L., and Kita, N. T.: Thermal constraints on the ureilite parent body (UPB): Evidence from the refractory spinel in polymict ureilite EET 87720 using in situ SIMS, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-326, https://doi.org/10.5194/egusphere-egu23-326, 2023.

     Constraining thermo-chemical evolution for the interior of terrestrial planets is substantial to understanding their evolutionary path. Thermo-chemical processes is controlled by stages of large-scale melting, or magma oceans (MO), due to the energy released during accretion, differentiation, radioactive decay of heat-producing elements and crystallization of the melt. Previous work shows that one of the product of considering fractional crystallization (FC) for  MO is a FeO-enriched molten layer or basal magma ocean (BMO) which is stabilized at the core-mantle boundary for a few billion years. The BMO is expected to freeze by FC because it cools very slowly. FC always yield a highly iron-enriched BMO and last stage cumulates. Other crystallization mode could be dominated and has not yet been systemically explored – at least for the Earth-like planets.

To explore the fate of the BMO cumulates in the convecting mantle, we explore 2D geodynamic models with a moving-boundary approach. Flow in the mantle is explicitly solved, but the thermal evolution and related crystallization of the BMO are parameterized. The composition of the crystallizing cumulates is self-consistently calculated  in the FeO-MgO-SiO2 ternary system according to Boukaré et al. (2015). In some cases, we also consider the effects of Al2O3 on the cumulate density profile. We then investigate the  entrainment and mixing of BMO cumulates by solid-state mantle convection over billions of years as a function of BMO initial composition and volume, BMO crystallization timescales, distribution of internal heat sources, and mantle rheological parameters (Ra# and activation energy), . We varied the initial composition of BMO by manipulating the molar fraction of FeO, MgO, and SiO -based on published experiments- to model different BMO-compositions: Pyrolitic composition, After 50% crystallization of Pyrolitic composition Boukaré et al. (2015), After 50% crystallization of Pyrolitic composition Caracas et al. (2019), and Archean Basalt.

For all our model cases, we find that most of the cumulates (first ~90% by mass) are efficiently entrained and mixed through the mantle. However, the final ~9% of the cumulates are too dense to be entrained by solid-state mantle convection, and rather remain at the base of the mantle as a strongly FeO-enriched solid layer. We conclude that this inevitable outcome of BMO FC – at least for Earth - leads to inconsistent evolutionary path comparing to recent geophysical constraints. FC substantially change the compositional, thermal, and geometrical properties for the lower mantle structures.  An alternative mode of crystallization may be driven by an efficient reaction between a highly-enriched last-stage BMO with the overlying mantle due to chemical disequilibrium. 

How to cite: Ismail, M. and Ballmer, M.: The Consequences of Fractional Crystallization for Basal Magma Ocean on the Long-term Planetary Evolution, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-723, https://doi.org/10.5194/egusphere-egu23-723, 2023.

EGU23-2786 | ECS | PICO | GD3.2

Differentiation of the Martian Highlands during its formation. 

Valentin Bonnet Gibet, Chloé Michaut, Thomas Bodin, Mark Wieczorek, and Fabien Dubuffet

The Martian crust is made up of sedimentary and volcanic rocks that are mainly mafic in composition. Nevertheless, orbital and in-situ observations have revealed the presence of felsic rocks (Payré et al, 2022), all located in the southern hemisphere, where the crust is thicker. These rocks likely formed by differentiation of a basic protolith. On Earth, this process occurs at plate boundaries and is linked to active plate tectonics. But on Mars, we have no evidence of active or ancient plate tectonics.

On one-plate planets, there exists a positive feedback mechanism on crustal growth: the crust being enriched in heat-producing elements, the lithosphere is hotter and thinner where the crust is thicker, which implies a larger melt fraction at depth and therefore a larger extraction rate and a larger crustal thickening where the crust is thicker. We proposed that this mechanism could have been at the origin of the Martian dichotomy (Bonnet Gibet et al, 2022). This mechanism further implies that regions of thicker crusts, characterized by a larger amount of heat sources, a thinner lithosphere and an increased magmatism, are also marked by higher temperatures. Here we investigate whether crustal temperatures in regions of thick crust may be maintained above the basalt solidus temperature during crust construction, which would allow for the formation of partially molten zones in the crust and hence differentiated rocks by extraction of the melt enriched in water and silica. In this scenario, felsic rock formation would be concomitant to crustal construction and dichotomy formation on Mars.

We use a bi-hemispheric parameterized thermal evolution model with a well-mixed mantle topped by two different lithospheres (North and South) and we account for crustal extraction and magmatism in these two hemispheres. We formulate a Bayesian inverse problem in order to estimate the possible scenarios of thermal evolution that are compatible with constraints on crustal thickness and dichotomy amplitude derived from the InSight NASA mission. The solution is represented by a probability distribution representing the distribution on the model parameters and evolution scenarios. This distribution is sampled with a Markov chain Monte Carlo algorithm, and shows that a non-negligible range of scenarios allows for partial melting at the base of the Southern crust below the Highlands during the first Gyr of Mars' evolution. On the contrary, partial melting of the base of the northern crust is insignificant. Models that fit InSight constraints and allow for differentiation of a fraction of the Southern crust point to a relatively low reference viscosity (~1020 Pa.s) that can be explained by a wet mantle at the time of crust extraction.

How to cite: Bonnet Gibet, V., Michaut, C., Bodin, T., Wieczorek, M., and Dubuffet, F.: Differentiation of the Martian Highlands during its formation., EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-2786, https://doi.org/10.5194/egusphere-egu23-2786, 2023.

Zircon is an important silicate mineral to help understand the evolution of geochemistry and genesis of magma in early planets. The composition of evolved magma can be deduced from the concentrations of elements in zircon and their partition coefficients between zircon and silicate melt. Although the phosphorus (P) contents range from ~100 to ~100000 ppm in extraterrestrial zircon, the effects of P on REE partition coefficients between zircon and silicate melt are still debated. Here we have studied the effect of P contents on the partition coefficients of elements between zircon and silicate melt using high-temperature experiment. With the increase of phosphorus content, the partition coefficients of alkaline elements and Al between zircon and silicate melt show a negative and positive trend, respectively, and there is no effect on itself and Ti. It is worth mentioning that phosphorus content has a negligible effect on REE partitioning, indicating that the REE partition coefficients in this study can be applied to extraterrestrial zircon even with varying P concentrations. After filtering out altered zircon and combining the experimentally updated partition coefficients of REE, the characteristic of evolved melt equilibrated with early protogenetic zircon can thus be yielded and then help to understand early magmatism on the planets. 

How to cite: Shang, S. and Lin, Y.: Experimentally revisiting the REE partition coefficients between zircon and silicate melt, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-3076, https://doi.org/10.5194/egusphere-egu23-3076, 2023.

EGU23-3530 | PICO | GD3.2

Implications of Bouguer Gravity Structure Under Major Lunar Basins 

David E Smith, Sander Goossens, and Maria T Zuber

Analysis of the lunar Bouguer gravity field under major basins reveals how gravity varies with spherical harmonic degree L and, potentially, with depth (to relate the two we use a relationship based on point masses).  We have studied 19 lunar basins based upon a GRAIL 1200 degree and order gravity model (GRGM1200B).  The vertical component of Bouguer gravity shows how the gravity is distributed in spherical harmonic degree between the lowest degree, 2, and the highest degree, 1200. Under each basin, this gravity spectrum of accelerations per individual spherical harmonic degree shows a benign region for L from 800 to 100, a range of approximately 20 km immediately below the surface, consistent with the observation that the upper crust is largely homogenous (Zuber et al., 2013). A region of more varied gravity signal occurs down to L~20, approximately 60 km deeper. The basin gravity signal merges with the deep interior at L~10, approximately 150 km below the surface. A set of profiles over latitude or longitude through an individual basin anomaly shows how the magnitude of the gravity signal changes with depth as it passes from the annular moat to the central high of the anomaly; all of which takes place between L~100-20, a depth range estimated to be ~20-80 km.  However, all basins are different to some extent. Outside of the basin anomaly the gravity spectra are relatively benign from just below the surface to L~40, a depth of approximately 45 km and consistent with the approximate average thickness of the lunar crust.  An exception to the general characteristics of the spectra of basins is South Pole-Aitken (SPA) which indicates a structure with few variations that is very similar to the regions that have near zero Bouguer gravity at the surface with no large anomalies in the top 100 km. We interpret this result for SP-A as a result of its largely compensated state.

How to cite: Smith, D. E., Goossens, S., and Zuber, M. T.: Implications of Bouguer Gravity Structure Under Major Lunar Basins, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-3530, https://doi.org/10.5194/egusphere-egu23-3530, 2023.

EGU23-3622 | ECS | PICO | GD3.2

Topographic signatures and statistics of different tectonic regimes and application to terrestrial planets 

Diogo Louro Lourenço, Michael Manga, and Paul Tackley

A tectonic regime is the surface expression of interior dynamics in a planet. With the help of numerical models, different tectonic regimes have been proposed. Some of these are: (1) plate tectonics or mobile lid, (2) stagnant lid, (3) episodic lid, (4) plutonic-squishy lid, (5) and heat pipe (e.g., Lourenço et al., G3 2020). Over time, a tectonic regime shapes the surface of a planet, including its surface topography. Using the numerical models, we can compute the topographies associated with different tectonic regimes including spatial and temporal measures of variations. In this study, we compute statistics for the topography formed by different tectonic regimes in numerical models and compare with the statistics of observed topography of different terrestrial planets, with the aim of linking a planet to a tectonic regime at the present-day. Venus’ topography is better matched by topography distributions obtained for plutonic-squishy lid models than those for stagnant- or episodic-lid models, while Earth’s oceanic topography is best matched by mobile-lid models.

How to cite: Louro Lourenço, D., Manga, M., and Tackley, P.: Topographic signatures and statistics of different tectonic regimes and application to terrestrial planets, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-3622, https://doi.org/10.5194/egusphere-egu23-3622, 2023.

In this work, we test the hypothesis of surface-erosion controlled plate tectonics preceded by plume-induced retreating subduction tectonic regime on Earth proposed by Sobolev and Brown (2019) using 2D global compressible convection models. To simulate the effect of increased sediment supply as a result of surface erosion after the emergence of continents in the late Archean and after the Neoproterozoic "snowball Earth" glaciation, we decrease the effective frictional strength of the oceanic lithosphere in models spanning the age of the Earth. These StagYY models self-consistently generate oceanic and continental crust while considering both plutonic and volcanic magmatism (Jain et al., 2019). Pressure-, temperature-, and composition-dependent water solubility maps calculated with Perplex (Connolly, 2009) are also utilised, which control the ingassing and outgassing of water between the mantle and surface (Jain et al., 2022). The core cools with time and different initial mantle potential temperature values are tested within the range of 1750-1900 K (Herzberg et al., 2010; Aulbach and Arndt, 2019).

Models that consider a more realistic upper mantle rheology (diffusion creep and dislocation creep proxy) show higher recycling of denser basaltic-eclogitic (oceanic) crust, efficient cooling of the planet, and higher mobilities (ratio of surface to mantle rms velocities) (Tackley (2000); Lourenço et al. (2020)). These models exhibit intermittent episodes of long-lasting mobile-lid regime and short-lived plutonic-squishy-lid regime in the Hadean and the early Archean accompanied by extensive subduction leading to rapid production and recycling of the continental crust. Models that consider adaptive frictional strength (to mimic sedimentation post glaciation and continental emergence) predict the transition to continuous plate tectonics in the late Archean, reproduce features of supercontinent cycles, and appear to be consistent with cooling history of the Earth inferred from petrological observations (Herzberg et al., 2010). 

The thermo-compositional evolution can vary between models due to the inherent randomness arising from the initial thermal perturbations and the initial positions of the tracers/particles. Accordingly, we intend to run multiple instances of every model considered in our parameter space to present statistically robust results. We also aim to test more realistic models where the lithospheric frictional strength adapts with the surface topography.

How to cite: Jain, C. and Sobolev, S.: Exploring the interplay between continent formation, surface erosion, and the evolution of plate tectonics on Earth, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-4755, https://doi.org/10.5194/egusphere-egu23-4755, 2023.

EGU23-6480 | ECS | PICO | GD3.2

Melting relations for putative mantles of Mercury and the compositional diversity of the crust 

Peiyan Wu, Yongjiang Xu, Yanhao Lin, and Bernard Charlier

The compositional diversity of volcanic rocks revealed by NASA’s MESSENGER at the surface of Mercury has been interpreted to result from partial melting of a heterogenous sulfur-rich Mercurian mantle. However, melting relations and the composition of partial melts for iron-free and sodium-rich mantle, together with the effect of sulfur as a key volatile, have not yet been studied in detail. In this study we present results from high-pressure and high-temperature experiments on the mineralogical and geochemical evolution of the mantle residue and melting products of primitive deep Mercury’s mantle with two starting compositions differing by their Mg/Si ratios. Both compositions have sulfur added as FeS. Experiments were conducted using a multi-anvil press under reduced conditions (by controlling the Si/SiO2 ratio of the starting composition) at pressures of 3 and 5 GPa.

The residual mantle of Mercury with the lower Mg/Si ratio of 1.02 contains olivine + orthopyroxene above ~15 wt% melting at 3 and 5 GPa, and olivine disappears at melting over ~30 wt.% at 5 GPa. The Mercurian mantle with the Mg/Si of 1.35 contains olivine + orthopyroxene in the residue above ~15 wt% melting at 3 and 5 GPa, and olivine only when the melting degree is over ~50 wt.%. Our experiments also show that the majority of chemical composition of the High-Magnesium region (HMR) can result from ~25±15 wt.% melting of a deep primitive mantle. Further work will enable us to evaluate the compositional diversity of the mantle that is needed to explain the broad range of surface lavas. We also aim at understanding the role of the highly refractory residual mantle as a controlling factor for the end of major volcanic activity on Mercury at 3.5 Ga.

How to cite: Wu, P., Xu, Y., Lin, Y., and Charlier, B.: Melting relations for putative mantles of Mercury and the compositional diversity of the crust, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-6480, https://doi.org/10.5194/egusphere-egu23-6480, 2023.

EGU23-7732 | PICO | GD3.2

Grain growth kinetics of bridgmanite under topmost lower-mantle 

Hongzhan Fei, Ulrich Faul, Maxim Ballmer, Nicolas Walte, and Tomoo Katsura

The absence of seismic anisotropy in most regions of the lower mantle suggests that diffusion creep may be the dominant mechanism in the lower mantle. Because the diffusion-creep rate is inversely proportional to the 2~3 power of grain size, knowledge of the grain-growth kinetics is crucial for studying lower-mantle dynamics. For these reasons, this study determined the grain-growth kinetics of bridgmanite at a pressure of 27 GPa using advanced multi-anvil techniques.

We first measured the grain sizes of bridgmanite in an olivine bulk composition with various annealing durations at 2200 K. The results were fitted to an equation dnd0n = kt, where d and d0 are the final and initial grain sizes, respectively, n is the grain-size exponent, t is the annealing duration, and k is the growth-rate constant. This fitting yielded n = 5.2 ± 0.3, which is much smaller than given by a previous study [Yamazaki et al., 1996], n = 10.6 ± 1.1. This discrepancy may be because Yamazaki et al.’s [1996] olivine starting material may have contained adhesive water, which enhanced grain growth at the beginning of annealing. We then conducted runs at various temperatures, yielding the activation energy of 260 ± 20 kJ/mol. These results suggest that the bridgmanite grain sizes over 0.1 – 1 Gyr should have grain sizes of 150-230 μm, which is one order of magnitude larger than Yamazaki et al.’s [2006] estimation. Consequently, the lower mantle should be much harder than previously considered.

Furthermore, we measured the grain-growth kinetics as a function of the fraction of coexisting ferropericlase. Although the grain-growth kinetics is almost independent of the ferropericlase fraction down to 20 vol.%, it rapidly increases with decreasing ferropericlase fraction at lower fractions. Over 0.1~4.5 Gyr, the bridgmanite grain sizes in pure-bridgmanite rock should be 2 ~ 3 orders of magnitude larger than those coexisting with 20 vol.% of ferropericlase. These results suggest that pure-bridgmanite rock has 4 ~ 9 orders of magnitude lower flow rates than pyrolite if the diffusion creep is dominant. Since the diffusion creep rate in pure-bridgmanite rock is so low, the dislocation creep should dominate in pure-bridgmanite rock. We estimated that the pure-bridgmanite rock should have 1 ~ 2.5 orders of magnitude more viscous than pyrolite if the stress condition is 0.1~0.5 MPa in the lower mantle. This variation may interpret the viscosity variation in the lower mantle inferred from the geoid analysis [Rudolph et al., 2015], subduction speed [van der Meer et al., 2018], and plume morphology [French & Romaniwicz, 2016].

How to cite: Fei, H., Faul, U., Ballmer, M., Walte, N., and Katsura, T.: Grain growth kinetics of bridgmanite under topmost lower-mantle, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-7732, https://doi.org/10.5194/egusphere-egu23-7732, 2023.

EGU23-7777 | ECS | PICO | GD3.2

Exploring the effects of terrestrial exoplanet bulk composition on long-term planetary evolution 

Rob Spaargaren, Maxim Ballmer, Stephen Mojzsis, and Paul Tackley

New terrestrial exoplanets are being discovered at an ever faster pace, and each discovery leads to a widening of our understanding of planetary diversity. A key aspect in the quest to better quantify terrestrial planet diversity is to gain information on plausible bulk compositions, as this physical-chemical quantity determines the planet's structure, which in turn controls physical properties of the its layers (core, mantle, crust, atmosphere). Recent insights in the expected range of bulk planet compositions allow us to investigate how this fundamental parameter affects the evolution of the planetary interior and surface, and consequently to guide next-generation ground- and space-based telescopic observations of exoplanet properties, such as atmospheric composition.

Here, we first simulate mantle mineralogies for exoplanets with various bulk compositions, using a Gibbs energy minimization algorithm, Perple_X. Using mineralogy and resulting physical properties, we employ a 2D global-scale model of thermochemical mantle convection to investigate the variations between Earth-sized exoplanets of different compositions in terms of interior evolution. We include the effects of composition on planet structure, mantle physical properties, and mantle melting. We investigate how composition affects thermal evolution, and whether it has an effect on the propensity of a planet towards plate tectonics-like behaviour.

In general, Earth tends to have an average composition for most elements, except for iron, which it is relatively rich in, and therefore it has an above average core size. Our preliminary results show that core size (and thus iron abundance) affects convective vigor, and thus thermal evolution of the interior. We further find major differences for planets with different ratios of Mg-silicates, as these minerals control mantle viscosity, and thereby thermal evolution. Planets with lower Mg/Si than Earth will have a significantly stronger mantle, impeding cooling on planetary lifetimes, while planets with much higher Mg/Si have weaker upper mantles, impacting surface mobility. Stellar Mg/Si is a good indicator of the relative abundances of these minerals, and can be an important source of information. Therefore, the host stellar abundances seem to be an indicator of rocky planet properties, and can be used in the target selection for future missions.

How to cite: Spaargaren, R., Ballmer, M., Mojzsis, S., and Tackley, P.: Exploring the effects of terrestrial exoplanet bulk composition on long-term planetary evolution, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-7777, https://doi.org/10.5194/egusphere-egu23-7777, 2023.

The short-lived isotope systems, including 146Sm-142Nd (half-life = 103 Ma) and 182Hf-182W (half-life = 8.9 Ma), provide evidence for mantle differentiation events in early Earth, as both the daughter nuclides are more incompatible than the parent nuclides. For the 146Sm-142Nd system, both positive and negative μ142Nd measurements are observed in Hadean-Archean mantle-derived rocks, which possibly indicates a major differentiation event of the silicate Earth before the extinction of 146Sm (e.g., Boyet and Carlson, 2005, Science). The diminishing trend of μ142Nd between Hadean and Archean, on the other hand, suggests continuous mantle mixing during this period. However, for the 182Hf-182W system, Hadean-Archean mantle-derived rocks often show positive μ182W anomalies followed by a decline in at 2.5~3.0 Ga ago without a mixing trend (e.g., Carlson et al., 2019, Chem. Geol.). Also, μ142Nd and μ182W often show no or negative correlation in Hadean-Archean mantle derived rocks (e.g., Rizo et al. 2016, Geochim. Cosmochim. Acta), which requires a mechanism to decouple these two isotopic systems.

In this study, we implement both 182Hf-182W and 146Sm-142Nd system in a global thermochemical geodynamic model, StagYY (Tackley, 2008, PEPI), to track the evolution of these isotope systems through Earth’s mantle evolution. Based on the particle-in-cell method, the geodynamic model incorporates melting and magmatic crust production that allow us to track both fractionation (by melting and crustal production) and mixing (through mantle convection) of trace elements through time. We discuss in detail how (1) the ‘basalt barrier’ at the base of the mantle transition zone (Davies, 2008 EPSL), (2) crustal delamination from intrusive magmatism, or plutonic-squishy-lid tectonics (Lourenco et al., Nat. Geo. 2018; GCubed 2020), and (3) late accretion could affect the tectonics of early Earth, and the preservation of geochemical heterogeneities and decoupling of two isotopic systems in the mantle through time.

 

How to cite: Tian, J. and Tackley, P.: Long-term preservation of geochemical heterogeneities in early Earth: tracking short-lived isotopes in geodynamic models, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-8965, https://doi.org/10.5194/egusphere-egu23-8965, 2023.

EGU23-9100 | ECS | PICO | GD3.2

Effect of grain-size evolution on the lower mantle dynamics 

Jyotirmoy Paul, Gregor Golabek, Antoine Rozel, Paul Tackley, Tomo Katsura, and Hongzhan Fei

Grain-size evolution is a crucial controlling factor for the lower mantle rheology. Notably, one order of grain size change can produce a viscosity change of the order of 100-1000 times. As diffusion creep dominates in the lower mantle, grain growth of lower mantle mineral assemblages, e.g., bridgmanite and ferropericlase, increase viscosity considerably. It has been quite challenging to constrain the grain-size evolution parameters for lower mantle mineral assemblages until recently; a new high-pressure experimental study (27 GPa, cf. Fei et al, 2021, EPSL) parameterised them. The experimental data found a slower grain growth of bridgmanite-ferropericlase phases than of the upper mantle mineral phases, e.g., olivine and spinel. Using the most updated knowledge of grain-size evolution, we develop 2-D spherical annulus numerical models of self-consistent mantle convection using the finite volume code StagYY and explore how grain-size evolution affects the lower mantle dynamics. We test our models with different heterogeneous grain size evolution and composite rheology that evolve self-consistently for 4.5 billion years. Our preliminary models show the self-consistent formation of thermochemical piles at the base of the core-mantle boundary where the grain size is maximum (~3 times than the surroundings). Even though the bridgmanite-ferropericlase grain growth is slower, a slight increase in the grain size of thermochemical piles can make them ~100-1000 times viscous, subsequently helping them to achieve morphological stability over billion years. In some of our models, we find sweeping stability of the piles for ~500 million years. 

How to cite: Paul, J., Golabek, G., Rozel, A., Tackley, P., Katsura, T., and Fei, H.: Effect of grain-size evolution on the lower mantle dynamics, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-9100, https://doi.org/10.5194/egusphere-egu23-9100, 2023.

EGU23-10101 | ECS | PICO | GD3.2

The Heterogeneous Earth Mantle: Numerical Models of Mantle Convection and their Synthetic Seismic Signature 

Matteo Desiderio, Anna J. P. Gülcher, and Maxim D. Ballmer

Our understanding of the compositional structure of Earth's mantle is still incomplete. Heterogeneity in the lower mantle, documented by both geochemical and geophysical observations, has not yet been explained within a definitive geodynamic framework. Moreover, the origin, geometry and interaction of such heterogeneities remain controversial. In the “marble cake” mantle hypothesis, slabs of basaltic Recycled Oceanic Crust (ROC) are subducted and deformed but never fully homogenized in the convecting mantle. Conversely, MgSiO3-rich primordial material may resist convective entrainment due to its intrinsic strength, leading to a “plum pudding” mantle. While previous geodynamic studies have successfully reproduced these regimes of mantle convection in numerical models, the effects of the physical properties of ROC on mantle dynamics have not yet been fully explored. Furthermore, predictions from numerical models need to be tested against geophysical observations. However, current imaging techniques may be unable to discriminate between these two end members, due to limited resolution in the lower mantle.

Here, we model mantle convection in a 2D spherical-annulus geometry with the finite-volume code StagYY. We investigate the style of heterogeneity preservation as a function of the intrinsic density and strength (viscosity) of basalt at lower-mantle conditions. Additionally, we use the thermodynamic code Perple_X and the spectral-element code AxiSEM to compute, respectively, seismic velocities and synthetic seismograms from the predictions of our models.

Our results fall between two end-member regimes of mantle convection: low-density basalt leads to a well-mixed, "marble cake"-like mantle, while dense basalt aids the preservation of primordial blobs at mid-mantle depths as in a "plum pudding". Intrinsically viscous basalt also promotes the preservation of primordial material. These trends are well explained by lower convective vigour of the mantle as intrinsically dense (and viscous) piles of basalt shield the core. In order to test these results, we translate the predicted compositional, temperature and pressure fields to seismic velocities for two opposite end-member cases. These two synthetic velocity maps are first analysed and compared in terms of their respective radial correlation matrices and spherical harmonic spectra. Then, we use AxiSEM to simulate wave propagation through the two velocity models. Finally, we discriminate between the two end-members by comparing statistical properties of the corresponding ensembles of synthetic seismograms. Our results highlight how the interplay between primordial and recycled heterogeneities shape the evolution of the thermal and compositional structure of the lower mantle. Furthermore, they provide a framework for relating the style of heterogeneity preservation in the Earth's lower mantle with specific features of the seismic waveforms.

How to cite: Desiderio, M., Gülcher, A. J. P., and Ballmer, M. D.: The Heterogeneous Earth Mantle: Numerical Models of Mantle Convection and their Synthetic Seismic Signature, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-10101, https://doi.org/10.5194/egusphere-egu23-10101, 2023.

An advanced understanding of how tectonic plates have moved since deep time is essential for understanding how Earth’s geodynamic system has evolved and interacted with the plate tectonic system, i.e., the longstanding question of what “drives” plate tectonics. In this work, we take advantage of the rapidly improving database and knowledge about the Precambrian world, and the conceptual breakthroughs both regarding the presence of a supercontinent cycle and possible dynamic coupling between the supercontinent cycle and mantle dynamics, to establish a full-plate global reconstruction back to 2000 Ma. We utilise a variety of global geotectonic databases to constrain our reconstruction, and use palaeomagnetically recorded true polar wander events and global plume records to help evaluate competing geodynamic models regarding the origin and evolution of first-order mantle structures, and provide new constraints on the absolute longitude of continents and supercontinents. After revising the configuration and life span of both supercontinents Nuna (1600–1300 Ma) and Rodinia (900–720 Ma), we present here a 2000–540 Ma animation featuring the rapid assembly of large cratons and supercratons (or megacontinents) between 2000 Ma and 1800 Ma after billion years of dominance by many small cratons, that kick started the ensuing Nuna and Rodinia supercontinent cycles and the emergence of hemisphere-scale (long-wavelength) degree-1/degree-2 mantle structures. We further use the geodynamically-defined type-1 and type-2 inertia interchange true polar wander (IITPW) events, which likely occurred during Nuna (type-1) and Rodinia (type-2) times as shown by the palaeomagnetic record, to argue that Nuna assembled at about the same longitude as the latest supercontinent Pangea (320–170 Ma), whereas Rodinia formed through introversion assembly over the legacy Nuna subduction girdle either ca. 90° to the west (our preferred model) or to the east before the migrated subduction girdle surround it generated its own degree-2 mantle structure. Our interpretation is broadly consistent with the global LIP record. Using TPW and LIP observations and geodynamic model predictions, we further argue that the Phanerozoic supercontinent Pangaea assembled through extroversion on a legacy Rodinia subduction girdle with a geographic centre at around 0°E longitude before the formation of its own degree-2 mantle structure, the legacy of which is still present in present-day mantle.   

How to cite: Li, Z.-X., Liu, Y., and Ernst, R.: A geodynamic framework for 2 billion years of tectonic evolution: From cratonic amalgamation to the age of supercontinent cycle, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-10404, https://doi.org/10.5194/egusphere-egu23-10404, 2023.

EGU23-11284 | ECS | PICO | GD3.2

Basin evolution and crustal structure on Mercury from gravity and topography data 

Claudia Camila Szczech, Jürgen Oberst, Hauke Hussmann, Alexander Stark, and Frank Preusker

Introduction:

Available gravity and topography data derived from MESSENGER mission provide a great opportunity to investigate the surface and the interior structures of Mercury’s impact basins. In contrast to previous studies, which focused on image data, topography, or gravity alone, we use the complementary data sets to obtain a more comprehensive picture of basins and possibly their related subsurface structures.

Methods:

In this study we use image, gravity and topography data obtained by the MESSENGER spacecraft, from the Mercury Dual Imaging System (MDIS), the Mercury Laser Altimeter (MLA) as well as a radio science experiment for gravity field modelling. Digital Terrain Models from stereo images (150m/px) [1] were used in combination with mosaiced image data (166m/px) [2] to support identification of the basins. Using the most recent gravity model [3], combined with a topography model [4], we calculated Bouguer anomalies [5] and determined a crustal thickness model[6].

Results:

We created an inventory of 319 impact basins (>150 km) classifying their morphological and gravitational characteristics, including measurements of gravity disturbance, Bouguer anomaly, crustal thickness and morphometrical measurements (Fig 1). Basins tend to undergo relaxation processes over time, which would explain the high number of modified basins.

Fig 1: A classification scheme was chosen according to rim preservation state, appearance of terraces, filling of the basin floor, depth and diameter.

 

With increasing diameter, basins were found to show more complex gravity signatures (Fig 2).  In both gravity anomalies, gravity disturbance as well as Bouguer anomaly, strong centred anomalies reflect high mass and/or density concentrations inside the impact basins, that were caused by an uplift of mantle material after the crater excavation phase [8]. The negative collar of the Bouguer anomaly profile suspected to be a consequence of depression of crust-mantle boundary, i.e. thickening of the crust. Consequently, profiles of Bouguer anomaly reflect profiles of the crust-mantle boundary.  With increasing diameter, the crustal thickness is showing a decrease in rim and centre proving a link between crustal thinning and impact basin formation (Fig 3). 

Fig. 2: [a]Gravity disturbance are mostly negative for small basins, but become positive for larger basins. [b] Bouguer anomaly showing positive centre and negative rim area (bullseye pattern).

 

Fig. 3: Bouguer anomaly contrast and crustal thickness ratio from centre and rim area. 

References:

[1]   Preusker F. et al., (2017). Planetary and Space Science, 142, 26–37.doi: 10.1016/j.pss.2017.04.012. [2] Hawkins, S.E., III, et al., (2007). Space Sci Rev 131: 247–338, DOI 10.1007/s11214-007-9266-3. [3] Konopliv, A., Park, R., & Ermakov, A. (2020). Icarus, 335, 113386 doi: 10.1016/j.icarus.2019.07.020. [4]  Neumann et al., (2016). 47th Annual Lunar and Planetary Science Conference (p. 2087). [6] Wieczorek et al., (2015). Treatise on Geophysics (pp. 153–193). Elsevier. doi: 10.1016/B978-0-444-53802-4. [7] Beuthe et al., (2020). Geophysical Research Letters, 47. doi: 10.1029/2020GL087261. [8] Melosh et al., (2013). Science, 340, 1552–1555.515 doi: 10.1126/science.1235768. 

How to cite: Szczech, C. C., Oberst, J., Hussmann, H., Stark, A., and Preusker, F.: Basin evolution and crustal structure on Mercury from gravity and topography data, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-11284, https://doi.org/10.5194/egusphere-egu23-11284, 2023.

EGU23-11648 | ECS | PICO | GD3.2

Long-term effect of a basal magma ocean on Martian mantle convection 

Kar Wai Cheng, Maxim Ballmer, and Paul Tackley

It has been proposed that a basal magma ocean (BMO) may have existed, or even still exists, at the base of the Martian mantle [1]. One formation scenario for such a BMO involves a mantle-scale overturn just after the crystallization of the main magma ocean. In this case, the BMO would be enriched in iron and heat-producing elements (HPE), and hence gravitationally stable at the base of the mantle, with potential effects on the efficiency of mantle convection. The Insight mission has allowed geophysical investigation of the Martian interior and has indeed provided seismic evidence of a basal liquid silicate layer just above the core-mantle boundary. It is thus crucial to understand the effect of such a layer on the long-term evolution of the interior of Mars.

Here, we model thermochemical mantle convection and crust production for a Mars-sized planet in a 2D spherical annulus geometry using code StagYY.  Assuming that the top of the BMO is at ~1800 km radius, we parameterize the basal magma ocean as a ‘primordial layer’ with a low viscosity and a high effective thermal conductivity to account for the enhanced effective heat flux in a liquid layer due to turbulent flow. HPE are preferentially partitioned into the silicate liquid layer following a mass balance equation assuming an interstitial porosity.  We systematically vary BMO thickness and interstitial porosity in order to study the outcome of the different HPE distributions.  The liquid density, which is attributed by the different degrees of iron enrichment, is also examined to explore the mechanical stability and entrainment of the BMO.

We present results of our models, comparing our present-day temperature profiles with areotherms deduced from seismic observation [2,3].  We find that the interstitial porosity is an important factor that determines the thermal structure of the mantle throughout Martian evolution. A value of ~50% provides the best fit with crustal production history, crustal thickness, HPE enrichment in the crust, as well as the seismically-constrained present-day areotherm. This result suggests that the initial HPE partitioning has not been controlled by end-member fractional crystallization of the main magma ocean (for which interstitial porosity would be close to 0%), and/or that some re-equilibration occurred during subsequent overturn. Meanwhile, the BMO thickness, within the uncertainties from seismic inversion, does not strongly influence Mars thermal evolution.

 

[1] Samuel et al. (2021) doi:10.1029/2020JE006613

[2] Khan et al. (2021) doi: 10.1126/science.abf2966

[3] Duran et al. (2022) doi: 10.1016/j.pepi.2022.106851

How to cite: Cheng, K. W., Ballmer, M., and Tackley, P.: Long-term effect of a basal magma ocean on Martian mantle convection, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-11648, https://doi.org/10.5194/egusphere-egu23-11648, 2023.

EGU23-12628 | ECS | PICO | GD3.2

The automatic detection of tectonic plates in 3D mantle convection models and plate motion changes 

Alexandre Janin, Nicolas Coltice, Julien Tierny, and Nicolas Chamot-Rooke

The rigid surface of the Earth is divided into a jigsaw puzzle of about 50 tectonic plates separated by boundaries. Nowadays, three-dimensional spherical mantle modelling manages to produce self-consistently a stiff surface fragmented into several rigid caps that exhibit a plate-like behaviour. It thus becomes possible to analyse the dynamics of these models through the prism of plate tectonics theory and compare it to plate reconstruction models for the Earth. Such an analysis requires a robust method to automatically detect plates and their boundaries from continuous geophysical fields. The method should further recognize diffuse plate boundaries, as observed on Earth and reproduced in mantle convection models. We propose here a method to automatically detect and track plates through time, based on a trans-disciplinary approach combining a geodynamical and kinematic analysis with applied mathematics and computer sciences. This analysis is performed using the free and open-source software Paraview and the open-source software platform TTK (Topology ToolKit) designed for an efficient topological analysis of scalar fields. We apply our method to a three-dimensional spherical mantle convection model generating Earth-like plate tectonics at its surface. Our results show that, as for the Earth, the motion of modelled plates is stable over million-years-long periods separated by abrupt reorganizations occurring in less than 5 Myrs. The full plate-motion analysis over 262 Myrs in the model allows us to discuss the spatial extent of kinematic changes and shows that a plate reorganization can have regional to global effects on the plate network.

How to cite: Janin, A., Coltice, N., Tierny, J., and Chamot-Rooke, N.: The automatic detection of tectonic plates in 3D mantle convection models and plate motion changes, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-12628, https://doi.org/10.5194/egusphere-egu23-12628, 2023.

EGU23-14366 | PICO | GD3.2

Exploration of the lunar deep interior through global deformation modeling. 

Arthur Briaud, Clément Ganino, Agnès Fienga, Nicolas Rambaux, Anthony Mémin, Hauke Hussmann, Alexander Stark, and Xyanyu Hu

The Moon is the most well-known extraterrestrial planetary body thanks to observations from ground-based, space-borne instruments and lunar surface missions. Data from Lunar Laser Ranging (LLR), magnetic, gravity, surface observations and seismic Apollo ground stations help us to quantify the deformation undergone by the Moon due to body tides. These observations provide one of the most significant constraints that can be employed to unravel the deep interior. The Moon deforms in response to tidal forcing exerted by, to first order, the Earth, the Sun and, to a lesser extent, by other planetary bodies. We use the degree-2 tidal Love number as a tool for studying the inner structure of our satellite. Based on measurements of the tidal Love numbers k2 and h2 and quality factors from the GRAIL mission, LLR and Laser Altimetry on board the LRO spacecraft, we perform a random walk Monte Carlo samplings for combinations of thicknesses and viscosities for models of Moon with and without inner core. By comparing predicted and observed parameters of the lunar tidal deformations, we infer constraints on the outer core viscosity, for a Moon with a thin outer core and a thick inner core, and a Moon with a thicker outer core but a denser and thinner inner core. In addition, by deducing the temperature and assuming the chemical composition of the low-viscosity zone, we obtain stringent constraints on its radius, viscosity and density. 

How to cite: Briaud, A., Ganino, C., Fienga, A., Rambaux, N., Mémin, A., Hussmann, H., Stark, A., and Hu, X.: Exploration of the lunar deep interior through global deformation modeling., EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-14366, https://doi.org/10.5194/egusphere-egu23-14366, 2023.

EGU23-14392 | ECS | PICO | GD3.2

Magma ocean crystallization model coupling fluid mechanics and thermo-chemistry: application to the lunar magma ocean. 

Laurine Rey, Tobias Keller, Ying-Qi Wong, Paul Tackley, Christian Liebske, and Max Schmidt

Understanding the dynamics of magma ocean crystallisation during planetary cooling can elucidate the initial mantle structure and subsequent evolution of early planetary bodies. However, most studies on magma ocean crystallisation focus on either the thermo-chemistry (e.g., Johnson et al. 2021) or the fluid dynamics of a cooling magma ocean (e.g., Maurice et al. 2017). This precludes investigations into coupled thermo-mechanical processes, such as the effect of convection and phase segregation on chemical differentiation. However, coupled models are challenging to implement due to their numerical complexity and limited experimental constraints on magma ocean crystallisation for model calibration.

We develop a two-phase, 6-component model in a 2D rectangular domain based on a multi-phase, multi-component reactive transport model framework (Keller & Suckale, 2019). Magma ocean convection is modelled using Stokes equations while crystal settling is calculated using a form of hindered Stokes law. The fluid mechanics model is coupled with a thermo-chemical model of evolving temperature, phase proportions, and phase compositions to form a reactive transport model, following Keller & Katz (2016). We apply this model to the lunar magma ocean (LMO) by describing the melt and crystal compositions with 6 pseudo-components (approximating forsterite-fayalite, orthopyroxene-clinopyroxene and anorthite-albite mineral systems). To calibrate the melting temperature and composition of each component, we fit data from fractional crystallisation experiments for a Taylor Whole Moon composition (Schmidt & Krättli 2022) using a transitional Markov Chain Monte Carlo method.

The 6-component melting model calibrated to experimental data is successfully implemented in the reactive transport model. First results indicate the importance of crystal settling speed and magma convection speed on convective mixing, magma ocean stratification, and crystal cumulate formation. The small size of the Moon and its relatively well-constrained magma ocean history, make the LMO an excellent case study to apply the model. However, with the aid of new experimental data for larger and chemically different planets, such as Mars, this model can provide more general insight into the early evolution of terrestrial bodies.

REFERENCES: Maurice et al. (2017) doi:10.1002/2016JE005250, Johnson et al. (2021) doi: 10.1016/j.epsl.2020.116721,  Keller & Suckale (2019) doi:10.1093/gji/ggz287, Keller & Katz (2016)  doi: 10.1093/petrology/egw030,  Schmidt & Krättli (2022) doi:10.1029/2022JE007187

How to cite: Rey, L., Keller, T., Wong, Y.-Q., Tackley, P., Liebske, C., and Schmidt, M.: Magma ocean crystallization model coupling fluid mechanics and thermo-chemistry: application to the lunar magma ocean., EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-14392, https://doi.org/10.5194/egusphere-egu23-14392, 2023.

Upon melting inside planetary upper mantles, trace elements which are incompatible in the solid rock – such as heat producing elements or volatiles - are redistributed into the melt. If the melt is less dense than the surrounding material, the melt transports the elements towards the surface, where it enriches the crust and leaves a depleted upper mantle behind. In the case of heat producing elements, this process can affect the thermal evolution and crust production of a planet, whereas in the case of volatiles, the outgassing and atmosphere evolution can be influenced. With the help of mineral/melt partition coefficients, we are able to quantify the amount of the redistributed elements and can therefore infer the impact on the aforementioned planetary processes. Mineral/melt partition coefficients depend highly on pressure, temperature, and composition. However, due to a lack of high-pressure experiments and models, they were typically taken as constant in mantle evolution models.

In this study, we developed a 1D interior evolution model and included a pressure, temperature, and melt composition dependent mineral/melt partition coefficient model that is applicable for higher pressures (Schmidt & Noack, 2021). We apply the model to the five planetary bodies Mercury, Venus, Earth, Moon, and Mars and show that the planet size has a significant effect on the partition coefficients and therefore on the redistribution of heat producing elements and volatiles. This makes most partition coefficients based on low-pressure experiments with an Earth-based composition quite inaccurate in interior evolution models. We quantify the resulting effects on the thermal evolution, crust production, and outgassing rate. Additionally, we vary other starting parameters and compare how this affects the amount of the elements that were redistributed into the crust or outgassed into the atmosphere. These findings help us to understand the effect of depth-dependent redistribution for different types of rocky planets and might be relevant for a wide range of mantle evolution models which include mantle melting and trace element redistribution.

Schmidt, J.M. and Noack, L. (2021): Clinopyroxene/Melt Partitioning: Models for Higher Upper Mantle Pressures Applied to Sodium and Potassium, SysMea, 13(3&4), 125-136.

How to cite: Schmidt, J. M. and Noack, L.: Planet size controls the redistribution of heat producing elements and volatiles from mantle to crust, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-14685, https://doi.org/10.5194/egusphere-egu23-14685, 2023.

EGU23-15144 | ECS | PICO | GD3.2

The behaviour of S in reduced systems and its application to Mercury 

Stefan Pitsch, Paolo A. Sossi, Max W. Schmidt, and Christian Liebske

Sulfide liquids in terrestrial environments are near mono-sulfidic and are FeS-rich with varying amounts of other chalcophile elements. At highly reducing conditions, such as on Mercury, elements like Ca, Mn and Mg can also form major components of sulfides and coexist with FeS [1].
Studies on the binary and ternary phase diagrams of the MgS-FeS-CaS systems have been conducted (separated from the influence of silicic melts) , owing to the limited amount of data on these systems [2,3]. With this study we also re-examine the behaviour of sulfur-enriched, highly reduced silicate melts (komatiitic and basaltic compositions) to asses formed phases as well as their gravitationally possible separation during the magma ocean stage of Mercury. The effect of and on the formation of phases is evaluated at 1 atm, similarly to a limited amount of foregone experiments conducted by [4]. We use both the acquired sulfide-phase diagram data and the information on the sulfide-silicate-melt interaction to assess mechanisms of sulfur accumulation on the surface of Mercury by gravitational separation within the magma ocean [5].   
Experiments were performed with stoichiometric mixes of pure components in graphite capsules sealed in evacuated silica tubes at ~10-5 bar. Quenched samples were prepared under anhydrous conditions, and phase compositions determined by energy-dispersive spectroscopy (binary and ternary phase diagrams) and electron probe micro-analysis (EPMA) (silicate-melt experiments).      
The solubility of FeS in oldhamite (CaS) is higher than previously reported, reaching 2.5 mol% at 1065°C. The eutectic is located at 8 ± 1 mol % CaS, significantly poorer in CaS than previously suggested [6], at 1065 ± 5 °C. Our data suggests that solid-solution compositions in the MgS-FeS binary are in accord with those reported in the only other study on this system [7]. However, we find the system to be eutectic in nature, with the eutectic point being located at 1180°C ± 2 °C and 0.3 mol% MgS. Formed liquids have been found to contain much higher concentrations of FeS than previously reported.

Our data show that Ca dissolves extensively in sulfides under graphite-saturated conditions at low pressures, which may have prevailed during crust formation on Mercury [8]. However, in silicate-melts, liquid FeS and solid niningerite (MgS) phases dominate for all investigated silicate compositions (komatiitic and basaltic compositions).  The produced solid phases are not light enough to be able to float in a Hermean magma ocean. Formed oldhamite solid solutions are small and interspersed in liquid FeS, which prohibits their effective separation of these dense phases.

 

[1]          Skinner + Luce (1971) AmMin

[2]          Nittler + Starr et al., (2011) Science

[3]          Dilner + Kjellqvist + Selleby (2016) J Phase Equilibria Diffus

[4]          Namur + Charier et al., (2016) Earth Planet. Sci. Lett

[5]          Malavergne et al. (2014) Earth Planet. Sci. Lett.

[6]          Heumann (1942) Arch Eisenhuttenwes

[7]          Andreev et al. (2006) Russ. J. Inorg. Chem.

[8]          Vander Kaaden + McCubbin (2015) J. Geophys. Res. Planets



How to cite: Pitsch, S., Sossi, P. A., Schmidt, M. W., and Liebske, C.: The behaviour of S in reduced systems and its application to Mercury, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-15144, https://doi.org/10.5194/egusphere-egu23-15144, 2023.

Terrestrial exoplanets, ranging in size up to approximately twice Earth-size (10 Earth masses), may have a range of characteristics that are not found in solar system planets, including but not limited to: larger size, different bulk composition (possibly resulting in being core-less), being tidally-locked to their host star, and being covered by water layers. Larger size has been proposed to result in sluggish deep-mantle convection and also (for stagnant-lid exoplanets) lower magmatism and outgassing, but internal differentiation is still expected to take place. Different bulk composition may lead to different viscosity (among other physical properties), modified melting behaviour and different core size (including the possibility of having no core). Tidally-locked exoplanets likely have hemispherical tectonics and internal structures, but the asymmetry would be reduced if they are continuously reorienting due to true polar wander. We are pursuing a range of studies investigating most of these different aspects using thermo-chemical convection models that include self-consistent lithospheric dynamics, partial melting and crustal production, using the code StagYY. Some of these studies are presented elsewhere at this meeting; this presentation will focus on additional interesting results.

How to cite: Tackley, P.: Studies of terrestrial exoplanet thermo-chemical-magmatic mantle and lithosphere dynamics and evolution, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-16119, https://doi.org/10.5194/egusphere-egu23-16119, 2023.

PS5 – Physical, chemical and dynamical aspects of small bodies (dwarf planets, rocky & icy moons, asteroids, comets, KBOs, rings, meteors and interplanetary dust)

EGU23-2452 | Orals | PS5.1

The Color Diversity of Kuiper Belt Objects 

Ralf Kaiser

Objects in the Kuiper Belt exhibit the reddest known surfaces and reveal a wider range of colors than any other Solar System population. The origin of this extraordinary color diversity is unknown, but likely the result of the prolonged irradiation of organic materials by Galactic Cosmic Rays (GCRs). However, laboratory experiments simulating irradiation processes have provided conflicting results and are highly dependent on the assumed initial composition, GCR flux, and exposure time. Here, we combine ultrahigh vacuum irradiation experiments with comprehensive spectroscopic analyses to examine the GCR processing of simple hydrocarbon surfaces of methane and acetylene under Kuiper Belt conditions. This study efficiently replicates the color diversity shown by Kuiper Belt Objects located at distances from 39 to 44 AU from the Sun such as Makemake, Orcus, and Salacia, and indicates effective exposure ages of at least 1,100 million years. Aromatic structural units carrying up to three rings as in phenanthrene (C14H10), phenalene (C9H10), and acenaphthylene (C12H8), of which some carry structural motives of nitrogen bases of DNA and RNA connected via unsaturated linkers, play a key role in producing the reddish colors. These studies demonstrate the level of molecular complexity synthesized by GCR processing and hint at the role played by irradiated ice in the early production of biological precursor molecules. Extrasolar counterparts to the Kuiper belt are known in the population of debris disks such as those around Fomalhaut and Vega, where these processes must also be relevant.

How to cite: Kaiser, R.: The Color Diversity of Kuiper Belt Objects, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-2452, https://doi.org/10.5194/egusphere-egu23-2452, 2023.

EGU23-3179 | ECS | Posters on site | PS5.1

Laboratory investigation of ion expansion produced by hypervelocity dust impacts 

Libor Nouzak, Kate Edwards, Alessandro Garzelli, Tobin Munsat, and Zoltan Sternovsky

In this laboratory study we present investigation of the angular distribution of expanding ions produced by hypervelocity dust impacts. Spacecraft operated by electric field antennas can characterize interplanetary and interstellar dust populations within our solar system from dust impacts. The recorded dust impact waveforms are diverse and their shape depends on the antenna mode of operation (dipole vs. monopole), impact location with respect to the antennas, spacecraft potential or dust particles properties. A unique experimental setup with delay line detector (DLD) is developed for measuring characteristics of the ion cloud expanding from the impact generated plasma. Dust particles of micron and sub-micron size are accelerated to velocities 1—80 km/s using the electrostatic dust accelerator operated at the University of Colorado. The ions produced after impact of accelerated particles on tungsten target plate are detected using the DLD that provides the position of their detection and time-of-flight. The angular distribution of ions with respect to target normal is calculated from these positions. The preliminary results indicate that the impact-generated ions expand in the form of a narrow cone and the cone angle increases with increasing dust speed.

How to cite: Nouzak, L., Edwards, K., Garzelli, A., Munsat, T., and Sternovsky, Z.: Laboratory investigation of ion expansion produced by hypervelocity dust impacts, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-3179, https://doi.org/10.5194/egusphere-egu23-3179, 2023.

EGU23-3325 | ECS | Posters on site | PS5.1

Bayesian inference of β-meteoroid parameters with Solar Orbiter 

Samuel Kočiščák, Sigrunn Holbek Sørbye, Andreas Kvammen, Ingrid Mann, Arnaud Zaslavsky, and Audun Theodorsen

Solar Orbiter’s Radio and Plasma Waves instrument (SolO/RPW) is capable of detecting hypervelocity dust impacts onto the spacecraft through the fast electrical phenomena that accompany the process. SolO operates within 1AU, in the environment with high density of β-meteoroids – dust grains escaping from the proximity of the Sun due to radiation pressure force counteracting gravity. Recently, Convolutional Neural Network (CNN) classified data were made available[1], analyzing all the recorded waveforms and providing us with the highest quality dataset of the impact events to date.

We present a model for the in-situ impact rate on SolO/RPW assuming β-meteoroids are the main component of the detections. We fit the model to the highest quality available CNN data assisted by Integrated Nested Laplace Approximation (INLA) for Bayesian inference with informative priors[2].

Taking into account spacecraft’s position and its velocity vector, we are able to infer mean radial velocity of the detected dust grains to be 63 ± 7 km/s. We are also able to constrain β-meteoroid predominance and dust’s mean acceleration and by extension constrain its mean β-parameter. The procedure is general enough to be used in a different setting for SolO, or by a different spacecraft in the future.

References:

[1] Kvammen, Andreas, et al. "Machine Learning Detection of Dust Impact Signals Observed by The Solar Orbiter." (2022). https://doi.org/10.5194/egusphere-2022-725

[2] Kočiščák, Samuel, et al. "Modelling Solar Orbiter Dust Detection Rates in Inner Heliosphere as a Poisson Process." arXiv preprint arXiv:2210.03562 (2022). https://doi.org/10.48550/arXiv.2210.03562

How to cite: Kočiščák, S., Holbek Sørbye, S., Kvammen, A., Mann, I., Zaslavsky, A., and Theodorsen, A.: Bayesian inference of β-meteoroid parameters with Solar Orbiter, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-3325, https://doi.org/10.5194/egusphere-egu23-3325, 2023.

EGU23-4008 | Posters on site | PS5.1

Measured mechanical, optical and electrical properties of dust partciles collected in the coma of comet 67/P 

Martin Hilchenbach, Oliver Stenzel, and Klaus Hornung

During the ESA ROSETTA science mission to comet 67P/Churyumov-Gerasimenko, the dust particle analysing instrument COSIMA sampled dust in the size range from a few um to mm equivalent diameter in the inner coma of the comet.  The particles were analysed in-situ with an optical microscope and a secondary ion mass spectrometer. The dust particles were collected on porous gold black surfaces with relative low impact velocity and the break up or fragmentation due to impact as well as by mechanical and/or electrical means have been studied. We summarize the results and conclusions on the measured mechanical, optical and electrical parameters such as porosity, material strength, reflectance, electrical conductivity and relative permittivity of the dust particles.

How to cite: Hilchenbach, M., Stenzel, O., and Hornung, K.: Measured mechanical, optical and electrical properties of dust partciles collected in the coma of comet 67/P, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-4008, https://doi.org/10.5194/egusphere-egu23-4008, 2023.

EGU23-4306 | Posters on site | PS5.1

Meteor phenomena in the atmosphere of Venus 

Apostolos Christou and Maria Gritsevich

Meteor astronomy employs the atmosphere of the Earth as a large area detector for 0.01-1000 mm meteoroids [1]. Monitoring the atmospheres of other planets for meteor activity offers the opportunity to study the parent bodies of as-yet-undetected meteor showers, test ablation models under non-terrestrial conditions and allow spacecraft operators to mitigate the risk of meteoroid impact damage [2]. By adjusting existing techniques to simulate meteoroid ablation in a Venus-like atmosphere [3-8], we show that Venusian meteors are generally brighter but shorter-lived than terrestrial meteors and ablate at a higher altitude, in a predominantly clear region of the atmosphere. These simulations are complemented with a list of cometary bodies and known meteoroid streams that we consider to be prime candidates for producing significant meteor activity at Venus [9,10]. Such predictions may be used in developing future observational campaigns to be carried out from Earth or from Venus orbit.

References: [1] Jenniskens, P. (2006) Meteor Showers and their Parent Comets, Cambridge University Press, Cambridge. [2] Christou A. A. et al (2019) In: Meteoroids: Sources of Meteors on Earth and Beyond, Cambridge University Press, p.119-135. [3] Christou A. A. (2004) Icarus 168, 23-33 [4] McAuliffe, J. P., Christou, A. A. (2006) Icarus 180, 8-22 [5] Gritsevich M., Koschny D. (2011) Icarus 212, 877-884 [6] Bouquet A. et al (2012) Planet. Space Sci. 103, 238-249 [7] Gritsevich, M. I. (2009) Adv. Space Res. 44, 323–334 [8] Lyytinen, E., Gritsevich, M. (2016) Planet. Space Sci. 120, 35-42 [9] Christou A. A. (2010) MNRAS 402, 2759-2770 [10] Christou, A. A., Vaubaillon, J. (2011) In: Proc. Meteoroids Conf, NASA/CP-2011-216469, p.26

How to cite: Christou, A. and Gritsevich, M.: Meteor phenomena in the atmosphere of Venus, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-4306, https://doi.org/10.5194/egusphere-egu23-4306, 2023.

EGU23-6180 | ECS | Orals | PS5.1

Machine learning detection of dust impact signals observed by the Solar Orbiter 

Andreas Kvammen, Kristoffer Wickstrøm, Samuel Kociscak, Jakub Vaverka, Libor Nouzak, Arnaud Zaslavsky, Kristina Rackovic Babic, Amalie Gjelsvik, David Pisa, Jan Soucek, and Ingrid Mann

At present, ongoing space missions (PSP, SolO) provide the opportunity to closely observe the dust distribution in the inner solar system. It is however challenging to automatically detect and separate dust impact signals from other observed features for two main reasons. Firstly, since the spacecraft charging causes variable shapes of the dust signals, and secondly because electromagnetic waves (such as solitary waves) may induce resembling electric field signals.

In this presentation, we propose a novel method, based on artificial intelligence, for detecting dust impacts in Solar Orbiter observations with high accuracy. Two supervised machine learning approaches are considered: the support vector machine (SVM) classifier and the convolutional neural network (CNN) classifier. Furthermore, we compare the performance of the machine learning classifiers to the currently used on-board classification algorithm and analyze 2 years of Solar Orbiter data.

Overall, we conclude that detection of dust signals is a suitable task for machine learning techniques. The convolutional neural network achieves the highest performance with 96% ± 1% overall classification accuracy and 94% ± 2% dust detection precision, a significant improvement to the currently used on-board classifier with 85% overall classification accuracy and 75% dust detection precision. In addition, both the support vector machine and the convolutional neural network detect more dust particles (on average) than the on-board classification algorithm, with 16% ± 1% and 18% ± 8% detection enhancement respectively.

How to cite: Kvammen, A., Wickstrøm, K., Kociscak, S., Vaverka, J., Nouzak, L., Zaslavsky, A., Rackovic Babic, K., Gjelsvik, A., Pisa, D., Soucek, J., and Mann, I.: Machine learning detection of dust impact signals observed by the Solar Orbiter, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-6180, https://doi.org/10.5194/egusphere-egu23-6180, 2023.

EGU23-6355 | ECS | Posters on site | PS5.1

Correlated Multi-Technique Characterisation of Sulfur-Bearing Serpentine in Carbonaceous Chondrites 

Niamh Topping, John C. Bridges, Leon J. Hicks, and Takaaki Noguchi

Phyllosilicate minerals in the carbonaceous chondrites provide insights into processes in primitive parent bodies of the early Solar System. It is widely agreed that the CM- and CI-type carbonaceous chondrites underwent aqueous alteration on their parent bodies, resulting in phyllosilicate-rich matrices, where the dominant mineral phase is serpentine. There are many previous studies investigating phyllosilicate structure in carbonaceous chondrites, however, the presence of sulfur in these minerals and its effect on crystal lattice structure has not been studied in detail. We are investigating how the presence of sulfur (up to ≃9-10 wt% SO3) in serpentine phyllosilicate regions effects basal lattice spacing measurements of serpentine-like minerals in CM- and CI-type chondritic and related asteroidal material.

Four specimens are being studied for this work: Winchcombe and Aguas Zarcas (CM-type), and Ryugu samples (A0058-C2001-08, A0104-00200502 and A0104-01700602) from Hayabusa2 and Ivuna (CI-type). All samples are TEM wafers. We have used a multi-technique approach to study the samples, with the E01 JEOL ARM200CF and E02 JEOL ARM300CF electron microscopes at the ePSIC facility at Diamond Light Source in Harwell, UK. EDS compositional data has been collected using the E01 microscope, whilst HRTEM and HAADF imaging data has been collected at E02. At E02 we are also applying a new 4D-STEM nano-diffraction technique in order to collect lattice spacing data to correlate with our other HRTEM results. Fe-K XANES analyses on Winchcombe and Ryugu have been carried out using the I18 microprobe and I14 hard x-ray nanoprobe respectively, also at Diamond Light Source, to constrain Fe3+/ΣFe. By combining these techniques we aim to better understand the physical and chemical structure of serpentine-like minerals in carbonaceous chondrites.

Initial analyses have shown that sulfur presence in carbonaceous chondrite phyllosilicates reduces the basal lattice spacings of serpentine-like minerals. In these sulfur-bearing regions, we have been finding lattice spacings in the range ~0.60-0.74nm for the CM-type chondrites. For the CI-type, these range between ~0.65-0.76nm. Differences in the reduced lattice spacing ranges are likely related to the redox state of the sulfur. In Ryugu and other carbonaceous chondrites the sulfur appears reduced; its content in serpentine is low and we see FeS grains. Comparatively, in Winchcombe (and others) more of the sulfur seems to be in the serpentine structure.

We can conclude that in serpentine-like minerals, the presence of sulfur appears to reduce basal lattice spacing values compared to the expected d-spacing value of 0.70nm for serpentine. Possible reasons for this include further investigations into the valency of the sulfur ions, the bonding environment within serpentine layers, and the location of sulfur in either the octa- or tetrahedral lattice sites. 

How to cite: Topping, N., Bridges, J. C., Hicks, L. J., and Noguchi, T.: Correlated Multi-Technique Characterisation of Sulfur-Bearing Serpentine in Carbonaceous Chondrites, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-6355, https://doi.org/10.5194/egusphere-egu23-6355, 2023.

EGU23-7896 | ECS | Posters on site | PS5.1

Comparison of Solitary waves and Dust Impact Signals Detected by Electric Field Instruments onboard MAVEN 

Samia Ijaz, Jakub Vaverka, Jana Šafránková, and Zdeněk Němeček

Dust impact on the spacecraft body can result in short pulses in the measured electric field. Our study is focused on these pulses detected by the Langmuir Probe and Waves (LPW) instrument onboard the Mars Atmosphere and Volatile Evolution (MAVEN) spacecraft. LPW detects electric field signals in dipole and monopole configurations using two long identical stacer booms. Out of all the modes, we use the medium frequency burst mode, the data covers 62.5 milliseconds using 4096 measured points which gives us a sampling frequency of 66.67 kHz. We present a preliminary statistical analysis over the year 2015 (360000 waveforms) and the analysis is focused on distinguishing dust impact signatures from solitary structures. To reliably distinguish solitary waves from dust impact signals by an automatic code is a challenging task as the solitary wave signatures in the electric field data can be similar to the transient pulses generated by dust impacts. Therefore, we choose two different parameters to classify two groups of events: the ratio of rising and decay times and the ratio of positive and negative peaks of the pulse. In total, we find approximately 10000 events which compose both solitary waves and the most probable dust impacts. We discuss signals generated by dust impacts and solitary waves for different operation modes of electric field probes, spacecraft potentials, and distance of probes to the spacecraft surface.

How to cite: Ijaz, S., Vaverka, J., Šafránková, J., and Němeček, Z.: Comparison of Solitary waves and Dust Impact Signals Detected by Electric Field Instruments onboard MAVEN, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-7896, https://doi.org/10.5194/egusphere-egu23-7896, 2023.

EGU23-8154 | ECS | Posters on site | PS5.1

Physical parameters of meteoroids 

Ioana Lucia Boaca, Maria Gritsevich, Alin Nedelcu, Tudor Boaca, François Colas, Adrien Malgoyre, Brigitte Zanda, and Pierre Vernazza

In this work we present the main characteristics that derive from the analysis of the luminous part of the trajectory of a meteoroid. Our study is based on applying the α-β algorithm (Gritsevich 2008, Gritsevich 2009, Gritsevich et al. 2012, Lyytinen and Gritsevich 2016, Sansom et al. 2019, Boaca et al. 2022) to the latest detections recorded by the MOROI (Nedelcu et al. 2018) component of the FRIPON network (Colas et al. 2020). Our input parameter are the height and velocity of the meteoroid and the way they change with time. Based on this we determine the ballistic coefficient α and the mass loss parameter β for each analysed meteor event. The α-β algorithm is used in order to decide which of the fireball events produce meteorites and which are fully ablating in the atmosphere. Furthermore, the α and β parameters allow us to determine the mass of the studied meteoroids e.g. at the beginning and at the end of the luminous trajectory.

Boaca I., et al. (2022), ApJ, 936, 150.

Colas, F., et al. (2020), A&A, 644, A53.

Gritsevich, M. I. (2008), DokPh, 53, 97.

Gritsevich, M. I. (2009), AdSpR, 44, 323.

Gritsevich, M. I., et al., (2012), CosRe, 50, 56.

Lyytinen, E., & Gritsevich, M. (2016), P&SS, 120, 35.

Nedelcu, D. A., et al. (2018), RoAJ, 28, 57.

Sansom, E. K., et al. (2019), ApJ, 885, 115.

Acknowledgement.

The work of IB and AN was partially supported by a grant of the Ministry of National Education and Scientific Research, PNIII-P2-1214/25.10.2021, program no. 36SOL/2021.  MG acknowledges the Academy of Finland project no. 325806 (PlanetS).

How to cite: Boaca, I. L., Gritsevich, M., Nedelcu, A., Boaca, T., Colas, F., Malgoyre, A., Zanda, B., and Vernazza, P.: Physical parameters of meteoroids, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-8154, https://doi.org/10.5194/egusphere-egu23-8154, 2023.

EGU23-8212 | Posters on site | PS5.1

Generation and Expansion of the Impact Plasma Cloud after Dust Impacts on Solar Orbiter 

Jakub Vaverka, Jiří Pavlů, Jana Šafránková, Zdeněk Němeček, Samia Ijaz, Samuel Kočiščák, David Píša, Jan Souček, Arnaud Zaslavsky, Christopher J. Owen, and Daniel Verscharen

Dust grain impacting the spacecraft body can be either partly or totally evaporated and ionized as well as a small part of spacecraft material. A cloud of charged particles (impact cloud) generated by such impact can consequently influence the spacecraft potential and/or measurements of on-board scientific instruments. Electric field antennas are sensitive to these disturbances and typically register signals generated by dust impacts as short transient pulses. This method is commonly used for the detection of dust grains even without dedicated dust detectors. Expanding impact clouds can also influence measurements of other scientific instruments such as magnetometers and particle detectors.

The presented study is focused on the understanding of the generation and consequent expansion of impact cloud after dust impacts on Solar Orbiter. The Time Domain Sampler (TDS), a subsystem of the Radio and Plasma Wave (RPW) instrument, is used for the detection of individual dust impacts. Three channels of short electric field waveforms (typically 62.5 ms) provide us with information about the influence of expanding particles on three electric antennas. We have analyzed more than 2000 waveform snapshots with dust impacts in various operation modes (monopole and dipole antenna configurations) of RPW/TDS. Additional information about particles generated by dust impact is provided by the Electron Analyser System (EAS), one of the Solar Wind Analyser (SWA) suite instrument.

How to cite: Vaverka, J., Pavlů, J., Šafránková, J., Němeček, Z., Ijaz, S., Kočiščák, S., Píša, D., Souček, J., Zaslavsky, A., Owen, C. J., and Verscharen, D.: Generation and Expansion of the Impact Plasma Cloud after Dust Impacts on Solar Orbiter, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-8212, https://doi.org/10.5194/egusphere-egu23-8212, 2023.

EGU23-8649 | Orals | PS5.1

Inventory of Interstellar (ISD) and Interplanetary Dust (IDP) at 1 AU 

Mihaly Horanyi, Zoltan Sternovsky, Jamey Szalay, Ethan Ayari, and Rebecca Mikula

The Interstellar Mapping and Acceleration Probe (IMAP) is scheduled to launch in 2025, to be stationed at the Sun-Earth L1 Lagrange point with a combination of 10 in-situ and remote sensing instruments. A primary science goal of  IMAP is to improve our understanding of the composition and properties of the local interstellar medium. The local interstellar medium contains plasma, magnetic fields, neutral atoms, cosmic rays, and dust which all influence the heliosphere through interconnected time-dependent and multi-scale processes. The Interstellar Dust Experiment (IDEX) instrument onboard IMAP will measure the flux, size distribution, and composition of interstellar dust particles (ISD), characterizing the inflowing solid matter from the local interstellar medium reaching the inner heliosphere. IDEX will determine whether the composition of the contemporary local interstellar cloud's dust population is consistent with being the feedstock for the formation of the Solar System. In addition to heliospheric science goals, IDEX  will also detect the shared pool of interplanetary dust particles (IDP) of cometary and asteroidal origin and determine whether some IDPs preserve unprocessed pre-solar molecular cloud particles or show signatures of processing in the solar system. IDEX will identify primary organic material from asteroids and various cometary families to determine if they share a common source or are formed from distinct reservoirs. IDEX dust detection is based on impact ionization, where elemental and molecular ions are generated in a high-velocity dust impact and analyzed in a time-of-flight (TOF) setup. This talk will discuss the expected scientific results of IDEX that are of primary importance to heliospheric, astrophysical, and planetary sciences. This talk will summarize our current understanding of the ISD and IDP inventory and the expected improvements by the IMAP mission.

How to cite: Horanyi, M., Sternovsky, Z., Szalay, J., Ayari, E., and Mikula, R.: Inventory of Interstellar (ISD) and Interplanetary Dust (IDP) at 1 AU, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-8649, https://doi.org/10.5194/egusphere-egu23-8649, 2023.

EGU23-9261 | Posters on site | PS5.1

Spectral Variation on the Trojan Asteroid 4709 Ennomos 

Joshua Emery

The Trojan asteroids are hypothesized to have been emplaced from the Kuiper Belt into Jupiter’s stable Lagrange regions early in Solar System history.  They therefore contain information about the materials present in the outer Solar System during planet formation and how those materials are affected by inward migration.  A bimodal distribution of visible to near-infrared (VNIR; 0.4 to 2.5 μm) spectral slopes suggest two distinct composition groups, but the actual compositions of those groups remain elusive due to a lack of absorption features at these wavelengths.  Evolutionary models of Trojans generally predict the sublimation loss of volatiles from surface layers, creating a refractory mantle.  Irradiation of surface layers may induce physical and/or chemical changes that further alter the surface relative to the interior.  Impacts could break through surface layers and reveal subsurface materials.  The absence of spectral variations on Trojans reported in the literature have suggested either that no exposures of sub-surface materials have been detected or that the sub-surface is spectrally identical to the surface layers.  An early report of a possible high albedo of the Trojan asteroid 4709 Ennomos was attributed to possible exposure of ice.  Follow-up spectra revealed no signatures of ice, but the asymmetric lightcurve is consistent with a bright spot on the surface.  In order to further investigate possible exposure of sub-surface materials on Ennomos, we have measured multiple NIR (0.7 to 2.5 μm) spectra at the NASA IRTF, including two sets that continuously cover half a rotation each.  The spectral slopes vary with rotation, from spectra consistent with the less-red Trojan spectral group (analogous to P-type asteroids) to slightly blue-sloped spectra (analogous to C- or B-type asteroids).  Nevertheless, all spectra remain featureless, including no indication of the presence of water ice.  Analyses of these spectra along with other published data of Ennomos place constraints on compositions responsible for the varying spectra.  We will discuss these results in the context of the Trojan population, including predictions for surface variability that the Lucy mission may see on the Trojans it visits.

How to cite: Emery, J.: Spectral Variation on the Trojan Asteroid 4709 Ennomos, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-9261, https://doi.org/10.5194/egusphere-egu23-9261, 2023.

EGU23-9586 | ECS | Orals | PS5.1

Covariance Analysis of Hera Radio Science Experiment including LIDAR Altimetric Crossovers 

Edoardo Gramigna, Riccardo Lasagni Manghi, Marco Zannoni, Paolo Tortora, Ryan S. Park, Nicole Dias, Paulo Gordo, Rui Melicio, Michael Kueppers, and Patrick Michel

Hera is a European Space Agency (ESA) space mission, part of the Asteroid Impact and Deflection Assessment (AIDA) international collaboration with NASA, with a targeted launch to the Didymos system next October 2024. Following last 26 September 2022 extremely successful NASA’s DART impact on Dimorphos, the secondary body of the Didymos binary system, all the attention is now focused on the Hera mission. The main goals of Hera are the detailed study and characterization of DART’s crater, analysis of the impact in terms of momentum transfer efficiency, and accurate estimation of the physical properties of Didymos and Dimorphos, in order to validate and demonstrate the kinetic impactor technique to deflect potentially hazardous asteroids in the future.

In this context, one of the main goals is to accurately estimate the mass and mass distribution of Didymos and Dimorphos, by means of radio science investigations. In particular, one of the very few direct measurements of the internal mass distribution of planetary bodies is the determination of their gravity field. The gravity of Didymos and Dimorphos will be estimated by precisely reconstructing the trajectory of Hera and the two companion CubeSats (Juventas and Milani) during a selected number of close encounters, by performing an orbit determination process. In particular, Hera will make use of an Inter-Satellite Link system (ISL) to track Juventas and Milani, measurements which will further improve Didymos’ system extended gravity field estimation.

Furthermore, the Hera spacecraft is equipped with a Light Detection and Ranging instrument (LIDAR), a time-of-flight Planetary ALTimeter (PALT) that will measure the distances from the Hera spacecraft to the target body surfaces. The PALT altimetric measurements can be combined with Earth-based radiometric, ISL radiometric, and Hera optical observables to enhance the gravity science scientific parameters.

This work discusses a covariance study of the Hera radio science experiment including crossovers estimation to the PALT LIDAR altimetry data. The trajectory constraints obtained from the radiometric tracking and optical data can be supplemented by altimetric crossovers, to further improve the reconstruction of the spacecraft trajectory with respect to the case without crossovers (i.e. PALT LIDAR altimetry data considered as single measurements, without estimating the surface landmarks probed multiple times by the LIDAR swaths). As a consequence of a better knowledge of Hera’s trajectory, the formal uncertainties of the scientific parameters of interest decrease, too. In particular, there is a potential further improvement of Dimorphos’ relative orbit estimation, as well as Didymos and Dimorphos gravity field, and their rotational state, with respect to the case without altimetric crossovers.

© 2023 EG, RLM, MZ, and PT wish to acknowledge Caltech and the NASA Jet Propulsion Laboratory for granting the University of Bologna a license to an executable version of MONTE Project Edition S/W. Italian Space Agency (ASI) sponshorship acknowledged, Agreement No. 2022-8-HH.0 in the context of ESA’s Hera mission. EG is grateful to Fondazione Cassa dei Risparmi di Forlì for financial support of his PhD fellowship. This project has received funding from the NEO-MAPP project (European Union’s Horizon 2020 programme, agreement No 870377).

How to cite: Gramigna, E., Lasagni Manghi, R., Zannoni, M., Tortora, P., Park, R. S., Dias, N., Gordo, P., Melicio, R., Kueppers, M., and Michel, P.: Covariance Analysis of Hera Radio Science Experiment including LIDAR Altimetric Crossovers, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-9586, https://doi.org/10.5194/egusphere-egu23-9586, 2023.

EGU23-9801 | ECS | Orals | PS5.1

Contribution of multiple scattering to the distribution of Lyman alpha emission in comet comae 

Yudai Suzuki, Kazuo Yoshioka, Kei Masunaga, Hideyo Kawakita, Yoshiharu Shinnaka, Go Murakami, Tomoki Kimura, Fuminori Tsuchiya, Atsushi Yamazaki, and Ichiro Yoshikawa

Comets are important in understanding the material balance of current and past planets. Water production rates from comet nuclei have been evaluated using various instruments including a Japanese satellite, Hisaki. In case of UV observations, water production rates are generally evaluated through the comparison of the observations of the Lyman alpha radiance distribution and kinetic model of hydrogen atoms generated by photodissociation of water molecules. However, dynamics of hydrogen atoms in comae in the vicinity of nuclei has not been well understood especially for long period comets with large water production rates.

In this study, we obtained the spatial distributions of Lyman alpha radiance through the analysis of spectroscopic data of long period comets such as C/2013 US_{10} (Catalina) observed by Hisaki. As a results, inclination of the Lyman alpha radiance was found to become flatter below the impact parameter of 5 × 10^{4} km. We attributed this variation of inclination to multiple scattering, and established a radiative transfer model considering multiple scattering of photons. Then we successfully reproduced the Lyman alpha radiance distributions in comae observed by Hisaki.

According to calculations using this model, multiple scattering becomes effective in comae when the hydrogen column density exceeds approximately 5 × 10^{22} /km^{2}. Additionally, multiple scattering was found to cause the sunward/anti-sunward radiance asymmetry less than 3 %, and the apparent increase of D/H ratio around the nuclei by a factor of more than 10.

Using these results, the feasibility of detecting deuterium and evaluating the D/H ratio via Hydrogen Imager (HI) onboard the Comet Interceptor spacecraft was discussed. It was found that deuterium could be detected with a sufficient S/N ratio and that the D/H ratio could be evaluated with relative error less than 60 % using the model. The largest error factor in D/H ratio calculation is the dependence of the results of radiative transfer model on hydrogen temperature. Constraint on observations by HI or calculation by models such as DSMC will enable the calculation of the D/H ratio with higher accuracy.

How to cite: Suzuki, Y., Yoshioka, K., Masunaga, K., Kawakita, H., Shinnaka, Y., Murakami, G., Kimura, T., Tsuchiya, F., Yamazaki, A., and Yoshikawa, I.: Contribution of multiple scattering to the distribution of Lyman alpha emission in comet comae, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-9801, https://doi.org/10.5194/egusphere-egu23-9801, 2023.

EGU23-11092 | ECS | Orals | PS5.1

O-bearing molecules in comet 67P revisited: evidence for abundant heterocycles 

Nora Hänni, Kathrin Altwegg, Michael Combi, Stephen Fuselier, Johan De Keyser, Daniel Müller, Martin Rubin, and Susanne Wampfler

Alongside meteorites, impacting comets are considered a major source of pristine organic matter delivered to the early Earth, see, e.g., Rubin et al. (2019). Their chemical inventory, hence, is a key towards understanding prebiotic chemistry and the processes that led to the evolution of carbon-based life on Earth. For comet 67P/Churyumov-Gerasimenko (hereafter 67P), especially the high-resolution Double Focusing Mass Spectrometer (DFMS) – part of the Rosetta Orbiter Spectrometer for Ion and Neutral Analysis (ROSINA; Balsiger et al. 2007) onboard the European Space Agency’s Rosetta spacecraft – obtained data that allows the study of this comet’s chemical composition in unprecedented detail (LeRoy et al. 2015, Schuhmann et al. 2019). For the time period around its perihelion in early August 2015, the comet was very active and extensive dust ejection was observed (Vincent et al. 2016). Decoupled from the cometary surface, the dust particles heat up and sublimation of also larger molecules is enhanced. Relying on reference spectra – either calibrated or from the database of the National Institute of Standards and Technology –, Hänni et al. (2022) showed how the mass spectrum of pure hydrocarbon species could be fully deconvolved, which led to the identification of new cometary organic species. Following the same approach, also heteroatom-bearing species can be investigated. After the pure hydrocarbon species, O-bearing organic molecules of the general formula CnHmOx (where n = 1-8, m = 0-14, and x = 1-2) depict the second-most abundant group of cometary volatile organics. This group of species is in the focus of our ongoing work, not only for their comparably high abundance in comets but also for their prebiotic relevance. The heteroelement O is common in biomolecules such as fatty acids, amino acids, and sugars. For the first time and with great certainty, we confirm abundant heterocycles like furan and pyran (including several derivatives), which have been long sought but not yet detected in the Interstellar Medium (ISM; Barnum et al. 2022). The presence especially of furan is of great interest because of the furanose moiety in the sugar/phosphate backbone of (deoxy)ribonucleic acid. Eventually, we compare and contrast 67P’s updated and extended inventory of O-bearing organic molecules to other comets (Biver and Bockelée-Morvan 2019) and the ISM (McGuire 2022), showing that our data delivers evidence for many new species.

 

Rubin et al. ACS Earth Space Chem. 2019, 3, 1792−1811.

Balsiger et al. Space Sci. Rev. 2007, 128, 745-801.

Le Roy et al. Astron. Astrophys. 2015, 583, A1.

Schuhmann et al. ACS Earth Space Chem. 2019, 3, 1854–1861.

Vincent et al. MNRAS 2016, 462 (Suppl_1), 184-194.

Hänni et al. Nat. Commun. 2022 13:3639.

Barnum et al. J. Phys. Chem. A 2022, 126, 2716−2728.

Biver and Bockelée-Morvan ACS Earth Space Chem. 2019, 3, 1550−1555.

McGuire The Astrophysical Journal Supplement Series 2022, 259:30, 51.

How to cite: Hänni, N., Altwegg, K., Combi, M., Fuselier, S., De Keyser, J., Müller, D., Rubin, M., and Wampfler, S.: O-bearing molecules in comet 67P revisited: evidence for abundant heterocycles, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-11092, https://doi.org/10.5194/egusphere-egu23-11092, 2023.

EGU23-11341 | Posters virtual | PS5.1

About the possibility of using AMATERAS data to check the detection of dangerous asteroids 

Beibit Zhumabayev and Ivan Vassilyev

Asteroids approaching the Earth from the direction of the Sun and may pose a danger to the Earth are detected either too late or are not detected at all by optical observations. They can be detected using passive radar, using the radio emission of the Sun as a probing signal [2,3]. It is most convenient to use Venus, Mercury and the Moon as calibration objects when working out the method of detecting small celestial bodies, since their position relative to the Sun is easy to calculate, and their sizes are well known. If the control bodies deviate from the direction of the Sun by 2 degrees, the delay of the signals reflected from Mercury, Venus and the Moon will be 484, 118 and 0.2 ms, respectively. Due to the relatively small delay values of the reflected signals, it is impossible to use most of the available solar radio telescopes with an integration time of 1 to 10 seconds to implement this method. The radio telescope of the AMATERAS project [1], capable of receiving signals of less than 0.7 SFU with an integration time of 10 ms, is suitable for receiving and isolating reflected signals. The beam width of the radiation pattern of the AMATERAS radio spectropolarimeter is about 4 degrees at a frequency of 150 MHz, which allows receiving signals simultaneously directly from the Sun and reflected from the Moon during periods of solar eclipses. With the passive location of Mercury and Venus, it is most expedient to use type I radio flashes with a duration of less than 1 second as a probing signal. When locating the Moon, it is more convenient to use type III radio flashes, during which the radiation frequency changes at a speed of up to 20 MHz/ s (2 kHz in 10 ms). For ten years of observations of the Sun, a large amount of data has been accumulated on the AMATERAS system, including during solar eclipses, which allows us to work out algorithms for direction finding of small celestial bodies approaching the Earth from the Sun in the post-processing mode.

References

[1] Iwai K., Tsuchiya F., Morioka A., Misawa H. IPRT/AMATERAS: A new metric spectrum observation system for solar radio bursts // Solar Phys. 2012. V. 277. P. 447–457. DOI: 10.1007/s11207-011-9919-y.

[2] Vassilyev I., Zhumabayev B. On the possibility of using the Orbita radio polygon for radar detection of asteroids // Satellite monitoring of geodynamic processes and space weather. – Almaty, 2020 – pp. 133-138.

[3] Pavelyev A., Gubenko V., Matyugov S., Zakharov A., Yakovlev O. Perspectives of the bistatic radar and occultation studying of the Venus and planetary atmospheres and surfaces EGU General Assembly 2013 EGU2013-10289, 07-10 April 2013.

How to cite: Zhumabayev, B. and Vassilyev, I.: About the possibility of using AMATERAS data to check the detection of dangerous asteroids, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-11341, https://doi.org/10.5194/egusphere-egu23-11341, 2023.

EGU23-14032 | Posters on site | PS5.1

Dust Interaction with Charged Particles in Laboratory 

Jiří Pavlů, Libor Nouzák, Jan Wild, Jana Šafránková, and Zdeněk Němeček

Dust in space is subject to various interactions of photons and charged particles. Whereas photoemission is rather well understood, the charging of dust grains due to the interaction with charged particles has many variations and was not study in detail so far. We report the first laboratory experiment dealing with some less pronounced and often neglected secondary processes, e.g., secondary electron emissions due to ion, electron or positron impacts. We employed a quadrupole trap to store a single micrometer-sized silicate dust grain and measure variations of its charge with an accuracy of one elementary charge. The determined yields of secondary processes exhibit surprisingly large values. We discuss the experimental results and formulate possible consequences for space dust charging.

How to cite: Pavlů, J., Nouzák, L., Wild, J., Šafránková, J., and Němeček, Z.: Dust Interaction with Charged Particles in Laboratory, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-14032, https://doi.org/10.5194/egusphere-egu23-14032, 2023.

EGU23-14828 | ECS | Posters on site | PS5.1

A Comparative Carbon XANES and EELS Study of Organic Matter in the Ivuna CI Chondrite 

Lukas Petera, Hitesh, G. Changela, John, C. Bridges, Yoko Kebukawa, Leon, J. Hicks, Niamh Topping, and Martin Ferus

An understanding the organic matter (OM) in primitive interplanetary materials can provide us with important constraints on both the early solar system carbon cycle and incipient prebiotic synthesis before the origin of life. As a window to the past, primitive chondrites preserve the most pristine record of parent body, nebular and interstellar components and the occurrence of OM in them has been shown in both soluble (SOM) (1)  and insoluble (IOM) (2) form. Total organic carbon (TOC) abundance reaches ~3-4 wt% in the most primitive carbonaceous chondrite (CCs) (3), such as Ivuna-type chondrites (CIs) – thus making them highly desirable for the OM studies, and relevant to the study of Asteroid 162173 Ryugu samples from the Hayabusa-2 mission.

A combination of both SOM and IOM analysis of organic bulk meteorite separates together with in-situ analysis of OM have provided a comprehensive account of chondritic OM (4). In the case of in-situ analysis, the combination of both scanning (SEM) and transmission electron microscopy (TEM) together with soft X-Ray scanning transmission microscopy (STXM) have shown the presence of micron to submicron distinctive organic particles (OPs) (5). Carbon K-edge X-ray absorption near edge structure (XANES) has shown the aromatic-carbonyl-carboxyl chemical nature of these organic particles (5). In addition, aromatic-poorer and carboxylic-richer diffuse OM (6) within both amorphous and phyllosilicate occurs as well.

As observation techniques are getting better, aberration corrected TEM coupled with electron energy loss spectroscopy (EELS) might provide the same results as carbon XANES, but with higher image magnification, rapid data acquisition and better accessibility. In this context, we present the results of a comparative carbon K-edge XANES and EELS study of CI meteorite Ivuna. An approximately 100 nm lamella of the Ivuna meteorite was prepared using focused ion beam (FIB)-SEM with the Helios 5 Hydra DualBeam (CEITEC, Masaryk University, Czechia) and analysed by TEM-EELS with the JEOL ARM200CF (ePSIC, Diamond Light Source, UK) and STXM-XANES at Beamline BL19A of the KEK Photon Factory, Japan. We observed that (I) XANES on samples that did not experience TEM-EELS are in agreement with the previous studies of aromatic-carbonyl-carboxylic macromolecular OPs and IOM, while (II) the TEM-EELS of OPs show aromatic-carbonyl functional chemistry but with amorphous carbon convoluting the carboxylic peak, and aromatic-poor spectra with a sharp carbonate peak in diffuse OM. The difference between XANES and EELS particularly in the diffuse OM can be interpreted by electron-beam damage. Thickness and e-beam damage leads to amorphous C formation in the OPs. In the case of more labile OM in the phyllosilicate, its change by heating and oxidation is expected.

 

References:

  • 1. M. A. Sephton, Nat. Prod. Rep., 19, 292–311 (2022).
  • 2. C. M. O. Alexander et al., Geochim. Cosmochim. Acta, 71, 4380–4403 (2007).
  • 3. S. Pizzarello et al., Meteorites early Sol. Syst. II, 1, 625–651 (2006).
  • 4. D. P. Glavin et al., in Primitive meteorites and asteroids, pp. 205–271 (Elsevier, 2018).
  • 5. H. G. Changela et al, Meteorit. Planet. Sci., 53, 1006–1029 (2018).
  • 6. Le Guillou C., et al, Geochim. Cosmochim. Acta, 131, 368–392 (2014).

How to cite: Petera, L., Changela, H. G., Bridges, J. C., Kebukawa, Y., Hicks, L. J., Topping, N., and Ferus, M.: A Comparative Carbon XANES and EELS Study of Organic Matter in the Ivuna CI Chondrite, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-14828, https://doi.org/10.5194/egusphere-egu23-14828, 2023.

EGU23-16469 | Posters on site | PS5.1

Dynamical analysis of mineral dust in the Saturnian system 

Mario Trieloff, Christian Fischer, Frank Postberg, and Jürgen Schmidt

Dust in the Saturnian system is dominated by ice grains stemming from the active moon Enceladus [1,2]. Moreover, a significant population of 1859 sub-micron sized mineral dust grains were detected by the Cosmic Dust Analyser (CDA) aboard the Cassini spacecraft. CDA inferred the composition of dust particles with an impact ionisation mass spectrometer via time of flight mass spectroscopy. The successful compositional characterization of 36 interstellar dust particles recorded by CDA showed the potential of this approach [3].

Our previous dynamic analysis [4] conservatively estimated orbital parameters of this non-icy particle population of which many dust particles occurred in confined time intervals (swarms).  Two main dynamic populations were identified: retrograde potentially endogenous and polar potentially exogenous swarms. Compositional analysis revealed two main types: iron-rich sulfide and oxide particles (58%) and Mg-rich silicates (34%) while a small share (8%) consisted of mixed type particles [4]. Retrograde swarms contained a significantly higher fraction of iron rich grains compared to exogenous swarms.

Here we present a refined approach to reconstruct orbital parameters. Considering the occurrence of certain element mass lines [5] within the mass spectra, we derive a minimum impact velocity. Assuming that the grains are bound to the Sun, we obtain as an upper bound for the impact speed onto CDA the escape velocity from the solar system at Saturn distance. Due to CDA's large field of view the impact direction is constrained within a range of 56°. We take into account the angular dependence of the sensitive area of the impact Target of CDA to derive the probability distribution of impact directions for a given detection. Combining both constraints we can determine a probability distribution density for the orbital elements which we use to evaluate the mean eccentricity and inclination for each swarm as well as for single detections.

Again, two disjoint dynamic populations are identified: almost certainly endogenous swarms with retrograde inclinations of about 170° and high-eccentricity exogenous swarms with nearly polar inclinations. The inclination of the retrograde endogenous particles is consistent with the previously suggested origin [4] from impact ejecta of Saturn's retrograde outer moons released by micro-meteoroid bombardment. In order to trace the origin of the exogenous particles their hyperbolic orbits in the Saturnian system are projected onto Saturn’s Hill sphere.

In this ongoing work we aim to identify potential sources like the Kuiper Belt and Oort Cloud or Centaur comets and present an updated compositional analysis with the potential to constrain the composition of the sources of the grains detected by CDA.

References

[1] Postberg F. et al (2008) Icarus 193, 438-454.

[2] Postberg F. et al. (2009) Nature 459, 1098-1101.

[3] Altobelli N. et al. Science 352, 312-318 (2016)

[4] Fischer C. et al. Poster EPSC 2018

[5] Fiege K. et al. Icarus 241, 336-345 (2014)

How to cite: Trieloff, M., Fischer, C., Postberg, F., and Schmidt, J.: Dynamical analysis of mineral dust in the Saturnian system, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-16469, https://doi.org/10.5194/egusphere-egu23-16469, 2023.

EGU23-16700 | ECS | Orals | PS5.1

Linking enstatite meteorites to a unique source. 

Chrysa Avdellidou, Marco Delbo, Alessandro Morbidelli, Kevin Walsh, Edhah Munaibari, Jules Bourdelle de Micas, Maxime Devogele, Sonia Fornasier, Matthieu Gounelle, and Gerard van Belle

The identification of meteorite parent bodies provides the context for understanding planetesimal formation and evolution as well as the key Solar System events they have witnessed. However, identifying such links has proven challenging and some appear ambiguous. Here, we identify that the family of asteroid fragments whose largest member is (161) Athor is the unique source of the rare EL enstatite chondrite meteorites, the closest meteorites to Earth in terms of their isotopic ratios. The Athor family was created by the collisional fragmentation of a parent body 3 Gyr ago in the inner main belt. We calculate that the diameter of the Athor family progenitor was 64 km in diameter, much smaller than the putative size of the EL original planetesimal. Therefore, we deduce that the EL planetesimal that accreted in the terrestrial planet region underwent a first catastrophic collision in that region, and one of its fragments suffered a more recent catastrophic collision in the main belt, generating the current source of the EL meteorites. 

How to cite: Avdellidou, C., Delbo, M., Morbidelli, A., Walsh, K., Munaibari, E., Bourdelle de Micas, J., Devogele, M., Fornasier, S., Gounelle, M., and van Belle, G.: Linking enstatite meteorites to a unique source., EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-16700, https://doi.org/10.5194/egusphere-egu23-16700, 2023.

EGU23-16988 | Orals | PS5.1

The upcoming seismo-acoustic observational campaign of an artificial meteor: The OSIRIS-Rex Sample Return Capsule re-entry 

Elizabeth Silber, Sarah Albert, Elizabeth Berg, Daniel Bowman, and Fransiska Dannemann Dugick

Meteoroids and asteroids are of broad scientific interest, from planetary sciences to hypersonic physics. However, impacts into the Earth’s atmosphere, especially by asteroids in a meter-size range, are sporadic and unannounced, making it impractical to plan a dedicated multi-instrument observation campaign aimed at studying and characterizing these objects. Thus, well-documented scientific observations of asteroids are rare and generally happen by chance. In these cases, many parameters of interest (e.g., composition, size, porosity, rotation, ablation rate, shock characteristics, hyperthermal chemical processes) remain poorly defined, and scientific analyses largely rely on assumptions and predictions derived from the theoretical domain. Since the end of the Apollo era, only four instances of a hypersonic re-entry of an artificial body from interplanetary space with an incident speed of 11-12 km/s have been observed and studied. These were the Sample Return Capsules (SRCs) that brought physical samples of extraterrestrial material back to Earth. Arriving from interplanetary space at hypervelocity, SRCs are considered analogues for low velocity meteoroids and asteroids impacting the Earth’s atmosphere, and as such provide unprecedented and unique opportunities to perform detailed studies of meteor phenomena, test and calibrate sensors, and validate and improve models. The next opportunity will present itself on 24 September 2023 with the re-entry of OSIRIX-REx SRC that will bring samples of the carbonaceous near-Earth asteroid Bennu. The OSIRIX-REx asteroid sample return mission was launched in 2016 with the aim to collect samples from the near-Earth asteroid Bennu and bring those samples back to Earth in pristine condition. Bennu was chosen because it is a readily accessible, primitive, carbonaceous asteroid, and it is also one of the most potentially hazardous known near-Earth objects. OSIRIX-REx SRC is identical to that of the Stardust SRC; that includes the mechanical design, and all aspects of re-entry. Landing is planned for 24 September 2023.The OSIRIX-REx re-entry presents a unique and exceptional opportunity to observe a well-defined artificial meteor, to perform detailed studies of hypersonic entry and event characterization, to test sensors, and validate and improve models. We will organize and lead multi-instrument observations of the OSIRIX-REx SRC re-entry. The instruments will include infrasound and seismic sensors strategically positioned in the immediate and extended region around the projected re-entry trajectory to maximize the scientific output. Data collected during this observational campaign will be made freely available to the broad scientific community following publication.

SNL is managed and operated by NTESS under DOE NNSA contract DE-NA000352.

How to cite: Silber, E., Albert, S., Berg, E., Bowman, D., and Dannemann Dugick, F.: The upcoming seismo-acoustic observational campaign of an artificial meteor: The OSIRIS-Rex Sample Return Capsule re-entry, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-16988, https://doi.org/10.5194/egusphere-egu23-16988, 2023.

EGU23-17070 | Posters on site | PS5.1

Wherever You Go, There You Are — Evolution of Cometary Dust Trails Produced by Outbursts 

Maria Gritsevich, Markku Nissinen, Jorma Ryske, Jari Suomela, Arto Oksanen, Veikko Mäkelä, Elizabeth Silber, and Josep Maria Trigo-Rodríguez

In the recent paper [1] we introduced the Dust Trail kit model capable of describing the evolution of a cometary dust trail. The model accounts for solar radiation pressure effects, gravitational disturbance caused by Venus, Earth and Moon, Mars, Jupiter and Saturn, and gravitational interaction of the particles in the trail with the parent comet itself. Excellent accuracy of computations is due to their implementation in Orekit Open Source Library for Operational Flight Dynamics, which executes Dormad-Prince numerical integration methods with higher precision. We demonstrate performance of the model by studying the comet 17P/Holmes, which underwent through a massive outburst in October 2007 — the largest documented outburst by a comet thus far. We simulate several particle populations with sizes ranging from 0.001 to 1 mm and by varying assumptions about ejection speed distribution of the particles at the start of the outburst. The model is validated against our earlier observations of the trail obtained in common nodes for 0.5 and 1 revolutions. Using these data, we made predictions for the two-revolution dust trail behavior near the outburst point and the observability from Earth of the cometary material released in the event [1]. We have further developed a set of Python scripts to calculate position of the dust trail for observatory topographical location coordinates [2]. Using these predictions, a set of new observations of the 2007 outburst dust trail was obtained in February, March, October, and December 2022. The trail is still observable by using even moderate ground-based telescopes. The existence of an observable dust trail requires sunlight scattered by a significant number of micron-sized particles produced in the phenomena. Both the surface brightness and the position of the dust trail are within the limits of the published predictions provided by the Dust Trail kit model [1, 2].

 

References

1. Gritsevich M., Nissinen M., Oksanen A., Suomela J., Silber E.A. (2022). Evolution of the dust trail of comet 17P/Holmes, Monthly Notices of the Royal Astronomical Society, 513(2), 2201–2214, https://doi.org/10.1093/mnras/stac822

2. Nissinen M., Gritsevich M. (2022). Instructions on where and how to observe the comet 17P/Holmes dust trail. Zenodo. https://doi.org/10.5281/zenodo.6977358

How to cite: Gritsevich, M., Nissinen, M., Ryske, J., Suomela, J., Oksanen, A., Mäkelä, V., Silber, E., and Trigo-Rodríguez, J. M.: Wherever You Go, There You Are — Evolution of Cometary Dust Trails Produced by Outbursts, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-17070, https://doi.org/10.5194/egusphere-egu23-17070, 2023.

We computed the total water vapor outgassing rate for comet 67P/Churyumov-Gerasimenko for a time period spanning several months before and after the perihelion in 2015. The two-layer surface model includes time-dependent solar illumination, thermal emission, sublimation, heat transport into the nucleus, and gas diffusion through the dust layer. The model parameters include among others the thickness of the top dust layer and the ice content in the bottom layer. We fitted the model parameters so that the temporal evolution of the computed water outgassing rate matches published outgassing rates derived from observations with the Microwave Instrument for the Rosetta Orbiter (MIRO). We will discuss the evolution of the retrieved dust thickness and ice content before and after perihelion and the variations between the northern and southern hemispheres of the nucleus.

How to cite: von Allmen, P., Jhalani, V., and Lee, S.: Sub-surface dust thickness and ice content in the nucleus of comet 67P/Churyumov-Gerasimenko constrained with Rosetta observations, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-17231, https://doi.org/10.5194/egusphere-egu23-17231, 2023.

EGU23-17435 | Posters on site | PS5.1

A discourse on the temperature measurement problem using meteor wind radar 

Emranul Sarkar and Thomas Ulich

Sodankylä's high latitude location serves an ideal ground for testing more comprehensive physics theory related to radio meteor data. The atmospheric scale height shows significant variation at this latitude.  Also, the observational geometry towards the plane of  ecliptic plane changes drastically with seasons. On theory, the reflected radio signal from the ablating meteor train can be used to continuously monitor atmospheric temperature at the 90 km altitudes. In practice, complication arises due to the selection effects in the system as well as the persistent effect of natural variability (size, mass, velocity, entry angle) in meteoroids property. The long-standing hypothesis that needs to be debated: Is the assumed equality between atmospheric scale height (H_KT) and the effective diffusion scale height (H_D) of meteor trails valid for these data? In this study, we argue that such an hypotheis can not be experimentally validated, and hence the need for subsequent calibration. Furthermore, long-term trend analysis showed that the discrepancy between H_KT and H_D  has non-linear seasonal trends. Alternatively, we demonstrate an alternative method of  scale-height measurement based on meteor height distribution. The technical and theoretical limits of this methodology are discussed and validated using 10 years of observational data.

How to cite: Sarkar, E. and Ulich, T.: A discourse on the temperature measurement problem using meteor wind radar, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-17435, https://doi.org/10.5194/egusphere-egu23-17435, 2023.

EGU23-969 | Posters on site | PS5.3

Lunar Mission Planning and Exploration using NASA’s Moon Trek Portal 

Emily Law and Brian Day and the Solar System Treks

NASA’s Moon Trek (https://trek.nasa.gov/moon/) is one of a growing number of interactive, browser-based, online portals for planetary data visualization and analysis produced by NASA’s Solar System Treks Project (SSTP). Moon Trek continues to be enhanced with new data and new capabilities enabling it to facilitate the planning and conducting of upcoming lunar missions by NASA, its commercial partners, and its international partners, as well as scientific research.

Moon Trek’s innovation visualization and analysis tools are already being used by a growing number of missions and scientists around the world. The tools deployed including interactive 2D and 3D visualization, a DEM and Ortho Mosaic Image production pipeline as well as tools for distance measurement, elevation profile generation, solar altitude and azimuth calculation, 3D print file generation, virtual reality visualization generation, lighting analysis, electrostatic surface potential analysis, slope analysis, rock detection, crater detection, rockfall detection, and profiling of raster data.

Moon Trek has added a new set of visualization and analysis tools include line of sight analysis (facilitating communications planning and detailed studies of solar illumination), traverse path planning, and 3D traverse path visualization tool, among others. This presentation for EGU will highlight Moon Trek’s latest tools and demonstrate their usage targeted for Lunar mission planning and exploration in this exciting Artemis era.

How to cite: Law, E. and Day, B. and the Solar System Treks: Lunar Mission Planning and Exploration using NASA’s Moon Trek Portal, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-969, https://doi.org/10.5194/egusphere-egu23-969, 2023.

This work studies the remanent magnetization under a weak and a strong magnetic anomaly in Tranquillitatis and in Oceanus Procellarum respectively, which show similar surface ages of 3.6 Ga and 3.3 Ga. A 3D amplitude inversion is used to reconstruct the distributions of magnetization underground. Since there is no globally measured surface magneticeld for the Moon, a crustal magnetic anomaly model with grid resolution of 0.2° is used. The depth to the bottom of the magnetic source is fixed by the boundary identified by a relative criterion, which is 20% of the recovered maximum magnetization. The results show that the two anomalies have different depths to the bottom and different volumes of magnetic sources. The depth to the bottom of the magnetic carriers, which is possibly the Curie depth, is about 30 km and 50 km under Oceanus and Tranquillitatis. The volumes of the two magnetic sources are at the scale of 104 and 105 km3, respectively. The Bouguer gravity anomalies with spherical harmonics reaching 1200 degree in the two studied regions are also checked. The results supports that the magma intrusions containing different abundances of metallic iron are the most possible origins of the magnetic sources in the studied regions. Besides, the thermal states of lunar crust under the two studied maria were probably different during the acquisition process of remanent magnetization.

How to cite: Wang, H. and Yao, S.: Depths to the Bottom and Volumes of Magnetic Sources under a Weak and a Strong Lunar Magnetic Anomaly Revealed by 3D Inversion, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-3164, https://doi.org/10.5194/egusphere-egu23-3164, 2023.

The planetary magnetic field, caused by convective currents in the cores and linking thermal and interior, is a fundamental way to determine the angular momentum exchange and secular variation in the core motions & core-mantle coupling system. But understanding the high temperature-pressure (e.g., ~5000 °C, 135~330 Gigapascals) rheology fluid flows in planetary cores is a tremendous interdisciplinary challenge. The fine-structure investigation requires understanding the fundamental rheology fluid dynamic involving turbulence and rotation from continuing hydro-dynamo-kinetic coupling scales well beyond the present traditional partial differential equation virtual test.

The lunar magnetic field is believed not currently to possess a feeble global magnetic field and can be ignored when exploring the solar-flare CME-induced solar storm transplant on the lunar surface. The hypothesis holds that the crustal magnetizations were acquired early in lunar history when dynamics were still operating. At that time, the dynamo magnetic fields were generated by the thermochemical convection of electrically conductive alloy metal liquid within lunar cores and reduced with the convection cooling process. The turbulence mechanical stirring of lunar core rheology fluids and perturbations by the tidal effect and orbital precession can contribute to sustaining dynamo fields.

With the supporting observations of China’s lunar and deep space exploration in recent years, it has become possible to re-estimates the past magnetic field by considering combining the tidal heating induced dissipation from viscous friction associated with the differential procession at a different angle and dynamo action (the non-ideal plasma; inner core-outer core-mantle; warm dense matter; liquid iron alloy; chemical-geological properties; density-temperature-pressure) together again.

In this work, based on the newly developed optimization methodology and numerical algorithm of relativistic hybrid particle-in-cell and lattice Boltzmann (RHPIC-LBM version 1.1.2), we establish the 3D lunular magnetic field modeling with combined rheology dynamo thermally and tidal-heating of its lunar cores and investigate the history of magnetic field evolution; And figure out the effect of tidal heating in the deepest lunar mantle,  and offer a possible unprecedented window on this intermediate state of rheology matter and providing a new virtual testing ground for dense rheology plasma theories.

How to cite: Zhu, B.: Exploration of Lunar magnetic fields with dynamo thermally and tidal heating-driven rheology model, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-3206, https://doi.org/10.5194/egusphere-egu23-3206, 2023.

EGU23-3992 | Posters on site | PS5.3

Lunar secondary crater distributions and ejecta fragment size velocity distributions: implications for regolith redistribution 

Kelsi Singer, Helle Skjetne, Julie Stopar, Mikayla Huffman, Clark Chapman, Lillian Ostrach, Brad Jolliff, and William McKinnon

We have performed an extensive study of secondary craters associated with specific primary craters on the Moon.  These data can be used to understand aspects of both (1) the secondary craters themselves and (2) the ejecta fragments that formed them.  Studying ejecta and secondary craters are a part of understanding the overall contributions of impacts to shaping and redistributing material across the lunar surface. 

We produced secondary crater size-range distributions for a large range of primary crater sizes (~0.8-660 km dimeter primaries).  Our results can be used to make a map of estimated maximum secondary crater sizes across the Moon.  They can also be used to test if a specific secondary crater cluster is likely related to a given primary crater.   

We also produced ejecta fragment size-velocity distributions for all our study sites.  These results can be used to understand the size and velocity of the ejecta fragments that were ejected as part of the primary impact.  This helps us understand the dynamics of the primary impact and the formation of fragments (or clusters of fragments) and how they are ejected during the passage of the shock wave through a planetary surface.  This new empirical data can be used to help constrain analytical and numerical models of dynamic fragmentation, place constraints on the largest ejecta fragments expected be ejected at escape velocity from the Moon, and used as inputs into models of regolith development and impact gardening. 

We will present the most current results on the above topics.  Initial results for 6 primary craters are presented in Singer et al. 2020 where we discovered a previously unrecognized trend where the size velocity distributions are dependent on the size of the impact (i.e., scale dependent).  We now have data on 10 additional primaries and further applications of the study. 

Singer, K. N., Jolliff, B. L., & McKinnon, W. B. (2020). Lunar secondary craters and estimated ejecta block sizes reveal a scale-dependent fragmentation trend. J. Geophys. Res., 125(8), e2019JE006313. doi:10.1029/2019JE006313

How to cite: Singer, K., Skjetne, H., Stopar, J., Huffman, M., Chapman, C., Ostrach, L., Jolliff, B., and McKinnon, W.: Lunar secondary crater distributions and ejecta fragment size velocity distributions: implications for regolith redistribution, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-3992, https://doi.org/10.5194/egusphere-egu23-3992, 2023.

EGU23-5040 | Orals | PS5.3

The ESA/DLR LUNA Habitat as geophysical experimentation facility 

Martin Knapmeyer, Brigitte Knapmeyer-Endrun, Michael Maibaum, Jens Biele, Cinzia Fantinati, Oliver Küchemann, Stephan Ulamec, and Jean-Pierre de Vera

Recently, NASA’s InSight mission has shown the value of geophysical landers by greatly increasing our knowledge of the interior of Mars. Correspondingly, geophysical experiments are also of great relevance to lunar exploration: a number of geophysical experiments were proposed in response to the ESA's 2020 call for ideas for a scientific utilization of the large logistics lander (Argonaut). Geophysical payloads are already planned for the Moon, e.g. the Farside Seismic Suite will land a broad-band seismometer in 2025. We here present how the LUNA Habitat training facility under construction in Cologne, Germany, can contribute to the development and testing of lunar geophysical instrumentation.

The about 700 square meters of the LUNA Habitat will be covered by 60 cm of EAC-1 regolith simulant on most of the area. On an area of 140 square meters, regolith depth increases to 3 m along a sloping bottom (25° and 40°). This part of LUNA provides an invisible, but explorable underground structure suitable for seismic profiling, ground penetrating radar, geoelectrics, geomagnetics and other techniques, as well as sufficient depth for drilling, subsurface sampling, and deployment of heat flow probes. Sculpting craters and even caves in the regolith, as well as cooling small portions of it, is envisioned. Support by the facility will include personnel with experience in geophysical measurements and data analysis, an end-to-end operational environment including a remote control center with standard communication technology, and, last but not least, training of astronauts in co-operation with robotic units to operate the equipment in lunar surface suits and under gravity offloading.

A four-element, Y-shaped array of short period seismometers, based on the layout of the Apollo 17 seismic experiment, will be deployed on the LUNA construction site before erecting the building to record seismic noise sources (car traffic on the DLR campus, the ENVIHAB short arm centrifuge, wind tunnel discharges, air traffic on the nearby CGN international airport etc.). It will also allow for ambient noise analysis aimed at the underground structure, which is expected to consist of Rhine sediments. An active refraction seismic experiment and the deployment of 12 nodal sensors will further aid in site characterization. LUNA will have a concrete floor of up to 60 cm thickness, but with a structured underside for static reasons. The array will be re-deployed on the concrete once the hall is erected to characterize in how far the new high-velocity layer hides the underlying sediments from seismic observation. After completion of LUNA, the effect of the regolith cover on seismic recordings will be characterized by a third array deployment. Documentation of construction details, especially steel enforcing in the concrete, is foreseen.  A broad-band seismometer will be installed in the LUNA Habitat permanently, once construction is finished, to support the identification of artificial noise sources and local seismicity in the recordings of customer instruments, and monitor possible changes in the background e.g. due to new buildings or other large-scale research facilities on the DLR campus.

How to cite: Knapmeyer, M., Knapmeyer-Endrun, B., Maibaum, M., Biele, J., Fantinati, C., Küchemann, O., Ulamec, S., and de Vera, J.-P.: The ESA/DLR LUNA Habitat as geophysical experimentation facility, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-5040, https://doi.org/10.5194/egusphere-egu23-5040, 2023.

EGU23-5929 | ECS | Orals | PS5.3

Mafic Mineral Anomaly in the Ohm Crater of the Moon 

Shreekumari Patel, Animireddi V Satyakumar, Paras Solanki, and Mohamed R El-maarry

The 64 km wide Ohm crater is a complex impact crater located on the northern side of the lunar farside. In this study, we generated abundance maps for FeO and TiO2 as well as Spectral Parameter maps to determine the composition. Orthopyroxene and Clinopyroxene, two mafic minerals, are present in the Ohm crater, according to spectral analyses of M3 data. A geostatistical technique is used to optimize the variation trend of diagnostic characteristics across different sites. We noticed that Opx dominates the rest of the crater, while Cpx dominates the western portion of Ohm. Opx denotes sources from above and/or below the crust-mantle boundary, whereas Cpx suggests impact melt crystallization of an anorthositic target crust. The NASA mission GRAIL, which is specifically designed to study gravity anomalies, has found negative anomalies near the Ohm crater that may indicate a thicker crust beneath the crater. Unequal Bouguer gravity anomalies and negative anomalies have been found in the vicinity of the Ohm crater, but they are not clearly connected to the internal morphology. Surface morphological features have no connection to these anomalies of uneven gravity. In addition, the Bouguer gravity signature may be affected by pre-existing subsurface density structure, and post-impact events (such as magmatism), which could account for some of the observed scatter. The regional gravity anomaly also indicates low values in the Ohm crater, suggesting that the thicker crust and the source of the geochemical anomalies are at deeper levels. Strong negative anomalies are seen in the predicted residual gravity data close to the Ohm crater, which suggests low-density bodies at the crustal level. We propose that the pyroxenes are the end product of impact melt crystallization based on regional and residual gravity anomalies, compositional and mineralogical features of the Ohm crater, and geophysical data. Ejecta from the SPA, Orientale, and Mascon Hertzsprung basins, which may or may not have differed from impact melt formed during the Ohm impact event, should also be looked at when analyzing the distribution of mafic minerals throughout the crater. The GRAIL crustal thickness model-1 for the Ohm crater indicates a thicker crust, demonstrating that the mantle upliftment is not the underlying cause of the geochemical anomalies in this area.

Acknowledgement: S. M. Patel and M. R. El-maarry acknowledge support for this work through an internal grant (8474000336-KU-SPSC).

How to cite: Patel, S., Satyakumar, A. V., Solanki, P., and El-maarry, M. R.: Mafic Mineral Anomaly in the Ohm Crater of the Moon, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-5929, https://doi.org/10.5194/egusphere-egu23-5929, 2023.

Because the Moon is much less flattened than the Earth, most lunar GIS applications use a spherical datum. However, nowadays, with the renaissance of lunar missions approaching, it seems worthwhile to define an ellipsoid of revolution that better fits the lunar gravity potential surface. The main long-term benefit of this might be to make the lunar adaptation of methods already implemented in terrestrial GNSS, gravimetry and GPS applications easier and somewhat more accurate.

In our work, we used a 660th degree and order potential surface called GRGM 1200A Lunar Geoid, developed in the frame of the GRAIL project. Samples were taken from the potential surface along a mesh that represents equal area pieces of the surface. The method of point grid selection was provided by a relatively simple Fibonacci sphere. We tried Fibonacci spheres with 100, 1000, 3000, 5000, 10000 and 100000 points and also separately examined the effect of rotating the network by length for a given number of points on the estimated parameters, but these differences was only noticeable for the lower resolution networks.

We estimated the best-fitting rotation ellipsoid semi-major axis and flatness data for the selenoid undulation values at the network points, which were obtained for a=1,737,576.6 m and f=0.000305. This parameter pair is already obtained for a 10000 point grid, while the case of reducing the points of the equidistant grid to 3000 does not cause a deviation in the axis data of more than 10 centimetres. As expected, the absolute value of the selenoid undulations has decreased compared to the values taken with respect to the spherical basal surface, with maxima exceeding +400 m still being found for Mare Serenitatis and Mare Imbrium, and the largest negative values for South Pole Aitken and Mare Orientale.

Supported by the ÚNKP-22-6 New National Excellence Program of the Ministry for Culture and Innovation from the source of the National Research, Development and Innovation Fund.

How to cite: Cziráki, K. and Timár, G.: Estimation of the parameters of a lunar ellipsoid of revolution based on GRAIL selenoid data and Fibonacci mesh, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-7979, https://doi.org/10.5194/egusphere-egu23-7979, 2023.

EGU23-8116 | Orals | PS5.3

Tungsten isotopes and the early evolution of the Moon 

Thomas Kruijer, Gregory Archer, and Thorsten Kleine

Key events in the early history of the Moon include its formation by a giant impact, the solidification of the lunar magma ocean, and late accretion. The 182Hf-182W system (t1/2 ~9 Ma) constitutes a versatile tool to study each of these processes because they can all result in measurable 182W variations. Here we review the 182W record of lunar rocks and highlight key constraints on the early evolution of the Moon. Tungsten isotope studies on lunar samples demonstrate that there are no resolvable 182W variations within the Moon, implying that lunar magma ocean differentiation later than ~70 Ma after Solar System formation. Nevertheless, the Moon is characterized by a uniform ~25 parts-per-million 182W excess over the present-day bulk silicate Earth (BSE). One possibility is that this 182W difference is radiogenic in origin, in which case the Hf-W system can potentially be used to date the formation of the Moon. However, this interpretation is problematic for two reasons. First, mixing processes during the giant impact very likely modified the 182W composition of the Moon and led to distinct initial 182W compositions of the Moon and Earth. Second, the pre-late accretion 182W compositions of the Moon and BSE overlap within uncertainty, and hence there is no resolved radiogenic 182W difference between the BSE and the Moon. Consequently, the Hf-W system does not provide reliable constraints on the age of the Moon. Instead, the Hf–W systematics are fully consistent with 'young' ages of the Moon, well after the effective lifetime of 182Hf.

How to cite: Kruijer, T., Archer, G., and Kleine, T.: Tungsten isotopes and the early evolution of the Moon, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-8116, https://doi.org/10.5194/egusphere-egu23-8116, 2023.

EGU23-10526 | ECS | Orals | PS5.3

Lunar Vertex: A PRISM Science Investigation of the Reiner Gamma Lunar Magnetic Anomaly and Swirl 

Sarah Vines, George Ho, David Blewett, Jasper Halekas, Benjamin Greenhagen, Brian Anderson, Dany Waller, Jörg-Micha Jahn, Peter Kollmann, Brett Denevi, Heather Meyer, Rachel Klima, Joshua Cahill, Lon Hood, Sonia Tikoo, Xiao-Duan Zou, Mark Weiczorek, Myriam Lemelin, Shahab Fatemi, and Edward Cloutis

Lunar Vertex is a mission at the intersection of multiple science communities, from planetary geology to space plasma physics. As the first Payloads and Research Investigations on the Surface of the Moon (PRISM1) investigation, scheduled for delivery to the Reiner Gamma (RG) magnetic anomaly in 2024 aboard a commercial lunar lander, Lunar Vertex will unravel the nature of the RG anomaly, the connection to and origin of the associated lunar swirl surface feature, and the structure and impact of the “mini-magnetosphere” in this region. Lunar Vertex includes a suite of magnetometers (Vector Magnetometer – Lander; VML), a fixed-mounted set of cameras (Vertex Camera Array; VCA), and a low-energy ion and electron plasma analyzer (Magnetic Anomaly Plasma Spectrometer; MAPS) on the lander. In addition, a second suite of commercial fluxgate magnetometers (Vector Magnetometer – Rover; VMR) and a multispectral imager (Rover Multispectral Microscope; RMM) are mounted on a dedicated rover that will traverse a distance of at least 500 m from the lander, providing additional multi-point measurements. The combination of magnetic field measurements taken during cruise and descent by VML and during surface operations by both VML and VMR will characterize the surface magnetic field within a strong lunar magnetic anomaly. The combined magnetic field and plasma measurements from VML and MAPS will provide direct observations of plasma populations reaching the lunar surface and the associated local magnetic field configuration. Furthermore, the lunar regolith within the RG magnetic anomaly and over different regions of the associated lunar swirl will be characterized by RMM and VCA to reveal the surface texture, composition, and particle distribution around both the lander and rover locations and the correspondence to potential surface weathering processes.

How to cite: Vines, S., Ho, G., Blewett, D., Halekas, J., Greenhagen, B., Anderson, B., Waller, D., Jahn, J.-M., Kollmann, P., Denevi, B., Meyer, H., Klima, R., Cahill, J., Hood, L., Tikoo, S., Zou, X.-D., Weiczorek, M., Lemelin, M., Fatemi, S., and Cloutis, E.: Lunar Vertex: A PRISM Science Investigation of the Reiner Gamma Lunar Magnetic Anomaly and Swirl, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-10526, https://doi.org/10.5194/egusphere-egu23-10526, 2023.

EGU23-10737 | ECS | Orals | PS5.3

An Ultra-Wideband Spectrometer for Lunar Heat-Flow Measurements 

Mehmet Ogut, Shannon Brown, Alan Tanner, Sidharth Misra, Chris Ruf, Chi-Chih Chen, and Matthew Siegler

The lunar heat-flow ultra-wideband spectrometer operates over an extended frequency band from 300 MHz to 6.0 GHz. It is a direct-acquisition single-chain digital spectrometer measuring 1024 spectral channels over 6 GHz bandwidth with each channel bandwidth about 6 MHz. The LHR instrument is intended to characterize the near surface regolith thermal and dielectric properties in order to determine the local geothermal heat flux. It would also reveal subsurface thermal and dielectric property changes due to buried ice, dielectric materials like ilmenite, and bedrock. The wide spectral bandwidth is expected to provide up to 1 m deep brightness temperature measurements from as close as 5 cm penetration depth at higher frequency end of the spectra. Using information obtained at multiple frequency bands, the subsurface temperatures and dielectric properties can be reconstructed.

 

The instrument is currently being developed at Jet Propulsion Laboratory in Pasadena, CA. The design includes a novel receiver architecture allowing a single chain design for the ultra-wideband channelized spectral operation for enabling the science objectives of the instrument. The lab-bench demonstration of the lunar spectro-radiometer has been performed including the calibration testing. The environmental testing will be further conducted before proceeding with the flight model. The final flight version of the spectro-radiometer instrument is expected to have light weight, low-power and small-size suitable for a deployment into a lunar rover or lander.

 

 

How to cite: Ogut, M., Brown, S., Tanner, A., Misra, S., Ruf, C., Chen, C.-C., and Siegler, M.: An Ultra-Wideband Spectrometer for Lunar Heat-Flow Measurements, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-10737, https://doi.org/10.5194/egusphere-egu23-10737, 2023.

EGU23-10755 | Posters on site | PS5.3

Radio Instrument Package for Lunar Ionospheric Observation: A Concept Study 

Christopher Watson, Thayyil Jayachandran, Anton Kascheyev, David Themens, Richard Langley, Richard Marchand, and Andrew Yau

The lunar ionosphere is a ~100 km thick layer of electrically charged plasma surrounding the moon.  Despite knowledge of its existence for decades, the structure and dynamics of the lunar plasma remain a mystery due to lack of consistent observational capacity. An enhanced observational picture of the lunar ionosphere and improved understanding of its formation/loss mechanisms is critical for understanding the lunar environment as a whole and assessing potential safety and economic hazards associated with lunar exploration and habitation. To address the high priority need for observations of the electrically charged constituents near the lunar surface, we introduce a concept study for the Radio Instrument Package for Lunar Ionospheric Observation (RIPLIO). RIPLIO would consist of a multi-CubeSat constellation (at least two satellites) in lunar orbit for the purpose of conducting “crosslink” radio occultation measurements of the lunar ionosphere, with at least one satellite carrying a very high frequency (VHF) transmitter broadcasting at multiple frequencies, and at least one satellite flying a broadband receiver to monitor transmitting satellites. Radio occultations intermittently occur when satellite-to-satellite signals cross through the lunar ionosphere, and the resulting phase perturbations of VHF signals may be analyzed to infer the ionosphere electron content and high- resolution vertical electron density profiles. As demonstrated in this study, RIPLIO would provide a novel means for lunar observation, with the potential to provide long-term, high-resolution observations of the lunar ionosphere with unprecedented pan-lunar detail.

How to cite: Watson, C., Jayachandran, T., Kascheyev, A., Themens, D., Langley, R., Marchand, R., and Yau, A.: Radio Instrument Package for Lunar Ionospheric Observation: A Concept Study, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-10755, https://doi.org/10.5194/egusphere-egu23-10755, 2023.

Boulders are a major surface feature on solid planets and small bodies, including asteroids and comets. Interest in these clasts range from applications relevant for landing site selection to geomechanical parameter characterization of the soil on which they rest [1], to measurements of their size frequency distributions [2] which is relevant for an understanding of their formation and erosion processes. On the Moon boulders are generally found in association with craters, hilltops, rilles, and other steep relief forms. Two main mechanisms of boulder formation are bedrock fragmentation and excavation by impacts, and progressive exposure of pre-existing blocks and fractured bedrock by removal of regolith from steep reliefs by diffusive creep.

An important issue are transport processes which can move the stones on the surface of their parent bodies. On the Moon, one group of boulders, frequently called “rolling stones”, have left tracks on the surface which can cover large distances. Mainly two mechanisms, meteoritic impact and moonquakes [3], have been cited in the literature as drivers of boulder displacements. Much less attention has been given to the hypothesis that other processes like thermal solar-induced rock breakdown [4] could deliver the initial momenta that could initiate the movement of meta stabile rocks.

From an AI -based mapping of the distribution of boulders with tracks on the lunar surface [5] we know that the majority of these boulders are found – not surprisingly - within craters. However, as the AI-based procedure strongly underestimated the number of boulders with tracks, we have conducted a new investigation to map these boulders. However, such a mapping it is only one prerequisite in understanding whether a thermally-induced breakdown could be responsible for an initial triggering of boulder movements. Boulders moving down the slopes disturb the mature regolith and move fresh lunar soil to the surface. This process should remotely be detectable through the stronger spectral features of the fresher optically immature regolith. The number of non-decayed boulders along crater walls should therefore be correlated with the strength of the absorption bands in spectra taken from those crater walls. Spectral characteristics of the refreshed crater walls are measurable through various quantities in the VIS-NIR (e.g. color ratios, etc.)

To start addressing the question to what extent a solar-induced breakdown can trigger rock movements, we have chosen lunar craters for which we have generated new boulder maps. For these craters we determine spectral characteristics and mineralogical composition based on a nonlinear spectral mixing model using M3 hyperspectral imager data from Chandrayaan-1. We are reporting the first results of spectral feature mapping for these craters and discuss the mineralogical interpretation, as well as the existence of a correlation between the number of observable boulders inside craters and identified spectral features of the regolith.

References:

[1] Filice, A., 1967, Science, 1967-06-16 156(3781): 1486-1487. [2] Ruesch, O. et al., 2022 Icarus, 387, 115200. [3] Kumar, S. et al., 2016, J. Geophys. Res. Planets, 121, 147– 179. [4] Molaro, J.L. et al., 2017, Icarus, 294, 247-261. [5] Bickel, V.T. et al., 2020, Nat Commun 11, 2862.

How to cite: Mall, U. and Surkov, Y.: Are day-night heating cycles a trigger for launching the “stones” on tour?, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-10887, https://doi.org/10.5194/egusphere-egu23-10887, 2023.

EGU23-11166 | ECS | Orals | PS5.3

Polar Ice Accumulation from Volcanically Induced Transient Atmospheres on the Moon 

Andrew Wilcoski, Paul Hayne, and Margaret Landis

Over the last few decades, observations have revealed the presence of water ice at the lunar poles and upended the notion of a completely dry lunar surface. These ice deposits hold information about the history of water on the Moon and in the Earth-Moon system, and are potential resources for future human exploration of the Moon. However, they remain relatively uncharacterized in abundance, distribution, and composition. Foremost among the open questions about lunar ice are: What were the sources of ice on the Moon’s surface, and how much water could have been delivered? The three most likely sources of lunar water ice are: (1) impact delivery from asteroids and/or comets, (2) solar wind ion implantation, and (3) volcanic outgassing of volatiles from the lunar interior. Here, we assess the viability of a volcanic source for water ice accumulated at the lunar poles.

[1] first suggested the occurrence of a volcanically induced transient atmosphere on the ancient Moon that would have been dominated by CO, but with a significant amount of H­2O. Further studies investigated the dynamics [2] and atmospheric escape processes [3] that would have affected such an atmosphere. [4] later suggested that a large number (30,000-100,000) of eruptions would have created less massive atmospheres during the Moon’s most volcanically active period (4-2 Ga).

We model the generation of transient atmospheres from 50,000 eruptions from 4 to 2 Ga, the subsequent escape of these atmospheres to space, and the concurrent accumulation of atmospheric water vapor as ice at the lunar poles [5]. The molecular composition of the modeled atmospheres is determined using estimates of outgassed volatile content for lunar volcanic eruptions derived from analyses of Apollo samples [4,6]. We model three atmospheric escape processes: (1) Jeans escape, (2) sputtering escape, and (3) photodissociative escape [3], and model photodissociative escape separately for both CO and H2O. We use maximum annual surface temperatures [7] measured by the Diviner Lunar Radiometer Experiment on board the Lunar Reconnaissance Orbiter [8] to calculate ice accumulation rates for each Diviner pixel within 30° latitude of the poles [5].

We find that water vapor is removed from a typical transient atmosphere in about 50 years via ice accumulation and photodissociative escape. About 41% of the total water vapor mass outgassed from 4 to 2 Ga is accumulated as ice on the surface. This demonstrates that a significant amount of ice (~8×1015 kg) could have been sourced from volcanic outgassing, though atmospheric escape processes also strongly control the efficacy of this mechanism.

 

[1] Needham, D. H. and Kring, D. A. (2017) EPSL, 478, 175-178. [2] Aleinov, I., et al. (2019) GRL 46, 5107-5116. [3] Tucker, O. J., et al. (2021) Icarus, 359, 114304. [4] Head, J. W., et al. (2020) GRL, 47, e2020GL089509. [5] Wilcoski, A. X., et al. (2022) PSJ 3.5, 99. [6] Rutherford, M. J., et al. (2017) Amer. Mineralogist, 102, 2045-2053. [7] Landis, Margaret E., et al. (2022) PSJ 3.2, 39. [8] Paige, D. A., et al. (2010) Space Sci. Rev., 150, 125- 160.

How to cite: Wilcoski, A., Hayne, P., and Landis, M.: Polar Ice Accumulation from Volcanically Induced Transient Atmospheres on the Moon, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-11166, https://doi.org/10.5194/egusphere-egu23-11166, 2023.

EGU23-13387 | ECS | Orals | PS5.3

Instrumentation for laser ablation ionisation mass spectrometry on the lunar surface 

Peter Keresztes Schmidt, Matthias Blaukovitsch, Nikita J. Boeren, Marek Tulej, Andreas Riedo, and Peter Wurz

With NASA’s increased focus on exploration of our Moon within the Artemis program, new scientific goals have been formulated to expand our knowledge on the history of our Solar System, including the evolution of the Earth-Moon system. Additionally, establishing a permanent human presence on the Moon has been declared a goal of the Artemis program, the success of which will inevitably depend on in-situ resource utilization (ISRU) of lunar material. In turn, successful ISRU requires methods capable of analysing and selecting suitable materials in place. To support these tasks, sensitive instrumentation capable of determining the elemental and isotope composition of geological samples from the lunar surface is essential. Consequently, defining and determining the technical requirements of such instrumentation, constructing it accordingly, and verifying its performance are all crucial steps in maximising the scientific return of such a mission. Furthermore, NASA’s Artemis program also aims to facilitate future human exploration of Mars, which implies that instrumentation applied successfully on the Moon might find its application on the Martian surface in the future.

 

We present our progress in designing, constructing and testing a prototype miniature laser ablation ionisation mass spectrometer (LIMS) for in-situ measurements on the lunar surface. The finalised instrument will be deployed on the Commercial Lunar Payload Service (CLPS) mission CP-22 scheduled for launch in late 2026 and land in the lunar south pole region. Our miniature reflectron-type time-of-flight mass analyser (160 mm x Ø 60 mm) designed for in-situ space applications was coupled to a pulsed Nd:YAG microchip laser system (SB1 series, Bright Microlaser Srl, Italy) operating at 532 nm (max. laser pulse energy of 40 µJ, pulse repetition rate of 100 Hz). The laser source and the optics were mounted colinearly to the optical axis of the instrument assembly into a cage system. This construction is modelled after the envisioned flight design, and therefore used to determine the required optical and electronic performance characteristics of the future flight instrument. The current flight design will be presented as well. Furthermore, validation of the technical implementation and verification of the scientific requirements will be discussed through the results of laser ablation experiments conducted on lunar regolith simulant.

How to cite: Keresztes Schmidt, P., Blaukovitsch, M., Boeren, N. J., Tulej, M., Riedo, A., and Wurz, P.: Instrumentation for laser ablation ionisation mass spectrometry on the lunar surface, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-13387, https://doi.org/10.5194/egusphere-egu23-13387, 2023.

EGU23-13471 | ECS | Posters on site | PS5.3

Statistical Analysis of Lunar 1 Hz Waves Using ARTEMIS Observations 

Yuequn Lou, Xudong Gu, Xing Cao, Mingyu Wu, Sudong Xiao, Guoqiang Wang, Binbin Ni, and Tielong Zhang

Like 1 Hz waves occurring in the upstream of various celestial bodies in the solar system, 1 Hz narrowband whistler-mode waves are often observed around the Moon. However, the wave properties have not been thoroughly investigated, which makes it difficult to proclaim the generation mechanism of the waves. Using 5.5-year wave data from ARTEMIS, we perform a detailed investigation of 1 Hz waves in the near lunar space. The amplitude of lunar 1 Hz waves is generally 0.05-0.1 nT. In the GSE coordinates, the waves show no significant regional differentiation pattern but an absence inside the magnetosphere. Correspondingly, in the SSE coordinates, they can occur extensively at ~1.1-12 RL, while few events observed in the lunar wake due to a lack of interaction with the solar wind. Furthermore, the wave distributions exhibit modest day-night and dawn-dusk asymmetries, but less apparent north-south asymmetry. Compared with nightside, more intense waves with lower peak wave frequency are present on the dayside. The preferential distribution of 1 Hz waves exhibits a moderate correlation with strong magnetic anomalies. The waves propagate primarily at wave normal angles < 60° with an ellipticity of [-0.8, -0.3]. For stronger wave amplitudes and lower latitudes, 1 Hz waves generally have smaller wave normal angles and become more left-hand circularly polarized. Owing to the unique interaction between the Moon and solar wind, our statistical results might provide new insights into the generation mechanism(s) of 1 Hz waves in planetary plasma environments and promote the understanding of lunar plasma dynamics.

How to cite: Lou, Y., Gu, X., Cao, X., Wu, M., Xiao, S., Wang, G., Ni, B., and Zhang, T.: Statistical Analysis of Lunar 1 Hz Waves Using ARTEMIS Observations, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-13471, https://doi.org/10.5194/egusphere-egu23-13471, 2023.

EGU23-13668 | ECS | Posters on site | PS5.3

Urban seismic noise investigation at the site of ESA/DLR’s future LUNA facility at Cologne, Germany 

Stefanie Hempel, Martin Knapmeyer, Jens Biele, and Hans-Herbert Fischer

As international efforts to return humans to the Moon are increasing, ESA's European Astronaut Center (EAC) and the German Aerospace Center (DLR) are expanding their facilities by the LUNA habitat providing a 700m²-wide testbed covered by 60cm lunar regolith simulant (EAC-1) for astronaut training, including deploying and operating geological and seismic regolith characterization experiments, In Site Resource Utilization technologies (ISRU), biological and chemical experiments by both telerobotic and human activity. The LUNA facility will be operated as collaboration between ESA and DLR's Microgravity User Support Center (MUSC, see also the presentation by Knapmeyer et al. at this conference).

Geophysical experiments have proven useful to investigate the subsurface structure at the landing sites of e.g. Apollo and Chang'e missions on the Moon, but also at the InSight landing site on Mars, and a seismometer experiment to the lunar far side is already scheduled (Far Side Seismic suite, in 2025). To support future geophysical investigations on the Moon, a first seismic experiment was conducted in June, 2018 at the previously envisioned site of the LUNA facility between the :envihab, a research facility of the Institute for Aerospace Medicine and the European Astronaut Center (EAC) at Cologne-Porz. This passive seismic experiment consisted of a four-element, Y-shaped array of short period seismometers, based on the layout of the Apollo 17 seismic experiment. It recorded regional seismicity as well as urban noise. These measurements will be repeated and expanded by an active seismic refraction experiment at the new construction site just south of the EAC - before, during and after the construction of the facility, before and after the installment of the regolith cover to investigate the impact of the LUNA facility on the data quality and coupling to the ground.

We present details of the 2018 experiment as well as preliminary results, analyzing ambient noise to map the dominant sources of urban noise such as car traffic and airplane traffic at the nearby CGN international airport, the operational noises of the :envihab centrifuge and the wind tunnel as well as nearby construction and drilling.

How to cite: Hempel, S., Knapmeyer, M., Biele, J., and Fischer, H.-H.: Urban seismic noise investigation at the site of ESA/DLR’s future LUNA facility at Cologne, Germany, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-13668, https://doi.org/10.5194/egusphere-egu23-13668, 2023.

EGU23-14255 | ECS | Posters on site | PS5.3

Photometry of rock-rich surfaces on airless bodies. 

Rachael Martina Marshal, Ottaviano Rüsch, Christian Wöhler, Kay Wohlfarth, Sergey Velichko, and Markus Patzek

Introduction and Methods:  Our understanding of the response of boulders to space weathering, micrometeorite abrasion, thermal fatigue, and consequently their evolution into regolith can be improved by characterizing the surface roughness of the uppermost layer of boulders. In the first phase of our study [1] we characterize the surface roughness of boulder fields photometrically by using the phase ratio methodology applied to orbital image data. In the second phase of our study (in-progress) we focus on characterizing the sub-mm scale topography and roughness of naturally fresh surfaces of meteorite samples. The photometric roughness of boulder fields on the lunar surface is studied by employing a normalized logarithmic phase ratio difference (NLPRD) metric, described in [1], to measure and compare the slope of the phase curve (reflectance versus phase angle) of a rock-rich field to a rock-free field . We compare the photometric roughness of rock-rich fields on simulated images, with the photometric roughness of rock-rich fields on Lunar Reconnaissance Orbiter Narrow Angle Camera (LROC NAC) images sampled around an Unnamed crater at Hertzsprung S.


Results and Discussion: The NLPRD is normalized to a rock-free reference surface, assuming the roughness of the regolith within the boulderfield is comparable to the roughness of the regolith at the rock-free reference regions, the higher roughness of the boulder-fields implies the presence of rocks with diverse sub-mm scale roughness and, possibly, variable single scattering albedo. In figure 1b, the spread in NLPRD values for different rock morphologies, is exceeded by the spread in  NLPRD of the NAC-resolved boulderfields. We find spatial clustering of photometrically smooth and rough boulderfields in the downrange and up-range respectively of the Unnamed crater at Hertzsprung S, reflecting ejecta asymmetry (in agreement with [2]) and possibly indicating asymmetric modification of ejecta rock surfaces during impact excavation process. Our results imply that rock physical properties at the start of the surface exposure period are a function of petrology as well as the (shock) effects imparted upon ejecta rock formation and excavation. The work-in progress deals with supplementing our findings with investigation of the sub-mm scale topography and roughness of meteorite and lunar samples. To study the sub-mm scale roughness of these samples we produce high-resolution DTMs at the µm scale using a non-contact optical profilometer. A sample high-resolution DTM of lunar breccia NWA11273 is shown in figure 2.



Figure 3 shows that variations of the mean slope with spatial scale exists within different meteorites types. Next, we will investigate the scale-dependent rock micro-texture of various samples (i.e., ordinary and carbonaceous chondrites, lunar basalts and breccias as well as meteorites from the HED clan), and provide typical values of surface roughness that will inform photometric modelling of rock surfaces.

References: [1] Marshal, R. M., Rüsch, O., Wöhler, C., Wohlfarth, K., & Velichko, S. (2022). Icarus, 115419 [2] Velichko, S., Korokhin, V., Velikodsky, Y., Kaydash, V., Shkuratov, Y., & Videen, G. (2020). PSS, 193.

How to cite: Marshal, R. M., Rüsch, O., Wöhler, C., Wohlfarth, K., Velichko, S., and Patzek, M.: Photometry of rock-rich surfaces on airless bodies., EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-14255, https://doi.org/10.5194/egusphere-egu23-14255, 2023.

EGU23-15759 | ECS | Posters on site | PS5.3

The MoonLIGHT Pointing Actuator (MPAc) project 

Laura Rubino, Alejandro Remujo Castro, Ubaldo Denni, Marco Muccino, Lorenzo Salvatori, Mattia Tibuzzi, Matteo Petrassi, Michele Montanari, Marco Traini, Luciana Filomena, Lorenza Mauro, Luca Porcelli, and Simone Dell'Agnello

Laser Ranging is a technique used to perform accurate precision distance measurements between a laser ground station and an optical target, a Cube Corner Retroreflector (CCR). Since 1969 it is possible to realize Lunar Laser Ranging (LLR) measurements thanks to Apollo and Luna missions that placed some arrays of CCRs on the lunar surface. LLR outputs include accurate tests of General Relativity, information of the composition of the Moon, its ephemerides and its internal structure or geocentric positions and motions of ground stations: research uniquely enabled by the Moon.

Despite laser ground stations have significantly improved during the years, the current limitation of the lunar optical target is due to lunar librations. In order to achieve more precise LLR measurements, MoonLIGHT project is designed by SCF_Lab joined UMD. The aim of the project is designing a next-generation of retroreflectors, prototyping, manufacturing and qualify them for the Moon’s environment. Moving from a multi small CCRs array to a single large 100 mm CCR, called MoonLIGHT, unaffected by the lunar librations.

The field of view of each CCR is limited: the retroreflector needs to be pointed precisely to the ground station. The Apollo CCR arrays were manually arranged by the astronauts. In 2018 INFN proposed to ESA the MoonLIGHT Pointing Actuators (MPAc) project, able to perform unmanned pointing operation of MoonLIGHT. In 2019 ESA chose MPAc among 135 eligible scientific project proposals. In 2021 ESA agreed with NASA to launch MPAc to the Reiner Gamma region of the Moon, with a Commercial Lunar Payload Services (CLPS), which is part of the Artemis program. The lander on which MPAc will be integrated is designed by Intuitive Machines (IM). The launch expected date is in April 2024.

MPAc must be able to perform two continuous perpendicular rotations to accurately point the frontal face of the CCR towards the Earth. The device is continuously evolving to ensure the success of the mission, that will take place in Ultra High Vacuum space conditions, in a wide operating temperature range. Terrestrial prototypes, with all the characteristics of the final structure, have been developed for the study of mechanical and electronics components. Qualification tests for space are being planned as the components for the Proto Flight Model (PFM) arrived to the LNF. Payload delivery is scheduled for August 2023.

MPAc will contribute to attain lunar orbit range accuracy below few mm. This will improve, in turn, the precision of the Parametrized Post-Newtonian (PPN) parameters and put more stringent constraints on departures from GR predictions with observations.

How to cite: Rubino, L., Remujo Castro, A., Denni, U., Muccino, M., Salvatori, L., Tibuzzi, M., Petrassi, M., Montanari, M., Traini, M., Filomena, L., Mauro, L., Porcelli, L., and Dell'Agnello, S.: The MoonLIGHT Pointing Actuator (MPAc) project, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-15759, https://doi.org/10.5194/egusphere-egu23-15759, 2023.

EGU23-15933 | ECS | Orals | PS5.3

Orbit Determination and Time Transfer for a Lunar Radio Navigation System 

Andrea Sesta, Mauro Di Benedetto, Daniele Durante, Luciano Iess, Michael Plumaris, Paolo Racioppa, Paolo Cappuccio, Ivan di Stefano, Debora Pastina, Giovanni Boscagli, Serena Molli, Fabrizio De Marchi, Gael Cascioli, Krzysztof Sosnica, Agnes Fienga, Nicola Linty, and Jacopo Belfi

Within the pre-phase A of the Moonlight project proposed and funded by the European Space Agency (ESA), the ATLAS consortium has proposed an architecture to support a Lunar Radio Navigation System (LRNS) capable of providing PNT (Positioning, Navigation, and Timing) services to various lunar users. The Moonlight LRNS will be a powerful tool in support of the lunar exploration endeavors, both human and robotic.

The ESA LRNS will consist of a small constellation of 3-4 satellites put in Elliptical Lunar Frozen Orbits (ELFO) with the aposelene above the southern hemisphere to better cover this region, given its interest for future lunar missions. This LRNS will be supported by a ground station network of small dish antennas (~30 cm), which can establish Multiple Spacecraft Per Aperture (MSPA) tracking at K-band. Any Earth station will be capable of sending a single uplink signal to multiple spacecraft thanks to Code Division Multiplexing modulation, while in the downlink multiple carriers can share the same K-band bandwidth by implementing Code Division Multiple Access (CDMA) on the onboard transponders. This allows the implementation of the Same Beam Interferometry (SBI) technique [1], which adds to spread spectrum ranging and Doppler measurements. In the scope of disseminating accurate PNT services to end users, the constellation will also be capable of maintaining a synchronization to the Earth station clocks to the ns level.

The performances of the proposed architecture have been validated through numerical simulations performed with the ESA GODOT software, enhanced with additional user-defined features and capabilities. For each satellite of the LRNS constellation, the attainable orbital accuracy is at level of a few meters for most orbit mean anomalies and it has been computed considering a setup which includes a perturbed dynamical model (mainly coming from uncertainties in the accelerations induced by the solar radiation pressure and orbital maneuvers) and a realistic error model for Doppler, ranging and SBI measurements.

REFERENCE:

  • Gregnanin, M. et al. (2012). Same beam interferometry as a tool for the investigation of the lunar interior. Planetary and Space Science 74, 194-201

How to cite: Sesta, A., Di Benedetto, M., Durante, D., Iess, L., Plumaris, M., Racioppa, P., Cappuccio, P., di Stefano, I., Pastina, D., Boscagli, G., Molli, S., De Marchi, F., Cascioli, G., Sosnica, K., Fienga, A., Linty, N., and Belfi, J.: Orbit Determination and Time Transfer for a Lunar Radio Navigation System, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-15933, https://doi.org/10.5194/egusphere-egu23-15933, 2023.

EGU23-16681 | Posters on site | PS5.3

Lunar plasma and electrostatic environment: numerical approach and its future prospects 

Yohei Miyake and Jin Nakazono

Mission preparation for lunar exploration using landers has been rapidly increasing, and strong demand should arise toward precise understanding of the electrostatic environment. The lunar surface, which has neither a dense atmosphere nor a global magnetic field, gets charged electrically by the collection of surrounding charged particles of the solar wind or the Earth's magnetosphere. As a result of the charging processes, the surface regolith particles behave as "charged dust grains". Dust particles have been suggested to have adverse effects on exploration instruments and living organisms during the lunar landing missions, and their safety evaluation is an issue to be solved for the realization of sustainable manned lunar explorations. It is necessary to develop comprehensive and organized understanding of lunar charging phenomena and the electrodynamic characteristics of charged dust particles.

It is widely accepted that the surface potential of the lunar dayside is, "on average" several to 10 V positive due to photoelectron emission in addition to the solar wind plasma precipitation. Recent studies, however, have shown that insulating and rugged surfaces of the Moon tend to make positive and negative charges separated and irregularly distributed, and intense and structured electric fields can be formed around them. This strong electric field lies in the innermost part of the photoelectron sheath and may contribute to mobilizations of the charged dust particles. Since this strong electric field develops on a spatial scale of less than the Debye length and can take various states depending on the lunar surface geometry, it is necessary to update the research approach. In this paper, we will discuss the direction of the near-surface plasma, electrostatic, and dust environment for upcoming lunar landing missions.

How to cite: Miyake, Y. and Nakazono, J.: Lunar plasma and electrostatic environment: numerical approach and its future prospects, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-16681, https://doi.org/10.5194/egusphere-egu23-16681, 2023.

EGU23-17528 | Posters on site | PS5.3

ILEWG/LUNEX EuroMoonMars & EuroSpaceHub Academy: Recent Highlights 

Bernard Foing, Henk Rogers, Serena Crotti, and Jara Pascual and the ILEWG LUNEX EuroMoonMars Team and EuroSpaceHub Academy

EuroMoonMars programme in Data Analysis, Instrumentation, Field Work and Astronautics: EuroMoonMars is an ILEWG programme [1-226] in collaboration with space agencies, academia, universities and research institutions and industries. The programme includes research activities for data analysis, instruments tests and development, field tests in MoonMars analogue, pilot projects , training and hands-on workshops , and outreach activities. Extreme environments on Earth often provide similar terrain conditions to sites on the Moon and Mars. In order to maximize scientific return it becomes more important to rehearse mission operations in the field and through simulations. EuroMoonMars field campaigns have then been organised in specific locations of technical, scientific and exploration interest. Lunex EuroMoonMars, has been organizing in collaboration with ESA, NASA, European and US universities a programme of data analysis, instrumentation tests, field work and analog missions for students and researchers in different locations worldwide since 2009, including Hawaii HI-SEAs, Utah MDRS, Iceland, Etna/ Vulcano Italy, Atacama, AATC Poland, ESTEC Netherlands, Eifel Germany, etc… Analogue missions provide a practical ground in which students can test the notions learnt at the university in a realistic simulation context. Over the course of these missions, students have access to special Space instrumentation, laboratories, Facilities, Science Operations, Human Robotic partnerships. In 2023 , EuroMoonMars and EuroSpaceHub Academy co-sponsored a series of EMMPOL Moonbase isolation simulation campaigns in Poland.

EuroSpaceHub programme for Space Innovation Workforce Development: The EuroSpaceHub project to facilitate accessibility to the Aerospace sector. EuroSpaceHub is a European-led project with collaborators worldwide, funded by the EIT HEI initiative - Innovation Capacity Building for Higher Education – with Agenda 2021-2027. The project includes six  core partners: Vilnius TU, ISU, U C Madrid,  Sikorsky Kyiv, Collabwith and Lunex. The project was created to foster collaboration, innovation and entrepreneurship in the European Aerospace sector. EuroSpaceHub Academy develops training programme for Space researchers and entrepreneurs.

Space Engineering Workforce Development: we have also developed a semester course of Space System Design Engineering at  EPFL Lausanne sicne 2020.

Interdisciplinary Space Workforce Development: In the frame of ISU International Space University and EuroSpaceHub academy, we performed lectures,  hands-on workshops including the operations of instruments on EuroMoonMars ExoGeoLab lander, workshops on MoonOutpost design performed in the frame of MSS master , or SSP Space Studies Programme. Together with ISU , EuroSpaceHub staff co-supervised various IP Individual Projects of students, and Master Research Projects.

EuroSpaceHub Participation to Congress and Events: We also co-sponsored the participation to conferences such as LPSC, EGU, IAC and the organization of events or workshops connecting the space scientists, engineers, innovators, entrepreneurs to space stakeholders. This included talks and expo booths at IAC International Astronautical Congress and Rome New Space Economy Forum.

How to cite: Foing, B., Rogers, H., Crotti, S., and Pascual, J. and the ILEWG LUNEX EuroMoonMars Team and EuroSpaceHub Academy: ILEWG/LUNEX EuroMoonMars & EuroSpaceHub Academy: Recent Highlights, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-17528, https://doi.org/10.5194/egusphere-egu23-17528, 2023.

EGU23-354 | ECS | Orals | PS5.4 | Highlight

Polygonal impact craters on Ganymede 

Namitha Rose Baby, Thomas Kenkmann, Katrin Stephan, and Roland J. Wagner

Polygonal impact craters (PIC) are impact craters that have at least one straight rim segment in planform [1-8]. Among all impact craters, PICs represent a small percentage. They exist on both rocky and icy planetary bodies [9]. To our knowledge no studies on PICs have been carried out for Ganymede. Here we are examining the straight segments of PICs and their relationship with adjacent lineaments or fractures. We use the global mosaic prepared by [10], which combines the best high-resolution images from Voyager 1, Voyager 2, Galileo and Juno spacecrafts. Despite the resolution limits and different illumination angles, we identified and mapped 459 PICs across Ganymede whose diameter range from 5 km to 153 km.  PICs, which were superimposed by other craters or terrains are not considered for this study. The number of straight segments possessed by PICs ranges from 1 to 9 with quadrangular, hexagonal and octagonal shapes being most common. Most of these PICs exhibit a central peak or a pit, with a minor fraction of them showing a dome. Straight rim segments of PICs align with the linear features adjacent to them and indicate that such lineaments are not exclusively surface features but lead to a localization of deformation and influence the cratering process. Straight rim segments of PICs in the dark cratered terrain (dc) are oriented along fractures and furrows. For instance, Galileo Regio have many PICs because of the NW-SE trending furrows and a high density of faults and fractures.  Here, most of the PICs have hexagonal shape with two of the straight segments parallel to the orientation of furrows and rest of the segments are at approximately perpendicular angle. Also, the presence of PICs suggests that they formed after formation of the linear features. The majority of linear features on anti-Jovian hemisphere trends in NW-SE direction while the preferred orientation of linear features on sub-Jovian hemisphere is in NE-SW direction [11]. However, the preliminary orientation analysis of straight segments of PICs using rose diagrams does not show a preferred orientation for the anti-Jovian and sub-Jovian hemispheres.

REFERENCES: [1] Fielder, G. (1961) PSS. 8(1), 1-8. [2] Kopal, Z. (2013) Springer. [3] Shoemaker, E.M. (1962) Physics and Astronomy of the Moon, Academic Press, New York, pp. 283-359. [4] Roddy, D.J. (1978) Lunar Planet. Sci. Conf. Proc. 9, 3891-3930. [5] Öhman et al. (2005) Impact Tectonics. Springer, Berlin, pp. 131–160. [6] Öhman et al. (2008) Meteorit. Planet. Sci. 43, 1605–1628. [7] Beddingfield et al. (2016) Icarus 274, 163-194. [8] Beddingfield and Cartwright (2020) Icarus 343, 113687. [9] Öhman et al. (2010) Geolog. Soc. Am. Special Papers 465, 51–65. [10] Kersten et al. (2022) pp. EPSC2022-450. [11] Rossi et al (2020) Journal of Maps, 16(2), 6-16.

How to cite: Baby, N. R., Kenkmann, T., Stephan, K., and Wagner, R. J.: Polygonal impact craters on Ganymede, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-354, https://doi.org/10.5194/egusphere-egu23-354, 2023.

The production of knowledge on how planetary worlds work is still mainly driven by remote observations that offer fragmented insights at the surface processes at meters scales and a hollowed vision on the near-surface structure down to few decameters deep. The latter statement also holds for remote polar environments on Earth where in-situ investigations do not necessarily sample exhaustively the vast extents of the cryosphere.

Yet, those superficial portions of planetary bodies hold signatures of outstanding processes related to the regional depositional and erosional history. They also host structures relevant to future in-situ exploration such as surface roughness and porosity for landing site reconnaissance, snow deposits, buried ice lenses and putative accessible aquifers.

Because of its meter-scale wavelengths, the surface echo strength recorded by air- and space-born radar sounders convolves many information on the (near-)surface structure and composition. The Radar Statistical Reconnaissance (RSR) is a technique developed over the last decade to disentangle those signatures, essentially extending the capability of a nadir radar sounder to be used as both a surface reflectometer and scatterometer. We review some recent application strategies of the RSR in the Terrestrial cryosphere and in the solar system. Future advancements and targets will also be presented to highlight the interplanetary development and challenges of this technique.

How to cite: Grima, C.: Deciphering the (Near-)Surface of Planets with Nadir-pointing Radar Statistics, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-2134, https://doi.org/10.5194/egusphere-egu23-2134, 2023.

EGU23-3916 | Posters on site | PS5.4 | Highlight

Moonquake-Triggered Mass Wasting Processes on Icy Worlds 

Robert Pappalardo, Mackenzie Mills, Mark Panning, Erin Leonard, and Samuel Howell

Intense tectonism is evident on many outer solar system satellites with some surface regions exhibiting ridge-and-trough structures which have characteristics suggestive of normal faulting. In some cases, topographic lows between subparallel ridges are sites of smooth material displaying few craters. We consider whether such smooth material can be generated by mass wasting triggered from local seismic shaking. We hypothesize that debris would flow from topographic highs into lows, initially mobilized by moonquake-induced seismic shaking during formation of local tectonic ridges, covering and infilling older terrain. We analyze the feasibility of seismicity to trigger mass movements by measuring fault scarp dimensions to estimate quake moment magnitudes. Seismic moment (Mo) is defined as the energy release caused by a fault rupture and subsequent quake, and moment magnitude (Mw) is a logarithmic scaling of Mo, a function of shear modulus µ (here adopted as 3.5 GPa for ice), Ab, the area of the rupture block face in m2, and p, the resulting scarp slip in m. Given that p is currently unknown for icy satellites, we consider a range of assumed values in our calculations. The resulting magnitude range is 5.3–8.6, and we use numerical modeling to estimate seismic accelerations resulting from such quakes.

Magnitude ranges are used to model resulting seismic accelerations. Interior models to create the synthetic seismograms were generated using Planetprofile, based on current constraints of spacecraft data. Synthetic seismograms were then reconstructed for arbitrarily placed receivers and a seismic source within the generated satellite interior models. The seismic source strength is set to be within our calculated magnitude range.

We adopt surface gravitational acceleration as the criterion which, if exceeded, implies that coseismic mass wasting is expected. Modeled seismic accelerations can exceed satellite gravitational accelerations, particularly near quake epicenters. Thus, seismic events could feasibly cause mass wasting of material to form some fine-scale smooth surfaces observed on at least three icy satellites: Ganymede, Europa, and Enceladus.

Currently, existing image resolution, areal extent, and stereo coverage are severely constrained. A better understanding of tectonic and coseismic mass wasting processes will be possible when the Europa Clipper and JUICE missions provide high-resolution surface imaging, including stereo imaging, along with subsurface radar sounding, for both Europa and Ganymede.

How to cite: Pappalardo, R., Mills, M., Panning, M., Leonard, E., and Howell, S.: Moonquake-Triggered Mass Wasting Processes on Icy Worlds, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-3916, https://doi.org/10.5194/egusphere-egu23-3916, 2023.

EGU23-4265 | ECS | Orals | PS5.4

Polar heat transport enhancement in sub-glacial oceans on icy moons 

Robert Hartmann, Richard J.A.M. Stevens, Detlef Lohse, and Roberto Verzicco

The icy moons of the solar system show several phenomena in their polar regions like active geysers or a thinner crust than at the equator, all of which might be related to a non-uniform heat transport in the underlying ocean of liquid water. We investigate the potential for local heat transport enhancement in these sub-glacial oceans by conducting direct numerical simulations of rotating Rayleigh-Bénard convection (RRBC) in spherical geometry at a water-like Prandtl number Pr=4.38, Rayleigh number Ra=106, and Rossby number ∞≥Ro≥0.03 (or in terms of the Ekman number ∞≥Ek≥6.28·10-5). We probe two ratios of inner to outer radius η=ri/ro=0.6 and η=0.8, which is closer to the presumed conditions on most icy moons, for different gravitational laws g(r)∝rγ. The simulations cover the full range from zero to rapid rotation close to where convection ceases, and therefore cross the rotation-affected regime of intermediate rotation rates with a potentially enhanced dimensionless heat transport Nu>Nunon–rot as known from planar RRBC.

Although the global heat transport does not increase (Nuglobal≤Nunon–rot), we find an enhancement up to 28% at high latitudes around the poles (Nuhl>Nunon–rot), which is compensated by a reduced heat transport at low latitudes around the equator (Null<Nunon–rot). In the tangent cylinder around the poles, Ekman vortices connect the inner and the outer shell, which allows for a more effective transport of heat through the bulk by Ekman pumping, whereas these vortices impede radial heat transport towards the equator. Interestingly, the polar enhancement decreases for the thinner shell (η=0.8 compared to η=0.6) with a larger tangent cylinder, but still remains significantly larger than the non-rotating reference value (≈10%).

We also analyze the thicknesses of the thermal and kinetic boundary layers λΘ and λu to identify whether a ratio λΘu≈1 is beneficial for the maximal polar heat transport, as hypnotized from planar RRBC. Overall, our study reveals that the same mechanisms, which govern the heat transport enhancement in planar RRBC, also enhance the heat transport in the polar regions in spherical RRBC. On the bigger picture, our results may help to improve the understanding of latitudinal variations in the crustal thickness on icy moons.

How to cite: Hartmann, R., Stevens, R. J. A. M., Lohse, D., and Verzicco, R.: Polar heat transport enhancement in sub-glacial oceans on icy moons, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-4265, https://doi.org/10.5194/egusphere-egu23-4265, 2023.

EGU23-4509 | Orals | PS5.4

The energetic ion environment around Ganymede to be investigated with JUICE 

Christina Plainaki, Stefano Massetti, Xianzhe Jia, Alessandro Mura, Elias Roussos, Anna Milillo, and Davide Grassi

In this work the radiation environment around Ganymede is investigated. We apply a single-particle Monte Carlo model to obtain 3-D distribution maps of the H+, O++, and S+++ populations at the altitude of ~500 km and to deduce surface precipitation maps. We perform these simulations for three distinct configurations between Ganymede’s magnetic field and Jupiter’s plasma sheet (JPS), characterized by magnetic and electric field conditions similar to those during the NASA Galileo G2, G8, and G28 flybys (i.e., when the moon was above, inside, and below the centre of Jupiter’s plasma sheet). Our results provide a reference frame for future studies of planetary space weather phenomena in the near-Ganymede region and surface evolution mechanisms. For ions with energies up to some tens of iloelectronvolts, we find an increased and spatially extended flow in the anti-Jupiter low-latitude and equatorial regions above Ganymede’s leading hemisphere. Our results also show that the ion flux incident at 500 km altitude is not a good approximation of the surface’s precipitating flux. To study, therefore, Ganymede’s surface erosion processes it may be best to consider also low-altitude orbits as part of future space missions. This study is relevant to the ESA JUpiter ICy moons Explorer mission, which will allow a detailed investigation of the Ganymede environment and its implications on the moon’s surface evolution.

How to cite: Plainaki, C., Massetti, S., Jia, X., Mura, A., Roussos, E., Milillo, A., and Grassi, D.: The energetic ion environment around Ganymede to be investigated with JUICE, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-4509, https://doi.org/10.5194/egusphere-egu23-4509, 2023.

EGU23-6132 | Posters virtual | PS5.4

Convection in Europa’s icy shell: the role of composite rheology and dynamic grain size evolution 

Tobias Rolf and Antonio Manjón-Cabeza Cordoba

Europa’s outermost layer is a shell of water ice with a probable thickness of a few to a few dozens of km. It is most likely underlain by a liquid water ocean in direct contact with mantle rock, which makes Europa a prime target for understanding habitability. Europa’s surface is heavily deformed and the mean surface age is low (< ~100 Myr), implying active resurfacing, perhaps even through subduction-like processes. While this requires future confirmation, convection in Europa’s icy shell is a viable mechanism to drive such processes. However, the pattern of convection and its link to resurfacing is poorly understood. Here, we use 2D numerical simulations to shed light on these aspects and implement a composite rheology featuring the different slip mechanisms potentially relevant for ice: diffusion creep, basal slip (BSL), grain-boundary sliding (GBS), and dislocation creep. We couple this to grain-size evolution (GSE) and test in basally and mixed basally-tidally heated cases in a 20 km-thick shell the parameters governing the deformation mechanism and GSE.

Without imposing a yield stress to modulate pseudo-plastic deformation, we typically observe an immobile layer at the top of the ice shell. This layer tends to deform via GBS/BSL and features very small grain-sizes (<40 µm), while grains are on the order of cm in the warmer deeper parts, due to stronger grain growth. The thickness of the immobile layer decreases with enhancing the rate of tidal heating and with the sensitivity of grain growth to temperature variations. The immobile layer is thinnest (10-20% of the total thickness), if grain growth in the interior is only moderately enhanced compared to the cold shallow parts, while a large contrast in grain growth increases the layer thickness until eventually convection in the ice shell ceases completely. The omnipresence of an immobile layer (no matter how thick) appears at odds with Europa’s strongly deformed surface and its low age, unless other processes can explain this aspect. Preliminarily, mobilization of the surface layer is possible in our models by imposing a small finite yield stress. Using a very low coefficient of friction, surface velocities can reach rates of up to tens of centimeters per year, under which the surface would be recycled efficiently.

 
 
 

How to cite: Rolf, T. and Manjón-Cabeza Cordoba, A.: Convection in Europa’s icy shell: the role of composite rheology and dynamic grain size evolution, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-6132, https://doi.org/10.5194/egusphere-egu23-6132, 2023.

EGU23-6345 | ECS | Posters on site | PS5.4

Ice Transit and Performance Analysis for Cryorobotic Subglacial Access Missions on Earth and Europa 

Marc S. Boxberg, Qian Chen, Ana-Catalina Plesa, and Julia Kowalski

It is widely recognised that the icy moons of our solar system are interesting candidates for the search for habitable environments beyond Earth. While upcoming space missions such as the Europa Clipper and JUICE missions will give us further insight into the local cryo-environment of Jupiter’s moon Europa, any conclusive survey to detect life will require the ability to penetrate and traverse the ice shell and access the subglacial ocean directly. Developing a robust, autonomous cryobot for such a mission is an extremely demanding challenge and requires a concentrated interdisciplinary effort by engineers, geoscientists and astrobiologists.

We report on recent progress in developing ice transit and performance models as a first step towards a modular virtual testbed. The modularity of the virtual testbed allows easy exchange of the trajectory model used, the environmental conditions, such as ice parameters, and the description of the cryobot. We introduce a trajectory model that allows the evaluation of mission-critical parameters such as transit time and energy demand for different cryobot designs and deployment scenarios both on Earth and on icy moons.

Specific analyses presented in this study highlight the trade-off between minimum transit time and maximum efficiency of a cryobot, and allow quantification of different sources of uncertainty for cryobot trajectory models. Based on the terrestrial scenarios, our results show that the fastest transit time for the TRIPLE IceCraft cryobot is consistently achieved at all deployment sites, while its average energy consumption is rather high. The most energy efficient cryobot considered in our work is the EnEx-RANGE APU, that is, however, not designed for carrying large payloads.

While we have focused on idealized models that, for example, assume a planar melting head and a laterally isolated probe, future extensions of the virtual testbed will include more detailed models and take into account non-uniform distributions of salt concentration observed in terrestrial ice drilling. Our models are a first major step forward in estimating the efficiency of melting probes and can help develop and improve robust, autonomous cryorobotic technologies for extraterrestrial missions that can ultimately shed light on the potential for life to exist in the alien oceans of Europa and other icy moons.

How to cite: Boxberg, M. S., Chen, Q., Plesa, A.-C., and Kowalski, J.: Ice Transit and Performance Analysis for Cryorobotic Subglacial Access Missions on Earth and Europa, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-6345, https://doi.org/10.5194/egusphere-egu23-6345, 2023.

EGU23-6487 | Posters on site | PS5.4

The chemical composition of the Soi crater region on Titan. 

Anezina Solomonidou, Michael Malaska, Rosaly Lopes, Athena Coustenis, Ashley Schoenfeld, Bernard Schmitt, Samuel Birch, and Alice Le Gall

The Soi crater region, with the well-preserved Soi crater in its center, covers almost 10% of Titan’s surface. Schoenfeld et al. (2023) [1] mapped this region at 1:800,000 scale and produced a geomorphological map showing that the area consists of 22 distinct geomorphological units. The region includes the boundaries between the equatorial regions of Titan and the mid-latitudes and extends into the high northern latitudes (above 50o). We analyzed 262 different locations from several Visual and Infrared Mapping Spectrometer (VIMS) datacubes using a radiative transfer technique [2] and a mixing model [3], yielding compositional constraints on Titan’s optical surface layer and near-surface substrate compositional constraints using RADAR microwave emissivity. We have derived combinations of top surface materials between dark materials, tholin-like materials, water-ice, and methane. We found no evidence of CO2 and NH3 ice. We discuss our results in terms of origin and evolution theories.

[1] Schoenfeld, A., et al. (2023), JGR-Planets 128, e2022JE007499; [2] Solomonidou, A., et al., (2020a), Icarus, 344, 113338; [3] Solomonidou, A., et al. (2020b), A&A, 641, A16.

How to cite: Solomonidou, A., Malaska, M., Lopes, R., Coustenis, A., Schoenfeld, A., Schmitt, B., Birch, S., and Le Gall, A.: The chemical composition of the Soi crater region on Titan., EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-6487, https://doi.org/10.5194/egusphere-egu23-6487, 2023.

EGU23-6803 | ECS | Orals | PS5.4

Coupling ice-ocean interface models with global-scale ice shell evolution models applied to Jovian moon Europa 

Tina Rückriemen-Bez, Benjamin Terschanski, Ana-Catalina Plesa, and Julia Kowalski

The astrobiological potential of the Jovian moon Europa has long been acknowledged [1]. Europa’s surface, icy shell, likely salty ocean, and silicate mantle play a key role in determining Europa’s habitability. In particular, the icy shell may harbor cracks and pockets filled with brine that could be niches for sustaining life.

One major question is how and to which degree brines are incorporated into the ice shell and how they evolve. Global models of the ice shell resolving spatial scales of several hundred meters to kilometers are able to constrain the long term evolution of solid salt intrusions [e.g. 2] and potentially brines. Two-phase extensions in global models, however, have so far only been applied to pure water ice shells [3]. Since global ice shell models cannot capture the intake of brine at the ice-ocean interface due to the large scales they act on, they rely on boundary conditions that incorporate the physics of the interface.

Meso-scale models of the ice-ocean interface [4, 5] operate on length scales of centimeters to meters. The transition between ice and seawater is treated as a mush containing a mix of solid and high-salinity brine, typically assumed to be in thermodynamic equilibrium [6]. Modern mushy-layer models [7] provide insight into the distribution of salt impurities [8].

We review inter-solver coupling strategies and discuss applicability to the coupling of the meso-scale ice-ocean interface and the planetary-scale convection. We propose a spatial homogenization of meso-scale simulation outputs and a Gauss-Seidel subcycling approach [9] to embed the fast into long-term variations. This work will lay the foundation for physically consistent scale-coupled evolution models of the cryohydrosphere of icy moons.

[1] K. P. Hand et al., Europa, 2009.
[2] L. Han and A. P. Showman, Geophysical research letters, 2005.
[3] K. Kalousová et al., Icarus, 2018.
[4] J. J. Buffo et al., Journal of Geophysical Research: Planets, 2020.
[5] J. J. Buffo et al., Journal of Geophysical Research: Planets, 2021.
[6] D. L. Feltham et al., Geophysical Research Letters, 2006.
[7] J. R. G. Parkinson et al., Journal of Computational Physics, 2020.
[8] J. J. Buffo et al., Journal of Geophysical Research: Planets, 2021.
[9] 3 - The coupling methods. In: Multiphysics Modeling, Academic Press, Oxford, 2016.

How to cite: Rückriemen-Bez, T., Terschanski, B., Plesa, A.-C., and Kowalski, J.: Coupling ice-ocean interface models with global-scale ice shell evolution models applied to Jovian moon Europa, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-6803, https://doi.org/10.5194/egusphere-egu23-6803, 2023.

EGU23-9149 | Posters on site | PS5.4

Airborne radar radiometry and coastline mapping of the highly-specular subglacial terrain on Devon island 

Christopher Gerekos, Anja Rutishauser, Kirk Scanlan, Natalie Wolfenbarger, Lucas Beem, Jason Bott, and Donald Blankenship

The highly-specular terrain present under Devon Ice Cap in the Canadian Arctic Archipelago has been the target of several multi-instrument investigation campaigns. Initial analysis of radar sounder data collected by the High Capability Radar Sounder (HiCARS) and the Multichannel Coherent Radar Depth Sounder (McCORDS) over the area using state-of-the-art quantitative methods suggested the terrain could be a hypersaline lake [Rutishauser et al., Science Advances, 2018], however, newer seismic and conductivity measurements suggest a rigid, electrically insulating material that is incompatible with liquid water [Killingbeck et al., AGU, 2022]. Starting from the hypothesis that the highly specular terrain consists of flat and smooth sediments originating from a paleolake, we propose to revisit the original radar data and to apply more advanced dielectric and subsurface rough scattering hypotheses in order to constrain the materials present in the subsurface. We also propose to use subsurface interferometric clutter discrimination [Scanlan et al., 2020, Annals of Glaciology] on Multifrequency Airborne Radar-sounder for Full-phase Assessment (MARFA) data to map the coastline of the supposed paleolake. Combining dielectric and subsurface topographic information with modeling of the thermophysical evolution of the lake over interglacial cycles could reveal the history of the formation of the structure. Preliminary work on the new radar data analysis is presented.

How to cite: Gerekos, C., Rutishauser, A., Scanlan, K., Wolfenbarger, N., Beem, L., Bott, J., and Blankenship, D.: Airborne radar radiometry and coastline mapping of the highly-specular subglacial terrain on Devon island, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-9149, https://doi.org/10.5194/egusphere-egu23-9149, 2023.

EGU23-10075 | ECS | Orals | PS5.4

Cassini Bistatic Radar Observations of Titan's Seas: Results about Dielectric Properties and Capillary Waves Detection 

Giancorrado Brighi, Valerio Poggiali, Paolo Tortora, Marco Zannoni, Alexander Hayes, Daniel Lalich, Lea Bonnefoy, Shannon MacKenzie, Phil D Nicholson, Kamal Oudrhiri, Ralph D Lorenz, and Jason M Soderblom

Between 2006 and 2016, the Cassini spacecraft carried out 13 bistatic radar observations of the surface of Saturn's largest moon, Titan. Unmodulated right circularly polarized radio signals were transmitted by the spacecraft to the moon’s surface. Cassini’s high gain antenna was pointed so that specular reflections from Titan’s surface were received on Earth. Proper processing of right (RCP) and left circularly polarized (LCP) echoes from the moon can provide information about surface roughness and near-surface relative dielectric constant (ɛr) of the illuminated terrains.

During Titan flybys T101, T102, T106, and T124, the track of the bistatic observations crossed the main stable liquid bodies of the north pole of Titan: Ligeia, Kraken, Punga Mare, and their estuaries. Strong and narrowband X-band (λ=3.6 cm) echoes were successfully detected from the seas at the Deep Space Network 70-meter station in Canberra.

Reflected spectra feature Dirac-like shapes, with a spectral broadening around 1 Hz and lower bounded by the processing time resolution. Compared to bistatic observations of other planets, this implies unprecedentedly low RMS slope values for Titan’s seas on an effective length-scale of a few meters. Profiles of reflected LCP and RCP power are in general consistent with purely coherent reflections from the Fresnel area around the moving specular point, indicating a very flat surface.

In addition, from the circular polarization power ratio, the surface dielectric constant can be derived. This can enrich our current understanding of the chemistry of Titan’s liquid hydrocarbon seas, further constraining their methane-ethane mixing ratio. From Cassini RADAR, VIMS, and ISS, Titan’s seas are expected to be ternary mixtures of methane, ethane and nitrogen (ɛr ≈ 1.6-1.9). From bistatic radar data, significant relative variations in liquid hydrocarbon composition are seen, and an unexpected correlation between the dielectric constant and incidence angle of observation seems to arise. The absolute values of permittivity are somewhat lower than expected.

From the computed dielectric constant values, physical optics models are used to constrain the RMS height of the surface. This analysis provides meaningful insights into the presence of small capillary waves in the order of millimeters over the liquid surfaces of Titan, as already detected by Cassini monostatic RADAR.

How to cite: Brighi, G., Poggiali, V., Tortora, P., Zannoni, M., Hayes, A., Lalich, D., Bonnefoy, L., MacKenzie, S., D Nicholson, P., Oudrhiri, K., D Lorenz, R., and M Soderblom, J.: Cassini Bistatic Radar Observations of Titan's Seas: Results about Dielectric Properties and Capillary Waves Detection, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-10075, https://doi.org/10.5194/egusphere-egu23-10075, 2023.

EGU23-10554 | ECS | Posters on site | PS5.4

RIME-REASON synergistic opportunities for surface and near-surface investigations of icy moons 

Kristian Chan, Cyril Grima, Christopher Gerekos, and Donald D. Blankenship

The near-surface (i.e., depths of tens of meters from the surface) of icy environments is subject to various processes resulting in changes to its structure, density, and composition. On Earth, surface meltwater can refreeze in firn to form meters-thick ice layers, which can inhibit subsequent vertical infiltration in favor of lateral runoff. On icy worlds such as Ganymede, landform degradation processes, such as mass wasting and impact erosion, could leave behind layered deposits of dark material of varying density and thickness. Therefore, characterizing such heterogeneity (layering) can reveal much about the different processes acting on the near-surface environment. These processes can be studied with a multi-frequency/bandwidth approach applied to surface radar reflectometry measurements.

Airborne ice-penetrating radar, traditionally designed to study the subsurface of ice sheets on Earth, can also be used to study the surface and near-surface ice. Upcoming missions to the Jovian icy moons will carry ice-penetrating radars, namely the Radar for Europa Assessment and Sounding: Ocean to Near-surface (REASON) on the Europa Clipper mission and the Radar for Icy Moons Exploration (RIME) on the JUpiter ICy moons Explorer (JUICE) mission. REASON will operate at center frequencies of 60 MHz and 9 MHz, with bandwidths of 10 MHz and 1 MHz, respectively. RIME will operate with only a center frequency of 9 MHz but with dual-bandwidth capabilities of 2.8 MHz and 1 MHz.

The Radar Statistical Reconnaissance method was applied to dual-frequency/bandwidth radar observations collected over Devon Ice Cap, Canadian Arctic, to deconvolve the total surface power into its coherent (Pc) and incoherent (Pn) components. Both Pc and Pn are used to map the spatial distribution and constrain the vertical thickness of ice layers embedded within firn. We extend this approach to Ganymede and assess its utility for studying near-surface layering in the context of rough surfaces. We simulate the radar surface echo with a generalized version of the multilayer Stratton-Chu coherent simulator previously published, but now compute the scattering contributions from every frequency component within the bandwidth of the emitted chirp. Simulated data are shown to validate the assumptions of the insensitivity to surface roughness parameters representative of Ganymede, when observing with different bandwidths but at the same center frequencies. Finally, we outline strategies for using RIME and REASON together for near-surface reflectometry studies over planned observations of the Jovian icy moons. Using observations obtained with the frequencies and bandwidths from both radars, particularly at crossover locations, can provide valuable knowledge of the near-surface structure, even when the surface may appear rough.

How to cite: Chan, K., Grima, C., Gerekos, C., and Blankenship, D. D.: RIME-REASON synergistic opportunities for surface and near-surface investigations of icy moons, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-10554, https://doi.org/10.5194/egusphere-egu23-10554, 2023.

EGU23-11227 | ECS | Posters on site | PS5.4 | Highlight

Detecting Europa’s water plumes with the Particle Environment Package on JUICE 

Hans Huybrighs, Rowan Dayton-Oxland, André Galli, Audrey Vorbuger, Martina Föhn, Peter Wurz, Arnaud Mahieux, David Goldstein, Thomas Winterhalder, and Stas Barabash

The repeated eruptions of water plumes on Europa have been suggested based on Hubble observations, Keck observations and in-situ magnetic field data from Galileo (Roth et al., 2014; Sparks et al., 2016, 2017, 2019; Jia et al., 2018; Arnold et al., 2019; Paganini et al., 2019). The possibility that such plumes could transport material from Europa’s subsurface, or from water reservoirs contained in the ice layer (Vorbuger and Wurz 2021), far above the surface creates an unprecedented opportunity to sample Europa’s subsurface environment and investigate its habitability. The JUpiter ICy moon Explorer (JUICE) is scheduled to make two flybys of Europa, one over the Northern and one over the Southern hemisphere, with the closest approach at 400 km altitude.

In this work we investigate the detectability of such water plumes using the Neutral and Ion Mass Spectrometer (NIM) and the ion mass spectrometer Jovian Dynamics and Composition analyser (JDC) of the Particle Environment Package (PEP) on JUICE. Using a Monte Carlo particle tracing model we simulate the density distribution of the plume and simulate the measured signature with NIM and JDC along the two JUICE flyby trajectories.

Using a particle tracing model we show that H2O molecules and H2O+ ions of the plume, as well as possible minor constituents such as CO and CH4, can be detected during the JUICE flybys. We find that the plume reported by Roth et al., 2014 is the most likely to be detected, even at the lowest mass fluxes, and that the southern-hemisphere JUICE flyby has the best coverage of all the presumptive plume sources. Lowering the altitude of the southern flyby will contribute to an increased chance of detecting the presumptive plume sources, and should be prioritized over lowering the other flybys if any deltaV is available.

Additionally, using a DSMC molecule and particle tracing model we investigate the effect of intermolecular collisions in the plume and demonstrate that such collisions will reduce the detectability of the plume. We also show that the JUICE flybys and the NIM characteristics will be suitable to discern the finer structure of the plume (e.g. shocks inside the plume), which will allow us to improve our understanding of the physics of Europa’s plumes.

Furthermore, we also investigate the separability of the plume from Europa’s asymmetric sputtered and sublimated water atmosphere and discuss the influence of the instrument pointing and operations on the plume detectability. We find that NIM’s operational constraints are not critical in terms of detecting H2O molecules of a plume.

How to cite: Huybrighs, H., Dayton-Oxland, R., Galli, A., Vorbuger, A., Föhn, M., Wurz, P., Mahieux, A., Goldstein, D., Winterhalder, T., and Barabash, S.: Detecting Europa’s water plumes with the Particle Environment Package on JUICE, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-11227, https://doi.org/10.5194/egusphere-egu23-11227, 2023.

EGU23-13378 | ECS | Posters on site | PS5.4

Modelling Europa’s collisional atmosphere using the DSMC method 

Leander Schlarmann, Audrey Vorburger, Shane R. Carberry Mogan, and Peter Wurz

In this study, we present preliminary results of modelling the potentially collisional atmosphere of the Jovian satellite Europa using the Direct Simulation Monte Carlo (DSMC) method [1]. In the DSMC method particular gas flows are calculated through the collision mechanics of representative atoms or molecules that are subject to binary collisions to simulate macroscopic gas dynamics.

NASA's Europa Clipper mission [2] and ESA's JUpiter Icy Moons Explorer (JUICE) [3] will encounter Europa with flybys in the 2030s to sample the atmosphere of the icy moon using mass spectroscopy. Measurements with the MAss Spectrometer for Planetary EXploration (MASPEX) onboard Europa Clipper and the Neutral gas and Ion Mass spectrometer (NIM) onboard JUICE will determine the composition of Europa's exosphere and, potentially, sample the plume material. From the exosphere measurements, the chemical composition of Europa's surface could be derived, whereas plume measurements would potentially allow conclusions about the chemical conditions of Europa's subsurface ocean.

Models of the collision-less exosphere for the icy moon [4, 5] have shown that Europa’s ice-sputtered atmosphere is dominated by O2 near the surface with an extended H2 corona at higher altitudes. Here, we compare the results of these studies with the DSMC model including deeper layers of Europa's collisional atmosphere.

[1] Bird, G. A. (1994). Molecular gas dynamics and the direct simulation of gas flows.
[2] Phillips, C. B., and Pappalardo, R. T. (2014). Eos, Transactions AGU, 95(20), 165-167.
[3] Grasset, O., et al. (2013). Planetary and Space Science, 78, 1-21.
[4] Vorburger, A., and Wurz, P. (2018). Icarus, 311, 135-145.
[5] Vorburger, A., and Wurz, P. (2021). J. Geophys. Res. Space Phys., 126(9), e2021JA029690.

How to cite: Schlarmann, L., Vorburger, A., Carberry Mogan, S. R., and Wurz, P.: Modelling Europa’s collisional atmosphere using the DSMC method, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-13378, https://doi.org/10.5194/egusphere-egu23-13378, 2023.

EGU23-14516 | Orals | PS5.4 | Highlight

Molecular Biosignature Detection on Ocean Worlds using a Prototype Laser-Desorption Ionisation Mass Spectrometer 

Nikita Jennifer Boeren, Peter Keresztes Schmidt, Coenraad Pieter de Koning, Kristina Anna Kipfer, Niels Frank Willem Ligterink, Marek Tulej, Peter Wurz, and Andreas Riedo

Recently, it has become evident that icy moons in our solar system might constitute excellent targets for the search for life beyond Earth. Both Europa and Enceladus are of high interest for the detection of biosignatures, mainly due to the putative presence of all ingredients required to form life (as we know it), i.e., liquid water, an energy source, and the required chemical ingredients. If life is indeed present on these two bodies, molecular biosignatures may be preserved and protected from the radiative environment in the near surface ice. In situ instrumentation on board of a payload could perform compound identification and biosignature detection facilitating better limits of detection and more specific compound detection compared to spectroscopic measurements from orbit.

Several (groups of) compounds are listed as molecular biosignatures, including certain amino acids and lipids.1 However, reliable in situ detection of molecular biosignatures is challenging. Not only does the instrumentation need to be flight-capable, it should also be sensitive enough to detect trace abundances, while simultaneously covering a high dynamic range, so as to not exclude highly abundant compounds. Additionally, instrumentation should preferably be capable of detecting many different classes of molecules and not be limited to a single compound or group of molecules.

ORIGIN (ORganics Information Gathering INstrument) is a space-prototype laser ablation ionisation mass spectrometer (LIMS) operated in desorption mode and designed for in situ detection of molecular biosignatures for space exploration missions. The simplistic and compact design make it a lightweight and robust system, which meets the requirements of space instrumentation. Currently, the setup consists of a nanosecond pulsed laser system and a miniature reflectron-type time-of-flight (RTOF) mass analyser (160 mm x Ø 60 mm). Biomolecules are desorbed and ionised by the laser pulse, after which the positive ions are separated based on their mass-to-charge ratio (TOF principle) by the mass analyser.

The molecular biosignature detection capabilities of ORIGIN have been recently demonstrated for amino acids, polycyclic hydrocarbons, and lipids 2–4. In this contribution, our envisioned concept of going from obtained ice samples to the detection of molecular biosignatures using LIMS will be discussed. In addition, we will show results of lipid biosignature detection using ORIGIN, covering sensitivity and dynamic range2, implying the future applicability for the detection of life on Icy Moons. Additionally, future projects of analogue ice studies with the ORIGIN space-prototype will be covered.

1. Hand, K. P. et al. Report of the Europa Lander Science Definition Team. (Jet Propulsion Laboratory, 2017).

2. Boeren, N. J. et al. Detecting Lipids on Planetary Surfaces with Laser Desorption Ionization Mass Spectrometry. Planet. Sci. J. 3, 241 (2022).

3. Kipfer, K. A. et al. Toward Detecting Polycyclic Aromatic Hydrocarbons on Planetary Objects with ORIGIN. Planet. Sci. J. 3, 43 (2022).

4. Ligterink, N. F. W. et al. ORIGIN: a novel and compact Laser Desorption – Mass Spectrometry system for sensitive in situ detection of amino acids on extraterrestrial surfaces. Sci. Rep. 10, 9641 (2020).

How to cite: Boeren, N. J., Keresztes Schmidt, P., de Koning, C. P., Kipfer, K. A., Ligterink, N. F. W., Tulej, M., Wurz, P., and Riedo, A.: Molecular Biosignature Detection on Ocean Worlds using a Prototype Laser-Desorption Ionisation Mass Spectrometer, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-14516, https://doi.org/10.5194/egusphere-egu23-14516, 2023.

EGU23-14989 | ECS | Posters on site | PS5.4

Hybrid concept for a forefield reconnaissance system for melting probes capable of moving through terrestrial and extraterrestrial cryospheres 

Fabian Becker, Michael Stelzig, Jan Audehm, Niklas Haberberger, Dirk Heinen, Simon Zierke, Klaus Helbing, Christopher Wiebusch, Martin Vossiek, and Georg Böck

The most promising places for the development of extraterrestrial life are the ocean worlds of our Solar system such as the icy moons Europa or Enceladus and their subglacial oceans.  Space mission concepts are being developed to explore the moons’ chemical composition, investigate their habitability, and search for biosignatures.
The TRIPLE Project, initiated by the German Space Agency at DLR, involves the development of technologies for rapid ice penetration and subglacial lake exploration. It consists of three components: (i) a melting probe that travels safely through the ice and carries (ii) an autonomous nano-scale underwater vehicle that explores the ocean and takes samples to be delivered to (iii) an astrobiological laboratory. The entire system will be tested in an analogue scenario in Antarctica as a demonstration for a future space mission. To ensure the success of the test, a retrievable melting probe is needed that can safely penetrate several kilometers of ice. The melting probe should also be able to detect the transition between the ice and the water body to stop at this boundary. 

The Forefield Reconnaissance System (FRS) for such a melting probe developed in the project TRIPLE-FRS combines radar and sonar techniques to benefit from both sensor principles inside the ice. The radar antennas as well as a piezoelectric acoustic transducer will be directly integrated into the melting head. This integration into the head should leave the melting capability of the melting probe as unaffected as possible. An in-situ permittivity sensor will also be developed to account for the propagation speed of electromagnetic waves, which is dependent on the surrounding ice structure. The goal of this system is to detect obstacles or other interference bodies to guarantee a safe transition through the ice. Damage-free melting must be secured to allow all other scientific exploration. In order to prove the functionality and performance of the system, several field tests on alpine glaciers are performed during the project. In this contribution, we describe the main ideas behind the system and show how it could serve as a baseline design for the future development of space missions to ocean worlds like Europa.

How to cite: Becker, F., Stelzig, M., Audehm, J., Haberberger, N., Heinen, D., Zierke, S., Helbing, K., Wiebusch, C., Vossiek, M., and Böck, G.: Hybrid concept for a forefield reconnaissance system for melting probes capable of moving through terrestrial and extraterrestrial cryospheres, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-14989, https://doi.org/10.5194/egusphere-egu23-14989, 2023.

EGU23-16101 | ECS | Posters on site | PS5.4

Coupling of Induced Magnetic Fields of Local Asymmetric Features in Subsurface Ocean Moons 

Jason Winkenstern and Joachim Saur

In the recent decades, both ground-based and satellite observations provided
indirect evidence for the existence of subsurface oceans within Europa’s icy
crust (Kivelson et al., 2000; Roth et al., 2014). Since then, the search for icy
moons with similar features has been ongoing (e.g., Cochrane et al., 2021).
Such a subsurface ocean interacts with the time-varying magnetic field of
its host planet, resulting in an induced magnetic field (Khurana et al., 1998;
Saur et al., 2010). To model these induction responses, a radially symmetric
interior structure is generally assumed (Zimmer et al., 2000; Schilling et al.,
2007). Geological arguments, however, can motivate cases for asymmetric
features, e.g. tidal heating and the existence of chaos terrain on Europa
(Styczinski et al., 2022). We approximate such an asymmetric feature by
modelling a radially symmetric subsurface ocean together with a local small-
scale water reservoir of spherical shape. This results in a non-linear coupling
mechanism between the induction responses of ocean and reservoir. In our
presentation we will discuss the nature of such a non-linear coupled induction
and its effects on the potential detectability of small-scale water features for
future missions such as Europa CLIPPER.

How to cite: Winkenstern, J. and Saur, J.: Coupling of Induced Magnetic Fields of Local Asymmetric Features in Subsurface Ocean Moons, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-16101, https://doi.org/10.5194/egusphere-egu23-16101, 2023.

EGU23-16162 | ECS | Posters on site | PS5.4 | Highlight

Combining Earth cryosphere microwave radiometry and radar to understand the properties of planetary ices 

Lea Bonnefoy, Catherine Prigent, Clément Soriot, and Lise Kilic

Interpreting microwave data on icy moons in terms of physical parameters is a key challenge offered by observations of Ganymede and Europa by both the current Juno (NASA) MicroWave Radiometer (MWR) and the future JUICE (ESA) Submillimeter Wave Instrument (SWI). From sub-millimeter to decimeter scale wavelengths, radiometry is sensitive to different depths and scatterer sizes: each frequency offers complementary information. Despite the large volume of available passive and active microwave satellite observations over the Earth cryosphere, physical interpretation of the co-variability of the multi-frequency observations is still challenging, especially when trying to reconcile radiometry and radar observations. To help interpret icy moon observations and improve our understanding of Earth’s ices, we assemble a multi-frequency active and passive microwave observation dataset from the SMAP (1.4 GHz, passive), AMSR2 (6 to 89 GHz, passive) and ASCAT (5 GHz, active) missions. The data are gridded over Earth’s land and ocean ices and averaged over 10 days, over two full years and then classified using a k-means method. We identify regions with microwave behavior analogous to that observed on icy moons and simulate them using the Snow Microwave Radiative Transfer (SMRT) model. Identifying structures responsible for given microwave signatures will help interpret the Juno MWR observations on Jupiter’s moons as well as the joint active/passive 2.2-cm Cassini data acquired from 2004 to 2017 on Saturn’s icy satellites.

 

How to cite: Bonnefoy, L., Prigent, C., Soriot, C., and Kilic, L.: Combining Earth cryosphere microwave radiometry and radar to understand the properties of planetary ices, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-16162, https://doi.org/10.5194/egusphere-egu23-16162, 2023.

EGU23-17280 | ECS | Orals | PS5.4

Radar Interferometry and Tomography for the Exploration of Enceladus’ Surface and Subsurface 

Andreas Benedikter, Marc Rodriguez-Cassola, Gerhard Krieger, Hauke Hussmann, Alexander Stark, Kai Wickhusen, Michael Stelzig, and Martin Vossiek

Orbital Synthetic Aperture Radar (SAR) interferometry (InSAR) and tomography (TomoSAR) are key techniques for the exploration of terrestrial ice sheets that are used operationally. However, in the context of planetary exploration, these approaches are rather exotic and have not been used yet. In the frame of DLR’s Enceladus Explorer (EnEx) initiative, we propose a multi-modal, multi-frequency orbital radar mission, operating -among others- in a SAR interferometric and tomographic mode capable of delivering high-accuracy and high-resolution topography, tidal deformation, and composition measurements as well as 3-D metric-resolution imaging of the ice crust along tens of kilometers wide swaths. The ice penetration capability of radar signals allows for the exploration of both surface and subsurface features down to hundreds of meters, depending on the used carrier frequency.

Multiple SAR acquisitions of the same area are needed to form interferometric and tomographic products. These acquisitions are collected successively following a repeat-pass concept using so-called periodic orbits with repeating trajectories. For the available observation geometries, the baselines between the repeat trajectories need to lie within a few hundreds of meters (i.e., the radar needs to fly within a tube of hundreds of meters). Unfortunately, the low Enceladus mass and its proximity to Saturn commonly lead to instabilities for highly inclined science orbits. We find that published orbit solutions do not exhibit sufficient stability for providing the necessary repeat passes. However, through a grid-search approach in a high-fidelity gravitational model, we identified highly stable periodic orbits that sustain the required repeat characteristic up to hundreds of days. The short repeat periods in the order of 1 to 4 days allow for a fast acquisition of InSAR observations and the formation of tomographic stacks within several days.

Based on a representative system, we present global performance simulations for both InSAR and TomoSAR products with a focus on the prominent south polar plume region of Enceladus. The performance of these products depends on several factors, including the system being used, the orbital geometry, the accuracy of the guidance, navigation, and control (GNC), the accuracy of the orbit determination, and the structure and composition of the ice crust, which affects the backscatter characteristics and potential decorrelation effects in the SAR acquisitions. We use an End-to-End (E2E) simulator developed at DLR for generating realistic SAR, InSAR, and TomoSAR products. The E2E is capable of accommodating the designed orbits, the Enceladus topography, deformation models, representative backscatter maps, and decorrelation effects, as well as any relevant instrument, baseline, and attitude errors.

How to cite: Benedikter, A., Rodriguez-Cassola, M., Krieger, G., Hussmann, H., Stark, A., Wickhusen, K., Stelzig, M., and Vossiek, M.: Radar Interferometry and Tomography for the Exploration of Enceladus’ Surface and Subsurface, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-17280, https://doi.org/10.5194/egusphere-egu23-17280, 2023.

EGU23-17371 | Orals | PS5.4

The TRIPLE project – Towards technology solutions for life detection missions 

Julia Kowalski, Marc S. Boxberg, Jan Thimo Grundmann, Jean-Pierre Paul de Vera, Dirk Heinen, and Oliver Funke and the TRIPLE consortium

The exploration of ocean worlds in the outer Solar System, for example, the Jovian moon Europa and the Saturnian moon Enceladus, are of particular interest for the search for extraterrestrial life. Direct in situ exploration of moons harbouring significant amounts of liquid water beneath their ice surface poses many challenges and requires a sophisticated technological approach. The TRIPLE project (Technologies for Rapid Ice Penetration and Subglacial Lake Exploration) initiated by the German Space Agency at DLR forms a national consortium to work on robotic technologies for sub-ice exploration. The planned system consists of the fully autonomous, untethered miniature submersible robot, called nanoAUV, the IceCraft, a melting probe for penetrating the ice with the nanoAUV as payload, and an astrobiology in-situ laboratory, the AstroBioLab, to study fluid and sediment samples.

Beneath a several kilometre-thick ice-shell of the moons considered here, global oceans are well hidden and not easily accessible, posing extreme challenges for any robotic exploration as it is addressed in the TRIPLE project. Therefore, ice drilling and state-of-the-art technologies need to be developed to meet the manifold requirements. In view of future missions to icy moons, in TRIPLE, an analogue terrestrial demonstration is intended for first time exploration of a subglacial lake at the Dome-C region in Antarctica. The Dome-C mission requires a retrievable melting probe that can penetrate a 4-kilometre-thick layer of ice. It is essential for the mission that the melting probe is able to detect and avoid obstacles along its trajectory and to anchor itself at the ice-water interface for release and support of the nanoAUV into the water. The AstroBioLab concept provides an automated sample analysis laboratory for habitability investigations. It shall not only be able to detect various biosignatures in samples taken from the subglacial habitats, but shall also provide unequivocal evidence of life. For the field test in a terrestrial analogue setting, portable and robust devices using fast analysis methods are particularly suitable, which, as far as possible, should not require time-consuming sample preparation. In this contribution, we give an overview of the TRIPLE project and report on its current status.

How to cite: Kowalski, J., Boxberg, M. S., Grundmann, J. T., de Vera, J.-P. P., Heinen, D., and Funke, O. and the TRIPLE consortium: The TRIPLE project – Towards technology solutions for life detection missions, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-17371, https://doi.org/10.5194/egusphere-egu23-17371, 2023.

EGU23-17429 | Orals | PS5.4 | Highlight

Exploring Europa, Jupiter’s Ocean World: A View from Earth 

Donald D. Blankenship, Duncan A. Young, Kristian Chan, Natalie S. Wolfenbarger, Christopher Gerekos, and Gregor B. Steinbrügge

Europa Subsurface Studies: The Europa Clipper is a NASA mission to study Europa, the ice-covered moon of Jupiter characterized by a global sub-ice ocean overlying a silicate mantle, through a series of fly-by observations from a spacecraft in Jovian orbit. The science goal is to “explore Europa to investigate its habitability”. The Radar for Europa Assessment and Sounding: Ocean to Near-surface (REASON) is one of the primary instruments of the scientific payload. REASON is an active dual-frequency (9/60 MHz) instrument led by the University of Texas Institute for Geophysics (UTIG). It is designed to achieve multi-disciplinary measurements to investigate subsurface waters and the ice shell structure (Sounding), the surface elevation and tides (Altimetry), near-surface physical properties (Reflectometry), and the ionospheric environment including plume activity (Plasma/Particles). REASON will play a critical role in achieving the mission’s habitability driven science objectives, which include characterizing the distribution of any shallow subsurface water, searching for an ice-ocean interface and evaluating a broad spectrum of ice-ocean-atmosphere exchange hypotheses. 

Terrestrial Analogs: The development of successful measurement approaches and data interpretation techniques for exploring Europa and understanding its habitability will need to leverage knowledge of analogous terrestrial environments and processes. Towards this end, we are investigating, and considering for future investigations, a range of terrestrial radio glaciological analogs for hypothesized physical, chemical, and biological processes on Europa and present airborne data collected with the UTIG/University of Kansas dual-frequency radar system over a variety of terrestrial targets relevant to Europa’s potential exchange processes and habitability.  These targets include water filled fractures, brine rich ice, subglacial lakes, accreted marine ice, and ice roughness ranging from porous ice regolith (firn) to extensive crevasse fields. Our goal is to provide context for understanding and optimizing the observable signature of these processes in future radar data collected at Europa with implications for its habitability.

How to cite: Blankenship, D. D., Young, D. A., Chan, K., Wolfenbarger, N. S., Gerekos, C., and Steinbrügge, G. B.: Exploring Europa, Jupiter’s Ocean World: A View from Earth, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-17429, https://doi.org/10.5194/egusphere-egu23-17429, 2023.

PS6 – Gas and ice giants: from sub-neptunes to super-jupiters, at home and abroad

EGU23-577 | ECS | Orals | PS6.1

Extending the NIR auroral map of Uranus through the 21st century 

Emma Thomas, Tom Stallard, Henrik Melin, Luke Moore, Mohammad Chowdhury, Ruoyan Wang, and Katie Knowles

Over 30 years of near infrared (NIR) observations at Uranus starting in 1992 with Trafton, et al., 1993, it is only in the last 5 years we have had any significant breakthroughs in mapping of NIR auroral morphology. The first confirmed auroral observations by Thomas, et al., (in review) and a tentative auroral detection by Melin, et al., (2019) have now shown that NIR aurora detections at Uranus are possible from ground-based observations. Thomas, et al. concluded that sections of the NIR northern aurora were observed for the first time and even outlined the first NIR auroral arcs, however due to observational limitations and the loss of Uranian Longitude System (ULS) a complete map could not be accomplished. With the ULS southern hemisphere now predominately facing the Earth (since the planet’s equinox of 2007), we are poised to reveal the auroral morphology of the southern aurora with detail never seen before. Success in this aim will yield the first insights into ionospheric magnetospheric interactions at Uranus when exposed to dynamic changes in the planet's magnetic field orientation to the solar wind and the first NIR maps to guide auroral expectations at sub-Neptune exoplanets.

In this study, we have taken ground-based observations of H3+ emissions from Uranus’s Equinox to 2022 and construct the first NIR composite map of the geographical equator and southern hemisphere to identify if similar auroral features appear as was observed in 2006, and to extend the NIR auroral mapping across Uranus.

How to cite: Thomas, E., Stallard, T., Melin, H., Moore, L., Chowdhury, M., Wang, R., and Knowles, K.: Extending the NIR auroral map of Uranus through the 21st century, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-577, https://doi.org/10.5194/egusphere-egu23-577, 2023.

EGU23-3990 | Orals | PS6.1

Composition Measurements of Uranus’ Atmosphere 

Peter Wurz, Audrey Vorburger, Olivier Mousis, and Ravid Helled

Knowing the composition of the giant planets is important in understanding their forma­tion and evolution history. The abundances of heavy elements, of noble gases, and isotope ratios reveals the physical and chemical conditions and processes that eventually led to their formation. The current knowledge of the composition of the giant planets is limited, with Jupiter being best studied thanks to the Galileo probe. Much less is known for Saturn, and almost nothing is known for Uranus and Neptune. Uranus and Neptune contain substantial hydrogen and helium at­mos­pheres, with bulk mass frac­tions of 5–20%. The remainder is thought to be "ices" and rocks, such as H2O, CH4, H2S, and NH3. Ura­nus and Neptune are the least-investigated planets in the solar system, but may be representative of similarly sized pla­nets com­mon in the population of exo-planets, thus provide some ground-truth.

Measurement of abundances in the atmosphere can be derived through a variety of re­mote sensing techniques, which is restricted to the upper layers of the atmosphere, but the number of useful observations from Earth is very limited. The most significant step forward in our know­ledge of giant planet internal composition was achieved with the Galileo probe into Jupiter’s atmos­phere. The prime instrument to probe the atmospheric composition on an descent probe is a mass spectrometer experiment (MSE), which comprises the actual mass spectro­meter for gas analysis, possible extensions by a gas-chromatographic pre-selection of the gaseous species, a cryogenic trap to enhance the measurement of noble gases and their isotopes, and an aerosol col­lector and pyrolysis system giving access to the composition of cloud and haze particles. To improve on the isotope measurements of selected species, a Tunable Laser Spectrometer can be added to measure the isotopic ratios with accuracy of selected molecules.

The atmos­pheric probe will enter on a specific location into Uranus’ atmosphere. Aside from technical constraints, what would be the scientific considerations for the locations? Entering at lower latitudes, perhaps near the equator where the zonal flow is retrograde or at higher latitudes with fast pro­grade zonal flows, or at a pole with very limi­ted horizontal flow, which might be easily ac­ces­sible because of Uranus’ rotation axis being close to the eclip­tic plane; at places with clouds running at constant lati­tudes or at cloud-free areas; at a dark spot (an anti­cyclonic storm) possibly providing upwelling from material; or other unique features observed on the surface.

An Uranus orbiter will provide complementary information of the atmosphere via remote sensing, e.g. mapping the “surface” of Uranus, tracking storms, clouds, and eddies in reflected sunlight, maps of key species, abundances of hydro­carbons in the photolysis layer, and some more. This will put the entry location of the probe in a global per­spective, is its entrance at a unique surface feature, is there presen­ce of clouds and hazes, and the temporal evo­lution during the orbital observations, like con­vec­tion, upward and downward energy flow, atmospheric wave activity, which shape atmospheric features such as cloud bands and vortices. In addition, micro­wave soun­ding might probe deep inside the atmosphere.

How to cite: Wurz, P., Vorburger, A., Mousis, O., and Helled, R.: Composition Measurements of Uranus’ Atmosphere, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-3990, https://doi.org/10.5194/egusphere-egu23-3990, 2023.

EGU23-5824 | ECS | Orals | PS6.1

Empirical structure models of Uranus and Neptune 

Benno Neuenschwander and Ravit Helled

Uranus and Neptune are still poorly understood. Their gravitational fields, rotation periods, atmosphere dynamics, and internal structures are not well determined. In this paper, we present empirical structure models of Uranus and Neptune where the density profiles are represented by polytropes. By using these models that are set to fit the planetary gravity field, we predict the higher order gravitational coefficients J6 and J8 for various assumed rotation periods, wind depths, and uncertainty of the low-order harmonics. We show that faster rotation and/or deep winds favour centrally concentrated density distributions. We demonstrate that an accurate determination of J6 or J8 with a relative uncertainty no larger than 10% could constrain wind depths of Uranus and Neptune. We also confirm that the Voyager II rotation periods are inconsistent with the measured shapes of Uranus and Neptune. We next demonstrate that more accurate determination of the gravity field can significantly reduce the possible range of internal structures. Finally, we suggest that an accurate measurement of the moment of inertia of Uranus and Neptune with a relative uncertainty of ∼ 1% and ∼ 0.1%, could constrain their rotation periods and depths of the winds, respectively.

How to cite: Neuenschwander, B. and Helled, R.: Empirical structure models of Uranus and Neptune, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-5824, https://doi.org/10.5194/egusphere-egu23-5824, 2023.

EGU23-6543 | ECS | Orals | PS6.1

Coupling a photochemical model of Triton's atmosphere with an electron transport code 

Benjamin Benne, Bilal Benmahi, Michel Dobrijevic, Thibault Cavalié, Jean-Christophe Loison, Kevin Hickson, Mathieu Barthélémy, and Jean Lilensten

Introduction

During the only flyby of Triton by Voyager 2 in 1989, a dense ionosphere was observed (Tyler et al. 1989). Results were surprising as the solar irradiation of this satellite is ten times lower than on Titan, and yet its ionosphere is denser. Thus, electronic precipitation from Neptune’s magnetosphere was hypothesized to bring the needed extra input energy (Krasnopolsky et al. 1993), as high energy electrons have been observed by the spacecraft in this area (Krimigis et al. 1989).  To understand how this precipitation could impact the composition of Triton’s atmosphere, we coupled an electron transport code to a photochemical model of this atmosphere.

Methodology 

We used the electron transport code TRANS that was utilized to compute the transport of electrons in various planetary atmospheres (see Gronoff et al. 2009 and references therein). We adapted it to Triton’s conditions and used the results from Strobel et al. (1990) and Sittler and Hartle (1996) to compute the input precipitation. This led us to calculate the mean magnetic field and the mean precipitation before adjusting it depending on energy, as detailed in Sittler and Hartle (1996). We then coupled TRANS with our most recent photochemical model of Triton’s atmosphere (Benne et al. 2022) by using TRANS outputs to compute the reaction rates of the electro-dissociation and electro-ionization reactions. Iterations were performed between the two codes until steady state was reached. After determining the nominal composition of the atmosphere, we ran a Monte Carlo simulation to characterize the effect of chemical uncertainties on the model results.

Results

With our previous model presented in Benne et al. (2022), we found a peak electronic number density larger by a factor of 2.5 to 5 compared to the one derived from Voyager 2 observations. By coupling the photochemical model with TRANS, we find that our electronic profile is now in agreement with these measurements, resulting from a significant decrease of the electro-ionization rate. In contrast with the results of Benne et al. (2022), Krasnopolsky and Cruikshank (1995) and Strobel and Summers (1995), the main ionization source is solar EUV radiation instead of magnetospheric electrons. This work also allows us to better understand how the varying magnetic environment impacts the atmospheric chemistry.

References

[1] Tyler, G. L. et al. Science 246, no. 4936 (December 15, 1989): 1466–73.

[2] Krasnopolsky, V. A. et al. Journal of Geophysical Research 98 (February 1, 1993): 3065–78.

[3] Krimigis, S. M. et al. Science 246, no. 4936 (December 15, 1989): 1483–89.

[4] Gronoff, G. et al. Astronomy & Astrophysics 506, no. 2 (November 2009): 955–64.

[5] Strobel, Darrell F. et al. Geophysical Research Letters 17, no. 10 (1990): 1661–64.

[6] Sittler, E. C., and R. E. Hartle. Journal of Geophysical Research: Space Physics 101, no. A5 (May 1, 1996): 10863–76.

[7] Benne, B. et al. Astronomy & Astrophysics 667 (November 2022): A169.

[8] Krasnopolsky, Vladimir A., and Dale P. Cruikshank. Journal of Geophysical Research 100, no. E10 (1995): 21271.

[9] Strobel, D. F., and M. E. Summers. 1995, 1107–48. Cruikshank, Dale P., Mildred Shapley Matthews, et A. M. Schumann. « Neptune and Triton », 1995.

How to cite: Benne, B., Benmahi, B., Dobrijevic, M., Cavalié, T., Loison, J.-C., Hickson, K., Barthélémy, M., and Lilensten, J.: Coupling a photochemical model of Triton's atmosphere with an electron transport code, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-6543, https://doi.org/10.5194/egusphere-egu23-6543, 2023.

EGU23-7738 | ECS | Orals | PS6.1

Impact of methane abundance on storm formation on Uranus & Neptune, revealed by a cloud-resolving model 

Noe Clement, Jeremy Leconte, Aymeric Spiga, Sandrine Guerlet, Gwenael Milcareck, and Franck Selsis

Despite the weak solar flux received by the ice giant planets, the storm activity of their atmospheres is intense. What is then the phenomenon responsible for this activity?

On Uranus and Neptune, a notable property draws attention: unlike the Earth, the species able to condense in the atmospheres of ice giants, methane in particular, are heavier than the ambient air, essentially hydrogen. This property makes convection difficult to start.

Convection in these atmospheres should therefore be a regime of strong intermittence where convective energy can be stored for a long time before being released in short episodes.

Our hypothesis is that this regime is at the origin of intense storms.

To study this hypothesis, we use a "cloud-resolving" model. This model is built from a dynamical core (The Weather Research and Forecasting model) solving the equations of motion, that has been initially developed for terrestrial applications and already adapted for simulations on Mars and Venus, coupled to independent physical parameterizations such as radiative transfer and micro-physics. The high resolution of the model grid can allow us to highlight moist atmospheric convection, by resolving cloud formation and dissipation.

Having successfully implemented the methane cycle in this model, we will present results from our 3D simulations, which reveal the impact of the methane cycle in tropospheric convection on Uranus & Neptune, having a special look at the methane abundance, that vary at different latitudes, and how it affects storms frequencies and intensities.

How to cite: Clement, N., Leconte, J., Spiga, A., Guerlet, S., Milcareck, G., and Selsis, F.: Impact of methane abundance on storm formation on Uranus & Neptune, revealed by a cloud-resolving model, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-7738, https://doi.org/10.5194/egusphere-egu23-7738, 2023.

EGU23-8881 | Orals | PS6.1

Hypotheses Concerning Global Magnetospheric Convection, Magnetosphere-Ionosphere Coupling, and Auroral Activity at Uranus 

Drew Turner, Ian Cohen, George Clark, Peter Kollmann, and Leonardo Regoli

We investigate the unique magnetosphere of Uranus and its interaction with the solar wind. Following previous seminal work, we developed and validated a simple yet valuable and illustrative model of Uranus’ offset, tilted, and rapidly-spinning magnetic field and magnetopause (nominal and fit to the Voyager-2 inbound crossing point) in three-dimensional space. With this model, we investigated details of the seasonal and interplanetary magnetic field (IMF) orientation dependencies of dayside and flank reconnection along the Uranian magnetopause. We found that anti-parallel (magnetic field shear angle greater than 170-degrees) reconnection occurs nearly continuously along the Uranian dayside and/or flank magnetopause under all seasons of the 84 (Earth) year Uranian orbit and the most likely IMF orientations. Such active and continuous driving of the Uranian magnetosphere should result in constant loading and unloading of the Uranian magnetotail, which may be further complicated and destabilized by sudden changes in the IMF orientation and solar wind conditions plus the reconfigurations from the rotation of Uranus itself. We demonstrate that unlike the other magnetospheric systems that are Dungey-cycle driven (i.e., Mercury and Earth) or rotationally driven (Jupiter and Saturn), global magnetospheric convection of plasma, magnetic flux, and energy flow may occur via three distinct cycles, two of which are unique to Uranus (and possibly also Neptune). Our simple model is also used to map signatures of dayside and flank reconnection down to the Uranian ionosphere, as a function of planetary latitude and longitude. Such mapping demonstrates that “spot”-like auroral features should be very common on the Uranian dayside, consistent with observations from Hubble Space Telescope. We further detail how the combination of Uranus’ rapid rotation and unique and very active global magnetospheric convection should be consistent with fueling of the surprisingly intense trapped radiation environment observed by Voyager-2 during is single flyby. Summarizing, Uranus is a very special magnetosphere that offers new insights on the nature, complexity, and diversity of planetary magnetospheric systems and the acceleration of particles in space plasmas. We still have much to learn about Uranus’ unique and intriguing magnetosphere, which might have important analogs to exoplanetary magnetospheric systems. Our hypotheses can be tested with further work involving more advanced models, new auroral observations, and unprecedented missions to explore the in situ environment from orbit around Uranus. Our results highlight why any future mission to orbit Uranus should include a complement of magnetospheric instruments in the payload.

How to cite: Turner, D., Cohen, I., Clark, G., Kollmann, P., and Regoli, L.: Hypotheses Concerning Global Magnetospheric Convection, Magnetosphere-Ionosphere Coupling, and Auroral Activity at Uranus, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-8881, https://doi.org/10.5194/egusphere-egu23-8881, 2023.

EGU23-9266 | ECS | Posters on site | PS6.1

Titania’s Messina Chasmata 

Erin Leonard, Chloe Beddingfield, Catherine Elder, and Tom Nordheim

Titania is the fourth major moon from Uranus and is the largest moon in the Uranian system. It has a diameter of ~1580 km, a density of ~1.7 g/cm3, and was imaged by Voyager 2 at a resolution of 2.9 km/pixel. Even with the low-resolution images, it is apparent that Titania has undergone significant tectonic deformation (Smith et al., 1986) and potentially recent heating events (e.g., Moore et al., 2004). Although there is a significant number craters on Titania, its surfaces exhibit evidence for resurfacing in the chasmata, large (>5 km wide, >1 km deep) canyons that extend for 10s of kilometers, located near the equator. In this work, we will reprocess the Voyager 2 images of Titania and perform new geologic mapping of Titania’s Messina Chasmata region. Using these images and a digital elevation model, we will investigate flexure reflected by Messina to estimate Titania’s heat fluxes in this region.

How to cite: Leonard, E., Beddingfield, C., Elder, C., and Nordheim, T.: Titania’s Messina Chasmata, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-9266, https://doi.org/10.5194/egusphere-egu23-9266, 2023.

EGU23-9714 | ECS | Orals | PS6.1

Voyager 2 Radio Occultation of Triton revisited using modernized analysis tools 

Andrea Togni, Andrea Caruso, Dustin Buccino, Marco Zannoni, Kamal Oudrhiri, and Paolo Tortora

In 1989 the Voyager 2 spacecraft performed a flyby of the Neptune system. In particular, a radio occultation of Triton’s ionosphere was performed on 25 August 1989. Results from this occultation experiment were published in Science by Tyler et al., and the atmospheric profiles of Triton were estimated via analysis of the real-time tracking and monitoring systems data at time resolutions of about 1 second.

In recent years, thanks to an increase in the computational power of microprocessors and an expansion in their fields of application, there has been a surge in the development of optimal estimators for stochastic signals. In this context, we present a re-analysis of the radiometric data received by the Voyager 2 spacecraft during its radio occultation experiment of Triton. Using one of the latest algorithms developed in the field of signal parameters estimation, we use the radiometric measurements received during the ingress and egress phases of the mission to accurately reconstruct the sky frequency, as received by the DSS-43 antenna at the time of occultation. In particular, by performing spectral interpolation and tuning the processing parameters, we increased the frequency resolution and detection threshold around the ingress and egress epochs to maximize the scientific return from the radiometric data collected over 30 years ago.

Since Voyager 2 transmitted two coherently related signals (at S and X bands), the two series of sky frequencies can be combined to isolate the Doppler frequency shift due to dispersive effects. The latter is used to compute the electron number density profiles inside the Triton ionosphere using a classical Abel transform-based method. Also, a Monte Carlo procedure is used to evaluate uncertainties in the derived profiles. The results of this analysis are consistent with those presented in the past literature, with the only difference of a slight (but important for the planning of future missions) shift in the ionosphere's peak altitude due to the use of updated Voyager and Triton ephemerides. The methods and data analysis approaches presented in this work are very relevant to the exploration of the Ice Giants, in particular for radio science observations of satellite tenuous exospheres and ionospheres.

 

How to cite: Togni, A., Caruso, A., Buccino, D., Zannoni, M., Oudrhiri, K., and Tortora, P.: Voyager 2 Radio Occultation of Triton revisited using modernized analysis tools, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-9714, https://doi.org/10.5194/egusphere-egu23-9714, 2023.

EGU23-10400 | Posters on site | PS6.1

Microphysical modeling of water ice aerosols in the ice giant atmospheres 

Erika L. Barth and Kevin McGouldrick

The temperature regimes and observed species abundances indicate that water should condense in the stratospheres of each of the giant planets. Water reaches its condensation temperature at higher altitudes than hydrocarbon photochemical products, and water ice particles could then act as condensation nuclei for hydrocarbons deeper in the lower stratosphere. This is especially true for Uranus, where sluggish atmospheric mixing confines hydrocarbons to relatively low altitudes. Additionally, water ice particles could explain the high-altitude hazes seen in high-phase angle Voyager 2 images of Neptune. Using PlanetCARMA  - an aerosol microphysics model which simulates nucleation, condensation, evaporation, coagulation, and vertical transport in a column of atmosphere – we will describe particle number density profiles and size distributions of water ice particles in the atmospheres of Uranus and Neptune. Sensitivity tests include (1) nucleation – homogeneous vs. heterogeneous (including varying size, abundance, and contact parameter for the cloud condensation nuclei); (2) Vapor pressure equation; (3) water abundance and flux; and (4) degree to which physical processes are important, such as coagulation, condensation, and evaporation. Understanding the role of water ice in the ice giant atmospheres is important to further our understanding of the observed stratospheric hazes as well as the more optically thick methane clouds seen in the troposphere.

How to cite: Barth, E. L. and McGouldrick, K.: Microphysical modeling of water ice aerosols in the ice giant atmospheres, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-10400, https://doi.org/10.5194/egusphere-egu23-10400, 2023.

EGU23-12413 | Posters on site | PS6.1

Miniaturized Radiometer for an Ice Giants mission for haze and cloud characterization 

Víctor Apéstigue, Daniel Toledo, Ignacio Arruego, Patrick Irwin, Pascal Rannou, Alejandro Gonzalo, Juan José Jiménez, Javier Martínez-Oter, Margarita Yela, Mar Sorribas, and Eduardo Sebastian

Uranus and Neptune, the Ice Giants, are the unique planets in the Solar System that have not received a dedicated mission. However, studying these planets is crucial for understanding the formation and evolution of our planetary system and the outer systems, for which the ice planet systems are very common.

Our current knowledge comes from Earth and space telescope limited observations and from the brief encounter with the Voyager 2 spacecraft almost three decades ago. The recent decadal survey [1] has established a flag mission to Uranus as the following strategic priority for the Nasa exploration program (apart from the ongoing missions to Mars and Europa). From ESA’s perspective, the outcomes from the Voyage 2050 [2] are also in alignment, recommending the agency’s participation in a future mission in a collaboration framework, as established in previous successful partnerships like Cassini-Huygens.

Several reference missions have been proposed during the last decade [3-4], most of them suggesting an orbiter plus a descent probe configuration. For the orbiter, the scientific priorities should be to study the planet's bulk composition and internal structure, magnetic field, atmosphere circulation, rings, and satellite system. In the case of the descent probe, its primary mission should be to obtain the atmospheric noble gas abundances, noble gas isotope ratios, and the thermal structure of the atmosphere using a mass spectrometer and a meteorological package.

Understanding the thermal structure and dynamics of Uranus’ atmosphere requires studying the vertically distributed aerosols (hazes and clouds) and their microphysical and scattering properties. Indeed, aerosols affect the absorption and reflection of solar radiation, directly affecting the energy balance that drives the planet. In this work we present a lightweight radiometer, as a part of the descending probe, dedicated to studying Uranus’s aerosols. The principle of measurement is based on the vertical variation of the solar radiance at different wavelengths and geometries of observations as the probe falls using photodetectors, field-of-view masks, and interferential filters. From these observations, information on the vertical structure of clouds and hazes, particle size, or scattering properties could be derived.

The radiometer takes its heritage from previous missions for Mars exploration [7-9] where its technology has demonstrated its endurance for extreme environments of operation, using limited resources in terms of power consumption, mass and volume footprints, and data budget. These characteristics make this instrument a valuable complementary probe’s payload for studying Uranus’ atmosphere with a high scientific return.

 

[1] Origins, Worlds, and Life: A Decadal Strategy for Planetary Science and Astrobiology 2023-2032.  [2] Linda J. Tacconi, Christopher S. Arridge, et al, Voyage2050 Final recommendations from the Voyage 2050 Senior Committee. [3] Christopher S. Arridge, et al.. 2012. [4] Sushil K.AtreyaaMark, et al.,2019 [5] Ian J. Cohen et al 2022 P [6] Athul Pradeepkumar Girija.  2023 [7] I. Arruego et al. 2017. [8] Apestigue, V. et al 2022 [9] Pérez-Izquierdo, J., Sebastián et al, 2016.

How to cite: Apéstigue, V., Toledo, D., Arruego, I., Irwin, P., Rannou, P., Gonzalo, A., Jiménez, J. J., Martínez-Oter, J., Yela, M., Sorribas, M., and Sebastian, E.: Miniaturized Radiometer for an Ice Giants mission for haze and cloud characterization, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-12413, https://doi.org/10.5194/egusphere-egu23-12413, 2023.

EGU23-15111 | ECS | Posters on site | PS6.1

The Hydrogen Upper Atmosphere of Uranus Seen Through Lyman Alpha Observations 

Sushen Joshi, Lorenz Roth, Nickolay Ivchanko, Randy Gladstone, and Laurent Lamy

Several aspects of Uranus’s upper atmosphere are not well understood. The temperature is substantially higher than can be explained by solar heating alone. Over the last three decades, it has been observed that the ionosphere is continuously cooling, beyond seasonal effects. Voyager 2 revealed a substantial H exosphere and atomic corona of Uranus extending several Uranus radii. Inspired by the cooling of Uranus’s ionosphere, we are interested in understanding how its H upper atmosphere changes over a long period of time. From 1998 to 2017, Uranus was observed in ultraviolet wavelengths using Hubble Space Telescope’s STIS instrument in several observing campaigns (before and after equinox at Uranus). We analyze this data at Lyman-alpha wavelength (121.56 nm) and do radiative transfer modeling to study variation in the H upper atmosphere. We present the evolution of the H upper atmosphere over this period that we understand from the preliminary radiative transfer modeling.

How to cite: Joshi, S., Roth, L., Ivchanko, N., Gladstone, R., and Lamy, L.: The Hydrogen Upper Atmosphere of Uranus Seen Through Lyman Alpha Observations, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-15111, https://doi.org/10.5194/egusphere-egu23-15111, 2023.

EGU23-15491 * | Orals | PS6.1 | Highlight

Uranus from JWST: First Results 

Michael Roman, Leigh Fletcher, Heidi Hammel, Henrik Melin, Naomi Rowe-Gurney, Jake Harkett, Oliver King, Stefanie Milam, Glenn Orton, Patrick Irwin, Julianne Moses, Imke De Pater, and Laurent Lamy

We present first results from the James Webb Space Telescope (JWST) observations of Uranus, which provide the first spatially resolved, infrared spectra of the planet’s atmosphere spanning from 1.66 to 28.6 µm. We evaluate these unprecedented JWST NIRSpec (1.66–3.05 µm, 2.87–5.14 µm) and MIRI (4.9-28.6 μm) spectra in the context of existing observations and questions concerning Uranus’ stratospheric chemistry and thermal structure [1].

Owing to its frigid atmospheric temperatures, Uranus’ infrared spectrum is extremely weak. Much of the spectrum has never been spatially resolved before, while some had never been clearly observed at all.

From the ground, spatially resolved observations of Uranus’ mid-infrared emission are limited to imaging observations targeting the brighter regions of the infrared spectrum (i.e. ~13 µm emission from stratospheric acetylene, and 17-25 µm from the H2 continuum). Images from the Very Large Telescope VISIR instrument at 13 µm show a stratospheric structure distinct to Uranus, with elevated radiance at high latitudes. The physical nature of this structure–-whether produced by chemical or thermal gradients–-is unclear given previously available data [1]. From space, the Spitzer Space Telescope observed Uranus' mid-infrared spectrum between ~7 and 36 µm, but it lacked the spatial resolution necessary to resolve potential thermal and chemical structure across the disk [2].

Now, with its exceptional sensitivity and outstanding spatial and spectral resolution, JWST reveals Uranus’ stratospheric temperature and chemistry with exquisite new detail, placing new constraints on hydrocarbon abundances and temperature structure across the disk.

With a projected lifetime of over a decade, JWST promises to continue providing exciting new insights into the atmospheric structure, composition, and variability of the ice giants for years to come.

[1] Roman, M.T, et al. "Uranus in northern..." AJ 159.2 (2020): 45.

[2] Rowe-Gurney, N., et al. "Longitudinal variations..." Icarus 365 (2021): 114506.

How to cite: Roman, M., Fletcher, L., Hammel, H., Melin, H., Rowe-Gurney, N., Harkett, J., King, O., Milam, S., Orton, G., Irwin, P., Moses, J., De Pater, I., and Lamy, L.: Uranus from JWST: First Results, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-15491, https://doi.org/10.5194/egusphere-egu23-15491, 2023.

EGU23-16957 | Orals | PS6.1

Charged particle bombardment– a dominant surface modification process on the Uranian moons? 

Tom Nordheim, Richard Cartwright, Leonardo Regoli, Michael Sori, Stephanie Menten, Chloe Beddingfield, Erin Leonard, Corey Cochrane, Catherine Elder, and Adam Masters

The Uranus system hosts a diverse set of large moons, from the enigmatic Miranda with its striking coronae, to the outermost and second-largest moon Oberon with its dark and ancient surface. These moons mostly orbit within Uranus’ magnetosphere, which while relatively depleted in low energy-plasma, was found by Voyager 2 to possess surprisingly intense electron radiation belts. Prominent energetic electron absorptions associated with the Uranian moons were observed by Voyager 2, indicating that these particles interact significantly with the moons. Thus, the surfaces of the moons are continuously bombarded by high energy electrons, which are capable of breaking chemical bonds in surface material, leading to radiolytic chemistry that can alter surface composition. In addition, charged particle bombardment can alter the microstructure of surface ice as well as affect grain sizes by sputtering. Ground-based remote sensing observations have revealed planetocentric and hemispherical trends in several key spectral parameters, including the abundance of CO2 ice, whose concentration on the trailing hemispheres of the moon hint at a possible radiolytic origin. Furthermore, possible signatures of NH3 have been detected on the surfaces of several of the moons, including Ariel, where the sub-observer longitudinal distribution of this species appears to support spatial association with geologic features and terrains. It is known from laboratory experiments that NH3 is readily decomposed by charged particle radiation. If NH3 or NH3-related compounds are present on the moons, it therefore could be an indication of recent emplacement or exposure. Here, we will present possible signatures of charged particle surface modification on the Uranian moons and discuss implications for observations by future missions to the Uranus system.

How to cite: Nordheim, T., Cartwright, R., Regoli, L., Sori, M., Menten, S., Beddingfield, C., Leonard, E., Cochrane, C., Elder, C., and Masters, A.: Charged particle bombardment– a dominant surface modification process on the Uranian moons?, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-16957, https://doi.org/10.5194/egusphere-egu23-16957, 2023.

EGU23-665 | ECS | PICO | PS6.2

A statistical study of the features of ion acceleration events in the Jovian magnetotail using Juno/JEDI data 

Georgia Moutsiana, George Clark, Matina Gkioulidou, Ioannis Daglis, and Barry Mauk

Planetary magnetospheres across our solar system are known to be very efficient accelerators of charged particles. Moreover, the energization processes of magnetotail plasma populations are thought to share similarities among the various magnetospheres. In the present study, we focus on the Jovian magnetosphere, which contains a variety of ion species with different charge states, resulting in a diverse set of acceleration-relevant factors that can be tested. Therefore, we investigate the features of ion acceleration processes in the Jovian magnetosphere, utilizing measurements from the Juno mission. In particular, we use magnetic field data from the MAG instrument, and energetic ion data from the JEDI instrument, in order to investigate the energization of hydrogen (~50 keV to ~1 MeV), oxygen (~170 keV to ~2 MeV) and sulfur (~170 keV to ~4MeV) ions during dipolarization events in Jupiter’s magnetosphere. Here, we present a statistical study of the characteristics of ion acceleration processes in the Jovian magnetotail, such as the maximum energy of each ion species, as well as the Magnetic Local Time (MLT) position and radial distance for each event. Results of our study are a first step towards a comparative analysis of energization processes around dipolarization events in the magnetotails of Earth and Jupiter.

How to cite: Moutsiana, G., Clark, G., Gkioulidou, M., Daglis, I., and Mauk, B.: A statistical study of the features of ion acceleration events in the Jovian magnetotail using Juno/JEDI data, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-665, https://doi.org/10.5194/egusphere-egu23-665, 2023.

EGU23-826 | ECS | PICO | PS6.2

Effect of Mushball on Jupiter's Ammonia Distribution: a General Circulation Model Study 

Xinmiao Hu, Peter Read, Vivien Parmentier, and Greg Colyer

Recent Juno microwave observations have revealed puzzling features of Jupiter’s ammonia distribution, including an ammonia-poor layer extending down to levels of tens of bars outside the equatorial region to at least ±40° [Li et al. 2017]. Guillot et al. [2020] showed that ammonia-rich hail, or “mushballs”, formed during a powerful thunderstorm, can efficiently transport ammonia to the deeper atmosphere and hence could cause the observed ammonia depletion. However, this mechanism has not been tested in numerical simulations in which convective events are self-consistently determined. 
We have developed a simple parameterization scheme for the mushball process and implemented it into a Jupiter GCM [Young et al. 2019] that includes the following relevant parameterizations: a simple cloud microphysics model for water and ammonia, a water moist convection scheme that transports ammonia as a passive tracer, a dry convection scheme, and a two-stream, semi-grey radiative transfer scheme. In the two-dimensional setup of the aforementioned GCM, we show that mushball precipitation can produce an ammonia depletion qualitatively similar to the Juno observations.
We present our preliminary results in three-dimensional simulations, in which a Jupiter-like zonal jet profile emerges spontaneously. We will show the role of different processes, including the mushball process, moist convection and meridional circulation in shaping ammonia distribution. Further, we compare our model output with Juno MWR result, and discuss the implication to future observations.

How to cite: Hu, X., Read, P., Parmentier, V., and Colyer, G.: Effect of Mushball on Jupiter's Ammonia Distribution: a General Circulation Model Study, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-826, https://doi.org/10.5194/egusphere-egu23-826, 2023.

EGU23-5439 | PICO | PS6.2

Galactic Cosmic Ray Cutoff Rigidities and Flux at Jupiter 

Martin Bødker Enghoff, Jacob Svensmark, John Leif Jørgensen, Matija Herceg, Stavros Kotsiaros, and John E. P. Connerney

Galactic cosmic rays (GCRs), primarily consisting of protons, are ubiquitous throughout the solar system. The greatest source is supernova activity and the flux in the solar system is modulated by the solar wind. Planets can be shielded if they possess a magnetic field. Jupiter’s magnetic field is the strongest in the solar system and has several interesting features such as the Great Blue Spot near the Equator. The JUNO satellite has mapped the magnetic field of Jupiter in great detail (Connerney et al, JGR Planets 127(2), 2022) resulting in the JRM33 model, composed of data from 32 polar orbits of JUNO around Jupiter.

We have calculated a cosmic ray cutoff rigidity map for Jupiter. This was done using a modified version of a particle trajectory program (the Geomagnetic Cutoff Rigidity Computer Program by Smart and Shea (2001, Tech. Rep. No. 20010071975)) with the first 12 degrees and orders of the spherical harmonic expansion from the JRM33 model as input. This is done for vertical GCR entry into Jupiter’s atmosphere at a height of 67.5 km above the 1 bar level and for distances further out where high energy particles have been detected by JUNO. The energies required to enter into Jupiter’s atmosphere varies by several orders of magnitude from above 2500 GeV at locations around the Great Blue Spot and going downwards towards the poles.

The modulation of the GCR proton flux into Jupiter’s atmosphere was then calculated. For the incoming GCR spectrum we used data from the BESS-POLAR II Antarctic mission (Abe et al, ApJ 822(2), 2016), collected at solar minimum where the modulation by the solar wind is at its lowest. By fitting the measured spectrum and using the calculated cutoff rigidities we have made a map of the proton flux into Jupiter’s atmosphere.

Finally, we have investigated several incidents of high energy heavy ion detections by JUNO (Becker et al, JGR Planets 126, 2021) by calculating the cutoff rigidities from several incoming angles at the locations where JUNO made the detections and along the corresponding M-shells.

How to cite: Enghoff, M. B., Svensmark, J., Jørgensen, J. L., Herceg, M., Kotsiaros, S., and Connerney, J. E. P.: Galactic Cosmic Ray Cutoff Rigidities and Flux at Jupiter, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-5439, https://doi.org/10.5194/egusphere-egu23-5439, 2023.

EGU23-7689 | PICO | PS6.2

The Search-Coil Magnetometer (SCM) of the Radio and Plasma Waves Investigation (RPWI) onboard the ESA JUICE mission 

Alessandro Retinò, Malik Mansour, Patrick Canu, Thomas Chust, Lina Hadid, Olivier Le Contel, Fouad Sahraoui, Ioannis Zouganelis, Dominique Alison, Nadjirou Ba, Alexis Jeandet, Fatima Mehrez, Laurent Mirioni, Rodrigue Piberne, Christophe Berthod, Nicolas Geyskens, Gerard Sou, Baptiste Cecconi, Jan Bergman, and Jan-Erik Wahlund

The JUpiter ICy moons Explorer (JUICE) mission is the first large-class (L1) mission of ESA Cosmic Vision. JUICE will be launched in April 2023 with an arrival at Jupiter in 2031 and at least four years making detailed observations of Jupiter’s magnetosphere and of three of its largest moons (Ganymede, Callisto and Europa). The Radio and Plasma Wave Investigation (RPWI) consortium will carry the most advanced set of electric and magnetic fields sensors ever flown in Jupiter’s magnetosphere, which will allow to characterize the radio emission and plasma wave environment of Jupiter and its icy moons. Here we present the scientific objectives and the technical features of the Search Coil Magnetometer (SCM) of RPWI. SCM will provide for the first time three-dimensional measurements of magnetic field fluctuations in the frequency range 0.1 Hz – 20 kHz within Jupiter’s magnetosphere. High sensitivity (~10 fT / √Hz at 1 kHz) will be assured by combining an optimized (20 cm long) magnetic transducer with a low-noise (4 nV / √Hz) ASIC pre-amplifier. Perturbations by the spacecraft are strongly reduced by accommodating SCM at about 10 m away from the spacecraft on the JUICE magnetometer boom. The combination of high sensitivity and high cleanliness of SCM measurements will allow unpreceded studies of electromagnetic fluctuations down to plasma kinetic scales, in particular in key regions such as the magnetopause, the auroral region and the magnetotail current sheet of Ganymede’s own magnetosphere which JUICE will orbit for many months. This will lead to important advances in understanding how fundamental plasma processes such as magnetic reconnection, turbulence and particle energization occur in Jupiter’s plasma environment.

How to cite: Retinò, A., Mansour, M., Canu, P., Chust, T., Hadid, L., Le Contel, O., Sahraoui, F., Zouganelis, I., Alison, D., Ba, N., Jeandet, A., Mehrez, F., Mirioni, L., Piberne, R., Berthod, C., Geyskens, N., Sou, G., Cecconi, B., Bergman, J., and Wahlund, J.-E.: The Search-Coil Magnetometer (SCM) of the Radio and Plasma Waves Investigation (RPWI) onboard the ESA JUICE mission, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-7689, https://doi.org/10.5194/egusphere-egu23-7689, 2023.

EGU23-9404 | PICO | PS6.2 | Highlight

Water-group pickup ions from Europa: A window into surface ice evolution 

Jamey Szalay, Frederic Allegrini, Robert Ebert, Fran Bagenal, Scott Bolton, Shahab Fatemi, David McComas, Angele Pontoni, Andrew Poppe, Yash Sarkango, Joachim Saur, Todd Smith, Philip Valek, Steven Vance, Audrey Vorburger, and Robert Wilson

Water-group gas continuously escapes from Jupiter’s icy moon Europa in both charged and neutral states. The neutral species form co-orbiting populations of particles, or neutral toroidal clouds, eventually becoming ionized to be incorporated into the Jovian plasma environment. In September 2022, Juno performed a close flyby at ~350 km, an altitude less than the satellite’s radius, allowing it to make direct observations of water-group pickup-ions originating from the moon’s surface. These observations, along with more remote measurements by Juno of Europa-genic water-group pickup ions, provide critical constraints on the evolution and loss processes of Europa’s icy surface. We will present direct observations of water-group pickup-ions from Europa in the context of understanding the breakdown and evolution of Europa’s surface ice.

How to cite: Szalay, J., Allegrini, F., Ebert, R., Bagenal, F., Bolton, S., Fatemi, S., McComas, D., Pontoni, A., Poppe, A., Sarkango, Y., Saur, J., Smith, T., Valek, P., Vance, S., Vorburger, A., and Wilson, R.: Water-group pickup ions from Europa: A window into surface ice evolution, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-9404, https://doi.org/10.5194/egusphere-egu23-9404, 2023.

EGU23-11036 | ECS | PICO | PS6.2 | Highlight

Towards a new era in giant exoplanet characterisation 

Simon Müller and Ravit Helled

Determining the composition of giant exoplanets is crucial for understanding their origin and evolution. However, the planetary bulk composition is not measured directly but must be deduced from a combination of mass-radius measurements, knowledge of the planetary age and evolution simulations. Accurate determinations of stellar ages, mass-radius, and atmospheric compositions from upcoming missions can significantly improve the determination of the heavy-element mass in giant planets. In this talk, we first demonstrate the importance of an accurate age measurement, as expected from Plato, in constraining the planetary properties. Well-determined stellar ages can reduce the bulk-metallicity uncertainty up to about a factor of two. We next infer the bulk metallicity of warm giants from the Ariel mission reference sample and identify the Ariel high-priority targets for which a measured atmospheric metallicity can clearly break the degeneracy in the inferred composition. We show that a knowledge of the atmospheric metallicity can broadly reduce the bulk-metallicity uncertainty by a factor of four to eight. We conclude that the accurate age determination from Plato and atmospheric measurements by Ariel and the James Webb Space Telescope will play a key role in revealing the composition of giant exoplanets.

How to cite: Müller, S. and Helled, R.: Towards a new era in giant exoplanet characterisation, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-11036, https://doi.org/10.5194/egusphere-egu23-11036, 2023.

EGU23-12293 | ECS | PICO | PS6.2

The effect of thermal non-equilibrium on aerosol formation in astrophysical environments 

Sven Kiefer, David Gobrecht, Leen Decin, and Christiane Helling

From our Solar System, we know that gas giant planets are covered in clouds and we expect the same to hold true for many exoplanet gas giants. Knowing the composition and size of cloud particles and where they form within exoplanet atmospheres is crucial to understand exoplanet observations. The first step in cloud formation is the nucleation of aerosols. These nano-sized particles function as seeds for condensation processes through which cloud particles grow. The nucleation and condensation processes are highly temperature dependent. The day side of ultra-hot Jupiters are expected to be cloudless whereas their night side and colder gas giants are expected to be covered in clouds. Recent observations and studies of stellar outflows have shown that thermal non-equilibrium can be present in low density environments and that thermal non-equilibrium can have a significant impact on the formation of larger clusters.

 

In this study, we investigate the effect of thermal non-equilibrium on the formation of aerosols. We derive a kinetic homogeneous cluster nucleation model for non-uniform cluster temperatures. We use this model to study the nucleation of titania (TiO2) which is considered to be an important condensate in exoplanet atmospheres. We analyse the impact of thermal non-equilibrium on the number densities of (TiO2)N, N=1-10, clusters. We find that small temperature offsets between different cluster sizes can have a significant impact on the formation of aerosols. Therefore, studies of low density environments should consider the effects of thermal non-equilibrium on nucleation. In collision dominated regimes, clusters are efficiently driven towards thermal equilibrium and thermal non-equilibria are unlikely to occur.

How to cite: Kiefer, S., Gobrecht, D., Decin, L., and Helling, C.: The effect of thermal non-equilibrium on aerosol formation in astrophysical environments, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-12293, https://doi.org/10.5194/egusphere-egu23-12293, 2023.

EGU23-12471 | ECS | PICO | PS6.2

Mid Infrared analysis of Jupiter South Pole from JWST MIRI-MRS observations: Thermo-chemical disturbances caused by auroral activity 

Pablo Rodriguez-Ovalle, Thierry Fouchet, Imke De Pater, Dominique Bockelee-Morvan, Emmanuel Lellouch, Manuel Lopez-Puertas, Prisca Briens, James Sinclair, Ricardo Hueso, Mike Wong, Thivault Cavalié, Mike Roman, Patrick Fry, Leigh Fletcher, Jake Harkett, Henrik Melin, and Glenn Orton

Jupiter’s Polar Regions host a very strong auroral activity. The Jovian auroras leave their imprint in the ultraviolet spectral region, but also in the Mid-Infrared, which suggests that they can influence the thermal structure by heating up not only the thermosphere, but also the stratosphere by particle precipitation. Some studies suggest that auroral activity also influences the atmospheric chemistry by enhancing or depleting some stratospheric hydrocarbons produced by photochemistry, as well as other components such as HCN. Some hypotheses link these variations with the presence of polar hazes at high latitudes on Jupiter.

JWST performed several observations of the Jovian System in 2022, most of them as part of the Early Release Science program 1373 (ERS-1373). One of these observations targeted the South Polar Region. On the 24th of December 2022, two spectrometers on board JWST, NIRSPec and MIRI carried out this observation, covering the spectral range from 1 to 28 μm (with the wavelengths beyond 15 microns completely saturated). Along with this observation, another earlier one was performed on July 2022 (OBS-1022), as part of the commissioning program. This complementary observation only covered the ranges 4.9-5.8, 7.4-8.8 and 11.5-13.5 μm, since it aimed only at testing the pointing of the instrument.

Both of these observations allowed us to obtain sufficient spectral and spatial information to map stratospheric temperature and hydrocarbons abundances.

We will show a complete analysis of the 1022 dataset. Despite the limited spectral range, we were able to measure stratospheric temperatures at pressures between 10 and 0.1 mbar and map the homopause height. To do so, we first needed to retrieve the homopause height (which determines the methane vertical profile of Jupiter) by a simultaneous analysis of fourteen different models of the atmosphere. We found that the auroral oval leaves an imprint in the stratosphere, creating a warmer region where the auroral oval can be spotted in the UV and IR. The analysis also shows an upwards displacement of the homopause level in the auroral oval, in agreement with previous studies but with a much better spatial resolution. We were also able to retrieve 3D maps of acetylene VMR.

Along with this analysis, we will present preliminary results on MIRI 1373 observation. This observation covers the full spectral region from 5 to 28 μm and, hence, it has sufficient information to determine the abundances and distributions of other molecules, such as ammonia, phosphine, ethylene and ethane among others. We will also present processed NIRCam images from the polar region as a support for the spectral analysis.

How to cite: Rodriguez-Ovalle, P., Fouchet, T., De Pater, I., Bockelee-Morvan, D., Lellouch, E., Lopez-Puertas, M., Briens, P., Sinclair, J., Hueso, R., Wong, M., Cavalié, T., Roman, M., Fry, P., Fletcher, L., Harkett, J., Melin, H., and Orton, G.: Mid Infrared analysis of Jupiter South Pole from JWST MIRI-MRS observations: Thermo-chemical disturbances caused by auroral activity, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-12471, https://doi.org/10.5194/egusphere-egu23-12471, 2023.

EGU23-12536 | ECS | PICO | PS6.2

Jupiter’s Frequency-Dependent Love Number estimation through joint analysis of JUICE-3GM and Europa Clipper radio science measurements and one century of astrometry data 

Andrea Magnanini, Marie Fayolle, Valery Lainey, Marco Zannoni, Dominic Dirkx, Paolo Tortora, Erwan Mazarico, and Luciano Iess

The future JUICE and Europa Clipper missions will probe the Jovian system performing several flybys of the moons Europa, Ganymede, and Callisto. The precise radio tracking data will provide an accurate estimation of the gravity and ephemerides of the Galilean moons. This is especially true for Ganymede, after JUICE insertion in a low circular orbit around the moon for at least four months. The evolution of the orbits of the Galilean moons will allow for an estimation of the dissipation in Jupiter at the orbital frequency of each Galilean moon, represented/parameterized through the imaginary part of its degree-2 Love number.

The imaginary part of the Jovian Love number  is a key parameter to evaluate the long-term orbital evolution of the Galilean moons and the Laplace resonance stability. Its secular effect on the orbit of the moons produces an acceleration both in the radial and tangential direction, and the longer the time span of observation, the better it can be estimated. However, the dissipations at the different satellite orbital frequencies are highly correlated due to the Laplace resonance, complicating their estimation. 

JUICE and Europa Clipper missions cover less than 5 years, but the accuracy in the determination of the moon’s orbit is good if not exquisite. This broad data set can be complemented by high quality astrometry measurements collected by ground observatories starting from 1891, past spacecraft missions (Voyager, Galileo) optical images and radar data. This approach has the potential to greatly improve the estimation accuracy for the dissipation parameters in Jupiter.

Future work will include the addition of radio-tracking measurements from the spacecraft Galileo and Juno, which together with JUICE and Europa Clipper will offer a 30 year time span of radio-metric data.

Unfortunately JUICE and Clipper, unlike Galileo and Juno, will fly never by Io, the moon which dominates the evolution of the Laplace resonance and the dissipation in the Jovian system. However Io can be observed from ground telescopes, and the available astrometric observations of the moon may allow a significant reduction of Io’s state solution uncertainties and correlations.

In this study, we analyze the attainable uncertainties for the parameters characterizing the dissipation in Jupiter’s system and the ephemerides of the Galilean moons combining simulated range & range-rate radio tracking data from JUICE and Europa Clipper with astrometry data, showing the synergies and the possible improvements in the uncertainties and correlations of the joint analysis, together with a discussion of the problems associated to the fusion of data sets of very different type.

How to cite: Magnanini, A., Fayolle, M., Lainey, V., Zannoni, M., Dirkx, D., Tortora, P., Mazarico, E., and Iess, L.: Jupiter’s Frequency-Dependent Love Number estimation through joint analysis of JUICE-3GM and Europa Clipper radio science measurements and one century of astrometry data, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-12536, https://doi.org/10.5194/egusphere-egu23-12536, 2023.

EGU23-14642 | ECS | PICO | PS6.2

Deriving mixing ratios of heavier neutral species in Saturn's ionosphere from light ion measurements and helium chemistry 

Joshua Dreyer, Erik Vigren, Fredrik L. Johansson, and J. Hunter Waite

Helium ions, He+, react only slowly with molecular hydrogen. A consequence of this is that He+ ions produced by, for example, photoionization of He in H2-dominated ionospheres, such as those of Jupiter and Saturn, can have principal loss mechanisms other than through reactions with molecular hydrogen even if the other reactants prevail in rather small volume mixing ratios. The Ion and Neutral Mass Spectrometer (INMS) onboard the Cassini mission operated in open-source ion mode during a few of the passages through Saturn’s upper atmosphere throughout the proximal orbits in 2017. Due to the high spacecraft velocity, exceeding 30 km/s, the retrieval of ion number densities was limited to light ion species with masses (for singly charged species) of < 8 Da. Direct measurements of mixing ratios of neutral species heavier than helium (such as H2O, CH4, NH3, N2,CO2 and CO) in Saturn's equatorial ionosphere are sparse and their retrieval was in part complicated by adsorption effects.

We seek to make an independent estimate of the mixing ratios of volatiles other than H2 and He by making use of a simple model focusing on the production and loss balance of helium ions. We first consider two models to estimate the local production rate of He+ from the measured density profiles of He and H2 and show that these give estimates in reasonable agreement with each other. Then we show that the calculated concentration of He+ exceeds the observed values by up to two orders of magnitude if we only account for the loss of He+ ions through reactions with molecular hydrogen. We take this as a strong indicator that the principal loss mechanism of He+ in Saturn’s ionosphere is through reactions with other species than H2, whose overall mixing ratio is denoted fX.  Based on the assumption of photochemical equilibrium at altitudes below 2500 km, we can then proceed by estimating fX to closest approach for Cassini's proximal orbits 288 and 292. Our derived mixing ratios for the inbound part of orbits 288 and 292 are in reasonable agreement with the direct measurements from INMS around closest approach and subceed them at higher altitudes. Comparisons with results from other studies potentially suggest an increased water influx around equatorial latitudes.

How to cite: Dreyer, J., Vigren, E., Johansson, F. L., and Waite, J. H.: Deriving mixing ratios of heavier neutral species in Saturn's ionosphere from light ion measurements and helium chemistry, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-14642, https://doi.org/10.5194/egusphere-egu23-14642, 2023.

EGU23-15246 | ECS | PICO | PS6.2

Investigating the compressibility of the Jovian magnetosphere 

Dimitrios Millas, Nicholas Achilleos, Patrick Guio, and Christopher S. Arridge

The Jovian magnetosphere can undergo significant changes in its size due to varying external (e.g. solar activity) or internal (e.g. hot plasma pressure) conditions. Simulations have shown that the difference in the dayside stand-off distance between a compressed and an expanded state can be around 30 Jovian radii.

In this work, we study the compressibility of the Jovian magnetosphere using a large ensemble of axisymmetric models, obtained from the recently updated UCL/AGA magnetodisc code. Each model is defined by its size (via the stand-off distance) and hot plasma content (via the hot plasma index). Using these models as virtual magnetopause crossings we estimate the compressibility index, calculated via changes in the dayside stand-off distance as a function of the external pressure, which characterises the overall response of the magnetosphere.

We find that the system size plays an important role in the Jovian case, as we observe a change in the compressibility index as a function of the stand-off distance. This has also been noted in existing studies on Saturn, using a linear relation between changes in the stand-off distance and the external pressure.

As a complementary study, we also estimate the compressibility index using magnetopause crossings from recently published catalogues based on JUNO data.

How to cite: Millas, D., Achilleos, N., Guio, P., and Arridge, C. S.: Investigating the compressibility of the Jovian magnetosphere, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-15246, https://doi.org/10.5194/egusphere-egu23-15246, 2023.

Mirror modes are large amplitude, non-propagating compressive structures often observed in the magnetosheath. They appear in the form of quasi-sinusoidal oscillations in the magnetic field, with clear magnetic dropouts (‘dips’) or enhancements (‘peaks’). Mirror modes are usually accompanied by a corresponding, anticorrelated signature in plasma density. Typically, the growth of mirror mode fluctuations is triggered when magnetized plasma traverses the bow shock (BS) or draping of the magnetic field around the magnetopause (MP), producing anisotropic ion distribution functions in a high plasma β environment.

In this work, nine years of in-situ Cassini data and the latest published catalogue of BS and MP crossings at Saturn were used to perform a detailed statistical analysis of magnetic fluctuations associated with mirror mode structures in Saturn’s magnetosheath. 182 single traversals through the magnetosheath between the bow shock and the magnetopause were used to study the evolution of mirror mode structures across Saturn’s outer and inner magnetosheath and to assess the effects of magnetic shear at the MP on the mirror mode structures near the MP. Violante et al. (1995) analysed two MP crossings at Saturn by Voyagers 1 and 2 and found that in the high magnetic shear MP, mirror waves appear with increasing amplitude and decreasing frequency until the MP, whilst in the other low magnetic shear case, the mirror waves ceased to grow in the presence of a plasma depletion layer but are still present, albeit with smaller amplitude.

The amplitude and frequency of mirror waves near the magnetopause are also examined against signs of magnetic reconnection. Tsurutani et al. (1982) suggested that the amplitude of mirror wave structures could impact magnetic reconnection at the MP boundary as alternating high and low regions and the plasma temperature anisotropies may lead to patchy and sporadic reconnection.

How to cite: Cheng, I. K. and Achilleos, N.: The role of magnetic shear on the evolution of mirror mode waves and their influence on magnetic reconnection at Saturn’s magnetopause, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-16080, https://doi.org/10.5194/egusphere-egu23-16080, 2023.

EGU23-1346 | ECS | Posters virtual | PS6.3

A Juno-era View of the Electric Currents in Jupiter's Magnetodisc 

Zhi-Yang Liu, Michel Blanc, and Qiu-Gang Zong

Jupiter's main auroral emission is believed to be governed by a magnetosphere-ionosphere coupling current system resulting from the radial outflow of the iogenic plasma. To better understand, here we delineate this current system from the viewpoint of the magnetodisc, using Juno data obtained in the night-to-dawn magnetosphere during 2016-2020. We first derive a spatial distribution of the height-integrated radial (Ir) and azimuthal (Ia) currents in the magnetodisc. Then, we calculate the divergence of the two current components, which, according to current continuity, gives the field-aligned current (FAC) connecting the magnetodisc and the ionosphere. The Ir-associated FAC, Jr, flows into and out of the magnetodisc at small and large radial distances, respectively, approximately consistent with the axisymmetric corotation enforcement model. On the other hand, Ia decreases with increasing local time in the local time extent covered, indicating an additional FAC (Ja) flowing out of the magnetodisc. From Ia and Ja, we conclude that the influence of the solar wind, which compresses the dayside magnetosphere and thus breaks the axisymmetry, reaches deep to a radial distance of at least 20 Jupiter radii. Further efforts in modeling Jupiter's magnetosphere should take this factor into account.

How to cite: Liu, Z.-Y., Blanc, M., and Zong, Q.-G.: A Juno-era View of the Electric Currents in Jupiter's Magnetodisc, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-1346, https://doi.org/10.5194/egusphere-egu23-1346, 2023.

EGU23-1511 | ECS | Orals | PS6.3

MHD simulations of Europa’s interaction with the jovian magnetosphere: insights from the Juno flyby 

Juan Sebastian Cervantes Villa, Joachim Saur, Jamey Szalay, and John Connerney

Europa, the smallest of the Galilean moons, is embedded within Jupiter’s magnetosphere where a rapidly flowing plasma interacts electromagnetically with the moon’s atmosphere and its surface. The magnetic field in the plasma is also affected by Europa’s induced magnetic field in a subsurface conducting layer. On September 29th, 2022 the Juno spacecraft flew by the vicinity of Europa at a distance of ~350 km, and it provided the first in-situ observations since Galileo’s last pass on January 3rd, 2000.

In this work, we model the large scale interaction of Jupiter’s magnetospheric plasma with Europa and its atmosphere for the conditions of the Juno flyby. We apply the single fluid MHD PLUTO code based on Mignone et al., [2007], and also employed by Duling et al. [2022] to describe Ganymede’s plasma interaction. Our model accounts for ion-neutral collisions, electron impact ionization, dissociative recombination, and electromagnetic induction in a subsurface water ocean. In particular, we prescribe Europa’s O2 atmosphere with a number of analytical models in which we consider several degrees of asymmetry. Furthermore, we include a tracer description in the model and solve advection equations for the production of the water-group pickup ions H+ and H2+. The simulation results are compared with in-situ measurements provided by the magnetometer and the JADE instrument onboard the Juno spacecraft. Our study is used to further constrain properties of the moon’s atmosphere and to quantify the effects of their variability on the plasma interaction.

How to cite: Cervantes Villa, J. S., Saur, J., Szalay, J., and Connerney, J.: MHD simulations of Europa’s interaction with the jovian magnetosphere: insights from the Juno flyby, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-1511, https://doi.org/10.5194/egusphere-egu23-1511, 2023.

EGU23-2468 * | Orals | PS6.3 | Highlight

High resolution imagery of Europa’s Surface by Juno’s Stellar Reference Unit 

Heidi Becker, Meghan Florence, Jonathan Lunine, Paul Schenk, Candice Hansen, Martin Brennan, Scott Bolton, and James Alexander

On 29 September 2022 Juno’s low-light Stellar Reference Unit (SRU) captured a high-resolution image (256-340 m/pixel) of a 3x104 km2 region of Europa’s surface between ~0-6°N and 43.5-51°W. The broadband visible image (450-1100 nm), with the highest resolution ever for that region, was collected at a sub-spacecraft altitude of 412 km during Juno’s close flyby of the icy Jovian moon while the surface was illuminated only by Jupiter-shine (incidence angle: 48-51 degrees). Prior coverage of the area by Galileo was under high-sun conditions at 1 km resolution, leading to characterization of the region as mostly ridged plain and undifferentiated linea. The SRU image reveals a much richer and complex picture; an intricate network of cross-cutting ridges and lineated bands interrupted by an intriguing 37 km (east-west) by 67 km (north-south) chaos feature that appears to be the result of a unique, local geologic process. Low-albedo deposits flank ridges near the chaos feature and bear similarity to features previously linked to hypothesized subsurface activity [Quick & Hedman, Icarus, 2020]. We will present updates to the geologic mapping of Europa enabled by the SRU image, our study of the chaos feature’s morphology, and puzzles awaiting future high-resolution imagery from Europa Clipper or JUICE.

 

 

The JPL authors’ copyright for this abstract is held by the California Institute of Technology. Government Sponsorship acknowledged.

How to cite: Becker, H., Florence, M., Lunine, J., Schenk, P., Hansen, C., Brennan, M., Bolton, S., and Alexander, J.: High resolution imagery of Europa’s Surface by Juno’s Stellar Reference Unit, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-2468, https://doi.org/10.5194/egusphere-egu23-2468, 2023.

EGU23-2727 | Posters on site | PS6.3

Jupiter’s hot spots as observed by JIRAM-Juno: limb-darkening in thermal infrared 

Davide Grassi, Alessandro Mura, Alberto Adriani, Giuseppe Sindoni, Christina Plainaki, Federico Tosi, Angelo Olivieri, Giuseppe Piccioni, Pietro Scarica, Francesco Biagiotti, and Scott Bolton

The Jupiter InfraRed Auroral Mapper (JIRAM) instrument on board the Juno spacecraft performed multiple observations of the Jupiter North Equatorial Belt (NEB) around the time of 12th Juno pericenter passage on April 1st 2018. The data consist in thermal infrared images (the JIRAM filter has a band pass centred around 4.8 μm) and show, among other atmospheric features, two bright hot-spots.

Images of the same areas at different emission angles were used to constraint the trend of the limb darkening function.

Comparison against simulated observations computed for different emission angles, total opacities, single scattering albedo ω0 and asymmetry parameter g suggest that ω0 ~ 0.9 and g ~ 0.32 provide best match with data, with the latter parameter only weakly constrained by JIRAM observations. Then, we computed the ω0 and g resulting from different size distributions (exploring the effective radius reff and variance v space), taking into account the complex refractive indices of ammonium hydrosulphide by [1] and [2].

Our analysis suggests that neither sets of refractive indices are consistent with JIRAM observations. A more reasonable agreement is found once tholines are adopted, with an effective radius of 0.6 μm. This value is broadly consistent with the mean radius of Hot Spot’s particles estimated by [3] on the basis of Galileo Entry Probe data. While a composition of pure tholine is not realistic for Jupiter conditions, our results indicate that scattering properties of clouds are largely dominated by optical properties of contaminants, as already suggested in [4]. Indeed, a thin (0.01 of total radius) coating of such compound over a NH4SH particle can effectively mask the optical properties of the latter. An effective radius of 0.4 μm for these coated particles produces the ω0 and g derived from JIRAM data.

 

[1] Howett C. J. A. et al., (2007) J. Opt. Soc. Am. B 24, 126-136.

[2] Ferraro J. R et al. (1980) Applied Spectroscopy, 34 (5), 525-533.

[3] Ragent B. et al, (1998), J. Geophys. Res., 103 (E10), 22891– 22909.

[4] Grassi D. et al. (2021) MNRAS, 503(4), 4892-4907.

 

This work was supported by the Italian Space Agency through ASI-INAF contract 2016-23-H.1-2018.

How to cite: Grassi, D., Mura, A., Adriani, A., Sindoni, G., Plainaki, C., Tosi, F., Olivieri, A., Piccioni, G., Scarica, P., Biagiotti, F., and Bolton, S.: Jupiter’s hot spots as observed by JIRAM-Juno: limb-darkening in thermal infrared, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-2727, https://doi.org/10.5194/egusphere-egu23-2727, 2023.

EGU23-3893 | ECS | Orals | PS6.3

Jupiter’s 3.3-micron CH4 polar brightening: Retrieval of methane effective temperature in the jovian auroral regions using Juno/JIRAM data 

Chiara Castagnoli, Bianca Maria Dinelli, Francesca Altieri, Alessandra Migliorini, Alessandro Mura, Alberto Adriani, Roberto Sordini, Federico Tosi, Raffaella Noschese, Giuseppe Piccioni, Maria Luisa Moriconi, Davide Grassi, Andrea Cicchetti, Alessandro Moirano, Gianrico Filacchione, Giuseppe Sidoni, Christina Plainaki, Pietro Scarica, and Diego Turrini

Despite the multiple evidence of the diffuse presence of methane in Jupiter’s auroral regions, the mechanisms leading to the CH4 brightening observed both from ground- and space-based platforms are not yet fully understood. During the first NASA/Juno’s orbit, the on-board imager/spectrometer JIRAM (Jovian Infrared Auroral Mapper) detected the 3.3-µm methane emission on both Jupiter’s poles. The signal was found to be mostly confined within the main auroral ovals, although the lack of spectral coverage over 80°S prevented a deep investigation of the southern methane spot. The CHpolar emissions at 3.3 µm are likely originated by non-thermal excitation mechanisms occurring above the 1 µbar level, such as auroral particle precipitation and/or Joule heating. However, aurorally driven upwelling of methane inside the main oval might also explain the enhanced concentrations of CH4 observed at the jovian poles. To address this controversy, we derive the effective temperature of methane in Jupiter’s auroral regions, which is a key information to understand the origin of the detected fluorescence. The goal is achieved by exploring three Juno’s orbits and focusing on the spectra with the highest methane emissions and the smallest contribution from other auroral features due to H3+. JIRAM measurements from the first perijove are used to investigate the northern methane brightening, while observations from perijoves 7 and 8 are examined for its southern counterpart. The analysis reveals similar temperatures in the north- and south-polar spots, mainly ranging between 400 K and 670 K. 

 

How to cite: Castagnoli, C., Dinelli, B. M., Altieri, F., Migliorini, A., Mura, A., Adriani, A., Sordini, R., Tosi, F., Noschese, R., Piccioni, G., Moriconi, M. L., Grassi, D., Cicchetti, A., Moirano, A., Filacchione, G., Sidoni, G., Plainaki, C., Scarica, P., and Turrini, D.: Jupiter’s 3.3-micron CH4 polar brightening: Retrieval of methane effective temperature in the jovian auroral regions using Juno/JIRAM data, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-3893, https://doi.org/10.5194/egusphere-egu23-3893, 2023.

The shape of two gas giants, Jupiter and Saturn, is determined primarily by their rotation rate, and interior density distribution. It is also affected by their zonal winds, causing a perturbation of O(10 km) at low latitudes. However, uncertainties in the observed cloud-level wind and the polar radius, translate to uncertainty in the shape with the same order of magnitude. This prevents an exact comparison against the shape based on radio-occultation measurements, the only other available data. The Juno (Jupiter) and Cassini (Saturn) missions gave unprecedentedly accurate gravity measurements, constraining better the uncertainty in the wind structure. Using an accurate shape calculation, and a joint optimization, given both gravity and radio-occultation measurements, we calculate the possible range of dynamical height for both planets. We find that for Saturn there is an excellent match to the radio-occultation measurements, while at Jupiter the shape does not reflect the radio-occultations measurements on that scale.

 

How to cite: Galanti, E., Kaspi, Y., and Guillot, T.: The shape of Jupiter and Saturn based on atmospheric dynamics, radio occultations and gravity measurements, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-3964, https://doi.org/10.5194/egusphere-egu23-3964, 2023.

EGU23-4260 | Orals | PS6.3

Evidence of Fresh Injections Related to the Interchange Instability in the Io Torus 

William Kurth, George Hospodarsky, Ali Sulaiman, Barry Mauk, George Clark, Frederic Allegrini, Jack Connerney, and Scott Bolton

The Juno Waves instrument often detects brief, band-limited emissions when the spacecraft crosses magnetic fields threading Io’s M-shell, or vicinity thereof, up to about 30 degrees magnetic latitude. The disturbances have durations of order one minute and are observed below the electron cyclotron frequency. While plasma densities are often not available, it is thought that the frequency of the events are below the plasma frequency of the surrounding medium. Often, the first electron cyclotron half-harmonic is weakened or disrupted at the time of the events. While the events can be seen in isolation, there are typically a few of them with temporal spacing between about 15 to 40 minutes. Similar features were commonly seen by the Cassini radio and plasma wave instrument at Saturn and were identified as ’fresh’ injections or evidence of inward-moving flux tubes due to the centrifugal interchange instability. As such, they were characterized as having depleted thermal plasma and enhanced energetic plasma with electron distributions unstable to wave modes such as the upper hybrid band and chorus. Such events were also observed by Galileo. As fresh injections, the energetic particles associated with them have not had time to drift in longitude due to gradient and curvature drift forces.

How to cite: Kurth, W., Hospodarsky, G., Sulaiman, A., Mauk, B., Clark, G., Allegrini, F., Connerney, J., and Bolton, S.: Evidence of Fresh Injections Related to the Interchange Instability in the Io Torus, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-4260, https://doi.org/10.5194/egusphere-egu23-4260, 2023.

EGU23-4314 | Posters on site | PS6.3

Exploring the Depth of Planetary-Scale Changes in Jupiter from Juno Microwave Radiometer Observations 

Glenn Orton, Leigh Fletcher, Fabiano Oyafuso, Cheng Li, Zhimeng Zhang, Shawn Brueshaber, Michael H. Wong, Thomas Momary, Steven Levin, Scott Bolton, Kevin Baines, Emma Dahl, and James Sinclair

The Juno Microwave Radiometer (MWR) has extended our knowledge of the structure and composition of the atmosphere down to several hundred bars, revealing meridional variability to great depth (e.g. Li et al. 2017 Geophys. Res. Lett. 44, 5317; Fletcher et al. 2021. J. Geophys. Res. 126, E06858). The MWR has revealed that some cyclonic and anticyclonic vortices may have roots at depths of tens of bars of pressure (Bolton, et al. 2021. Science 374, 968.), but 5-µm hot spots and associated plumes appear to be restricted to shallow depths above the water cloud (Fletcher et al. 2020, J. Geophys. Res. 125, e06399). We report ongoing work on evolution of the microwave brightness of Jupiter’s axisymmetric bands over 2016-2022. We have examined the regions where changes have taken place at visible wavelengths, as documented by images from professional and amateur observers, to judge their depth. Preliminary results show that microwave brightness variability from channels sensitive to depths corresponding to 9-50 bars of atmospheric pressure are generally much lower than those at pressures of 0.7-3 bars. One exception to this is in the northern component of Jupiter’s Equatorial Zone (2°N-6°N), whose measured variability at depth does not correspond to any visible or infrared feature in the upper atmosphere, although it might be considered a precursor to the short-lived 2018-2019 Equatorial Zone disturbance. At the lower pressures, a decrease in the antenna temperature in the northern component of the North Equatorial Belt (12°N-15°N) is coincident with its visible brightening and drop of 5.1-µm radiance, both implying increased cloud and NH3 opacity in 2021. Even though the visibly dark North Equatorial Belt expanded northward into latitudes more typically associated with visibly bright regions that are cold at 5.1 µm (16°N-19°N), known as the North Tropical Zone (Fletcher, et al. 2017. Geophys. Res. Lett. 44, 7140), we do not detect any corresponding change of the MWR antenna temperature.  Although there are substantial changes in the visible and 5.1-µm appearance of the northern component of the North Temperate Belt (24°N-26°N) as well as in the MWR antenna temperatures, the two do not appear to be correlated with one another. An important part of our next steps in this research will be to examine which of the MWR variabilities in the zonal-mean microwave brightness are the result of zonally discrete features in the atmosphere, particularly the North Equatorial Belt (6°N-15°N). 

How to cite: Orton, G., Fletcher, L., Oyafuso, F., Li, C., Zhang, Z., Brueshaber, S., Wong, M. H., Momary, T., Levin, S., Bolton, S., Baines, K., Dahl, E., and Sinclair, J.: Exploring the Depth of Planetary-Scale Changes in Jupiter from Juno Microwave Radiometer Observations, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-4314, https://doi.org/10.5194/egusphere-egu23-4314, 2023.

EGU23-4351 * | Orals | PS6.3 | Highlight

Juno observations of Io 

Alessandro Mura, Federico Tosi, Francesca Zamboni, Candice Hansen, Rosaly M. Lopes, Heidi N. Becker, Julie Rathbun, Alberto Adriani, Christina Plainaki, Giuseppe Sindoni, and Roberto Sordini

NASA’s Juno mission has been observing the Jovian aurorae since 2016 from a polar, highly elliptical orbit.
Although not in the main scientific objectives, Juno took images and spectra of the Galilean moons from a
very favourable position, using some of the cameras on board: JIRAM, JunoCam and SRU. In particular, The
Jovian Infrared Auroral Mapper (JIRAM) is a dual-band imager and spectrometer. The imager channel is a
single detector with 2D capability and with 2 different filters (L band, from 3.3 to 3.6 µm; M band, from 4.5
to 5 µm); the spectrometer is a 1-D detector with a spectral resolution of 9 nm in the range 2 - 5 µm. The
pixel angular resolution (0.01°) is fine enough for imaging the moons from the polar, highly elliptical orbit of
Juno; the spatial resolution at the surface of the moons varies along the s/c distance and is of the order of
100 km/pixel or even finer. Here we present JIRAM’s images and spectra of Io after
six years of Juno mission, together with JunoCam and SRU images of Io. On Io, these observations
characterize the location and possible morphology, and some temperatures, of the volcanic thermal
sources; the identification and distribution of SO 2 , the possible identification of CO 2 and other materials. 
Recent Juno flybys, at distance down to 50'000 km, allows unprecedented imaging of the moon with resolution of about 10 km.
This allows reconstructing the morphology of hot spots, and a better mapping of their distribution, in location and emitted power.

How to cite: Mura, A., Tosi, F., Zamboni, F., Hansen, C., Lopes, R. M., Becker, H. N., Rathbun, J., Adriani, A., Plainaki, C., Sindoni, G., and Sordini, R.: Juno observations of Io, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-4351, https://doi.org/10.5194/egusphere-egu23-4351, 2023.

EGU23-4751 | Orals | PS6.3

Major results from the Hisaki mission and future perspectives 

Fuminori Tsuchiya, Yasumasa Kasaba, Ichiro Yoshikawa, Go Murakami, Atsushi Yamazaki, Kazuo Yoshioka, Tomoki Kimura, Chihiro Tao, Ryoichi Koga, Hajime Kita, Kei Masunaga, Masato Kagitani, Shotaro Sakai, and Masaki Kuwabara

Hisaki is an earth orbiting extreme ultraviolet spectroscope dedicated for observing solar system planets. Thanks to its monitoring capability, Hisaki has carried out unprecedented continuous observation of Io plasma torus, Jovian aurora, and Mars and Venus upper atmosphere since December 2013. One of notable phenomena observed by Hisaki is significant enhancements of neutral gas (sodium and oxygen) from Io occurred in the spring of 2015. Hisaki revealed that not only the plasma source, but transport, heating, and loss processes of magnetospheric plasma were influenced by the variation in the neutral source input. The presentation will include related topics from recent Hisaki publication. Since the autumn of 2016, the Juno spacecraft was in the orbit around Jupiter. Hisaki monitored activities of Jovian aurora and the plasma torus in the Juno era. These datasets will provide opportunities to compare in-situ observation by Juno with the global view by Hisaki. 
JAXA approved the Hisaki mission period by the end of March 2023. As a future remote observation platform, we are going to propose a UV space telescope, LAPYUTA (Life-environmentology, Astronomy, and PlanetarY Ultraviolet Telescope Assembly), a Japanese-leading mission using heritages of UV instruments for planetary science (e.g., Hisaki) and space telescope techniques for astronomy. One of goals of this mission is dynamics of our solar system planets and moons as the most quantifiable archetypes of extraterrestrial habitable environments in the universe. Water plume that gushes from the subsurface ocean of Galilean moons and tenuous atmosphere which is generated by bombardment of energetic charged particles to the surface are primary targets of LAPYUTA. As the plume activity and the atmosphere are not stable, continuous monitoring with high spatial resolution is essential. The icy moon's plume and ambient space will be deeply explored with the spacecraft by NASA's and ESA's icy moon missions in 2020s-2030s. The complementary remote sensing by LAPYUTA will visualize their global structure and temporal dynamics.

How to cite: Tsuchiya, F., Kasaba, Y., Yoshikawa, I., Murakami, G., Yamazaki, A., Yoshioka, K., Kimura, T., Tao, C., Koga, R., Kita, H., Masunaga, K., Kagitani, M., Sakai, S., and Kuwabara, M.: Major results from the Hisaki mission and future perspectives, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-4751, https://doi.org/10.5194/egusphere-egu23-4751, 2023.

EGU23-5820 | ECS | Orals | PS6.3

Modelling the Io Plasma Torus and Application to the Variability of the Io Footprint Position observed by Juno-JIRAM 

Alessandro Moirano, Alessandro Mura, Bertrand Bonfond, Jack Connerney, Vincent Dols, Grodent Denis, Vincent Hue, and Jean-Claude Gérard and the JIRAM team (INAF-IAPS, CNR-ISAC, ASI; Italy)

Jupiter hosts very intense auroral emissions, which originates from various magnetospheric processes. One of these emissions is associated with the orbital motion of the innermost Galilean satellite Io, which orbits at ~5.9 RJ from Jupiter’s centre (1 RJ = 71492km). At that distance, the magnetospheric plasma is forced to corotation by the strong planetary magnetic field. Therefore Io, which orbits at a slower speed than the corotating plasma, is continuously swept by both the plasma and the Jovian magnetic field. The relative velocity between Io and the plasma triggers a perturbation that propagates along the magnetic field lines and towards the ionosphere as Alfvén waves. Along their way, the Alfvén waves can accelerate electrons into the planetary atmosphere, where they ultimately generate an auroral emission called the Io footprint. The position of the Io footprint depends on the speed of the Alfvén waves, which in turn depends on the magnetic field geometry and magnitude as well as on the plasma mass distribution around Io, whose sulfur-dioxide-rich atmosphere constantly supply a dense cloud of plasma around Jupiter, called the Io Plasma Torus.

In 2016, Juno reached the Jupiter system and, since then, the Jovian InfraRed Auroral Mapper (JIRAM) has been observing the infrared emission associated with the Io footprint with a spatial resolution of ~ few tens of km/pixel. Thanks to the high resolutions of JIRAM, we report evidences of variability in the Io footprint position that are not related to the System III (i.e: the frame corotating with Jupiter) longitude of Io. Using a model for the plasma distribution of the Io Plasma Torus and the magnetic field, we quantitatively determine the state of the plasma distribution corresponding the JIRAM observations. This is the first attempt to retrieve quantitative information on the torus variability by using the Io footprint position. The best-fit plasma density and temperature are consistent with previous observations and analysis of the Io Plasma Torus from the Voyager 1, Voyager 2, Cassini, Galileo and Hisaki spacecrafts. Besides, we found that both density and temperature can exhibit remarkable non-System III variability, which can be ascribed either to local time asymmetry of the plasma in the Io torus or to temporal variation in the torus mass loading.

How to cite: Moirano, A., Mura, A., Bonfond, B., Connerney, J., Dols, V., Denis, G., Hue, V., and Gérard, J.-C. and the JIRAM team (INAF-IAPS, CNR-ISAC, ASI; Italy): Modelling the Io Plasma Torus and Application to the Variability of the Io Footprint Position observed by Juno-JIRAM, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-5820, https://doi.org/10.5194/egusphere-egu23-5820, 2023.

EGU23-6784 | Orals | PS6.3

Parallax measurements of Jupiter's cloud tops in JunoCam images, and applications 

Gerald Eichstädt, Glenn Orton, Candice Hansen-Koharcheck, Tristan Guillot, and Scott Bolton

JunoCam, Juno's wide-angle visible light camera, has been able to take series of close-up RGB images of the same Jupiter cloud-tops from different angles within only several minutes.
Within this kind of long-baseline observations, cloud motion usually takes a less prominent role than parallax.  
We select features in which it appears reasonable to assume that all relative cloud displacements can be attributed to parallax.  
Although we do not assume that we can determine absolute camera pointing with sufficient accuracy, we can determine relative camera pointing very well, at least locally.  
We first reproject two suitable JunoCam images to the same perspective. Then we stereo-correspond a pair of nearby patches of the first selected image with that of the second image. 
The change of the distances between the two patches returns our desired parallax.
Such stereo-corresponding patches can only be determined in a sufficiently reliable way, if both patches have sufficient small-scale contrast. Cloud-top patches of similar parallax may have an irregular shape. 
We have to deal with these challenges in order to retrieve a sufficiently dense mesh of parallax measurements. 
Because the set of parallax measurements is likely to be noisy and inconsistent, we feed our measurements into an embedded-springs model in order to find a good fit. Spring embedding is more generally known as force-directed graph drawing [1]. In more detail, a parallax measurement relates the elevations of two respective cloud-top patches. That way, we get interconnected islands of relative elevations. The resulting system of equations is likely to be overdetermined and not fully consistent. The spring embedding provides us with the elasticity to retrieve a reasonable solution anyway.
Separating parallax measurements from best-fit calcuations provides the flexibility to refine both portions independently.

A second source of cloud-top altitude estimates comes from JunoCam's methane-band images near a wavelength of 890 nanometers.  
These images are usually noisy and crowded with camera artefacts, most of which are either of a systematic nature or of a point-noise type. In addition there is also statistical photon noise. 
We derive reduced and lower-resolution versions of those methane-band images with most of the camera artefacts removed and some of the photon noise smoothed.  
Those reduced methane-band images can be cross-calibrated with our parallax measurements, whenever we have sufficient overlaps.  
Methane-band images can then be used to fill in cloud-altitude data at a higher resolution where parallax measurements are coarse. 
However, those cross-calibrations can only locally be assumed to be valid since changing observational conditions change the appearence of cloud-top features in methane-band images.
Despite their lack of a photometric calibration, the 890-nm band images provide a qualitative verification of our parallax measurements.

The talk will focus on parallax measurements alone, but we note that observations of small-scale shadows, shading, and hazes along the limb in JunoCam's RGB images also contribute information about cloud-top topography. 
A future extension of the parallax method to JIRAM data appears possible.

[1] Kobourov, Stephen G. (2012), Spring Embedders and Force-Directed Graph Drawing Algorithms, arXiv:1201.3011, Bibcode:2012arXiv1201.3011K

How to cite: Eichstädt, G., Orton, G., Hansen-Koharcheck, C., Guillot, T., and Bolton, S.: Parallax measurements of Jupiter's cloud tops in JunoCam images, and applications, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-6784, https://doi.org/10.5194/egusphere-egu23-6784, 2023.

EGU23-7025 | ECS | Posters virtual | PS6.3

Evidence for electrostatic and Alfvénic accelerations in the Europa footprint tail revealed by Juno in-situ measurements 

Jonas Rabia, Vincent Hue, Jamey R. Szalay, Nicolas André, Quentin Nénon, Michel Blanc, Frederic Allegrini, Scott J. Bolton, Jack E.P. Connerney, Robert W. Ebert, Thomas K. Greathouse, Philippe Louarn, Alessandro Mura, Emmanuel Penou, and Ali H. Sulaiman

Moon-magnetosphere interactions result from the encounter between a magnetospheric plasma flow and moons, which act as obstacles to the plasma flow. In the Jovian magnetosphere, the Galilean moons orbit with a Keplerian velocity much slower than the plasma velocity, driven in near corotation by the planetary magnetic field. Therefore, they disturb the magnetospheric plasma flow, which in turn generates Alfvén waves in their close environments. These waves propagate along the magnetic field lines, accelerating particles and triggering auroral emissions in the giant planet atmosphere.

Since August 2016, the Juno mission has made it possible to characterize in-situ the moon-magnetosphere interactions. Several crossings of the flux tubes connected to the orbits of the Galilean moons have been reported, revealing a diversity of particle properties and acceleration processes. However, Europa-magnetosphere interaction, whose remote and in-situ signatures are weaker and more difficult to identify than those of Io, remain poorly known.

We characterize the precipitating electrons accelerated in the Europa-magnetosphere interaction by analyzing in-situ measurements and remote sensing observations recorded during 10 crossings of the flux tubes connected to Europa's auroral footprint tail by Juno. The electron downward energy flux exhibits an exponential decay as a function of down-tail distance from Europa's main auroral spot, with an e-folding factor of 7.2°. Electrons are accelerated at energies between 0.3 and 25 keV, with a characteristic energy that decreases down‐tail. We show that in the near tail (∆λFrac < 6°), acceleration is due, at least in part, to electrostatic processes while in the far tail (∆λFrac > 6°) broadband energy spectra are evidence for Alfvénic acceleration. The size of the interaction region at the equator is estimated to be 4.5 Europa radii, consistent with previous estimates based on theory and UV observations.

How to cite: Rabia, J., Hue, V., Szalay, J. R., André, N., Nénon, Q., Blanc, M., Allegrini, F., Bolton, S. J., Connerney, J. E. P., Ebert, R. W., Greathouse, T. K., Louarn, P., Mura, A., Penou, E., and Sulaiman, A. H.: Evidence for electrostatic and Alfvénic accelerations in the Europa footprint tail revealed by Juno in-situ measurements, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-7025, https://doi.org/10.5194/egusphere-egu23-7025, 2023.

EGU23-7806 | Posters on site | PS6.3

Juno Microwave Radiometer Observations of Europa’s Subsurface Ice Shell 

Scott Bolton, Zimeng Zhang, Shannon Brown, Lea Bonnefoy, Erin Leonard, Steve Levin, Jonathan Lunine, Sid Misra, Paul Hartogh, Matt Siegler, David Stevenson, and Samantha Trumbo

On 29 Sep 2022, Juno had a close flyby of Jupiter’s moon Europa, flying within 500 km of the surface. During the flyby, Juno’s Microwave Radiometer (MWR) observed Europa, obtaining several swaths across Europa using Juno’s spin to map Europa’s subsurface ice shell at six frequencies ranging from 600 MHz to 22 GHz.  The ice transparency at microwave frequencies is dependent on purity; assuming pure ice, the observations probe depths ranging from meters to kilometers. The MWR observations represent the first resolved interrogation of Europa’s subsurface ice shell revealing new constraints on porosity, fracturing, differences in terrain type and possibly the thickness of the conductive ice shell.  These unprecedented measurements on Europa and Ganymede will provide new insights into the  comparative nature of the surfaces and interiors of the Jovian satellites.

How to cite: Bolton, S., Zhang, Z., Brown, S., Bonnefoy, L., Leonard, E., Levin, S., Lunine, J., Misra, S., Hartogh, P., Siegler, M., Stevenson, D., and Trumbo, S.: Juno Microwave Radiometer Observations of Europa’s Subsurface Ice Shell, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-7806, https://doi.org/10.5194/egusphere-egu23-7806, 2023.

EGU23-8942 | Orals | PS6.3

3D Monte Carlo simulation of Ganymede's atmosphere - lessons learned from Juno's Ganymede flyby 

Audrey Vorburger, Shahab Fatemi, André Galli, Lorenz Roth, Lucas Liuzzo, Andrew Poppe, Shane Carberry Mogan, and Peter Wurz

Among Jupiter's satellites, Ganymede undoubtedly has one of the most complex atmospheres. This is primarily due to the fact that Ganymede has its own magnetic field, which forms a small magnetosphere within the much larger magnetosphere of Jupiter. This interaction not only results in atmospheric auroral emissions in the UV range but also strongly influences Ganymede’s space environment.

With the recent Ganymede flyby by the Juno spacecraft, new information on Ganymede’s environment has become available. We have included these measurements into our 3D Monte Carlo model, determining Ganymede’s resulting H2O, O2, H2, O, and H atmosphere. Our simulations show that accounting for all major source and loss processes, sublimation is still the dominating source process for the water in Ganymede’s atmosphere, delivering more than three orders of magnitude more molecules to the atmosphere than all other source processes combined. For the non-condensing atmospheric species (O2 and H2), on the other hand, it is the auroral electrons that mainly govern the atmospheric structure and density. The auroral electrons also govern the structure and density of the atomic species O and H, which are mainly added to the atmosphere by electron-impact dissociation of O2 and H2 in the auroral belts. Comparison with available spectroscopic observations of Ganymede’s atmospheric constituents shows that our results agree well with the results inferred from these observations, with the exception of H, where our derived line-of-sight column density is about one order of magnitude lower than the column density inferred from Lyman-α measurements.

Our analysis shows that for a complete understanding of Ganymede's atmosphere, simultaneous observations of Ganymede's surface, atmosphere, and plasma environment at different times and locations are particularly important. Such measurements are planned with the Jupiter ICy moons Explorer, in particular with the Particle Environment Package (PEP). In this presentation we will show how PEP will help us learn more about Ganymede’s complex atmosphere, providing simultaneous in-situ electron, ion, and neutral gas measurements.

How to cite: Vorburger, A., Fatemi, S., Galli, A., Roth, L., Liuzzo, L., Poppe, A., Carberry Mogan, S., and Wurz, P.: 3D Monte Carlo simulation of Ganymede's atmosphere - lessons learned from Juno's Ganymede flyby, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-8942, https://doi.org/10.5194/egusphere-egu23-8942, 2023.

EGU23-9005 | Orals | PS6.3

How the Juno Ganymede Flyby Has Changed our Understanding of its Aurora and Atmosphere 

J. Hunter Waite, Thomas Greathouse, Shane Carberry Mogan, Rob Ebert, Jack Connerney, William Kurth, G. Randall Gladstone, Frederic Allegrini, Robert Johnson, Audrey Vorberger, Phillip Valek, George Clark, Scott Bolton, and Candice Hansen-Koharcheck

Juno flew within 1053 km of the surface of Ganymede on June 7, 2021. A unique data set of the interaction of its magnetosphere with the magnetosphere of Jupiter was obtained during the flyby. Auroral imaging was carried out by the UVS experiment simultaneous with the in-situ sampling of the polar cap ionosphere by the Waves, MAG, JEDI, and JADE experiments onboard Juno. Significant outflow of Ganymede’s polar cap ionosphere was observed as well as an in-situ sampling of reconnection processes near the magnetospheric boundary on the flank of the trailing side of the magnetospheric interaction region. Assuming that the electrons measured in the reconnection/interaction region are representative of the electrons producing the aurora, we use the UVS auroral vertical profiles obtained from the flyby and modeling to dramatically improve our understanding of the Ganymede atmosphere. The results of the relevant flyby measurements and the modeling of the atmosphere and aurora will be presented in this talk.

 

How to cite: Waite, J. H., Greathouse, T., Carberry Mogan, S., Ebert, R., Connerney, J., Kurth, W., Gladstone, G. R., Allegrini, F., Johnson, R., Vorberger, A., Valek, P., Clark, G., Bolton, S., and Hansen-Koharcheck, C.: How the Juno Ganymede Flyby Has Changed our Understanding of its Aurora and Atmosphere, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-9005, https://doi.org/10.5194/egusphere-egu23-9005, 2023.

EGU23-9135 | Posters on site | PS6.3

Ionospheres of Ganymede and Europa Observed by Radio Occultation with Juno 

Dustin Buccino, Marzi Parisi, Edoardo Gramigna, Luis Gomez Casajus, Paolo Tortora, Marco Zannoni, Andrea Caruso, Paul Withers, Ryan Park, Paul Steffes, Steve Levin, and Scott Bolton

NASA’s Juno spacecraft performed close flybys of the Galilean moons Ganymede in June 2021 and Europa in September 2022. During each of these encounters, the Juno spacecraft passed behind the moons as observed from Earth, providing the geometry for a radio occultation experiment to measure the electron densities of the ionospheres of these moons – the first opportunity to do so since the Galileo mission in the 1990s. Electrons encountered along the radio propagation path advance the signal’s phase. These small changes are detectable in the sensitive receivers of the Deep Space Network antennas. Ganymede’s tenuous ionosphere was detected on occultation ingress but no ionosphere was detected on egress. The interaction of the ionosphere with Ganymede’s intrinsic magnetosphere is believed to be the reason for the variability of the ionosphere, since ingress occurred on an open-field line region where electron impact ionization could be higher. At Europa, the occultation probed the Southern mid-latitudes on ingress and near the equatorial region on egress, with results consistent when compared with the six radio occultations of Europa from Galileo. Future occultation science with Juno will occur in 2023 and 2024 with radio occultations of Jupiter’s atmosphere and ionosphere.

How to cite: Buccino, D., Parisi, M., Gramigna, E., Gomez Casajus, L., Tortora, P., Zannoni, M., Caruso, A., Withers, P., Park, R., Steffes, P., Levin, S., and Bolton, S.: Ionospheres of Ganymede and Europa Observed by Radio Occultation with Juno, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-9135, https://doi.org/10.5194/egusphere-egu23-9135, 2023.

EGU23-9139 | Posters virtual | PS6.3

A public domain data-based modeling of long-term variability of Jupiter’s inner electron radiation belt 

Daniel Santos-Costa, Fabiano A. Oyafuso, Steven M. Levin, John E.P. Connerney, Emma Woodfield, Timothy Keebler, Thangasamy Velusamy, Sooman Han, Imke de Pater, Insoo Jun, Henry B. Garrett, Rob Wilson, Rob W. Ebert, Frederic Allegrini, Randy Gladstone, Peter Kollmann, Barry Mauk, William Kurth, Heidi N. Becker, and Scott J. Bolton

Until the arrival of Juno at Jupiter in 2016, the inner electron radiation belt dynamics has been examined from ground-based observations of Jupiter’s Synchrotron Emission (JSE) and theoretical modeling of the relativistic electron population. Simulations of JSE variability on month-to-year timescales only confirm a partial control of the Jovian Electron Radiation Belt (JERB) by large-scale solar-wind-driven particle transport. Juno prime mission and first years of the extended mission provide unique measurements of JSE from within JERB environment allowing us to further address the origins of JSE variability on a timescale of months. 

In the present work, we use Juno MicroWave Radiometer (MWR) data from mid-2016 to mid-2022 at different wavelengths to support our investigation of the origins of JERB dynamical behavior. Juno/MWR data from NASA Planetary Data System, ground-based observations of Jupiter and simulated Heliospheric Environment (HE) at the giant planet are combined to constrain the modeling of long-term variability of JSE as it would be observed from Earth. The Juno-data constrained trend of JSE at 11.5-cm wavelength is combined with single-dish observations to cover a multi-decade observation period. Using a simulator of JSE that accounts for the influence of physical parameters on jovian electron belts distributions, we present simulations of JSE to discuss the connection between JERB and HE and identify the magnetospheric physical processes (e.g., particle source and transport, interactions with planetary environment) which might have controlled JSE for the period 1962-2022. 

Acknowledgments: Key data processing, JERB model improvements and simulations of Juno/MWR measurements are carried out at Southwest Research Institute and primarily funded by NASA NFDAP program. This work benefits from collaborations with various Juno instrument teams and also from a larger science community.

How to cite: Santos-Costa, D., Oyafuso, F. A., Levin, S. M., Connerney, J. E. P., Woodfield, E., Keebler, T., Velusamy, T., Han, S., de Pater, I., Jun, I., Garrett, H., Wilson, R., Ebert, R. W., Allegrini, F., Gladstone, R., Kollmann, P., Mauk, B., Kurth, W., Becker, H. N., and Bolton, S. J.: A public domain data-based modeling of long-term variability of Jupiter’s inner electron radiation belt, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-9139, https://doi.org/10.5194/egusphere-egu23-9139, 2023.

EGU23-9315 * | Orals | PS6.3 | Highlight

Results From The Juno Microwave Radiometer At Jupiter 

Steve Levin and the The Juno Microwave Radiometer Team

Juno is a spinning spacecraft in a highly eccentric polar orbit about Jupiter, with perijoves at about 5000 km above the cloud tops, and has completed 50 orbits as of April 2023.  From Juno’s unique vantage point, the Juno Microwave Radiometer (MWR) has measured the radio emission in 6 channels, at wavelengths ranging from 1.4 to 50 cm, with 100 mS sampling throughout each spin of the spacecraft, since the first science pass in August of 2016.  This data set covers the Jovian atmosphere over a wide range of latitudes, longitudes and emission angles, as well as observations of the inner radiation belts and of Ganymede and Europa.  MWR has yielded a number of results, as well as prompting new questions, related to Jupiter’s atmospheric composition and dynamics at depths as deep as 300 km, distribution of lightning, microwave reflection over the auroral region, Jovian synchrotron emission, and the ice shells of Ganymede and Europa. We will present an overview of MWR results to date.

 

How to cite: Levin, S. and the The Juno Microwave Radiometer Team: Results From The Juno Microwave Radiometer At Jupiter, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-9315, https://doi.org/10.5194/egusphere-egu23-9315, 2023.

EGU23-9336 | Orals | PS6.3

Global and Regional Numerical Modeling of Water and Ammonia Cycles on Jupiter 

Yuan Lian, Tristan Guillot, Andrew Ingersoll, and Cheng Li

Data analysis of Juno MWR instrument measurements of brightness temperature at six channels showed that ammonia vapor was depleted in the region between ammonia cloud base all the way down to 40-60 bars. The vertical extent of depletion is far greater than previous thought, which assumed that ammonia in the sub-cloud layers were well mixed. We use a state-of-the-art Global Circulation Model (GCM), JupiterMPAS, to investigate the physical and dynamical processes below the water cloud base in hoping to interpret water and ammonia abundances retrieved over a wide range of latitudes. Two mechanisms that may affect ammonia distributions have been examined: “mushball” microphysics and mesoscale circulations. JupiterMPAS model results show that: 1. the mushball microphysics is a viable method to produce ammonia depletion in the region above water cloud base; 2. the treatment of lower boundary conditions in the JupiterMPAS model can impact tracer distribution in the sub-cloud layers; 3. depletion of ammonia via strong mesoscale downdrafts is possible, but its effect on global ammonia distribution is very limited.

How to cite: Lian, Y., Guillot, T., Ingersoll, A., and Li, C.: Global and Regional Numerical Modeling of Water and Ammonia Cycles on Jupiter, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-9336, https://doi.org/10.5194/egusphere-egu23-9336, 2023.

EGU23-9472 | ECS | Posters virtual | PS6.3

Spatial- and Temporal- Variations in Jupiter’s Atmosphere 

Zhimeng Zhang, Virgil Adumitroaie, Michael Allison, John Arballo, Sushil Atreya, Gordon Bjoraker, Scott Bolton, Shannon Brown, Leigh Fletcher, Tristan Guillot, Samuel Gulkis, Andrew Ingersoll, Michael Janssen, Steven Levin, Cheng Li, Jonathan Lunine, Glenn Orton, Fabiano Oyafuso, Paul Steffes, and Michael Wong

Jupiter has ubiquitous clouds and enormous surface structures shrouding the planet. Juno MWR provides the unprecedented chance to answer remaining major questions about the composition and dynamical properties of the great bulk of the atmosphere that lies beneath. Since the launch of Juno, there has been a large effort to collect complementary ground- and space-based observations to help interpret the MWR data. The Jovian Infrared Auroral Mapper (JIRAM) onboard Juno complements the observations of MWR, by giving alternative and reference tropospheric measurements that provides the boundary condition for the interpretation of the MWR data [Adriani et al 2014]. Similarly, HST has a 6-month overlap with 13 Juno orbits and color images were constructed from images of Jupiter in red, green, and blue filters by JunoCam [Hansen et al., 2014]. We study the dynamics within the atmosphere by relating the exterior information provided by these surface maps to the deep interior detected by MWR.

Since Aug 27, 2016, MWR has obtained over 40 perijoves, all scanning Jupiter’s atmosphere from North to South, covering various longitudes. We extend our calibration stability investigation to cover 6 years of observations, using our error analysis process. After removing the calibration drift, we combine observations from all perijoves to study the global-averaged atmosphere and the discrete features. We compare them with Jupiter’s surface atmosphere images taken by JunoCam, HST and JIRAM, and retrieve the corresponding NH3 volume mixing ratio from surface to over 100 bars.

How to cite: Zhang, Z., Adumitroaie, V., Allison, M., Arballo, J., Atreya, S., Bjoraker, G., Bolton, S., Brown, S., Fletcher, L., Guillot, T., Gulkis, S., Ingersoll, A., Janssen, M., Levin, S., Li, C., Lunine, J., Orton, G., Oyafuso, F., Steffes, P., and Wong, M.: Spatial- and Temporal- Variations in Jupiter’s Atmosphere, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-9472, https://doi.org/10.5194/egusphere-egu23-9472, 2023.

EGU23-9559 | Orals | PS6.3

Compositional diversity of the Europa-Ganymede plasma environment 

Jamey Szalay, Fran Bagenal, Frederic Allegrini, Scott Bolton, Robert Ebert, David McComas, Yash Sarkango, Philip Valek, and Robert Wilson

Jupiter’s plasma sheet is understood to be dominated by Io-genic material, mostly in various charge states of sulfur and oxygen. This material moves radially away from Jupiter, filling its magnetosphere. The material in the plasma sheet interacts with Europa and Ganymede, which are also sources of magnetospheric pickup ions, mostly in the form of both atomic and molecular hydrogen and oxygen. Juno’s plasma instrument JADE, the Jovian Auroral Distributions Experiment, has provided the first comprehensive in-situ observations of the composition of Jupiter’s plasma sheet with its Time-of-Flight mass-spectrometry capabilities. Here, we present observations of the magnetospheric composition in the Europa-Ganymede region of Jupiter’s magnetosphere. We highlight how Europa-genic material is often present and at times can be the dominant population for certain atomic masses, revealing a more complex and compositionally diverse magnetosphere than previously thought.

How to cite: Szalay, J., Bagenal, F., Allegrini, F., Bolton, S., Ebert, R., McComas, D., Sarkango, Y., Valek, P., and Wilson, R.: Compositional diversity of the Europa-Ganymede plasma environment, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-9559, https://doi.org/10.5194/egusphere-egu23-9559, 2023.

EGU23-9764 | ECS | Posters virtual | PS6.3

Plasma properties in Ganymede’s wake as observed by Juno/JADE 

Angèle Pontoni, Frédéric Allegrini, Fran Bagenal, Scott Bolton, John Connerney, Robert Ebert, Jamey Szalay, Phil Valek, and Rob Wilson

We present plasma observations from a previously unexplored wake region of Ganymede’s magnetosphere obtained by the Jovian Auroral Distributions Experiment (JADE) onboard the Juno spacecraft as it flew by Ganymede on June 7th, 2021. This region is highlighted by 1) plasma deflection well downstream of Ganymede's magnetopause, consistent with magnetic field perturbations, 2) plasma composition that is a mix of that in Jupiter’s adjacent plasma sheet or in Ganymede's magnetosphere, and 3) proton, heavy ion and electron distributions that are compressed compared to both adjacent regions. We derive ion and electron velocity distributions, pitch angles, temperatures, and densities inthis newly explored region of Ganymede’s magnetosphere. 

How to cite: Pontoni, A., Allegrini, F., Bagenal, F., Bolton, S., Connerney, J., Ebert, R., Szalay, J., Valek, P., and Wilson, R.: Plasma properties in Ganymede’s wake as observed by Juno/JADE, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-9764, https://doi.org/10.5194/egusphere-egu23-9764, 2023.

EGU23-9873 | Orals | PS6.3

Overview of Juno's Results from Europa and Ganymede 

Candy Hansen and Scott Bolton

The evolution of Juno's elliptical polar orbit has brought it close enough to Jupiter at the inbound equatorial plane crossing to intersect the orbits of the Galilean moons.  A close pass by Ganymede occurred 7 June 2021, at an altitude of 1046 km.  The spacecraft came within 350 km of Europa's surface on 29 September 2022. 

            The Juno payload, designed to probe Jupiter's magnetosphere with a comprehensive complement of fields and particles instruments, was ideal for studying Ganymede's unique mini-magnetosphere.  The spacecraft approached Ganymede from the night side, went behind Ganymede as seen from the earth (achieving an earth occultation), passed through the moon's magnetosphere, and then departed on the sunlit ~sub-jovian side.  Juno's remote sensing instruments collected new data in the visible and near-infrared, and, for the first time, mapped the surface and subsurface with 6 microwave channels.  Remote sensing of Ganymede returned new results on geology, surface composition and thermal properties of the subsurface. 

            Europa, with its tenuous atmosphere, has a unique interaction with the jovian environment, also investigated with Juno's fields and particles instruments.  The production of water molecules from sputtering of the surface is compared to the processing and eventual loss of molecules from the atmosphere.  Juno's remote sensing instruments returned high resolution images and spectra that are being used to expand our understanding of the tectonic history of Europa's surface.  The Microwave Radiometer probe of the subsurface ice shows Europa to be very different than Ganymede. 

 

How to cite: Hansen, C. and Bolton, S.: Overview of Juno's Results from Europa and Ganymede, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-9873, https://doi.org/10.5194/egusphere-egu23-9873, 2023.

EGU23-10194 | Orals | PS6.3

In situ ion composition observations of Ganymede’s outflowing ionosphere 

Philip Valek, J. Hunter Waite, Frederic Allegrini, Robert Ebert, Fran Bagenal, Scott Bolton, John Connerney, William Kurth, Jamey Szalay, and Robert J. Wilson

On 7 June 2021 the Juno spacecraft passed through the Ganymede magnetosphere, with a closest approach altitude of 1046 km. While in the magnetosphere, the Jovian Auroral Distributions Experiment-Ion (JADE-I) sensor observed outflowing ionospheric ions. These are the first in situ observations of the ionospheric ion mass composition. The outflowing ions consist of O2+, O+, H2+, H+, and H3+. Ion densities estimated from the measurements agree with the electron density determined by the Waves instrument to within a factor of 2.5. The light ions appear to be in hydrostatic equilibrium, and the altitude profile is generally symmetric between the inbound and outbound legs of the flyby. H3+ ions are an exception to this, with the ratio of H3+/H2+ being ~a factor 4 lower on the outbound than the inbound leg. The heavy ions have higher densities outbound than inbound. The outflowing flux of light ions peak near closest approach, but the heavy ions peak outbound of the flyby.

How to cite: Valek, P., Waite, J. H., Allegrini, F., Ebert, R., Bagenal, F., Bolton, S., Connerney, J., Kurth, W., Szalay, J., and Wilson, R. J.: In situ ion composition observations of Ganymede’s outflowing ionosphere, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-10194, https://doi.org/10.5194/egusphere-egu23-10194, 2023.

EGU23-10295 | ECS | Orals | PS6.3

Ganymede’s internal structure after Juno and before JUICE. 

Anton Ermakov, Ryunosuke Akiba, Luis Gomez Casajus, Marco Zannoni, James Keane, Paolo Tortora, Ryan Park, Dustin Buccino, Daniele Durante, Marzia Parisi, David Stevenson, Zhimeng Zhang, Shannon Brown, Steven Levin, and Scott Bolton

We use the magnetic and gravity field data jointly to place constraints on the internal structure of Ganymede. The magnetic induction constraint comes mostly from the Galileo data, as the Juno flyby occurred when Ganymede was near the center of the magnetodisk, thus leading to low sensitivity to magnetic induction. The gravity field model of Ganymede jointly derived from the Galileo and Juno data to place constraints on Ganymede’s internal structure. Unlike in the previous works, the hydrostaticity was not imposed on the degree-2 gravity coefficients. Thus, despite including additional data from Juno, the uncertainties on the degree-2 coefficients increased. In addition, we explicitly treat the effect of non-hydrostaticity on the derived moment of inertia and find significantly wider confidence intervals on the moment of inertia. This leads to a larger allowed parameter space for the internal structure model.

The new gravity solution confirms the past detection of non-hydrostatic anomalies. In our analysis, localized non-hydrostatic features with amplitudes higher than those found on Titan by the Cassini mission are identified. Titan is a useful comparison case as it shares with Ganymede nearly the same mean radius, mean density, and therefore, surface gravity. Thus, the non-hydrostatic deviations of the same amplitude either in shape or in gravity would correspond to approximately the same level of non-hydrostatic stress. On Titan, the gravity field for degree l > 2 reaches at most 5 mGal (Durante et al., 2019), which is a factor of 5 smaller than the largest anomalies found on Ganymede. One key difference between the two bodies is the lack of atmosphere-based erosion processes on Ganymede. Such erosional processes could have led to faster removal of non-hydrostatic signals at Titan reducing the amplitude of its gravity anomalies. In addition, Titan’s outer shell could be thinner and, therefore, less rigid than that of Ganymede, thus not being able to support as much non-hydrostaticity.

Further insights on Ganymede’s interior will be coming from the JUICE mission in the next decade. Currently, the lack of an accurate shape model prevents separating degree-2 hydrostatic and non-hydrostatic contributions. Combined gravity, topography and rotation data acquired by JUICE will be crucial in determining the non-hydrostatic contribution to the degree-2 field to constrain Ganymede’s internal structure.

How to cite: Ermakov, A., Akiba, R., Gomez Casajus, L., Zannoni, M., Keane, J., Tortora, P., Park, R., Buccino, D., Durante, D., Parisi, M., Stevenson, D., Zhang, Z., Brown, S., Levin, S., and Bolton, S.: Ganymede’s internal structure after Juno and before JUICE., EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-10295, https://doi.org/10.5194/egusphere-egu23-10295, 2023.

EGU23-10373 | Orals | PS6.3

Jovimagnetic Secular Variation and Jupiter’s rotation Period 

Jack Connerney, Sidey timmins, john jorgensen, Stavros Kotsiaros, Peter Jorgensen, Matija Herceg, Jeremy Bloxham, scott Bolton, and Steve Levin

The Juno spacecraft, in polar orbit about Jupiter since July 2016, continues to map the gas giant’s complex magnetic field with ever-increasing resolution in space and time. Comparison of spherical harmonic models (JRM33 and JRM09) derived from Juno measurements representative of different epochs revealed secular variation of the field near the isolated and intense patch of negative flux near the equator known as the Great Blue Spot (GBS). The feature drifts eastward relative to the deep interior at a rate of a few cm/s; if carried at depth by zonal winds, they must penetrate to depths of ~3000 km where the electrical conductivity is sufficient to grip the magnetic field. A dedicated magnetic survey above the GBS was conducted during Extended Mission orbits 36-42 to better characterize the GBS and its evolution during the mission; another is under consideration for later in the mission. Jupiter’s planetary rotation period (per IAU) has been determined with greater accuracy than that provided by observations of its radio emissions (System III (1965): 9h 55m 29.711s +/-0.04s) via a new spherical harmonic analysis allowing for time-dependent dipole coefficients. The drift of the dipole during Juno’s prime mission (by 0.12°/yr) determined this way yields an improved planetary rotation period of 9h 55m 29.698s, if the migration of the dipole is attributed to the limited accuracy of the IAU adopted planetary rotation period. A similar result is obtained by comparison of the JRM33 model with models representing earlier epochs (Voyager in 1979 and Ulysses in 1992). If time permits, we will also discuss particle motion in the complex (high degree and order) magnetic field near Jupiter’s surface and its relevance to local particle fluxes.

How to cite: Connerney, J., timmins, S., jorgensen, J., Kotsiaros, S., Jorgensen, P., Herceg, M., Bloxham, J., Bolton, S., and Levin, S.: Jovimagnetic Secular Variation and Jupiter’s rotation Period, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-10373, https://doi.org/10.5194/egusphere-egu23-10373, 2023.

EGU23-10437 | Posters on site | PS6.3

Analysis of the Effect of Jupiter's Northern Aurora on Juno Microwave Radiometer Observations 

Fabiano A. Oyafuso, Steven Levin, Jack Hunter Waite, Paul Steffes, and Scott Bolton

Juno's Microwave Radiometer (MWR) is intended to measure Jupiter's thermal emission using six channels that effectively probe different depths of Jupiter’s atmosphere [Li et al. 2017 Geophys. Res. Lett. 44, 531].  However, MWR has also observed non-thermal effects such as lightning [Brown et al. 2018 Nature 558, 7708], synchrotron emission [Levin et al AGU 2022], and reflections due to aurorae [Hodges et al EGU 2022].  Each effect diminishes with increasing channel (i.e. frequency) and is usually significant only in the two or three longest wavelength channels.  In this work we characterize the impact of the northern aurora on measured MWR intensities.  Near the poles significant reductions (up to a few hundred K) in intensities from those expected from Jupiter's thermal emission are found in every orbit in the two longest wavelength channels (~50cm and ~24cm) and for some orbits can be identified at wavelengths as short as 6cm.  They are shown to correlate well with regions poleward of the location of the mean auroral oval measured by Juno's Ultraviolet Imaging Spectrometer (UVS).  Intriguingly, several orbits demonstrate sudden changes in brightness temperatures that vary on timescales of one to two spins of the spacecraft.  These variations are suggestive of a transient phenomenon (on the order of a minute or less) that is coherent on a length scale comparable to a significant fraction of the size of MWR's polar footprints (~0.1 RJ). We will present an analysis of this effect in the MWR data and compare with measurements from UVS and with field and particle measurements of temporal and spatial variations to assess the physical connections between the changes in microwave emissions and auroral processes.

How to cite: Oyafuso, F. A., Levin, S., Waite, J. H., Steffes, P., and Bolton, S.: Analysis of the Effect of Jupiter's Northern Aurora on Juno Microwave Radiometer Observations, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-10437, https://doi.org/10.5194/egusphere-egu23-10437, 2023.

EGU23-10447 | Orals | PS6.3

Observations of the Sub-Surface Thermal and Structural Properties of Ganymede’s Ice Shell from the Juno Microwave Radiometer 

Shannon Brown, Scott Bolton, Sidharth Misra, Steve Levin, Zhimeng Zhang, Dave Stevenson, Matt Siegler, Jianqing Feng, and Lea Bonnefoy

On 7 June 2021, Juno had a close flyby of Jupiter’s moon Ganymede, flying within 1000 km of the surface. During the flyby, Juno’s Microwave Radiometer (MWR) observed Ganymede obtaining several swaths across Ganymede using Juno’s spin to partially map Ganymede’s ice shell in six channels ranging from 600 MHz to 22 GHz. The radiance at these frequencies originates from successively deeper layers of the sub-surface and may reach to depths of 20km at 0.6 GHz. The MWR observations cover a latitude range from 20S to 60N and an east longitude range from -120 to 60 degrees, roughly centered on the Perrine region. The local solar time varies from around noon to mid-night over the longitude range. We present resolved brightness temperature maps and associated microwave spectra of Ganymede with a spatial resolution of up to ~140 km (approximately 1/40th of Ganymede’s diameter). The microwave brightness temperature at all MWR wavelengths is anti-correlated with the visible brightness of the terrain, but is too large to be explained by albedo variations alone, suggesting sub-surface ice properties are not uniform with location. The dark regions tend to exhibit the warmest microwave spectra and brighter regions are observed to have a lower brightness temperature (up to half the blackbody temperature).The coldest microwave feature observed by MWR is the Tros crater and the immediate surrounding region. A radiative transfer algorithm, coupled with a thermal model for the conductive layer of Ganymede’s ice shell are fit to the MWR spectra providing an estimate of the conductive shell thickness. The microwave observations are globally colder than would be expected for pure water ice alone, suggesting thin highly reflective layer, possibly silicate dust, on the surface, although other interpretations remain possible. We suggest that scattering at sub-surface interfaces (e.g. fractures) explains the depressed brightness temperatures observed in brighter terrain types. Juno performed a close fly-by of Europa in September 2022, enabling a comparison of the sub-surface properties of these two icy satellites.      

How to cite: Brown, S., Bolton, S., Misra, S., Levin, S., Zhang, Z., Stevenson, D., Siegler, M., Feng, J., and Bonnefoy, L.: Observations of the Sub-Surface Thermal and Structural Properties of Ganymede’s Ice Shell from the Juno Microwave Radiometer, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-10447, https://doi.org/10.5194/egusphere-egu23-10447, 2023.

EGU23-10459 | Orals | PS6.3

Model Comparisons with Juno Observations of the Io Plasma Torus 

Edward Nerney, Fran Bagenal, Robert Wilson, and Phillip Phipps

Nasa’s JUNO spacecraft, now in its extended mission, is finally passing through the Io plasma torus (IPT) taking in situ measurements of the plasma environment using the JUNO-JADE instrument. Through September of 2025 we will have almost 40 passes through the IPT of JUNO observations. Further, there is recent evidence from ground based optical telescopes that Io recently had a major eruption increasing neutral emission close to Io around Thanksgiving of 2022 (C. Schmidt, personal communication, 2022). We have been developing a nominal torus model based on in situ plasma measurements from previous missions, emission modeling of UV spectra, and ground based optical emission derived plasma parameters. Physical chemistry modeling informs our model and is another point of comparison. We use Phipps & Bagenal (2021) to define the centrifugal equator, along with the newest JUNO based magnetic field model (Connerney et al. 2022), and using diffusive equilibrium to find the plasma distribution along a magnetic field line. We will compare our IPT model with observations from JUNO before, during, and after the Thanksgiving 2022 eruption. We will compare JUNO observations with a physical chemistry model of the IPT to constrain the source rate, radial transport diffusion coefficient, transport timescale, and how these vary throughout the eruption.

How to cite: Nerney, E., Bagenal, F., Wilson, R., and Phipps, P.: Model Comparisons with Juno Observations of the Io Plasma Torus, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-10459, https://doi.org/10.5194/egusphere-egu23-10459, 2023.

EGU23-10747 | Orals | PS6.3

A new value of Jupiter’s deep isentrope - implications for Jupiter’s deep thermal and compositional structure 

Cheng Li, Michael Allison, Sushil Atreya, Leigh Fletcher, Andrew Ingersoll, Liming Li, Glenn Orton, Fabiano Oyafuso, Paul Steffes, Michael Wong, Zhimeng Zhang, Steven Levin, and Scott Bolton

We analyze the Juno microwave observations of Jupiter’s atmosphere and find a warmer interior temperature than previously assumed based on the Voyager’s radio occultation measurement (Lindal et al., 1981, JGR-Space Physics, 86.A10, 8721-8727) and the Galileo Probe (Seiff et al., 1998, JGR-Planets, 103.E10, 22857-22889). By analyzing globally averaged observations from 1.4 – 50 cm wavelength, we find that the deep isentrope of Jupiter is at  169 +/- 1 K referenced at 1 bar pressure level. The globally averaged kinetic temperature at 1-bar is closer to 175 K and Jupiter’s weather layer is stably stratified. On the other hand, the 1-bar temperature inverted from Juno microwave observations at the Equatorial Zone between 0 and 5 oN remains low at 166 K, consistent with the previous remote sensing measurements made at the equator from the infrared (Fletcher et al., 2016, Icarus 278, 128-161). This also implies a vertical temperature gradient at the equator which is super-adiabatic. Our results suggest that the potential temperature difference between 1-bar and the deep isentrope is approximately  2.8 +/- 1.4 K. To avoid dynamic instability, the super-adiabatic temperature gradient must be stabilized by a change of mean molecular weight within the 5 – 10 bars pressure levels which only water can provide. The result implies that an abundance of water at the equator is constrained to a value between 2.2 and 6.2 times solar.

How to cite: Li, C., Allison, M., Atreya, S., Fletcher, L., Ingersoll, A., Li, L., Orton, G., Oyafuso, F., Steffes, P., Wong, M., Zhang, Z., Levin, S., and Bolton, S.: A new value of Jupiter’s deep isentrope - implications for Jupiter’s deep thermal and compositional structure, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-10747, https://doi.org/10.5194/egusphere-egu23-10747, 2023.

EGU23-11438 | ECS | Orals | PS6.3

Simulations of eddy-driven jets and circulation on gas giants 

Keren Duer, Eli Galanti, and Yohai Kaspi
Jupiter's atmosphere consists of three dynamical regimes: the equatorial eastward flow and retrograde jets surrounding it; the midlatitudes with alternating eddy-driven jets and circulation; and the turbulent poles. Despite intensive research conducted on each of these regimes over the past decades, they remain only partially understood. Saturn's atmosphere also encompasses similar distinguishable regimes, but evidence for deep meridional cells is lacking. Models offer a variety of explanations for each of these regions, and only a few are capable of simulating more than one of the regimes at once. This study presents new numerical simulations, using a 3D anelastic GCM, that can reproduce the equatorial flows as well as the midlatitudinal pattern of the mostly barotropic, alternating eddy-driven jets and the meridional circulation cells accompanying them. These simulations are consistent with recent gravity and microwave data coming from the Juno mission. The dynamics of the simulation are greatly influenced by varying the simulation's inner depth. As expected for a gas giant, we find that the vertical eddy momentum fluxes are just as important as the meridional eddy momentum fluxes, which drive the midlatitudinal circulation on Earth. The number of the jets/cells, their extent, strength, and location are directly related to the boundary conditions and the Ekman number. Studies have shown that the rotation rate, the forcing scheme, and the Rayleigh number are also responsible for the emergence of jets in simulations of gas giants, but we keep these constant in our simulations. Our simulations also capture the tilted convection columns outside of the tangent cylinder, leading to the superrotation at the equator and the adjacent subrotating jets. A combination of boundary conditions leads to a stacked circulation cell pattern that is aligned with numerous jets that are conceptually similar to the meridional circulation in Jupiter's midlatitudes, as suggested by several studies. This analysis provides another step toward understanding the deep atmospheres of gas giants.

How to cite: Duer, K., Galanti, E., and Kaspi, Y.: Simulations of eddy-driven jets and circulation on gas giants, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-11438, https://doi.org/10.5194/egusphere-egu23-11438, 2023.

EGU23-11468 | Orals | PS6.3

µASC observations of Jovian energetic electrons interaction with Europa moon 

Matija Herceg, John L. Jørgensen, Troelz Denver, Julia Sushkova, Peter S. Jørgensen, John E. P. Connerney, and Scott J. Bolton

Since Juno’s orbit insertion, the attitude reference for the MAG investigation onboard Juno, the micro Advanced Stellar Compass (µASC), and as a part of its additional functionality, continuously measures high energy electron fluxes in Jupiter’s magnetosphere. The µASC camera head unit (CHU) sensitivity to electrons with kinetic energy greater than 15 MeV and protons with energies >80MeV, provides a means of in-situ mapping of electron fluxes sampled during 47 Juno orbits.

The focus of this study are events observed when Juno is traversing M-shell of the Galilean moon, Europa, which shows distinctly different signature from that the other moons.

We present µASC observations of energetic electrons interaction with Europa moon. Europa generates a wake, that affect the high energy electron driftshell, by scattering electrons into the loss-cone. The wake is then dissolved and these interactions are observed around 20° down tail. On the upstream side, the energetic drift shell is free from hard radiation as Europa acts as an obstacle for the energetic electrons. This assymetry result in a lower electon density on the upstream side resulting in an E-field filling in the e- population from surrounding driftshells in less than 10°.

How to cite: Herceg, M., Jørgensen, J. L., Denver, T., Sushkova, J., Jørgensen, P. S., Connerney, J. E. P., and Bolton, S. J.: µASC observations of Jovian energetic electrons interaction with Europa moon, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-11468, https://doi.org/10.5194/egusphere-egu23-11468, 2023.

EGU23-11490 * | Orals | PS6.3 | Highlight

Comet dust tail detection by the Juno spacecraft’s magnetometer investigation 

Peter S. Jørgensen, John L. Jørgensen, John E. P. Connerney, Christina A. Toldbo, Mathias Benn, Anja C. Andersen, Troelz Denver, and Scott J. Bolton

During transit from Earth to Jupiter, NASAs Juno spacecraft carried out scientific measurements along its trajectory, using a subset of its instrument suite. One of the instruments turned on during the journey was the micro Advanced Stellar Compass, part of the MAG investigation. The fully autonomous microASC uses a camera to image the sky for attitude determination, its primary function, but it also logs objects appearing multiple times in the camera FOV that are not found in the instrument’s star catalog. In doing so, it routinely logged the motion of illuminated spallation products evolving from the impacts of interplanetary dust particles (IDPs) on the spacecraft. The system is capable of detection of IDPs with a diameter larger than ~5µm, i.e. particles in the size range responsible for the Zodiacal light. The detection mode was activated just after Juno performed a deep space manoeuver at 2.2AU setting the spacecraft up for a gravity assist from a close Earth flyby, sending Juno on a trajectory to rendezvous with Jupiter. The first leg of the journey, from 2.2AU to 0.8AU and to the Earth flyby, was in the ecliptic plane, whereas the trajectory from Earth to Jupiter rose well above the ecliptic plane. This resulted in measured IDP density profiles both in and above the ecliptic plane. In December 2015, half a year before Jupiter orbit insertion, a conspicuously high rate of dust impacts was detected for a fortnight. A closer analysis showed that Juno happened to pass through the tail of a Jupiter family comet.

We here present the observations of the particle population during the December 2015 event, discuss the dust tail evolution and morphology, and present the implications for the comet’s size and volatility.

How to cite: Jørgensen, P. S., Jørgensen, J. L., Connerney, J. E. P., Toldbo, C. A., Benn, M., Andersen, A. C., Denver, T., and Bolton, S. J.: Comet dust tail detection by the Juno spacecraft’s magnetometer investigation, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-11490, https://doi.org/10.5194/egusphere-egu23-11490, 2023.

EGU23-11952 | ECS | Orals | PS6.3

Jupiter and Saturn normal modes observed through Juno and Cassini gravity measurements 

Daniele Durante, Tristan Guillot, Luciano Iess, David Stevenson, Christopher Mankovich, Steve Markham, Paolo Racioppa, Linda Spilker, and Scott Bolton

Recently, the Juno and Cassini spacecraft shed light on the interior of both Jupiter and Saturn, the two gas giants of the Solar System. Juno is currently orbiting Jupiter in a highly elliptical 53.5-day orbit, with a perijove altitude of about 4000 km. After the 33rd passage in April 2021 (labeled PJ33), the mission ended its nominal mission and entered its extended mission. On the contrary, the Cassini spacecraft ended its mission on September 15th, 2017 with a deliberate plunge into Saturn’s atmosphere. In its final phase, the Grand Finale, Cassini provided insights on Saturn’s rings, atmosphere, and interior. Out of the 22 proximal orbits, six pericenter passes have been devoted to the determination of the gravity field of the planet.

The gravity science experiments on board Juno and Cassini precisely measured, respectively, Jupiter and Saturn zonal gravitational fields. The measured gravity harmonics have been used to constrain the interior structure and atmospheric zonal flow on both planets.

The Cassini data analysis have shown the need to include unknown accelerations to properly fit the data to the expected noise (Iess, 2019). Similar unexplained accelerations have been observed also on Juno gravity data (Durante, 2020). Since Jupiter and Saturn are gas giants, unconventional phenomena can be at play, including normal modes, non-zonal atmospheric dynamics, or flows in the dynamo region.

The analysis of the accelerations acting on Cassini provided evidence for p-modes on the planet (Markham, 2020), while the analysis of Juno gravity data revealed p-modes on Jupiter and provided upper bounds on lower frequency f-modes. Here, we show the results for normal modes on both Jupiter and Saturn obtained with the analysis of gravity data of both Juno and Cassini.

How to cite: Durante, D., Guillot, T., Iess, L., Stevenson, D., Mankovich, C., Markham, S., Racioppa, P., Spilker, L., and Bolton, S.: Jupiter and Saturn normal modes observed through Juno and Cassini gravity measurements, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-11952, https://doi.org/10.5194/egusphere-egu23-11952, 2023.

EGU23-12188 | Posters on site | PS6.3

Jovian synchrotron radiation multi-zonal parametric model: an update from Juno MWR observations 

Virgil Adumitroaie, Steven Levin, Fabiano Oyafuso, and the Juno MWR Team

The Microwave Radiometer (MWR), Juno’s remote-sensing experiment, captures the thermal and non-thermal radiation emitted by the atmosphere and the magnetosphere, which is present in the Jovian orbital environment. Other scientific instruments on the spacecraft record the signatures of space-charged particles and the planet’s magnetic field. To retrieve the atmospheric composition values from MWR’s low-frequency radiative observation, the contributions from three existing emission sources (the cosmic microwave background (CMB), the planet, and synchrotron radiation belts) must be untangled numerically. The multi-parameter, multi-zonal model of Levin et al. (2001) for synchrotron emission employs an empirical electron-energy distribution. Initially, this distribution has been adjusted exclusively from Very Large Array (VLA) observations made from Earth before the Juno mission.  This is a report on the recent model update based on a subset of MWR in-situ data. The approaches considered, challenges confronted, and the latest results are discussed here.

How to cite: Adumitroaie, V., Levin, S., Oyafuso, F., and MWR Team, T. J.: Jovian synchrotron radiation multi-zonal parametric model: an update from Juno MWR observations, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-12188, https://doi.org/10.5194/egusphere-egu23-12188, 2023.

EGU23-12234 | Orals | PS6.3

Jupiter's Atmosphere Profiling 

Mathias Benn, John L. Jørgensen, Peter S. Jørgensen, Troelz Denver, Matija Herceg, and Jack E. Connerney

The micro Advanced Stellar Compass (µASC), an instrument onboard Juno serving as attitude reference for the Juno Magnetic Field investigation, providing accurate bias free attitude information continuously throughout the mission. The µASC is equipped with four optical sensors, configured for low-light scenarios, which enables detection of stars and objects as faint as 7-8Mv.

During each perijove passage the highly elliptical Juno orbit configuration, in combination with the 13° off pointing of the star tracker cameras from the Juno spin axis in the anti-sun direction, enables observations of the Jupiter horizon at a high slant angle. During such observation opportunities, the Jovian horizon is some 40,000km distant, offering detailed imaging of the upper atmosphere, luminous phenomenon herein, as well as any haze layer or elevated clouds, before the planet atmosphere transitions into the dark space star field. The orbital motion of Juno, further result in continuous occultation’s of stars setting behind the horizon.

After 40+ perijoves such images have been acquired from the µASC, distributed from Jupiter North Pole down to +30deg of latitude at a wide range of longitudes. This coverage enables altitude profiling of the top atmosphere as described by latitude and longitude for both dusk and dawn conditions of Jupiter.

Images and objects observed by the aforementioned technique are presented together with the detected energies within the sensitivity range of the observing star tracker camera and their implications for the atmospheric density profile.

How to cite: Benn, M., Jørgensen, J. L., Jørgensen, P. S., Denver, T., Herceg, M., and Connerney, J. E.: Jupiter's Atmosphere Profiling, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-12234, https://doi.org/10.5194/egusphere-egu23-12234, 2023.

EGU23-12662 | ECS | Posters on site | PS6.3

The Jovian ionospheric conductivity derived from a broadband precipitated electron distribution 

Guillaume Sicorello, Bertrand Bonfond, Jean-Claude Gérard, Denis Grodent, Leonardos Gkouvelis, Randy Gladstone, and Annika Salveter

The Pedersen ionospheric conductivity at Jupiter can be computed using a precipitated electron flux either obtained by direct in situ measurements or inferred from UV auroral spectra (Gérard et al., 2020). In the latter case, a mono-energetic distribution was used to represent the electron flux. However, based on the Juno spacecraft recent findings, it appears that the impinging electron flux is best approximated with a broadband distribution (Mauk et al., 2017; Salveter et al., 2022). In this study, we estimate the impact of such a distribution on the conductivity. In particular, we examine the ratio between the Pedersen conductances computed with a mono-energetic and with a broadband distribution, which can be modelled with a kappa distribution. A similar methodology as in Gérard et al. (2020) is followed to compute the conductances. The altitude distributions of H, H2 and CH4, included in the atmosphere model, are taken from Grodent et al’s (2001) model.

Among other results, we find that the ratio between conductances depends on the electron mean energy of the precipitating electrons population. For a mono-energetic distribution, an optimal energy exists, around 30-40 keV, for which the conductance arising from the precipitation is maximum. If the mean electron energy is well below this optimal energy, the conductance calculated for a kappa distribution is enhanced compared to the mono-energetic case because part of the electron energy distribution reaches this optimal level. The conductance is also underestimated for a mono-energetic electron precipitation well above the optimal value. The opposite trend is observed around the optimal energy as most of the electrons of the broadband distribution have either lower or higher energies, while all electrons of the mono-energetic distribution have an energy close to the optimum.

In conclusion, compared to a realistic broadband electron distribution on Jupiter, a mono-energetic distribution tends to overestimate the conductivity for mean energies in the 7 – 450 keV range and to underestimate it outside this range. In the future, this new relationship between the mean energy and the conductivity will be used to update the conductance maps built from the data from Juno.

References:

Gérard, J.‐C., Gkouvelis, L., Bonfond, B. et al. (2020). J. Geophys. Res Space Phys., 125, e2020JA028142. https://doi.org/10.1029/2020JA028142.

Grodent, D., Waite, J. H. and Gérard, J.-C. (2001). J. Geophys. Res., 106 (A7), 12933–12952. https://doi.org/10.1029/2000JA900129.

Mauk, B., Haggerty, D., Paranicas, C. et al. (2017). Nature, 549, 66–69. https://doi.org/10.1038/nature23648.

Salveter, A., Saur, J., Clark, G. et al. (2022). J. Geophys. Res Space Phys., 127, e2021JA030224. https://doi.org/10.1029/2021JA030224.

How to cite: Sicorello, G., Bonfond, B., Gérard, J.-C., Grodent, D., Gkouvelis, L., Gladstone, R., and Salveter, A.: The Jovian ionospheric conductivity derived from a broadband precipitated electron distribution, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-12662, https://doi.org/10.5194/egusphere-egu23-12662, 2023.

EGU23-12691 | Orals | PS6.3

Overview of the 3GM experiment on board the JUICE mission 

Fabrizio De Marchi, Paolo Cappuccio, Giuseppe Mitri, Luciano Iess, and Mauro Di Benedetto

The ESA’s Jupiter Icy moons Explorer (JUICE) L-class mission is devoted to the study of the Jovian system.

It will be launched in 2023 and, after an 8-year cruise phase (with 3 gravity assists to Earth and 1 to Venus), will start a tour of the Galilean moons that will last 3.2 years.

The onboard Geodesy and Geophysics of Jupiter and the Galilean Moons (3GM) radio science experiment will accomplish a detailed study of Europa, Ganymede and Callisto thanks to a state-of-the-art radio tacking system. 3GM will rely on a multi-frequency link enabled by two onboard units: the Ka-band Transponder (KaT) payload (establishing a full 2-way link in Ka band) and the Deep Space Transponder (DST), enabling 2-way coherent X/X and X/Ka link used for telemetry and telecommand. The multi-frequency link allows accurate measurements of range (≈1-4 cm @60s) and range rate (≈0.003 mm/s @1000s) at nearly all Sun-probe-Earth angles.

The data achieved during the tour phase (2 flybys at Europa and 21 flybys at Callisto) will be used to estimate the Europa’s quadrupole gravity field and Callisto’s static gravity field to at least degree and order 7 and its tidal Love number k2 with an accuracy of ~0.06 [1]. This will allow 3GM to detect the presence or absence of a subsurface ocean underneath the ice shell of Callisto.

At the end of the tour phase, JUICE will be the first spacecraft to orbit around and icy satellite, allowing a comprehensive study of the moon. The Ganymede 9-month orbital phase is composed of a 5-month elliptical orbit followed by a 4-month circular orbit at 500 km of altitude (GCO-500). The mission could be extended for a 200 km altitude campaign if the residual propellant will be sufficient to decrease the orbital radius.

Range and Doppler data achieved by 3GM during the GCO-500 will be used to infer the static (up to degree 35-45) gravity field, the rotational state, and the tidal response of Ganymede.

Ganymede’s k2 is subject to time-varying tides due to Jupiter, Io, Europa and Callisto. In particular, the Ganymede’s gravitational perturbations due to the satellites has a high spectral content. This signal can be used to estimate k2 at a set of frequencies, up to 4d-1. The profile of k2 as a function of the frequency, due to the subsurface ocean, is expected to show a peak at a certain resonance frequency, its value being strictly related to the ocean’s depth. We show that the accuracy of the 3GM radio science data is sufficient to detect the peak, if present, and measure its amplitude. In this case the ocean thickness can be estimated with a 7% uncertainty [2].

References:

[1] Cappuccio, P.; Di Benedetto, M.; Durante, D.; Iess, L. (2022) Planet. Sci. J. 3 199

[2] De Marchi, F.; Cappuccio, P.; Mitri, G.; Iess, L. (2022)  Icarus 386 115150

How to cite: De Marchi, F., Cappuccio, P., Mitri, G., Iess, L., and Di Benedetto, M.: Overview of the 3GM experiment on board the JUICE mission, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-12691, https://doi.org/10.5194/egusphere-egu23-12691, 2023.

EGU23-14420 | ECS | Orals | PS6.3

The Structure of the warped Io Plasma Torus constrained by the Io Footprint 

Stephan Schlegel and Joachim Saur

The location of the Io Plasma Torus is routinely assumed to be the centrifugal equator of Jupiter's magnetosphere, i.e. the position along the magnetic field lines farthest away from Jupiter's rotational axis. In many models, the centrifugal equator is assumed to lay on a plane, calculated from a (shifted) dipole magnetic field, rather than on a warped surface which incorporates Jupiter's higher magnetic field moments. In this work, we use Hubble Space Telescope observations of the Io Main Footprint to constrain density, scale height and lateral position of the Io Plasma Torus. We show that the leading angle of the footprints can be used to calculate expected travel times of Alfvén waves along the magnetic field lines. For the magnetic field we use the JRM33 magnetic field model. The inversion results show peak densities between 1830 / cm3 and 2032 / cm3 and scale heights between 0.92 RJ and 0.97 RJ consistent with current literature values. Using a warped multipole centrifugal equator instead of a planar dipole the quality of the fit increases by about 25 %. To evaluate these findings quantitatively, a Monte-Carlo-Test was conducted confirming that the multipole centrifugal equator explains the data much better. Furthermore, in a second set of inversion the latitudinal displacement of the torus due to quadropole moments has been fitted using a half synodic periodicity. The best fit locations are comparable to the predicted multipole centrifugal equator location, calculated from the JRM33 model. The additional half synodic periodicity of Io's orbital position inside the torus due to the incorporated quadropole moments alters Io's relative position to the torus center by about  0.15 RJ , which changes the plasma density in Io's vicinity by up to 20 %. 

How to cite: Schlegel, S. and Saur, J.: The Structure of the warped Io Plasma Torus constrained by the Io Footprint, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-14420, https://doi.org/10.5194/egusphere-egu23-14420, 2023.

EGU23-14691 | Orals | PS6.3

Jupiter’s magnetodisc and magnetospheric currents during Juno’s prime mission. 

Gabrielle Provan, Jon Nichols, Stan Cowley, Rob Wilson, Fran Bagenal, and Jack Connerney

We study Jupiter’s magnetic field and plasma parameters during Juno’s prime mission, using data from Juno’s FGM magnetometer and ion measurements from the  Jovian Auroral Distributions Experiment Ion (JADE-I) sensor on Juno.  We compare the observed poloidal magnetic field and  plasma density, angular velocity and temperature profiles, with predictions from the Nichols et al. (2015)  axisymmetric magnetic vector potential model.  This  magnetodisc model balances the j x B force of the azimuthal magnetodisc currents with the outwards forces of the plasma pressure gradient, plasma pressure anisotropy and the centrifugal force associated with the rotating plasma.  By varying the model parameters for each orbit we model how Jupiter’s mass outflow rate, plasma angular velocity and ‘hot’ and ‘cold’ plasma temperatures and densities vary throughout Juno’s prime mission.  We further examine how changes in magnetospheric conditions are related to variations in the magnetosphere–ionosphere coupling parameters, in particular by studying the azimuthal and radial currents and the ionospheric field-aligned current density. 

How to cite: Provan, G., Nichols, J., Cowley, S., Wilson, R., Bagenal, F., and Connerney, J.: Jupiter’s magnetodisc and magnetospheric currents during Juno’s prime mission., EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-14691, https://doi.org/10.5194/egusphere-egu23-14691, 2023.

EGU23-14751 | Orals | PS6.3

Jupiters high energy particle environment observed by Juno 

John Jørgensen, Troelz Denver, Matija Herceg, Julia Sushkova, Jack Connerney, Christina Toldbo, mathias Benn, Scott Bolton, and Steven Levin

The Advanced Stellar Compass (ASC), part of the MAG experiment onboard Juno, has been measuring the Jovian high energy particle environment since orbit insertion. We’ve produced a detailed map of the distribution of trapped high energy particles, predominantly electrons (>10MeV), using data from Juno’s first 47 orbits. The observations also demonstrate the significant influence that space weather at Jupiter has on the local particle flux. The ASC is a star tracker designed with four low light cameras to provide accurate attitudes for the MAG experiment’s vector magnetometers, located on a boom at the end of one of the spacecraft solar wings at 10 and 12m from the center of the spacecraft. At this location the ASC cameras are subjected to the high energy particle omniflux for all 4pi.  Electrons with an average energy of 20MeV and protons with energy in excess of 100MeV will pass through the camera radiation shielding to the camera CCDs to liberate signal electrons. To enable robust attitude estimation, the signal from the penetrating radiation is first removed by a software filter before star field recognition is performed. Registering the particle count in each image, these measurements effectively provide for a high time resolution measurement of the high energy particle omniflux. We present the detailed map of high energy particles throughout Jupiter’s magnetosphere and demonstrate how the local flux responds to solar activity.

How to cite: Jørgensen, J., Denver, T., Herceg, M., Sushkova, J., Connerney, J., Toldbo, C., Benn, M., Bolton, S., and Levin, S.: Jupiters high energy particle environment observed by Juno, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-14751, https://doi.org/10.5194/egusphere-egu23-14751, 2023.

EGU23-14801 | ECS | Posters on site | PS6.3

The Role of Vortex Shielding on Polar Crystal Formation & Vortex Dynamics on Jupiter 

Aaron Carruthers, Stephen Thomson, and William Seviour
The Juno mission in 2016 revealed that Jupiter’s polar regions contain a set of vortices cohabiting in tightly-packed crystal formations. These crystals were
noted for their remarkable stability, even withstanding the intrusion of a stray cyclone drifting into the arrangement. Wind and infrared measurements of these vortices give estimates of their radial extent and velocity profiles, indicating these vortices are surrounded by an annulus of opposing potential vorticity (pv), commonly referred to as a shield.
However, the underlying mechanisms that lead to the development and maintenance of vortex shielding on planetary vortices are generally poorly under-
stood. For example, the sensitivities of the shielding process to planetary parameters, such as deformation radius, are largely unexplored.
Recent work has shown that, in a shallow water framework, these shields are pertinent to the crystal stability. Particularly, recent modelling efforts have
placed strict bounds for this shielding in terms of magnitude. Although much work has been devoted to this topic, there are still significant questions remaining and large gaps in our understanding of these polar vortex crystals.
Here we present a preliminary exploration of the parameter space, using a quasi-geostrophic beta plane model to simulate the drift of Gaussian pv pulses
in Jupiter-like conditions. These initial results indicate that vortex shielding may have a strong dependence on the deformation radius and the background pv gradient, suggesting a strong dependence on latitude. These preliminary results will form the basis of our work modelling Jovian polar crystal formation
and vortex shield development in more detailed atmospheric settings.
 
 

 

How to cite: Carruthers, A., Thomson, S., and Seviour, W.: The Role of Vortex Shielding on Polar Crystal Formation & Vortex Dynamics on Jupiter, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-14801, https://doi.org/10.5194/egusphere-egu23-14801, 2023.

EGU23-15308 | ECS | Orals | PS6.3

The Effects of a Stably Stratified Region on the Formation of Zonal Winds on Gas Planets 

Paula Wulff, Ulrich Christensen, Wieland Dietrich, and Johannes Wicht

The outer regions of both Gas Giants in our Solar System, Jupiter and Saturn, feature strong, alternately Eastward and Westward moving zonal winds. Cloud tracking has yielded latitudinal profiles of these winds, which are longitudinally invariant and steady in time to a high degree and reach all the way to the polar regions. However, reproducing these features in numerical simulations has proved difficult as certain physical transitions at various depths are required to both enable winds to form and be maintained at the higher latitudes, and then be quenched at the depths inferred from gravity measurements.
A sub-adiabatic region in combination with an increase in electrical conductivity seems to be key, but makes the dynamics rather complex. In this study we analyse how the two transitions affect the zonal winds formed in an overlying convecting region, as well as how they then penetrate into the respective stably stratified and dynamo regions.
Particularly in the case of Jupiter evidence is accumulating for a stably stratified layer, shallower than where Helium rain may be expected, based on interior models and magnetic field modelling. However, the nature of such a shallower layer and its exact depth is still very undetermined. This study helps to constrain the depth at which this stratified region begins relative to the depth of the transition into the dynamo region. We find that when the transition to high electrical conductivity is much deeper than the transition into the stable region, zonal winds form at all latitudes. When the boundary of the dynamo region becomes shallower, high-latitude jets are diminished in amplitude and cease to reach the polar regions.

How to cite: Wulff, P., Christensen, U., Dietrich, W., and Wicht, J.: The Effects of a Stably Stratified Region on the Formation of Zonal Winds on Gas Planets, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-15308, https://doi.org/10.5194/egusphere-egu23-15308, 2023.

EGU23-15858 | ECS | Posters on site | PS6.3

Response of the Jovian radio emission to magnetospheric disturbances inferred from in situ Juno observations. 

Corentin Louis, Caitriona Jackman, George Hospodarsky, Aoife O'Kane Hackett, Elliot Devon-Hurley, Philippe Zarka, William Kurth, Robert Ebert, Dale Weigt, Alexandra Fogg, James Waters, Seán McEntee, John Connerney, Philippe Louarn, Steven Levin, and Scott Bolton

During its 53-day polar orbit around Jupiter, Juno often crosses the boundaries of the Jovian magnetosphere, namely the magnetopause and bow shock, as well as the plasma disc (located at the centrifugal equator). The positions of the magnetopause and bow shock allow us to determine the dynamic pressure of the solar wind (using both the updated model of Joy et al. 2002 by Ranquist et al., 2020 and/or in situ data) which allows us to infer magnetospheric compression or relaxation, while the observations of plasma disc perturbations allows us to infer magnetospheric reconfigurations.

The aim of this study is to examine Jovian radio emissions during magnetospheric perturbations. We then use our analysis to determine the relationship between the solar wind and Jovian radio emissions (observed and emitted from different regions of the magnetosphere, from different mechanisms, and at different wavelengths from kilometers to decameters).

In this presentation, we show case studies for each typical case (bow shock, magnetopause and plasma disk crossings) and show that the activation of new radio sources is related to magnetospheric disturbances. By performing a statistical study of these crossings, we show the relationship between the activation of new radio sources (emission intensity and extension, source positions) and the solar wind (dynamic pressure, magnetic intensity, …). The final aim is to be able to use observations of planetary radio emission as a proxy for the solar wind conditions.

How to cite: Louis, C., Jackman, C., Hospodarsky, G., O'Kane Hackett, A., Devon-Hurley, E., Zarka, P., Kurth, W., Ebert, R., Weigt, D., Fogg, A., Waters, J., McEntee, S., Connerney, J., Louarn, P., Levin, S., and Bolton, S.: Response of the Jovian radio emission to magnetospheric disturbances inferred from in situ Juno observations., EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-15858, https://doi.org/10.5194/egusphere-egu23-15858, 2023.

EGU23-16086 | Orals | PS6.3

Hubble and Juno observations of Jupiter’s auroras and magnetospheric dynamics during the Juno Extended Mission 

Jonathan D. Nichols, John Clarke, Denis Grodent, Bertrand Bonfond, Stanley Cowley, Randy Gladstone, Fran Bagenal, Glenn Orton, Bob Lysak, Frederic Allegrini, Jack Connerney, Barry Mauk, George Clark, Rob Wilson, and Rob Ebert

We present simultaneous Juno and Hubble Space Telescope of Jupiter's far-ultraviolet auroras obtained as part of a programme of observations covering 3 years of Juno's Extended Mission.  We show that bright, expanded dusk-side southern main emission is associated with large-scale convection dynamics, dusk-side main emission arcs are associated with field-aligned currents, and equatorward diffuse emission and patches are associated with plasma injections in the middle magnetosphere occurring within intervals of enhanced plasma density, ongoing interchange motion and magnetospheric convection.  These results shed light on the relation between the main auroral emission and magnetosphere-ionosphere coupling currents, and radial force balance in the magnetosphere. We also report on unusually bright and expanded southern auroral emissions observed during PJ 43.

How to cite: Nichols, J. D., Clarke, J., Grodent, D., Bonfond, B., Cowley, S., Gladstone, R., Bagenal, F., Orton, G., Lysak, B., Allegrini, F., Connerney, J., Mauk, B., Clark, G., Wilson, R., and Ebert, R.: Hubble and Juno observations of Jupiter’s auroras and magnetospheric dynamics during the Juno Extended Mission, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-16086, https://doi.org/10.5194/egusphere-egu23-16086, 2023.

EGU23-16574 | Orals | PS6.3

Global Model of Chorus Waves and Electron Lifetime Derived From Juno Observations 

Yixin Hao, Dedong Wang, Yuri Shprits, John Menietti, and Alexander Drozdov

Gyroresonant wave-particle interactions with whistler mode chorus waves plays a dual role in the precipitating loss and acceleration of energetic electrons in Jovian magnetosphere, which plays fundamental role in both Jovian radiation belt dynamics and auroral emission. Knowledge of the chorus wave power as a function of multi-dimensional spatial location and their spectral distribution are critical inputs for Jovian radiation belt modeling. In this work we present a global, analytical model of the typical Jovian chorus waves (0.1fce<f<0.8fce) based on the measurements made by Juno spacecraft in orbits 1 through 45, with which the whole nightside sector is covered. The radial, latitudal and local time dependence of the chorus wave intensity are derived. Mean-squared and most-probable spectral distributions are also statistically in separated M-shell and magnetic latitude sectors. With the updated chorus wave model, the wave-particle interaction is further quantified in terms of pitch angle, energy and mixed diffusion coefficients. We present an estimation of electron loss rate due to pitch angle scattering and henceforth precipitating to Jovian atmosphere in the format of electron lifetime as a function of energy and M-shell.

How to cite: Hao, Y., Wang, D., Shprits, Y., Menietti, J., and Drozdov, A.: Global Model of Chorus Waves and Electron Lifetime Derived From Juno Observations, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-16574, https://doi.org/10.5194/egusphere-egu23-16574, 2023.

EGU23-16614 | Orals | PS6.3

A Juno model of the Io - Jupiter electromagnetic interaction 

Stavros Kotsiaros, John E. P. Connerney, John L. Jørgensen, Matija Herceg, and Yasmina Martos

Juno’s highly elliptical polar orbit offers unique in-situ measurements of the electrodynamic interaction between Jupiter and its moon Io. These occur both near Io and near the surface of Jupiter and at distances between. Magnetic field data obtained during multiple traversals of magnetic field lines connected to the orbit of Io reveal remarkably rich and complex current densities along flux tubes connected to Io’s position along its orbit. Using Juno’s many traversals of Io's flux tube (IFT), we derive a model of the strength of the interaction with regards to distance along Io’s extended tail and Io’s position in the plasma torus, illuminating the interaction of Jovian magnetospheric plasma with Io and setting important constraints in the Io-Jupiter interaction.The model is based on an inverse methodology to distribute currents along  the IFT in such a way as to match the magnetic field signature observed during Juno’s traversals of the IFT as well as passages near the IFT. We derive, by means of non-linear optimization, the distribution of current within the IFT (during traversals) as well as the size and morphology of the IFT that best fits the magnetic field observations. We compare our results with observations of the IFT obtained near Io as Voyager 1 passed nearby.

How to cite: Kotsiaros, S., Connerney, J. E. P., Jørgensen, J. L., Herceg, M., and Martos, Y.: A Juno model of the Io - Jupiter electromagnetic interaction, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-16614, https://doi.org/10.5194/egusphere-egu23-16614, 2023.

EGU23-17034 | Orals | PS6.3

(Un)stable Jupiter models with CD21 H/He-EOS 

Nadine Nettelmann

The atmospheric metallicity Zatm of Jupiter inferred from interior models responds sensitively to assumed uncertainties in the H/He equation of state at around 10-50 GPa pressure levels and the 1-bar outer boundary temperature [1,2]. If an adiabatic temperature profile and 166 K 1-bar temperature is assumed, a perturbation toward lower densities in the 10-50 GPa region seems required for most H/He-EOSs, in order match the JUNO's gravitational harmonic J4 value with >1x solar atmospheric  metallicity. In contrast, Galileo and JUNO measurements revealed higher atmospheric enrichments in the noble gases and ammonia of 2-3x solar. Yet for water, current uncertainties still permit lower than 1x solar in Jupiter's equatorial atmosphere [3]. 

Here, we adopt the recently proposed H/He-EOS CD21 [4] to compute a series of Jupiter interior models. We show that CD21-EOS based adiabats are less dense at ~20 GPa while denser at ~2 GPa as compared to the CMS19 H/He-EOS. The CD21 EOS allows us to lift the atmospheric metallicity by a ΔZatm ~1x solar when fitting J4, while its denser behavior at 2 GPa moves the models away from the formerly good fit to J6 that was possible with CMS19 EOS [1].

As our adiabatic models yield too low atmospheric metallicities, we insert an outer stable region, as recently suggested to explain Jupiter's magnetic field [5]. We find that a super-adiabatic stable region should occur at ~1 GPa or farther out in order to noticably influence the density in the ~50 GPa region. However, our models suggest that an outer stable region alone is insufficient to enhance the metallicity to 1x solar. Therefore, we vary in addition the 1-bar surface temperature toward warmer interiors as indicated by recent re-analysis of Voyager remote sensing data.

Overall, this work aims at predicting Jupiter's deep water abundance for comparison against formation models [6] and JUNO observations. 

[1] Nettelmann, Movshovitz, Ni et al, PSJ 2:241 (2021) 
[2] Miguel Y, Bazot M, Guillot T et al, AA 662:A18 (2022) 
[3] Li Ch, Ingersoll A, Bolton S et al, NatAst 4:609 (2020) 
[4] Chabrier G, Debras F, ApJ 917:4 
[5] Moore KM, Barik A, Stanley S, et al, JGR Planets 127:e2022JE007479 (2022)
[6] Helled R, Stevenson DJ, Lunine J, et al, Icarus 378:114937 (2022) 

How to cite: Nettelmann, N.: (Un)stable Jupiter models with CD21 H/He-EOS, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-17034, https://doi.org/10.5194/egusphere-egu23-17034, 2023.

EGU23-17132 | ECS | Orals | PS6.3

New insights into Jovian radio emissions 

Corentin Louis, William Kurth, Scott Bolton, Adam Boudouma, Brieuc Collet, Sadie Elliott, George Hospodarsky, Masafumi Imai, Caitriona Jackman, Laurent Lamy, Philippe Louarn, Yasmina Martos, Ali Sulaiman, and Philippe Zarka
Jupiter is the planet with the most intense and extensive radio radiation in our solar system. The radio spectrum is composed of no less than half a dozen components, from low-frequency emissions, such as quasi-periodic bursts (QP) or trapped continuum radiation (from a few kHz to tens of kHz), to high-frequency emissions produced over the poles, ranging from a few MHz to 40 MHz. Since July 2016, Juno has been orbiting Jupiter, performing a polar orbit every 53 days during its prime mission, sampling all latitudes, longitudes and local times. These polar orbits allow Juno to pass directly into the auroral zones, where electrons are accelerated and produce the auroral radio emissions, but also through the plasma disk, where other types of radio emissions are produced. 
In this presentation, I will focus on the main results obtained by Juno during its main mission concerning radio emissions, and show how radio emissions can be used to infer in situ conditions.

How to cite: Louis, C., Kurth, W., Bolton, S., Boudouma, A., Collet, B., Elliott, S., Hospodarsky, G., Imai, M., Jackman, C., Lamy, L., Louarn, P., Martos, Y., Sulaiman, A., and Zarka, P.: New insights into Jovian radio emissions, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-17132, https://doi.org/10.5194/egusphere-egu23-17132, 2023.

EGU23-17133 | Orals | PS6.3

Jupiter’s magnetic field and the generation and control of decameter radiation observed by the Juno spacecraft during the prime mission 

Yasmina M Martos, John Connerney, Masafumi Imai, William Farrell, and William Kurth

Decametric radio emissions (DAM) originating in Jupiter’s polar magnetosphere ought to originate on magnetic field lines at the local electron gyrofrequency. The Io-related DAM have received the most attention since the 1980’s. The maximum frequency of these emissions ought to be bounded by the maximum magnetic field strength above the footprint of the instantaneous Io Flux Tube (IFT). However, there remains a lack of agreement between the frequency extent of Io-related decameter radiation and the frequency extent predicted by Jovian magnetic field models. Here, we analyze peak frequencies and source locations of Io and non-Io-related DAM observed by Juno during the prime mission (~10,600 events) and show how the latest magnetic field model can accommodate and control Io-DAM. We note that the observed peak frequencies appear to be truncated at 37 MHz although the magnetic field in the northern hemisphere would allow events to 55 MHz at some longitudes. Lower frequencies than the ones allowed by the magnetic field are consistently observed for most of the Io’s longitude. To reconcile this discrepancy, we analyze the upper electron density limit distribution along the magnetic field lines, the possible existence of plasma cavities and the locations in the magnetosphere where the extraordinary mode is no longer achieved. For this, we make use of beaming angles of Io-DAM and the geometry of the Jovian magnetic field.

How to cite: Martos, Y. M., Connerney, J., Imai, M., Farrell, W., and Kurth, W.: Jupiter’s magnetic field and the generation and control of decameter radiation observed by the Juno spacecraft during the prime mission, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-17133, https://doi.org/10.5194/egusphere-egu23-17133, 2023.

EGU23-17176 | ECS | Posters on site | PS6.3

Chandra Long-Exposure Observations of Jupiter’s X-ray Auroral Emissions Near Juno Apojove 2021 

Seán McEntee, Caitríona Jackman, Dale Weigt, Corentin Louis, William Dunn, Adam Boudouma, Jack Connerney, William Kurth, Ralph Kraft, Graziella Branduardi-Raymont, and Randy Gladstone

In this study we analyse a 40 hour (~ 4 jovian rotation) Chandra X-ray observation beginning on 15 September 2021 in order to study the morphology and time variability of the auroral X-ray emissions at Jupiter. At the time of this observation, Juno's orbit had taken the spacecraft into the dusk magnetosphere of Jupiter, thought to be the most likely source region for driving of jovian auroral X-rays. One leading theory for the driver of these emissions is Ultra Low Frequency (ULF) waves propagating along jovian magnetic field lines which can be initiated by processes on the dusk flank of the magnetosphere. This was the first time that this region had been observed by an orbiter since Galileo > 20 years ago, and never before has there been contemporaneous in situ and X-ray observations here. The long exposure time of this observation enables monitoring of the auroral regions over multiple jovian rotations, which is key to understand how variable the X-ray emissions can be. This allows for the identification of short timescale changes in the magnetospheric dynamics. Wavelet transforms and Rayleigh testing are used to search for statistically significant quasi-periodic pulsations of the X-ray emissions in the dataset. We combine the remote X-ray analysis with examination of data from the Juno Waves instrument, which has already shown that quasi-periodic emissions in the radio waveband can change on timescales of a few hours. Furthermore, we incorporate data from the Juno MAG instrument to provide magnetospheric context over the duration of the Chandra X-ray observation, and identify a possible compression event in the second half of the 40 hour time window. The Tao et al. (2005) solar wind propagation model also suggests a disturbed/compressed magnetosphere at this time, which is further supported by comparing the measured magnetic field against the baseline Kivelson and Khurana (2002) lobe magnetic field model.

How to cite: McEntee, S., Jackman, C., Weigt, D., Louis, C., Dunn, W., Boudouma, A., Connerney, J., Kurth, W., Kraft, R., Branduardi-Raymont, G., and Gladstone, R.: Chandra Long-Exposure Observations of Jupiter’s X-ray Auroral Emissions Near Juno Apojove 2021, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-17176, https://doi.org/10.5194/egusphere-egu23-17176, 2023.

EGU23-17178 | Orals | PS6.3

How high are Jupiter’s clouds? Analysis of JunoCam images of the “Nautilus” 

Tristan Guillot, Marylyn Rosenqvist, Michael Wong, Glenn Orton, Gerald Eichstädt, Shawn Brueshaber, Caleb Keaveney, Candice Hansen, Kevin Kelley, Thomas Momary, Jonathan Lunine, Julia Mayer, and Scott Bolton

Jupiter is known for its active meteorology and stormy weather, but still remaining are the questions how high are its clouds and what are they made of? Using images acquired by JunoCam, Juno’s visible light camera, we analyze the length of the clouds’ shadows to infer their heights. We focus on the “Nautilus” a 3000-km cyclonic vortex seen during Juno’s 14th perijove and observed simultaneously with the Hubble Space Telescope. We show that individual clouds or cloud fronts with typical lengths of ∼200 km extend about ∼10 to 20 km above the deeper surrounding cloud deck. That white cloud deck forms the spiral of the cyclone, which we show lies ∼20 to 30 km above a reddish-colored region. An analysis of the HST images confirms that the white region is higher than its surrounding darker, reddish cloud deck. These respective elevations are consistent with the white clouds being made of fresh ammonia ice while most of the reddish clouds underneath are made of ammonium hydrosulfide NH4SH, as predicted by equilibrium cloud models.

How to cite: Guillot, T., Rosenqvist, M., Wong, M., Orton, G., Eichstädt, G., Brueshaber, S., Keaveney, C., Hansen, C., Kelley, K., Momary, T., Lunine, J., Mayer, J., and Bolton, S.: How high are Jupiter’s clouds? Analysis of JunoCam images of the “Nautilus”, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-17178, https://doi.org/10.5194/egusphere-egu23-17178, 2023.

EGU23-17402 | Orals | PS6.3

A Deep Model on Jupiter’s Circumpolar Vortices 

Tao Cai, Kwing Chan, and Hans Mayr

Juno spacecraft has observed large-scale circumpolar vortices on Jupiter’s both poles. It remains unclear how these large-scale vortices are generated and maintained. Here we propose a deep model to explain their formation and maintenance. From numerical simulations, we find that the polygonal patterns of circumpolar vortices can be naturally formed in a deep rotating convection and maintained for a long time. Several processes are involved in the formation of the circumpolar vortices. Small cyclonic vortices are generated from random turbulence in rotating convection at first. Then these small vortices merge and grew bigger to form large-scale cyclones. Finally, the polar beta effect pushes the large-scale cyclones to form a polygonal pattern around the pole. Our model suggests that Jupiter’s circumpolar vortices probably are deeply rooted. This work was supported by the Science and Technology Development Fund, Macau SAR through No. 0156/2019/A3.

How to cite: Cai, T., Chan, K., and Mayr, H.: A Deep Model on Jupiter’s Circumpolar Vortices, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-17402, https://doi.org/10.5194/egusphere-egu23-17402, 2023.

PS8 – Life in the cosmos

EGU23-663 | ECS | Orals | PS8.1

Stability of organic species in ocean world interiors with geochemical models 

Seda Işık, Mohit Melwani Daswani, and Emre Işık

The icy moons in the Solar System, such as Europa, Enceladus and Titan, are  of great interest to the astrobiological and biogeochemical communities, owing to their subsurface liquid oceans. These oceans are potential targets for deep explorations of biochemical processes in our cosmic neighbourhood.

In our study, we use the Deep Earth Water (DEW) model to calculate the thermodynamic properties of water and aqueous compounds. We employ DEWPython, a modular software interface, enabling access to both DEW and SUPCRT models, with the purpose of investigating the stability of organic molecules in ocean worlds. In particular, we model the equilibrium constant and Gibbs free energy (GFE) as a function of pressure and temperature for reactions involving metabolically essential amino acids, basic molecules possibly involved in the emergence of life (H2, NH3, CH4, etc.), as well as products of water-rock interaction such as serpentinization and abiotic methanogenesis. Considering the results from space missions such as Europa Clipper and Dragonfly, such molecular stability analyses can contribute to the search for conditions ideal for habitability and extraterrestrial life.

We map out reaction networks, by first calculating the individual equilibrium constants and GFE changes of the hydrothermal reactions that (i) form a given organic species from inorganics, and then (ii) decompose into other (in)organic molecules. In the final step, we obtain the net equilibrium constant as a measure of the stability of the species, by proportioning the total equilibrium constant of the reactions responsible for the formation of a particular species to those responsible for its destruction. At a given pressure and temperature, a value greater or less than unity indicates that the formation of a species is favourable or unfavourable, respectively.

Our current results suggest that alanine and glycine, two common and simple amino acids, can remain stable throughout the ocean columns, and just beneath the seafloors, of Titan and Europa, and thus could potentially be sampled by plumes or cryovolcanism.

In the next development phase of our model, we will further constrain the depths at which the species of interest can be found, by identifying and ruling out regions of high pressure ice stability, using the SeaFreeze model.

The research was carried out at the Jet Propulsion Laboratory, California Institute of Technology, under a contract with the National Aeronautics and Space Administration (80NM0018D0004). © 2022. Jet Propulsion Laboratory, California Institute of Technology. Government sponsorship acknowledged.

Fig 1 : Alanine stability (contours) through Europa’s ocean and ocean floor (colored lines). Positive (negative) regions indicate stable (unstable) conditions.

How to cite: Işık, S., Daswani, M. M., and Işık, E.: Stability of organic species in ocean world interiors with geochemical models, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-663, https://doi.org/10.5194/egusphere-egu23-663, 2023.

EGU23-2787 | ECS | Posters on site | PS8.1

Chemical identification of fossil filament entrapped in Messinian gypsum using space Laser Mass Spectrometry, application for Mars astrobiology. 

Youcef Sellam, Salome Gruchola, Matteo Reghizzi, Stefano Lugli, Andreas Riedo, and Peter Wurz

The search for evidence of extant and extinct life on Mars is of big interest for future robotic and human exploration missions. The properties and characteristics of evaporites such as gypsum make them an easily accessible target in the search for biosignatures of extraterrestrial life. On Earth, a diverse microbial community inhabits gypsum in modern brines. These microbes are easily entombed within gypsum due to its fast precipitation. Studies of primary lower gypsum deposits, accumulated in the Mediterranean Basin during the Messinian salinity crisis (5.97 – 5.33 Ma), revealed a well-preserved and prominent archive of diverse microbial life. Similar archives might exist on Mars considering the desiccation of large bodies of water there, representing a promising target for exploring the possibility of life on Mars. The recent imaging mapping and analysis done by orbiters and rovers on the surface of Mars led to the discovery of abundant gypsum and evaporite minerals suggesting the evaporation of large lakes and lacustrine systems and as the surface of Mars dried out, hypersaline lakes would have filled the ancient lake system. A similar scenario happened on Earth when thick layers of gypsum were deposited during the Messinian salinity crisis when the Mediterranean was turned into the youngest salt giant in Earth’s history.

Previous chemical and molecular laser mass spectrometry analyses done on microfossils preserved in different rock records showed these instruments’ ability to detect biosignatures related to ancient life. In this study, we successfully investigated the chemical composition of fossil filaments interpreted to be benthic microbial assemblages dominated by chemotrophic sulfide-oxidizing bacteria, sulfate-reducing bacteria, and planktonic cyanobacteria. This study demonstrated the efficiency of a miniaturized next-generation Laser based Mass Spectrometer (LMS) designed for future space explorations in the detection of microbial chemical biosignatures trapped in Messinian gypsum, shading light to the potential application to the search for life on Mars.

 

 

 

 

Literature

 

Natalicchio, M., Birgel, D., Dela Pierre, F., Ziegenbalg, S., Hoffmann-Sell, L., Gier, S., & Peckmann, J. (2022). Messinian bottom-grown selenitic gypsum: An archive of microbial life. Geobiology, 20, 3– 21. https://doi.org/10.1111/gbi.12464.

Bayles, M., Belasco, B.C., Breda, A.J., Cahill, C.B., Da Silva, A.Z., Regan, M.J., Jr., Schlamp, N.K., Slagle, M.P. and Baxter, B.K. (2020). The Haloarchaea of Great Salt Lake as Models for Potential Extant Life on Mars. In Extremophiles as Astrobiological Models (eds J. Seckbach and H. Stan-Lotter). https://doi.org/10.1002/9781119593096.ch4.

Lukmanov, RA., Tulej, M., Ligterink, NFW., et al. ( 2021). Chemical identification of microfossils from the 1.88-Ga Gunflint chert: Towards empirical biosignatures using laser ablation ionization mass spectrometer. Journal of Chemometrics, 35 ( 10):e3370. doi:10.1002/cem.3370.

How to cite: Sellam, Y., Gruchola, S., Reghizzi, M., Lugli, S., Riedo, A., and Wurz, P.: Chemical identification of fossil filament entrapped in Messinian gypsum using space Laser Mass Spectrometry, application for Mars astrobiology., EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-2787, https://doi.org/10.5194/egusphere-egu23-2787, 2023.

There is a lot of enthusiasm in the exoplanet community for the detection and characterization of super-Earth and sub-Neptunes. These planets seem most abundant among observable planets, and yet we know little about their interiors. Indirect evidence implies that sub-Neptunes have thick H/He envelopes on top of massive magma oceans, while super-Earths have lost their H/He envelopes. There is a lack of similar planets in the Solar System and therefore their origin and atmospheric evolution represent an important challenge for our understanding of planets.

Moreover, the majority of current formation and evolution models suffer from simplified assumptions of chemically inert interiors and cold rocky interiors in solid-state, as well as the neglect of volatile-exchange at the rock-atmosphere interface. This prevailing view is shifting: (1) the majority of exoplanets are partly molten, i.e., they host global magma oceans; (2) redox reactions between magma and atmospheric volatiles affect bulk composition; and (3) magma oceans represent huge reservoirs for volatiles. The exoplanet community is just beginning to explore new dimensions of these complexities. I will give an overview of general and personal efforts on this front.

How to cite: Dorn, C.: Deep volatile reservoirs in super-Earths and sub-Neptunes, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-3391, https://doi.org/10.5194/egusphere-egu23-3391, 2023.

It is often assumed that quest for intelligent life is equivalent to quest for any life in general. In particular, the Drake Equation predicts that there should be many exoplanets in our galaxy hosting active, communicative civilizations (ACCs) but the Fermi Paradox notes that there is no evidence that any others exist. The paradox may be explained by recognizing that advanced complex life is only likely to develop on a very small fraction of planets hosting any life. Here, we suggest that ACCs can only develop on a convecting silicate body with life, prolonged plate tectonics and significant expanses of oceans and continents, and that meeting all three of these requirements may be extremely difficult to achieve.  Continents and oceans are required because early life evolution must happen in water but late evolution capable of creating technology must happen on slowly but continuously evolving land masses due to the critical influence of landscape and habitat diversity in space and time for accelerating the evolution of complex species. We further suggest that oceanic-continental plate tectonic environments of the modern Earth have formed only very recently at 1.0-0.5 Ga and accelerated the evolution of complex life in five ways: 1) increased nutrient supply; 2) increased free oxygen in the atmosphere and ocean; 3) climate amelioration; 4) accelerated habitat formation; and 5) moderate sustained environmental pressure.  The absence of comparable factors on the other possible types of global tectonic environments (such as squishy lid, stagnant lid, volcanic heat pipe) characteristic for silicate bodies (e.g., early Earth, Mars, Venus, Mercury, Moon, Io) makes the emergence of both complex life and ACCs on such bodies unlikely.  The Fermi Paradox may therefore be resolved if: 1) two additional terms are added to the Drake Equation: foc (the fraction of exoplanets with significant continents and oceans) and fpt (the fraction of habitable planets that have had plate tectonics operating for at least 500 Ma; and 2) the product of foc and fpt is very small.  The lack of evidence for extraterrestrial civilizations in our galaxy may reflect the scarcity of long-lived oceanic-continental plate tectonic environments in particular requiring goldilocks condition in term of the stable surface water volume allowing for long-term coexistence of both dry lands and oceans. 

How to cite: Gerya, T. and Stern, R.: The Key Role of Plate Tectonics for Accelerating the Evolution of Complex Life: Quest for the Missing Extraterrestrial Civilizations, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-4382, https://doi.org/10.5194/egusphere-egu23-4382, 2023.

EGU23-5257 | Posters on site | PS8.1

Total stellar irradiance and lithophile element devolatilization trends for the terrestrial planets 

Stephen Mojzsis, Robert Spaargaren, and Ramon Brasser

Abundance patterns ranging from (ultra-)refractory (e.g. W, Zr, Al, Ca and Rare Earth Elements), to moderately volatile (e.g. Li, K and Na) and highly volatile (e.g. Zn, Cl, Br, I and In) lithophile elements show a broadly ‘hockey stick’ element depletion trend for Earth and Mars [1,2]. This is because refractory element abundances relative to solar composition and normalized to Mg or Al [3] are weakly affected by devolatilization processes but the moderately volatile elements describe a devolatilization depletion factor with a particular slope (α). Volatile elements with 50% condensation temperatures (TC,50%) 750-500 K (Zn) are unfractionated with respect to one another [4]. This pattern is recapitulated in some carbonaceous chondrite meteorite groups (CM, CV and CR). Such secular trends in lithophile element abundances potentially yield useful clues regarding the parameter space of planetary accretion such as localization of feeding zones, supply of volatile species to the planets and the degree to which orbital architecture may have changed due, for example, to migration. Nucleosynthetic isotopic tracers (e.g. 50Ti, 54Cr, 62Ni), as well as mass-independent oxygen isotopes (expressed in the conventional notation as: 'D17OVSMOW) of the sampled terrestrial planets, deviate from the volatile-rich carbonaceous chondrites (CC). The terrestrial planets instead show affinities with the non-carbonaceous feedstocks (NC) that are poorer in volatiles than CC. Here, we show that Earth and Mars, along with best estimates of the bulk compositions of Mercury and Venus inferred from geochemical models coupled with remote and in situ analysis, display both a hockey stick element depletion pattern and systematically different devolatilization depletion factors of the moderately volatile lithophiles (slope, α). We further find that the degree of devolatilization in TC,50% as a function of depletion trend (α) plotted against total stellar irradiance (S0 in in Wm-2) correlates with heliocentric distance (au) and thus, stellar luminosity, following a power law . This relationship accounts for the bulk compositions and volatile inventories of the inner planets, and strongly implies that they formed locally, in agreement with recent studies [7-9]. We also find that some NC achondrite meteorite groups (e.g. angrites, ureilites) record extreme lunar-like depletion trends (α) that we interpret to be from a special origin (i.e. colossal impacts with re-condensation). To lowest order, these observations reveal information about complex processes in planet formation scenarios while considering the already-assembled planet. Finally, imminent data (e.g. JWST spectra) for ionized lithophile elements in the atmospheres of ultra-short period exoplanets will allow us to quantitatively assay formation models that are too simple and/or seem to indicate an unwitnessed process in the history of a planet such as migration.

 

References: [1] Carlson et al. Space Sci. Rev. 214:121 (2018); [2] Vollstaedt et al. ApJ 897:82 (2020); [3] Wang et al. Icarus 328:287-305 (2019); [4] Braukmuller et al. Nat. Geosci. 12:564-568 (2019); [5] Sossi et al. Nat. Astro. 6:951-960 (2022); [6] Yoshizaki & McDonough. Geochem. 81:125746 (2021); [7] Mah et al. MNRAS 511, 158–175 (2022); [8] Mah et al., A&A 660, A36; [9] Brasser & Mojzsis. Nat. Astro. https://doi.org/10.1038/s41550-019-0978-6.

How to cite: Mojzsis, S., Spaargaren, R., and Brasser, R.: Total stellar irradiance and lithophile element devolatilization trends for the terrestrial planets, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-5257, https://doi.org/10.5194/egusphere-egu23-5257, 2023.

EGU23-5425 | Orals | PS8.1 | Highlight

Detection of phosphate in Enceladus’ ocean with implications for geochemistry and habitability in the outer solar system 

Frank Postberg, Yasuhito Sekine, Fabian Klenner, Christopher R. Glein, Zenghui Zou, Bernd Abel, Kento Furuya, Jonathan K. Hillier, Nozair Khawaja, Sascha Kempf, Lenz Noelle, Takuya Saito, Jürgen Schmidt, Takazo Shibuya, Ralf Srama, and Shuya Tan

Enceladus’s subsurface global ocean (1) can be probed by sampling the gaseous and icy material the moon expels into its cryovolcanic plume and - even further out - into Saturn’s E ring (2,3,4,5). Hydrothermal outflows caused by tidal heating (4,5,6), together with rich organic chemistry (7,8) imply that the moon appears to be one of most habitable places in our solar system. Among the critical elements C, H, N, O, P and S that are considered to be essential for life, all except phosphorous have either been identified (5,7,8) or - in the case of sulfur - tentatively detected (9). Recent geochemical modelling claims that P will be severely depleted in ocean worlds and thus P could be a bottle neck for the emergence of life in subsurface oceans (10).

Here we present results from a re-analysis of mass spectrometric data from Cassini’s Cosmic Dust Analyzer (CDA), showing proof of sodium-phosphate salts in ice grains originating from Enceladus’s subsurface ocean. We found a small number of ice grains whose spectra clearly indicate the presence of at least two sodium orthophosphates: Na3PO4 and Na2HPO4. These CDA spectra have been subsequently reproduced in the laboratory which enables the quantitative evaluation of CDA spectra (11). We infer phosphate concentrations in the Enceladus ocean in the order of a few mM, at least 100-times higher concentrations than in Earth’s ocean.

We carried out geochemical experiments and calculations showing that such high phosphate abundances can be achieved in Enceladus, either at the cold seafloor or in hydrothermal environments with moderate temperatures. The driver enabling the abundant availability of phosphate is the high observed concentration of dissolved carbonate species, which shift phosphate-carbonate mineral equilibria toward dissolution of solid phosphates into Enceladus’ ocean. We show that interactions between chondritic rocks and CO2-rich fluids generally lead to conditions where dissolved phosphate concentrations tend to maximize. Therefore P-rich oceans would commonly occur in ocean worlds beyond in the outer Solar System beyond the CO2 snow line.

These results demonstrate that Enceladus has a high availability of dissolved P, which is thus likely not a limiting factor for development of putative life on Enceladus and probably on other ocean worlds in the outer Solar System. Since phosphate plays many roles in organic synthesis (12), Enceladus and other icy bodies could moreover serve as natural analogs of P-rich environments on early Earth, where chemical evolution might have been promoted.

1 Thomas et al., Icarus 264 (2016), 2 Postberg et al., Nature 459 (2009), 3 Postberg et al., Nature 474 (2011), 4 Hsu et al., Nature 519 (2015), 5 Waite et al., Science 356 (2017), 6 Choblet et al. , Nat Astron 1 (2017), 7 Postberg et al., Nature 558 (2018) , 8 Khawaja et al., MNRAS 489 (2019), 9 Postberg et al., ISBN: 9780816537075 (2018), 10 Lingam & Loeb, Astron. J., 2018., 11 Klenner et al., Rapid Commun Mass Spectrom 33 (2019), 12 Powner et al., Nature 459 (2009)

How to cite: Postberg, F., Sekine, Y., Klenner, F., Glein, C. R., Zou, Z., Abel, B., Furuya, K., Hillier, J. K., Khawaja, N., Kempf, S., Noelle, L., Saito, T., Schmidt, J., Shibuya, T., Srama, R., and Tan, S.: Detection of phosphate in Enceladus’ ocean with implications for geochemistry and habitability in the outer solar system, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-5425, https://doi.org/10.5194/egusphere-egu23-5425, 2023.

EGU23-5578 | Posters on site | PS8.1

Interior heating of rocky exoplanets from stellar flares with application to Trappist-1 and Proxima Centauri 

Alexander Grayver, Dan Bower, Joachim Saur, Caroline Dorn, and Brett Morris

Many stars of different spectral types with planets in the habitable zone are known to emit flares. Until now, studies that investigated the long-term impact of stellar flares and associated Coronal Mass Ejections (CMEs) assumed that the planet's interior remains unaffected by interplanetary CMEs, only considering the effect of energetic particles interactions on the atmosphere of planets. Here, we show that the magnetic flux carried by flare-associated CMEs results in planetary interior heating by ohmic dissipation and leads to a family of new interior–exterior interactions. We construct a physical model to study this effect and apply it to the TRAPPIST-1 and Proxima Centauri stars whose flaring activity has been constrained by Kepler and TESS observations. We pose our model in a stochastic manner to account for uncertainty and variability in major input parameters. Our results suggest that the heat dissipated in the silicate mantle is both of sufficient magnitude and longevity to drive geological processes and hence facilitate volcanism and outgassing particularly for the innermost planets. Furthermore, our model predicts that Joule heating can further be enhanced for planets with an intrinsic magnetic field compared to those without. The associated volcanism and outgassing may continuously replenish the atmosphere and thereby mitigate the erosion of the atmosphere caused by the direct impact of flares and CMEs.

How to cite: Grayver, A., Bower, D., Saur, J., Dorn, C., and Morris, B.: Interior heating of rocky exoplanets from stellar flares with application to Trappist-1 and Proxima Centauri, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-5578, https://doi.org/10.5194/egusphere-egu23-5578, 2023.

EGU23-6149 | ECS | Orals | PS8.1 | Highlight

Looking for biosignatures in a pristine Mars analogue environment on Earth 

Vera Palma, Nicasio Jiménez-Morillo, Francesco Sauro, Matteo Massironi, José M. De la Rosa, José A. González-Pérez, Bogdan Onac, Igor Tiago, Ana Teresa Caldeira, and Ana Z. Miller

The Selvagens Islands (Madeira, Portugal), located in the North Atlantic, are a small archipelago of volcanic origin formed by two main islands, which emerged in the Oligocene (25-29 Ma). These oceanic islands are recognized as a unique example of marine and terrestrial biodiversity, characterized by many endemic species. Still unblemished by civilization, this isolated and undisturbed ecosystem makes the volcanic caves from Selvagens a promising model system for investigating biosignatures preserved in the rock record valuable for astrobiology. 

The Inferno Cave, one of the three main terrestrial caves of the Selvagens Islands, has copious amounts of fine white powder crusts scattered throughout the cave. From the mineralogical point of view, the whitish powdery deposits are mainly composed of gypsum and minor amounts of clay minerals. Thermal analyses (TG/DTG-DsC) revealed the presence of labile and stable organic matter (OM), with contrasting relative abundances among the gypsum samples. The stable isotope composition of carbon was determined by elemental analysis coupled to isotope ratio mass spectrometry (EA/IRMS) to decipher the origin of the organic fraction preserved in the gypsum deposits. Two well-differentiated organic matter pools were distinguished: one comprising 𝛿13C values > –19 ‰ related to microbial activity (i.e., microbial degradation of fresh organic matter), and another with 𝛿13C < –20 ‰), which may suggest the preservation of recalcitrant biomarkers from aboveground vegetation. U-series results from the gypsum deposits were used to produce isochron ages needed to generate an age-depth model for the 1-m thick gypsum deposit.

A detailed study of the organic fraction preserved in the gypsum deposits was conducted by pyrolysis gas chromatography/ mass spectrometry (Py-GC/MS) and by GC-MS after extraction of total lipids. Preliminary results show the presence of n-alkanes of low molecular weight (<C21). In addition, long-chain n-alkanes (C>21) were also observed, which indicates a direct contribution of plant biomass from the overlying surface. Interestingly, the Py-GC/MS analysis also shows relatively large contents of mid-chain branched alkanes associated with a direct biological source focused on microorganisms since they are known to biosynthesize such alkanes. A predominance of chemolithotrophic microbial communities was found based on the 16S rRNA gene analysis, which is consistent with the biological origin of the mid-chain branched alkanes. 

The mineralogical, biogeochemical, and microbiological characterization of the gypsum samples from the pristine Selvagens Islands is thus a reliable way to infer the biogenicity of cave mineral deposits, recognize biosignatures, and determine paleoenvironmental changes from a natural environment, free from anthropogenic influence. Considering the analogies with Mars, the Selvagens Islands are also suitable for space research, including astronaut training and rover testing for future planetary missions.

Acknowledgements: This work received support from the Portuguese Foundation for Science and Technology (FCT) under the MICROCENO project (PTDC/CTA-AMB/0608/2020). The financial support from the Spanish Ministry of Science and Innovation (MCIN) under the research project TUBOLAN PID2019-108672RJ-I00 funded by MCIN/AEI/ 10.13039/501100011033 is also acknowledged. A.Z.M. was supported by the CEECIND/01147/2017 contract from FCT, and the Ramón y Cajal contract (RYC2019-026885-I) from the MCIN.

 

How to cite: Palma, V., Jiménez-Morillo, N., Sauro, F., Massironi, M., De la Rosa, J. M., González-Pérez, J. A., Onac, B., Tiago, I., Caldeira, A. T., and Miller, A. Z.: Looking for biosignatures in a pristine Mars analogue environment on Earth, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-6149, https://doi.org/10.5194/egusphere-egu23-6149, 2023.

EGU23-7267 | Orals | PS8.1 | Highlight

Europa Clipper Mission Update 

Haje Korth, Robert Pappalardo, Bonnie Buratti, Kate Craft, Sam Howell, Rachel Klima, Erin Leonard, and Alexandra Matiella Novak

With a launch readiness date of late 2024, NASA’s Europa Clipper will set out on a journey to explore the habitability of Jupiter’s moon Europa. At the beginning of the next decade, the spacecraft will orbit Jupiter, flying by Europa more than 40 times over a four-year period to observe this moon’s ice shell and ocean, study its composition, investigate its geology, and search for and characterize any current activity. The mission’s science objectives will be accomplished using a highly capable suite of remote-sensing and in-situ instruments. The remote sensing payload consists of the Europa Ultraviolet Spectrograph (Europa-UVS), the Europa Imaging System (EIS), the Mapping Imaging Spectrometer for Europa (MISE), the Europa Thermal Imaging System (E-THEMIS), and the Radar for Europa Assessment and Sounding: Ocean to Near-surface (REASON). The in-situ instruments comprise the Europa Clipper Magnetometer (ECM), the Plasma Instrument for Magnetic Sounding (PIMS), the SUrface Dust Analyzer (SUDA), and the MAss Spectrometer for Planetary Exploration (MASPEX). Gravity and radio science will be achieved using the spacecraft's telecommunication system, and valuable scientific data will be acquired by the spacecraft’s radiation monitoring system. The project, flight system, and payload have completed their Critical Design Reviews, and the project has completed its System Integration Review, so that Europa Clipper is now formally in mission Phase D. The spacecraft and payload are currently under construction, as assembly, testing, and launch operations (ATLO) are well underway. Recent major milestones include the delivery to ATLO of the Propulsion Module and six instruments (E-THEMIS, Europa-UVS, EIS-WAC, PIMS, MASPEX, SUDA) and the assembly of the solar array wings. The integration of these instruments’ sensors on the spacecraft and its nadir-viewing deck and of the instrument electronics in vault has begun. The remaining instruments (ECM, EIS-NAC, MISE, REASON) are in mature stages of assembly and will be delivered in the next months. The science team is in the process of evaluating minor changes to the candidate tour, and is preparing a set of manuscripts describing the mission’s science and instruments for publication in the journal Space Science Reviews.

How to cite: Korth, H., Pappalardo, R., Buratti, B., Craft, K., Howell, S., Klima, R., Leonard, E., and Matiella Novak, A.: Europa Clipper Mission Update, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-7267, https://doi.org/10.5194/egusphere-egu23-7267, 2023.

EGU23-8065 | Posters on site | PS8.1

Temperate exoplanets observable with Ariel : an update with new targets from TESS 

Therese Encrenaz, Athena Coustenis, Billy Edwards, Karan Molaverdikhani, Marc Ollivier, and Giovanna Tinetti

In 2018 and 2022, we have published an analysis about the observability of temperate planets (with an equilibrium temperature of about 350-500 K) with Ariel. This presentation is an update of this analysis which aims at using new targets identified in particular from the TESS database and analysing their observability with Ariel. Using the parameters of these new targets, we give an estimate of the number of transits needed for these objects to be observed in the Tier 2 mode of the space mission, and we define the information which could be derived about their atmospheric composition. We have identified about 15 targets which could be observable with ARIEL in the Tier 2 mode, which allows an identification of the main atmospheric absorbers. This list includes a gas giant, a few big Neptunes and several super-Earths/small Neptunes. This study is a follow-up of Encrenaz et al., Exp. Astr. 46, 31 (2018) and Exp. Astr. 53, 375 (2022).

How to cite: Encrenaz, T., Coustenis, A., Edwards, B., Molaverdikhani, K., Ollivier, M., and Tinetti, G.: Temperate exoplanets observable with Ariel : an update with new targets from TESS, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-8065, https://doi.org/10.5194/egusphere-egu23-8065, 2023.

EGU23-10768 | ECS | Orals | PS8.1

Four-phase modelling of metal-silicate differentiation in planetesimals 

Fakhri Bintang, Tobias Keller, and Luke Daly

Collisions of planetesimals with pre-differentiated cores aided in the formation of the cores in the terrestrial planets in our Solar System. The differentiation of the interior of planetesimals from a primitive chondritic composition to differentiated metallic core and silicate mantle is therefore an important step in the development of the early Solar System, setting the initial conditions for collisional planetary growth. However, meteoritic evidence of the differentiation stage of planetesimals are rare and challenging to interpret. Therefore, mathematical models are necessary to constrain the timescales and elucidate the physics behind metal-silicate segregation in planetesimals. We present progress towards a new numerical model which models the thermo-chemical and fluid-mechanical evolution of silicate-metal planetesimals. The model is comprised of four material phases: solid and liquid silicates, and solid and liquid Fe-FeS metal. Hence, the model quantifies the different segregation rates of metal alloys at various stages of planetary melting. The thermo-chemical evolution quantifies the melting and chemical fractionation of the materials using two separate phase diagrams for the silicate and iron systems respectively and calibrated based on enstatite chondrite meteorites as the starting primitive material. The fluid mechanics represents conditions where the silicate liquid phase dominates and captures the settling of solid particles and immiscible liquid metal droplets by hindered Stokes settling. Our model will simulate core formation under a range of initial planetesimal compositions, nebular compositions, and planetesimal sizes. We also intend to implement compatible element partitioning into our model, in particular Hf-W isotope partitioning, to compare our model results with the meteoritic record. Results from our model will allow more robust estimations of the timescales for planetesimal core formation.

 
 

How to cite: Bintang, F., Keller, T., and Daly, L.: Four-phase modelling of metal-silicate differentiation in planetesimals, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-10768, https://doi.org/10.5194/egusphere-egu23-10768, 2023.

EGU23-11015 | Posters on site | PS8.1

Extreme compositional diversity among rocky exoplanets 

Paolo Sossi, Lukas Carmichael, and Kaustubh Hakim

To date, more than 5000 exoplanets have been discovered, of which roughly 1800 are thought to be rocky on the basis of mass and radius measurements. However, the resulting densities are degenerate with respect to the compositions of these planets, necessitating other constraints. Of these, the most readily available is the composition of the host star (e.g. Adibekyan et al. 2021). On this basis, the compositions of rocky exoplanetary mantles are expected to be similar to those found in our own Solar System (e.g. Putirka and Rarick, 2019; Spargaaren et al. 2022). Here, we evaluate this conclusion by examining stellar compositions in the system Fe-O-Mg-Si-Ca-Al for F- and G-type stars in the Hypatia and GALAH databases. In reducing the multidimensionality of the dataset, we apply a Principal Component Analysis (PCA) to identify the prevailing chemical trends among the stellar population. We find that the first principal component describes the positive correlation among major element abundances, though O abundance increases less markedly with Fe than those of metals. Therefore, increasing metallicity (as defined by Fe/H) results in an increase in the metal/oxygen ratio of the star. Consequently, the core mass fraction of rocky planets around such stars cannot be treated as a free parameter. Instead, we predict compositions of hypothetical Earth-like planets (i.e., assuming planet/star chemical fractionation equivalent to Earth/Sun) and show that planets around low metallicity stars can be coreless, while those orbiting high metallicity stars should have Fe-free mantles and abundant Si in their cores.

How to cite: Sossi, P., Carmichael, L., and Hakim, K.: Extreme compositional diversity among rocky exoplanets, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-11015, https://doi.org/10.5194/egusphere-egu23-11015, 2023.

EGU23-11114 | ECS | Posters on site | PS8.1

Abiotic factors affecting the presence of airborne halophilic microorganisms in the extreme atmospheric conditions of an underground salt mine 

Aleksandra Puławska, Magdalena Kowalewicz-Kulbat, Jolanta Kalinowska, Gabriela Arciszewska, Dominika Drzewiecka, and Maciej Manecki

Underground salt mines represent the most extreme environments which combine low nutrient availability, darkness, and hypersaline conditions. Halophilic (“salt-loving”) microorganisms are known to constitute the natural microbial communities of hypersaline ecosystems around the world (salt rocks, underground brines, saline lakes, etc.). For the first time halophilic microorganisms were detected in the air of the Bochnia Salt Mine, Poland. 

The purpose of this study was to determine the impact of various abiotic factors of the atmosphere on the presence and abundance of halophilic microbial communities present in mine air. Samples of aerosol components were collected at four different locations: one on the surface (at the air intake) and three underground at increasing distances from the intake. The inorganic aerosol was collected by dry (filter-based) and wet (scrubber-based) sampling method using portable air pumps. Besides microclimatic conditions, the content of water-soluble constituents, trace elements, carbon, and minerals were determined in aerosols. Simultaneously, the airborne cultivable microorganisms were collected by MAS-100 sampler. Mesophilic microorganisms were cultivated as a control, on general tryptic-soya (TSA) media, at 37°C and 28°C for up to one month. Halophilic ones were grown on a specific HBM medium containing 20% and 25% of NaCl concentration, at 37°C and 28°C for up to three months.

The primary component of aerosol was NaCl (1000-3000 µg·m-3). It enters the air mainly in the form of a solution droplets due to the deliquescence of rock salt in humid air (up to 80% of relative humidity). The wet aerosol in salt mine is also composed of SO42- (110-300 µg·m-3), Ca2+ (90-280 µg·m-3), K+ (50-190 µg·m-3), Mg2+ (15-40 µg·m-3), and Fe3+ (10-50 µg·m-3). The dry fraction of aerosol does not exceed 200 µg m-3 and is composed of fragments of natural rock salt (halite), anhydrite, gypsum, and clay minerals. The maximum indoor concentrations of airborne halophilic microorganisms cultivated at 37°C or 28°C reached 1910 CFU (colony-forming units) ·m-3 and 1210 CFU·m-3, respectively. Moreover, the content of halophilic microorganisms increased with the increase of the water-soluble constituents and NaCl concentrations. Our results suggest that airborne salt-saturated droplets may be a major factor influencing the abundance of live halophilic microorganisms in the atmosphere while the presence of mesophilic microorganism (which are associated with the outdoor environment) and the presence of humans seem to have no effect on the presence of halophilic microbial community.

Our research indicates that halophilic microorganisms can survive in the air of the underground Bochnia Salt Mine. Abiotic factors, like high moisture content in the air and saline aerosol in liquid form may play an important role in their survival in the air. This way some extremophile microorganisms, given favorable environmental conditions, can survive even in such a hostile environment as the atmosphere in the underground mine. This could be important for astrobiology research, since various extremophiles, including halophiles, are considered excellent candidates for life beyond our planet.

The study was supported by the Polish National Science Center (NCN) grant No. 2021/41/N/ST10/02751.

 

How to cite: Puławska, A., Kowalewicz-Kulbat, M., Kalinowska, J., Arciszewska, G., Drzewiecka, D., and Manecki, M.: Abiotic factors affecting the presence of airborne halophilic microorganisms in the extreme atmospheric conditions of an underground salt mine, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-11114, https://doi.org/10.5194/egusphere-egu23-11114, 2023.

EGU23-11232 | ECS | Posters on site | PS8.1

The Effect of Nonlinear Viscoelasticity on Planetary Love Numbers 

Ron Maor and David Goldsby

The planetary Love number is a dimensionless parameter representing the deformation response of a planet
to stress (Love, 1927). In its original formalism, the Love number was defined for pure elastic deformations,
but this definition was later extended to linear viscoelastic deformations using the Correspondence Principle
(Peltier, 1974). Currently, there are multiple methods for calculating planetary Love numbers that can
incorporate advanced rheological models (Henning and Hurford, 2014; Renaud and Henning, 2018; Melini
et al., 2022), yet all of these methods require that the rheology will be limited to linear viscoelasticity.
On the other hand, laboratory studies of attenuation on different geological materials suggest a nonlinear
viscoelastic behavior due to the movement of dislocations within the lattice (Gueguen et al., 1989; McCarthy
and Cooper, 2016). At high enough stresses, dislocations can escape pinning points and interact with
each other (Gremaud, 2009), leading to permanent deformations and attenuation that is dependent on
the amplitude of the oscillations. In this work, we are taking the first step into incorporating nonlinear
viscoelasticity in the calculation of planetary Love numbers. Assuming a homogeneous, incompressible,
self-gravitating sphere with nonlinear rheology, we are using a numerical scheme to calculate the complex
Love number. The results of the numerical model are then compared to the known analytical solutions for
the linear case.

How to cite: Maor, R. and Goldsby, D.: The Effect of Nonlinear Viscoelasticity on Planetary Love Numbers, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-11232, https://doi.org/10.5194/egusphere-egu23-11232, 2023.

EGU23-11789 | ECS | Orals | PS8.1 | Highlight

Investigation of the Influence of Stellar Particle Events and Galactic Cosmic Rays on the Atmosphere of TRAPPIST-1e 

Andreas Bartenschlager, John Lee Grenfell, Konstantin Herbst, Miriam Sinnhuber, Ben Taysum, and Fabian Wunderlich

The launch of the James Webb Space Telescope (JWST) in December 2021 opens up the possibility of studying the composition of exoplanetary atmospheres in habitable zones, such as TRAPPIST-1e, in the near future. With the help of numerical models of the exoplanetary atmospheres, the observations and the processes behind them can be better understood and interpreted (Herbst et al., 2022). We investigate the influence of stellar energetic particles (SEPs) and galactic cosmic rays (GCRs) on the atmospheric chemistry of exoplanets around a very active M-star using the ion chemistry model ExoTIC. In collaboration with the University of Kiel and DLR Berlin, we perform model experiments with different N2 or CO2 dominated atmospheres, depending on the initial CO2 partial pressure, as well as humid and dry conditions (Wunderlich et al., 2020), taking into account the ionization rates for such events. A further specification regarding the scenarios results from the distinction between dead and alive atmospheres, whose atmospheric composition is characterized by a lower or higher oxygen fraction in the initial conditions. Within ExoTIC we can calculate the impact of the ionization events on these atmospheres both as a single and as a series of events with different strengths. Preliminary results show a significant impact of SEP events on the chemical composition of the atmosphere, including biosignatures such as O3 . The strength and structure of these impacts depend on the composition of the starting atmosphere, in particular on the availability of oxygen as well as nitrogen and water vapour.

How to cite: Bartenschlager, A., Grenfell, J. L., Herbst, K., Sinnhuber, M., Taysum, B., and Wunderlich, F.: Investigation of the Influence of Stellar Particle Events and Galactic Cosmic Rays on the Atmosphere of TRAPPIST-1e, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-11789, https://doi.org/10.5194/egusphere-egu23-11789, 2023.

One of the major goals - and possibly the most challenging one in 21st century exoplanet research - is the investigation of the atmospheric properties for a large number of terrestrial exoplanets. On the one hand, a statistically significant dataset is invaluable for understanding the diversity of planetary bodies, but on the other hand, this is driven the motivation to search for habitable conditions and identify potential biosignatures, i.e., indications of biological activtity, outside our Solar System. First steps in this direction will be taken in the coming 10-15 years with funded or selected ground- and space-based projects and missions. In addition, the US astrophysics decadal recommended a UV-optical-NIR space telescope (the Habitable Worlds Observatory) with an aperture diameter of at least 6 meters as next flagship mission for the 2040s. This telescope shall be sensitive enough to survey dozens of Earth-sized exoplanets. A highly synergistic approach to this mission, which focuses on the reflected light of the exoplanets, is to directly detect the exoplanets’ thermal emission in the mid-infrared by means of a space-based nulling interferometer. In this contribution, we summarize the current status of the European-led LIFE initiative, which has the goal to develop the science, the technology and a roadmap for such an ambitious space mission that will allow humankind to detect and characterize the atmospheres of hundreds of nearby extrasolar planets including dozens that are similar to Earth. Given the outcome of ESA’s "Voyage 2050" process and the corresponding recommendations from the ESA Senior Committee, the direct detection of the thermal emission of temperate terrestrial exoplanets is given very high scientific priority in ESA future science program and is considered as a candidate theme for a future L-class mission. The unique discovery space for a mid-infrared mission, in particular for the detection of atmospheric biosignatures in exoplanets, will be discussed, the international scope of the inititiative (including contributions from the US, Japan and Australia) will be highlighted, and synergies between LIFE and the NASA's future Habitable Worlds Observatory mission will be emphasized.

How to cite: Quanz, S. P. and collaboration, T. L.: The LIFE initiative - establishing a space mission to search for biosignatures in exoplanet atmsopheres in the mid-infrared, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-13456, https://doi.org/10.5194/egusphere-egu23-13456, 2023.

EGU23-13634 | ECS | Posters on site | PS8.1

Large Interferometer for Exoplanets (LIFE): characterizing the mid-infrared thermal emission of terrestrial exoplanet atmospheres 

Tim Lichtenberg and Sascha P. Quanz and the LIFE collaboration

LIFE (www.life-space-mission.com) is an initiative to develop the science, technology and a roadmap for an ambitious space mission that will allow humankind to detect dozens of warm, terrestrial exoplanets and hundreds of exoplanets overall at mid-infrared (MIR) wavelengths (Quanz et al., 2018, 2022). For most of the detected exoplanets direct estimates of their effective temperature and radius will be available, and a for a significant subset the atmospheric composition will be investigated including the search for potential biosignatures (Des Marais et al., 2002; Léger et al., 2019). Characterizing exoplanet atmospheres using their thermal emission at MIR wavelengths — compared to studies at optical/near-infrared wavelength looking at planets in reflected light — offers the possibility to study a broader set of molecular features (Schwieterman et al., 2018) and get a better understanding of the atmospheric structure (Line et al., 2019). Hence, in particular for questions related to the habitability of exoplanets, a mission like LIFE offers unprecedented scientific potential.

The current baseline design of LIFE features a 4-aperture interferometer array with a 6:1 baseline ratio to reduce the impact of instability noise (Lay, 2006). A beam combiner spacecraft is located at the center of the array. The size of the individual apertures is currently under study, but based on detection yield simulations including all relevant astrophysical noise sources, diameters of 2–3.5 m are under consideration. The aperture size is primarily driven by the number of detectable planets and the time-on-target required for in-depth atmospheric characterization. The current wavelength range requirement is 4–18.5 μm, but additional studies are underway for further verification. A spectral resolution of at least R=30, but better R=50, seems required in order to reliably quantify the abundance ratios of main molecular species in the atmosphere of an Earth-twin planet at several pc distance. The minimum mission lifetime is 5-6 years in order to have sufficient time for both a dedicated search phase, to identify the most interesting and promising targets, and a characterization phase for in-depth investigations of a subset of those. LIFE shall be launched to the Earth-Sun L2 point.

While the general feasibility of the required null-depth and stability was demonstrated in the context of Darwin and TPF-I (Martin et al., 2012), a corresponding experiment under cryogenic conditions is underway in the form of the Nulling Interferometric Cryogenic Experiment (NICE) at ETH Zurich (Gheorghe et al., in prep.). A more general overview of the readiness of key technologies for a space mission like LIFE was presented in Defrère et al. (2018).

 

Defrère, D., et al. 2018, Exp. Astron., 46, 475

Des Marais, D. J.,  et al. 2002, Astrobiology, 2, 153

Lay, O. P. 2006, in SPIE Astronomical Telescopes + Instrumentation (SPIE), 62681A-14

Léger, A., et al. 2019, Astrobiology, 19, 797

Line, M., et al. 2019, BAAS, 51, 271

Martin, S., et al. 2012, Appl. Opt., 51, 3907

Quanz, S. P., et al. 2018, SPIE Conf. Ser., 10701, 107011I

Quanz, S. P., et al. 2022, A&A, 664, A21

Schwieterman, E. W., et al. 2018, Astrobiology, 18, 663

 

How to cite: Lichtenberg, T. and Quanz, S. P. and the LIFE collaboration: Large Interferometer for Exoplanets (LIFE): characterizing the mid-infrared thermal emission of terrestrial exoplanet atmospheres, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-13634, https://doi.org/10.5194/egusphere-egu23-13634, 2023.

EGU23-14069 | ECS | Posters on site | PS8.1

Exploring hemispheric tectonics on tidally locked super-Earths 

Tobias G. Meier, Dan J. Bower, Tim Lichtenberg, Paul J. Tackley, Mark Hammond, and Brice-Olivier Demory

Many super-Earths are very close-in to their host star and are therefore likely to be tidally locked. Tidally locked super-Earths experience intense solar heating on their permanent dayside, whereas the nightside surface can reach extremely cold temperatures. For the case of super-Earth LHS 3844b, a bare-rock super-Earth with a radius around 1.3 Earth radii, we have shown that this strong contrast between the dayside and nightside surface temperature can lead to a so-called hemispheric tectonic regime. Such a regime is characterised by a strong downwelling on one hemisphere and upwellings that rise on the other side. We further define hemispheric tectonics as a special case of degree-1 convection (one upwelling and one downwelling), where the downwelling gets pinned to either the dayside or nightside and upwellings are preferentially on the other hemisphere.  

Here, we focus on super-Earth GJ 486b, which has also a radius around 1.3 Earth radii, but for which it is unknown whether it was able to retain an atmosphere. We investigate how different surface temperature contrasts affects the likelihood of hemispheric tectonics.  
For this, we run 2D geodynamic simulations of the interior mantle flow using the mantle convection code StagYY. The models are fully compressible with an Arrhenius-type viscosity law where the mantle is mostly composed of perovskite and post-perovskite. The lithospheric strength is modelled through a plastic yielding criterion and the models are basally heated. We use general circulation models (GCMs) of potential atmospheres to constrain the surface temperature assuming different efficiencies of atmospheric heat circulation. We find that degree-1 convection is a consequence of the strong lithosphere, while hemispheric tectonics is favoured for strong surface temperature contrasts between the dayside and nightside, and higher surface temperatures. 

Our results show that hemispheric tectonics or degree-1 convection could operate on super-Earth GJ 486b (or other tidally locked super-Earths), even if the surface temperature contrast between the dayside and nightside is not as strong as for LHS 3844b. Upwellings that rise preferentially on one hemisphere could lead to generation of melt and subsequent outgassing of volatiles on that side. Imprints of such outgassing on the atmospheric composition could possibly be probed by current and future observations such as JWST, ARIEL, or the ELT. 

How to cite: Meier, T. G., Bower, D. J., Lichtenberg, T., Tackley, P. J., Hammond, M., and Demory, B.-O.: Exploring hemispheric tectonics on tidally locked super-Earths, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-14069, https://doi.org/10.5194/egusphere-egu23-14069, 2023.

EGU23-15078 | ECS | Posters on site | PS8.1

Space environment and Poynting fluxes around the Trappist-1 exoplanets and effects of coronal mass ejections on their habitability 

Filip Elekes, Joachim Saur, and Alexander Grayver

Trappist-1 is an extraordinary planetary system with 7 confirmed terrestrial exoplanets, some of which may lie in the habitable zone around the central M dwarf star. M dwarfs are magnetically very active and probably emit a stellar wind that interacts with the planets. Stellar winds and their interaction with planetary atmospheres and magnetospheres, if the planets are magnetized, affect the energy budget of their surroundings and ultimately the habitability of those planets. During coronal mass ejections (CMEs) intersecting the planets the exposure to increased stellar wind pressure, density and velocity might result in significant heating of the planets surroundings and interior (Grayver et al. 2022)[1]. We aim to better understand the space environment around the Trappist-1 planets and their interaction with the surrounding stellar wind. We perform magnetohydrodynamic simulations to study the interaction of the planets with the stellar wind. We also study the effect of CMEs on the energy budget of planetary atmospheres and magnetospheres, their heating, and possible effects on exoplanet habitability.

References

  • A. Grayver et al., The Astrophysical Journal Letters 941, L7 (2022)

How to cite: Elekes, F., Saur, J., and Grayver, A.: Space environment and Poynting fluxes around the Trappist-1 exoplanets and effects of coronal mass ejections on their habitability, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-15078, https://doi.org/10.5194/egusphere-egu23-15078, 2023.

EGU23-15251 | Posters on site | PS8.1

Atmospheric lifetime from a hypothetical Mars-sized planet orbiting Barnard’s Star 

Dave Brain and the MACH Team

Atmospheric escape from exoplanets is a topic of great interest for the exoplanet community since atmospheric retention is an important component of surface habitability. While atmospheric escape has been detected from large exoplanets, it remains difficult to measure for smaller (rocky) planets. Indeed, for rocky planets orbiting active stars it is thought that it may be difficult for atmospheres to be retained at all. In the absence of detailed observations, one option is to leverage observations and models for planets in our own solar system.

Here we consider atmospheric escape from Mars – if it orbited an M Dwarf star similar to Barnard’s star. Our analysis considers five escape processes: hydrodynamic escape, thermal escape, photochemical escape, ion escape, and sputtering. To estimate the escape rate via each process from our hypothetical “ExoMars”, we employ models for escape that have either been validated using observations or verified against other models. We provide escape rate estimates for important species in the Martian upper atmosphere: O, O2, H, and CO2, and use them to estimate the lifetime of the Martian atmosphere.

How to cite: Brain, D. and the MACH Team: Atmospheric lifetime from a hypothetical Mars-sized planet orbiting Barnard’s Star, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-15251, https://doi.org/10.5194/egusphere-egu23-15251, 2023.

EGU23-15340 | Posters on site | PS8.1

The host star as a crucial factor for the prevalence of Earth-like Habitats 

Manuel Scherf, Helmut Lammer, and Laurenz Sproß

The existence of an Earth-like Habitat (defined as a rocky exoplanet within the Habitable Zone of Complex Life that hosts an N2-O2-dominated atmosphere with minor amounts of CO2) is depending on a certain set of known (and, potentially, unknown) astrophysical and geophysical requirements that have to be met to allow for its evolution and environmental stability. A few of these requirements are already quantifiable to a certain extent by our current scientific knowledge while others are still under debate. One crucial factor that has to be taken into account when estimating the prevalence of Earth-like Habitats within the galaxy is a planet’s host star. Its radiation and plasma environment may affect the stability of an Earth-like atmosphere to such an extent that it can even render its stable existence unlikely around highly active stars. A star’s metallicity and location within the galactic disk may pose further restrictions on the prevalence of Earth-like Habitats within the Milky Way. Taking these factors into account, we will, based on current quantifiable scientific knowledge, derive that only a certain fraction of stars within the galaxy will in principle be able to host planets with Earth-like atmospheres. Interestingly, K dwarfs with a stellar mass around 0.8 MSun may constitute a particularly interesting environment for the existence of Earth-like Habitats. M stars, on the other hand, exhibit several different problems; planets suitable for life as we know it may therefore be a rare occasion around the smallest, but most abundant, stars within the galaxy.

How to cite: Scherf, M., Lammer, H., and Sproß, L.: The host star as a crucial factor for the prevalence of Earth-like Habitats, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-15340, https://doi.org/10.5194/egusphere-egu23-15340, 2023.

Interpreting atmospheric spectra of exoplanets requires understanding the underlying atmospheric physics and chemistry. Studies have previously shown that for tidally locked, Earth-like exoplanets that orbit M-dwarf stars, photochemistry supports a highly structured 3-D ozone distribution, including a stratospheric ozone layer. We use a 3-D coupled Climate-Chemistry model (CCM), the Met Office Unified Model with the UK Chemistry and Aerosol framework, to describe the atmosphere of Proxima Centauri b. The chemical network includes the Chapman ozone reactions and the hydrogen oxide and nitrogen oxide catalytic cycles. We find that ozone is mainly produced on the dayside of the planet, initiated by the incoming stellar radiation. The ozone is then advected to the nightside, where it descends at the locations of permanent Rossby gyres that result in localised ozone hotspots. We will show that a stratospheric dayside-to-nightside circulation drives this nightside ozone distribution. This finding illustrates the 3-D nature of exoplanetary atmospheres and the potential impact on spectroscopic observations.

How to cite: Braam, M., Palmer, P., and Decin, L.: Stratospheric dayside-to-nightside circulation responsible for nightside ozone hotspots on tidally-locked exoplanets, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-15501, https://doi.org/10.5194/egusphere-egu23-15501, 2023.

EGU23-15709 | Posters on site | PS8.1

Carbonate Compensation Depth in Exoplanet Oceans and Ocean pH 

Kaustubh Hakim, Meng Tian, Dan J. Bower, and Kevin Heng

The carbonate-silicate cycle is thought to play a key role in maintaining temperate climates on Earth via continental silicate weathering and seafloor carbonate precipitation. Present-day carbonate precipitation on Earth’s seafloor is mainly attributed to calcium carbonates. However, observations of refractory element ratios in stellar photospheres and planet formation models suggest a large diversity in exoplanet bulk composition and thereby the near-surface composition. In this work, we compute exoplanet ocean pH and carbonate compensation depth (CCD). We find that ocean pH exhibits a limited range of values as a function of ocean temperature and partial pressure of CO2, where the limits are given by the absence and presence of carbonates. The CCD increases with ocean temperature and partial pressure of CO2. If the CCD is above the seafloor, the carbonate-silicate cycle ceases to operate and therefore high ocean temperature and partial pressure of CO2 favor the carbonate-silicate cycle. With the help of pure carbonate systems of key divalent elements, we show that magnesium, calcium and iron carbonates produce an increasingly wider parameter space of deep CCDs, suggesting that chemical diversity promotes the carbonate-silicate cycle. This work motivates the inclusion of more chemically diverse targets than Earth twins in the search for life in exoplanets.

How to cite: Hakim, K., Tian, M., Bower, D. J., and Heng, K.: Carbonate Compensation Depth in Exoplanet Oceans and Ocean pH, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-15709, https://doi.org/10.5194/egusphere-egu23-15709, 2023.

EGU23-16508 | Posters on site | PS8.1

A Comprehensive and Self-consistent Model of Terrestrial Planet Formation 

Nader Haghighipour and Jeffrey Sudol

We have developed the currently most comprehensive and self-consistent approach to realistically simulate the formation of terrestrial planets in our solar system including the formation of Mars. Our approach begins with simulating the collisional growth of planetesimals and continues with resolving giant impacts and the full formation of terrestrial planets. It takes into account the dynamical friction due to the debris and planetesimal disks, migration of planetesimals and embryos, and the perturbation as well as possible migration of giant planets. As the most important step toward a fully comprehensive and realistic model, our approach incorporates SPH simulations into N-body integrations in real time allowing, for the first time, collisions to be simulated accurately as they occur. Results point to several important findings. For instance, in the context of our solar system, almost all simulations produced an Earth-analog. They also demonstrated that the similarities between the size and mass of Earth and Venus are a natural outcome of the formation process, and Mars-sized planets appear in systems where the mass distribution in the planetesimal disk is non-uniform. When studying the effects of giant planets, results showed that secular resonances are the main reason that our solar system does not have Super-Earths. They are also the reason that terrestrial planets form interior to 2.1 AU. Simulations also show that the capture into resonance of migrating giant planets does not play a significant role on the formation of terrestrial planets, and while giant planets may affect the inventory of planet-forming material and water-carrying objects, especially when they migrate, they play no role in the mechanics of the formation of terrestrial planets and the transfer/transport of water to them. Formation and water delivery is merely due to the mutual interactions of planetary embryos, a process that occurs even when no giant planet exists. We will present the results of our study and discuss their applications to extrasolar planets. 

How to cite: Haghighipour, N. and Sudol, J.: A Comprehensive and Self-consistent Model of Terrestrial Planet Formation, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-16508, https://doi.org/10.5194/egusphere-egu23-16508, 2023.

The long-term evolution of the atmospheres or rocky planets depends on several different factors, including (but not limited to) volcanic outgassing by partial melting of the rocky interior. Uprising melt may contain different assembladges of volatiles (CHONS) depending on the general mantle composition and redox state, the local volatile inventory, as well as melting depth. All these factors are assumed to vary for mobile-lid planets with an active surface recycling mechanism (e.g. plate tectonics or convective mobile resurfacing) when compared to stagnant-lid planets. 

In addition, the strength of volcanic activity varies for stagnant-lid and mobile-lid planets, with stronger activity and hence volcanic outgassing expected for the latter case. Atmospheres with pressures above Earth values also severely influence which volatiles will be further outgassed into the atmosphere depending on the solubility of the individual gas species. The outgassing fluxes therefore strongly depend on the evolution of the atmosphere, including atmosphere losses to space or by condensation or weathering. Ultimately, different atmospheric compositions will evolve for planets with low-pressure atmospheres (i.e. low-mass planets, planets without an active surface mobilization process, or planets with efficient atmosphere sinks/losses) and high-pressure atmospheres.

Our studies allow us to predict ranges of likely atmospheric properties depending on planet mass and the surface mobility regime, that can then be compared to observations (i.e. with JWST or in the more distant future with the proposed LIFE mission).

How to cite: Noack, L. and Brachmann, C.: Outgassing efficiency and atmopsheric composition should differ for mobile-lid and stagnant-lid planets, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-16709, https://doi.org/10.5194/egusphere-egu23-16709, 2023.

GJ 1148 is an M-dwarf star, which has two well-separated Saturn mass planets with an orbital period ratio of around 13 and eccentricities of around 0.375 at the current epoch. A plausible scenario for producing the orbital architecture of the GJ 1148 system is planet-planet scattering. To test this scenario, we perform scattering experiments, assuming the third planet of 0.1 MJ (Jupiter’s mass) in the initial GJ 1148 system with initial orbital separations set to 3.5, 4, and 4.5 mutual Hill radii Rm,H respectively and initial semi-major axis of the innermost planet ai,1 in the range of 0.10-0.50 AU. The majority of scattering results in planet-planet collisions, followed by planet ejections, and planet removals as its distance to the star are smaller than a critical value of 0.02 AU. Among them, only the post-ejection two-planet systems have similar properties to the GJ 1148 system, and when ai,1 is around 0.21 AU, the semi-major axis of the inner planet GJ 1148 b can be reproduced. We further perform simulations with ai,1 in a narrower range between 0.16 and 0.30 AU, and found one system with similar orbital properties to the GJ 1148 system. Therefore, the simulation results suggest that the GJ 1148 system may have lost a giant planet. The two-sample Kolmogorov–Smirnov (KS) test on simulations with and without GR apsidal precession shows that it does not affect the ejection outcomes. When setting the mass of the third planet to 0.227 MJ of GJ1148 c, the optimal ai,1 move to about 0.29 AU.

How to cite: Yuan, L. and Lee, M. H.: Scattering of Giant Planets Around M-dwarf: The Implication for the Origin of the Hierarchical and Eccentric Two-planet System like GJ 1148, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-16843, https://doi.org/10.5194/egusphere-egu23-16843, 2023.

EGU23-17476 | Posters on site | PS8.1

Effect of energetic particles on the atmosphere of terrestrial exoplanets 

Nicolas Iro, John Lee Grenfell, Konstantin Herbst, Miriam Sinnhuber, Benjamin Taysum, and Andreas Bartenschlager

M-dwarf stars have been preferred targets of exoplanet search due to the favourable parameters of the system for remote characterisation. However, planets in the habitable zones of these stars are expecting to experience intense radiation.

We present the INCREASE project (INfluence of strong stellar particle Events and galactic Cosmic Rays on Exoplanetary AtmoSpherEs), aiming at modelling the effect of energetic particles on the atmosphere of terrestrial exoplanets. The INCREASE model suite is an almost self-consistent simulation chain coupling the state-of-the-art magnetospheric and atmospheric propagation and interaction models PLANETOCOSMICS (Desorgher et al. 2006) and AtRIS (Banjac57 et al. 2019) with the atmospheric chemistry and climate models 1D-TERRA (e.g., Wunderlich et al. 2020) and ExoTIC. Finally, spectral characterisation is done using the GARLIC line by line radiative transfer model.

By combining these models, we are able to constrain the habitability of such planets, the stability of their atmosphere as well as simulating observational features.

How to cite: Iro, N., Grenfell, J. L., Herbst, K., Sinnhuber, M., Taysum, B., and Bartenschlager, A.: Effect of energetic particles on the atmosphere of terrestrial exoplanets, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-17476, https://doi.org/10.5194/egusphere-egu23-17476, 2023.

EGU23-17577 | ECS | Posters on site | PS8.1

N-body interactions in proto-planetary disks: A study of collision velocities and impact angles 

Maximilian Zimmermann and Elke Pilat-Lohinger

We show the distribution of collision parameters of planetesimals and planetary embryos in an evolving protoplanetary disk for various binary star–giant planet configurations. This statistical study provides an overview which and how many of the mutual disk object collisions have to be studied in more detail with SPH (smooth particle hydrodynamics) simulations and which can be approximated by a “corrected“ perfect merging process. In all configurations the gas has been already depleted and thus, only gravitational interactions are
taken into account.The binary star systems (with M = 1 M ⊙ for both) have seperations of 50 au or 100 au and eccentricities of 0.0 or 0.3. In the 50 au binary star the giant planet (with M ≈ MJ ) is placed at 3 or 5 au and in the 100 au binary systems at 4.5 or 6 au. In all configurations the planetsimal/embryo disk consists of about 1500 objects which move in nearly circular and planar orbits between the host-star and the giant planet. In the different simulations the disk objects have masses either from Ceres to Moon mass in case of planetesimals or from Moon to Mars mass in case of planetary embryos. To study the gravitational interactions of the whole system our recently developed GPU N-body integrator GANBISS is used, which is able to simulate some thousand (massive) disk objects in binary star systems.

How to cite: Zimmermann, M. and Pilat-Lohinger, E.: N-body interactions in proto-planetary disks: A study of collision velocities and impact angles, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-17577, https://doi.org/10.5194/egusphere-egu23-17577, 2023.

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