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.