Presentation type:

PL1 – Diagnosis, trends, causalities, and predictions of extreme weather events in a climate change environment

Plinius17-7 | Posters | PL1

Tornadoes in Italy: comparative analysis of two Mediterranean tornado hotspots 

Elenio Avolio and Mario Marcello Miglietta

Tornadoes are among the most extreme hazardous weather phenomena. Several recent studies have assessed their important impact also in mid-latitudes European countries. An update climatology of the EF1+ tornadoes in Italy confirms that the central Tyrrhenian (CT) and the South-Eastern (SE) regions of the Italian peninsula represent two of the areas most affected by tornadoes in the Mediterranean.

Two recent works, in particular, analyzed some case studies affecting these two regions: Avolio and Miglietta (2021) studied four tornado-spawning supercells over SE regions, that hit the same (Ionian) areas and that were characterized by similar synoptic conditions; in a more recent work (Avolio and Miglietta, 2022; under review), the same authors performed a synoptic/mesoscale analysis of the main patterns associated to the most intense tornadoes in the CT regions, also analyzing a significant event hitting the surroundings of Rome.

Aim of this work is to propose a comparative analysis between these two tornado hotspots: the possible causes that generate these events in relation to the peculiarities of the two areas are analyzed by using upper air observations, radar images, ERA5 reanalysis, and high resolution WRF simulations. While for tornadoes in southeastern Italy the synergy of orographic forcing and air-sea interaction in a strongly sheared environment appears fundamental, in the Tyrrhenian regions the genesis is mainly related to the presence of convergence lines over the sea.

How to cite: Avolio, E. and Miglietta, M. M.: Tornadoes in Italy: comparative analysis of two Mediterranean tornado hotspots , 17th Plinius Conference on Mediterranean Risks, Frascati, Rome, Italy, 12–15 Oct 2021, Plinius17-7, https://doi.org/10.5194/egusphere-plinius17-7, 2021.

Plinius17-19 | Posters | PL1

Analysis of the development mechanisms of a large-hail storm event, on the Adriatic Sea using an atmosphere-ocean coupled model (COAWST)

Antonio Ricchi, Vincenzo Mazzarella, Frank Marzano, Mario Marcello Miglietta, Errico Picciotti, Mario Montopoli, Luca Baldini, Gianfranco Vulpiani, Alessandro Tiesi, Simone Mazzà, and Rossella Ferretti

On the morning of 10 July 2019, an intrusion of relatively cold and dry air, over the Adriatic Sea, through a "bora jet", gave rise to a frontal structure at the ground, which moved rapidly from the Northern to the Southern Adriatic. The intense thermal gradient (together with a high positive sea surface temperature anomaly), the interaction of the jet with the complex topography of Apennines and the coastal boundary, generated a storm structure that moved parallel to the central Italy coast. In particular, between 8UTC and 12UTC, a supercell developed along the coast to the north of Pescara city (middle Adriatic), producing rainfall that reached 130 mm in 3 hours, and a violent hailstorm (estimated diameter greater than 10 cm).

In this work, the frontal dynamics and the genesis of the thunderstorm are studied using the numerical system COAWST. Local polarimetric radar observations are also used to check the consistency of the simulations in the mature phase of the supercell. Numerical experiments are performed using a 1 km grid over central Italy, initialized using the ECMWF IFS analysis/forecasts. The sensitivity study investigates the role of the orography, the sea surface temperature (SST) and the coupling between ocean and atmosphere. Orography tests include simulations where the relevant peaks of the Apennine range (such as Gran Sasso and Picentini) are removed as well as cases where their peaks are modified compared to their real values. In terms of SST, we employ, using an uncoupled approach, the ECMWF SST dataset, the MFS-CMEMS Copernicus dataset at 4 km, 0.01°C Satellite SST, and we investigate the role of the SST anomaly (adding +1°C and +2°C to the real field). The role of the ocean-atmosphere interaction is tested using the COAWST numerical model using an ocean model numerical grid at 1 km resolution over the whole Adriatic Sea.

How to cite: Ricchi, A., Mazzarella, V., Marzano, F., Miglietta, M. M., Picciotti, E., Montopoli, M., Baldini, L., Vulpiani, G., Tiesi, A., Mazzà, S., and Ferretti, R.: Analysis of the development mechanisms of a large-hail storm event, on the Adriatic Sea using an atmosphere-ocean coupled model (COAWST), 17th Plinius Conference on Mediterranean Risks, Frascati, Rome, Italy, 12–15 Oct 2021, Plinius17-19, https://doi.org/10.5194/egusphere-plinius17-19, 2021.

Plinius17-10 | Orals | PL1

Some tools to forecast the extreme precipitation events in the Mediterranean areas

Jose Luis Sanchez, Andres Merino, Eduardo García-Ortega, Andres Navarro, Francisco Javier Tapiador, and Jose Luis Marcos

The extreme precipitation events had received priority attention due to its environmental, social and economic implications. Over the last decades, atmospheric modeling has been an essential tool to minimize their impact, with mesoscale numerical models development. However, model validation has large challenges in the case of the precipitation field. The reasons are well known, namely, precipitation measurement uncertainties, use of gridded datasets vs direct observations, statistical goodness-of-fit measures selection, etc. In this regard, accumulated precipitation throughout the event has been commonly used as an indicator of model performance. Nevertheless, because of their potentially dramatic consequences, intense sub-daily precipitation is of great importance for risk assessment. Thus, intense precipitation over a very short period often result flash floods in the Mediterranean area, for which a sub-event precipitation assessment is required. In this work hourly precipitation outputs of the WRF model has been analyzed within extreme precipitation events in Iberian Peninsula. The WRF testing was carried out considering three microphysics and two planetary boundary layer parameterizations. The results shown poor results for WRF hourly precipitation vs. observation from point to point. However, the parametrizations were relevant, with the Goddard and Thompson microphysics and MYNN PBL performing better.

How to cite: Sanchez, J. L., Merino, A., García-Ortega, E., Navarro, A., Tapiador, F. J., and Marcos, J. L.: Some tools to forecast the extreme precipitation events in the Mediterranean areas, 17th Plinius Conference on Mediterranean Risks, Frascati, Rome, Italy, 12–15 Oct 2021, Plinius17-10, https://doi.org/10.5194/egusphere-plinius17-10, 2021.

Plinius17-31 | Orals | PL1

The role of Atmospheric Rivers in the Mediterranean in heavy precipitation events over the Alps

Silvio Davolio, Mario Marcello Miglietta, Marco Vercellino, Lucia Drago Pitura, Lorenzo Giovannini, Francesco Sioni, Federico Grazzini, Sante Laviola, and Vincenzo Levizzani

Heavy precipitation events on the southern side of the Alps are typically associated with a favourable large-scale environment, characterized by an upper-level trough or cut-off cyclone over the western Mediterranean. This configuration induces, at the meso -scale, a meridional transport of large amount of moisture towards the orography, often organized in the form of a pre-frontal low-level jet. The thermodynamic characteristics of the impinging moist flow and its interaction with the orography determine the distribution and the intensity of the rainfall.

The present study shows that, besides the local contribution from the Mediterranean Sea, a relevant amount of moisture may move from the tropics towards the Mediterranean within long and narrow filament-shaped structures, known as atmospheric rivers (AR). To this aim, a detection algorithm, designed for the open oceans, has been adapted to the peculiar morphology of the Mediterranean and applied to identify ARs during some of the most severe weather events affecting the Alpine region in the last decades. Moreover, some diagnostic tools, such as an algorithm for the calculation of the atmospheric water budget, have been employed to compare and investigate such AR events.

The presence of ARs across the Mediterranean has been recently associated with heavy precipitation over southern Europe and Italy in particular. However, their role has not been fully assessed yet, in terms of contribution to the rainfall amount and of interaction with the cyclones driving their evolution. Therefore, high resolution numerical simulations are exploited to investigate how the transport of water vapour associated with the AR may have impacted on the severity and dynamics of a recent heavy precipitation event affecting the western Alps, and to disentangle how much rainfall can be attributed directly to the presence of the AR.

How to cite: Davolio, S., Miglietta, M. M., Vercellino, M., Drago Pitura, L., Giovannini, L., Sioni, F., Grazzini, F., Laviola, S., and Levizzani, V.: The role of Atmospheric Rivers in the Mediterranean in heavy precipitation events over the Alps, 17th Plinius Conference on Mediterranean Risks, Frascati, Rome, Italy, 12–15 Oct 2021, Plinius17-31, https://doi.org/10.5194/egusphere-plinius17-31, 2021.

Plinius17-34 | Posters | PL1

An ANN forecasting system for convective storms: the legacy of the LAMPO project 

Giovanna Venuti, Ehsan Mehdipour, Eugenio Realini, Valerio Guglieri, Matteo Sangiorgio, Giorgio Guariso, Stefano Barindelli, Enrico Solazzo, Riccardo Biondi, and Matteo Cislaghi

Localized and rapidly developing convective storms are still a challenge for meteorological predictions. These events can seriously impact our lives, especially in areas prone to flash floods. The possibility to monitor rapid increases of atmospheric water vapor, a key ingredients of convective storms development, was the starting point for the LAMPO (Lombardy bases Advanced Meteorological Predictions and Observations) research project, financed by the CARIPLO foundation and carried on by Politecnico di Milano and ARPA Lombardia. Aiming at the mitigation of hydrogeological risks in the metropolitan area of Milano, the project explored the possibility to enhance the forecasting of convective storms in the Seveso River catchment, responsible for river floods and producing huge damages to the city. By exploiting standard meteorological data from the ARPA network, radar derived information on convective cell position from MeteoSwiss and innovative GNSS-derived water vapor products from the POLIMI spinoff GReD, the project allowed for the definition of a prototypal forecasting system based on a neural network model. Trained on a decade of properly selected and pre-processed data, the system forecasts the occurrence of convective storms one hour in advance with more than 80% accuracy.

The innovative aspects of the LAMPO project, including the experimental activities related to the low-cost GNSS network ad hoc installed for meteorological purposes, will be presented together with envisaged future perspectives.

How to cite: Venuti, G., Mehdipour, E., Realini, E., Guglieri, V., Sangiorgio, M., Guariso, G., Barindelli, S., Solazzo, E., Biondi, R., and Cislaghi, M.: An ANN forecasting system for convective storms: the legacy of the LAMPO project , 17th Plinius Conference on Mediterranean Risks, Frascati, Rome, Italy, 12–15 Oct 2021, Plinius17-34, https://doi.org/10.5194/egusphere-plinius17-34, 2021.

Plinius17-46 | Posters | PL1

A modelling hindcast of four waterspouts along the Tuscany coast with sensitivity tests to SST anomalies

Valerio Capecchi, Alberto Ortolani, and Bernardo Gozzini

As reported by the European severe weather database, waterspouts are a frequent phenomenon along the Tyrrhenian coasts. They are more frequently observed during autumn than other seasons and, although less intense than tornadoes, can cause relevant damages when they make landfall. Based on information from weather station data, newspaper articles, eye-witness reports, photos or videos of the damages, the area of the Rosignano Solvay municipality (central coast of Tuscany, Italy) has experienced four of such high-impact events in the last 10 years. We present the numerical reconstructions of the atmospheric conditions that led to the waterspout events. The Meso-NH model, fed by ECMWF global analyses, is used to produce short-term and high-resolution (grid spacing up to 100 m) predictions. By looking at the atmospheric parameters correlated to the waterspout formation, we speculate about the ability of numerical forecasts in reconstructing the favorable conditions for waterspouts formation and development. We also discuss any usefulness of such short-term forecasts for issuing tornado-probability alerts. Furthermore, to investigate any possible influence of warmer sea surface temperatures (SSTs) on waterspout formation, we performed a sensitivity test by changing (namely increasing) SST values by approximately 1 K in a limited coastal perimeter. This is done to mimic the local warming effect that can occur due to the flux of hot water from the drainage ditch of the Solvay industrial plant. In such inner grid, a simplified 1-D ocean mixed layer model is used to account for the interaction between the sea and the atmosphere and correct the fluxes due to gustiness and precipitation. Preliminary analysis show that warmer sea temperatures (in the way they were simulated) may increase the probability of occurrence of waterspouts.

How to cite: Capecchi, V., Ortolani, A., and Gozzini, B.: A modelling hindcast of four waterspouts along the Tuscany coast with sensitivity tests to SST anomalies, 17th Plinius Conference on Mediterranean Risks, Frascati, Rome, Italy, 12–15 Oct 2021, Plinius17-46, https://doi.org/10.5194/egusphere-plinius17-46, 2021.

Plinius17-29 | Orals | PL1

Numerical simulations of banded orographic convection over the eastern Italian Alps: influence of atmospheric conditions and local topography

Tullio Degiacomi, Andrea Zonato, Silvio Davolio, Mario Marcello Miglietta, and Lorenzo Giovannini

Elongated and quasi-stationary convective rainbands triggered by small-scale orography and capable of producing heavy precipitation are often observed over the Italian Alps. Such features occurred in the final and most intense phase of the Vaia storm over the eastern Italian Alps, on the evening of 29 October 2018. South-east/north-west oriented bands, driven by the strong Sirocco wind, caused floods and landslides in several locations. In the present work, the thermodynamic conditions favorable for their formation and the triggering by small-scale topographic features are investigated through semi-idealized numerical simulations with the Weather Research and Forecasting (WRF) model.

Simulations are initialized using radio-sounding data measured at Udine-Rivolto, upstream of the eastern Italian Alps, at 18:00 UTC, 29 October. The small-scale energy needed to develop convection is provided by prescribing background thermal fluctuations embedded in the low-level flow or applying random perturbations to the topographic field.

The first tests using a simplified smooth ridge highlight that rainbands develop even without the triggering effect of small-scale topographic features. The simulated convection tends to organize in non-stationary bands which result from flow-parallel roll-type circulations with tilted updrafts reaching 6-7 km altitude. A sensitivity analysis with simulations at 1, 0.5 and 0.2 km grid spacing highlights that results are independent of the model resolution.

The influence of stability, wind intensity and wind shear on the development of rainbands is also investigated, using different idealized sounding profiles in the absence of small-scale topographic triggers. Similar to previous studies, results highlight that band-shaped convection is favored in vertically sheared intense flows without rotation of wind direction with altitude and weakly unstable cap clouds. The presence of convective inhibition in the boundary layer is fundamental for constraining the release of convection over the idealized ridge. On the other hand, intense instability or saturated layers within the mid-upper part of the statically unstable cap cloud disrupt the convective organization.

The presence of small-scale topographic perturbations, capable of releasing energy in the upstream edge of the unstable cap cloud in the form of lee waves, causes stationary rainbands which enhance the spatial variability in cumulative precipitation. The intensity of convection is efficiently amplified by individual obstacles when the induced wave pattern is in phase with the forced ascent generated by the main ridge. Moreover, the coupling between induced gravity waves and low-level convergence zones due to flow channeling and deflection has been revealed effective for rainband formation.

Finally, simulations with the real eastern Alpine orography demonstrate that, under Sirocco conditions, highly stationary bands are triggered by the topographic perturbations of the south-eastern Alpine foothills, individuating the favorable location of orographic rainbands for future similar convective events.

How to cite: Degiacomi, T., Zonato, A., Davolio, S., Miglietta, M. M., and Giovannini, L.: Numerical simulations of banded orographic convection over the eastern Italian Alps: influence of atmospheric conditions and local topography, 17th Plinius Conference on Mediterranean Risks, Frascati, Rome, Italy, 12–15 Oct 2021, Plinius17-29, https://doi.org/10.5194/egusphere-plinius17-29, 2021.

Plinius17-83 | Posters | PL1

The assimilation of the rain-rate from satellites: preliminary results of the AEROMET project

Rosa Claudia Torcasio, Alessandra Mascitelli, Giulia Panegrossi, Claudio Transerici, Stefano Dietrich, Fabio Del Frate, and Stefano Federico

The Mediterranean Basin is often hit by severe meteorological events, that can cause floods and flash floods. The intensity of these storms is both due to the presence of a warm sea, that contributes to feed the storm with high water vapor amounts, and to the complex orography of the region, which intensifies the precipitation over specific areas. The prediction of these events is very challenging, since different spatial and temporal scales are involved. 

Numerical Weather Prediction (NWP) models with a high spatial horizontal resolution are able to represent these kinds of events, but without a high precision in space, time and amount.  For a better representation of extreme rainfall events, an important role can be played by the information given at the local scale to the NWP models by initial conditions. 

Data Assimilation (DA) can be a fundamental instrument to help NWP models to improve their prediction, through the production of better initial conditions. However, DA needs observational data, and there is a lack of meteorological data in open sea, where radar data are not available. In this context, satellite observational data are very interesting because they can provide data both over sea and over land. 

The AEROMET (AEROspatial data assimilation for METeorological weather prediction) project aims to study the satellite rain-rate assimilation in the Weather Research and Forecasting (WRF) model to improve the prediction of convective meteorological systems, with a particular focus to systems which originate over the sea. The assimilation method considers a certain rain-rate threshold, which is representative of convective precipitation, avoiding in this way to add an excessive water vapor amount to the model. In this work, we show the preliminary results of the AEROMET project. Examples are presented to show the feasibility of the method and statistics will be shown to quantify its impact on rainfall prediction.

 

ACKNOWLEDGMENTS 

This work was done in the framework of the AEROMET project (A0375-2020-36588 - “Progetti di Gruppi di Ricerca 2020” LazioInnova - FESR Fondo Europeo di Sviluppo Regionale Programma Operativo regionale del Lazio). 

How to cite: Torcasio, R. C., Mascitelli, A., Panegrossi, G., Transerici, C., Dietrich, S., Del Frate, F., and Federico, S.: The assimilation of the rain-rate from satellites: preliminary results of the AEROMET project, 17th Plinius Conference on Mediterranean Risks, Frascati, Rome, Italy, 12–15 Oct 2021, Plinius17-83, https://doi.org/10.5194/egusphere-plinius17-83, 2021.

Plinius17-32 | Orals | PL1

Regional Precipitation Index: ranking storms in Greece

Kostas Lagouvardos, George Papavasileiou, Vasiliki Kotroni, Katerina Papagiannaki, Stavros Dafis, and Elisavet Galanaki

The METEO unit of the National Observatory of Athens has developed a methodology for ranking rain storms in Greece, following a similar procedure in the USA, where ranking of snow storms is routinely performed. The rain storm ranking in Greece is performed through the calculation of the Regional Precipitation Index (RPI) which takes into account:

a)         The daily accumulated precipitation and its exceedance of specific percentile thresholds.

b)         The total area where these exceedances occur.

c)         The population of the area that these exceedances occur.

First, RPI calculations were applied in ERA5-Land rainfall re-analysis, available at 0.1 deg resolution, for a 30-year period spanning from 1991 to 2020 and all major storms that occurred within this period were ranked and correlated to the reported societal impacts. The ranking of the storms is performed based on the percentiles of all non-zero RPI in the examined period. As major storms we define the top 2% of RPI. Then, a proposed methodology for the application of the methodology on daily forecast fields provided by high-resolution numerical weather prediction models is tested and discussed. This work, was funded by the European Climate Foundation.

How to cite: Lagouvardos, K., Papavasileiou, G., Kotroni, V., Papagiannaki, K., Dafis, S., and Galanaki, E.: Regional Precipitation Index: ranking storms in Greece, 17th Plinius Conference on Mediterranean Risks, Frascati, Rome, Italy, 12–15 Oct 2021, Plinius17-32, https://doi.org/10.5194/egusphere-plinius17-32, 2021.

Plinius17-33 | Orals | PL1

Evaluation of aerosol direct and indirect effects on extreme precipitation events over Liguria Region 

Francesco Ferrari, Federico Cassola, Andrea Mazzino, Marcello Mario Miglietta, Mauro Morichetti, and Umberto Rizza

Liguria region in the last years has been affected by devasting floods as result of extreme precipitation events. During these events, many records in terms of precipitations amount/rates over the Italian peninsula were overtaken, such as181mm/h during the 4 November 2011 Genoa flood, and 741 mm/12h and 884 mm/24h during the 21 October 2021 Rossiglione flood.

 

From a synoptic point of view, similar configurations characterize the extreme events that affected Liguria region, i.e., the presence of a deep pressure minimum west of the region and a strong high pressure over eastern Europe. Such conditions are favorable to the triggering of a quasi-stationary mesoscale convective systems over the Ligurian Sea.

Furthermore, this kind of configuration is favorable to the formation and transport of wide plumes of aerosol, mainly mineral dust from the Sahara Desert and sea salt aerosols generated under high

wind condition in the Mediterranean basin.

 

The present study aims to evaluate the impact that these aerosol plumes can have on the triggering and evolution of the deep convective systems responsible for Liguria flooding events. This study is carried out through numerical simulations performed with the WRF (Weather Research and Forecasting)-Chem model, version 4.0.  WRF-Chem is the WRF model coupled with the Chemistry: the model simulates the emission, transport, mixing, and chemical transformation of trace gases and aerosols as well as the meteorology.

In particular, the object of the presented research is to investigate the influence that cloud-aerosol-radiation interactions may have on the physics and dynamics of the rainfall events, primarily by means of the so-called direct (aerosol-cloud) and indirect (aerosol-radiation) interactions.

 

For this purpose, 3 different sets of simulations were performed: a control run, in which the chemical part of WRF-Chem model has not been activated, i.e., the production and transport of aerosol and its direct and indirect effects on atmosphere are not taken into account; a run in which the dust transport is considered and only aerosol direct effect are accounted for; a final run in which both direct and indirect effects are taken into account.

How to cite: Ferrari, F., Cassola, F., Mazzino, A., Miglietta, M. M., Morichetti, M., and Rizza, U.: Evaluation of aerosol direct and indirect effects on extreme precipitation events over Liguria Region , 17th Plinius Conference on Mediterranean Risks, Frascati, Rome, Italy, 12–15 Oct 2021, Plinius17-33, https://doi.org/10.5194/egusphere-plinius17-33, 2021.

Plinius17-79 | Orals | PL1

Assessment of projected Mediterranean SST influence on severe precipitation events

Luca Furnari, Jessica Castagna, Giuseppe Mendicino, and Alfonso Senatore

While observations of Mediterranean SST (Sea Surface Temperature) are showing an increasing trend during the last decades, future CMIP6 (Coupled Model Intercomparison Project Phase 6) projections highlight a further increase of approximately 3 °C, according to the SSP3-7.0 (Shared Socioeconomic Pathway) scenario. Among the coastal areas of the Mediterranean Basin, the Calabrian peninsula (southern Italy) is particularly prone to severe hydrometeorological events due to the intense atmosphere-sea interactions, further enhanced by local complex orography.

This study evaluates how the observed and projected Mediterranean SST increase affects the precipitation patterns in Calabria. We performed four months of simulations in a particularly rainy period from September to December 2019 using WRF (Weather Research and Forecasting) model by varying the SST lower boundary conditions. First, we considered actual conditions provided by ERA5 reanalysis. Then, we hypothesised past (a homogeneous decrease of −1 °C, referring approximately to 1980) and future (a homogeneous increase of +3 °C, referring to the end of this century) SST scenarios. Other boundary conditions, also given by ERA5, were not modified.

We focused on 20 rainfall events that actually occurred during the analysed period, whose intensities and spatial patterns were affected by different SST values. Most of the more dangerous events, coming south-eastwards from the Ionian Sea, increased their intensity with higher SST, fueling the atmosphere with water vapour more efficiently. Still, due to the enhanced atmospheric instability, such events were often solved in off-shore storms before reaching the coastline. Therefore, the analysis suggests that if only the SST changes are considered, the frequency of severe inland events will increase due to the enhanced air-sea flux exchange, but the intensity will not.

Further studies will be based on improved, fully-coupled atmospheric, oceanic and hydrological modelling systems and extend the analysis to different Mediterranean regions.

How to cite: Furnari, L., Castagna, J., Mendicino, G., and Senatore, A.: Assessment of projected Mediterranean SST influence on severe precipitation events, 17th Plinius Conference on Mediterranean Risks, Frascati, Rome, Italy, 12–15 Oct 2021, Plinius17-79, https://doi.org/10.5194/egusphere-plinius17-79, 2021.

Plinius17-67 | Orals | PL1

Future changes in sub-daily precipitation return levels over an alpine transect from a convection-permitting model 

Eleonora Dallan, Bardia Roghani, Giorgia Fosser, Christoph Schaer, Marco Marani, Marco Borga, and Francesco Marra

Fast hydro-geomorphic hazards such as flash floods and debris flows cause numerous fatalities and large damage, and are triggered by sub-daily extreme precipitation. Projecting future changes in these extremes is thus of great importance for risk management and adaptation strategies. High-resolution climate models, called convection-permitting models (CPMs), represent land-surface characteristics and small-scale processes in the atmosphere, such as convection, more realistically than coarser resolution models. Subdaily extremes could be better represented, and thus CPMs provide higher confidence in the estimate of future changes in extreme precipitation. However, the existing CPM runs are available for relatively short time periods (10–20 years at most) that are too short for deriving precipitation frequency analyses with conventional extreme value methods.

Here, we evaluate the potential of a novel statistical approach based on many “ordinary” events rather than just yearly maxima or a few values over a high threshold. This method has the potential to provide reliably estimate of rare return levels from short data record, thus offering the chance to be effectively applied to the analysis of CPM data for reliable frequency analysis on future precipitation. We focus on an Eastern Alpine transect, characterized by a complex orography, where significant changes in sub-daily annual maxima have been already observed. We estimate future changes under the RCP8.5 scenario using COSMO-crCLIM model simulations at 2.2 km resolution. We focus on three 10-year time slices (historical 1996-2005, near-future 2041-2050, and far future 2090-2099). A bias assessment is also performed by comparing the estimated extremes from the historical time-slice to the ones from long records of observed precipitation. We estimate extreme precipitation for duration ranging from 1 h to 24 h and assess the changes between the time periods. Specifically, we analyze: annual maxima, return levels, and parameters of the statistical model.

Although the storms' frequency will generally decrease in the region, the mean annual maxima exhibit a general increase in the near and far future, especially at shorter durations. The change in the extreme return levels shows a similar trend, with larger increase in the far future at the shorter duration. Interestingly, the changes show a spatial organization that can be associated to the orographic features of the area: the stronger increasing changes are located in the high elevation zone, while in the lowlands weak decrease and weak increase emerge in the near and far future, respectively.

This analysis demonstrates the possibility to have reliable estimates of future extreme precipitation from short CPM runs by using a novel method based on ordinary-events. The relevant findings from this analysis are useful for improving our knowledge about the projected future changes in extreme precipitation and thus for improving the strategies for risk management and adaptation.

How to cite: Dallan, E., Roghani, B., Fosser, G., Schaer, C., Marani, M., Borga, M., and Marra, F.: Future changes in sub-daily precipitation return levels over an alpine transect from a convection-permitting model , 17th Plinius Conference on Mediterranean Risks, Frascati, Rome, Italy, 12–15 Oct 2021, Plinius17-67, https://doi.org/10.5194/egusphere-plinius17-67, 2021.

Plinius17-50 | Orals | PL1

Predictions of Extreme Weather Events in a Climate Change Environment in the Northwest Italy

Peter Enos Tuju, Francesco Ferrari, and Andrea Mazzino

The recent decade has witnessed an overwhelming increase in convective storms such as heavy rains, hailstorms, tornadoes, strong winds, and lightning leading to extreme weather events around the globe. Principally, the thunderstorm producing cloud is the main environment in which these convective storms related to extreme weather events develop. Convective storms characterize the deadliest extreme weather events that pose wider socio-economic risks and impacts resulting in disruptions of social functions and services, damage to properties and infrastructures, injuries, and loss of life to people. However, the predictability of such extreme weather events still presents the most challenging task in operational weather forecasting. Thus, accurate and reliable forecasts of such weather phenomena are of critical importance to mitigate the adverse impacts and risks associated with extreme weather events. 

The current work is intended to simulate the convective weather storms pertaining to hailstorms, lightning, tornadoes, and strong winds that hit the Northwest part of Italy during the most recent decade. The emphasis will be placed on the Ligurian region, which is among the regions forming the North-west part of Italy with complex weather systems.  The high-resolution Numerical Weather Prediction (NWP) model, namely the Advanced Research of the Weather and Research Forecasting (ARW) modeling system will be used to simulate such weather events. The study will amount to two tasks. The very earliest task will investigate the implications of three resolutions (10 km, 3.3 km, and 1.1 km) of the ARW modeling system in simulating such weather phenomena. The latter task will use the obtained resolution to further investigate the implications of different parameterization schemes of the microphysics category in the ARW model. Observed data and/or reports from reliable sources will be used to verify the simulations from the ARW model using various approaches. Different results from diverse approaches will be presented and discussion will be performed based on the results obtained. Finally, the conclusion will be drawn based on the results and discussions.

How to cite: Tuju, P. E., Ferrari, F., and Mazzino, A.: Predictions of Extreme Weather Events in a Climate Change Environment in the Northwest Italy, 17th Plinius Conference on Mediterranean Risks, Frascati, Rome, Italy, 12–15 Oct 2021, Plinius17-50, https://doi.org/10.5194/egusphere-plinius17-50, 2021.

Plinius17-69 | Orals | PL1

Quantifying the contribution of diabatic processes in the intensification of Mediterranean tropical-like cyclones (Medicanes)

Stavros Dafis, Emmanouil Flaounas, Chantal Claud, Vassiliki Kotroni, and Konstantinos Lagouvardos

The classification of Mediterranean cyclones has always been a challenging task, especially when grouping warm-core and small-scale cyclones such as the Mediterranean tropical-like cyclones (Medicanes). The sudden intensity changes of Medicanes, the evolution of deep convection and the large spread of forecast tracks in numerical weather forecast models highlight the challenges in understanding the dynamics of these weather systems. In this study, numerical diagnostics are used to explain the evolution and contribution of diabatic processes in case studies of Medicanes. High-resolution simulations with WRF model are utilized and are evaluated against observations, before implementing the Pressure Tendency Equation (PTE). The decomposition of PTE shows interesting results about the contribution of diabatic processes and large-scale forcing during each Medicane. Moreover, an online Potential Vorticity (PV) tracer module is implemented in the WRF model, that provides another metric for the role of latent heating during the same Medicanes. Both approaches help to identify important differences among the case studies and shed a new light on a new pathway of Medicane development.

How to cite: Dafis, S., Flaounas, E., Claud, C., Kotroni, V., and Lagouvardos, K.: Quantifying the contribution of diabatic processes in the intensification of Mediterranean tropical-like cyclones (Medicanes), 17th Plinius Conference on Mediterranean Risks, Frascati, Rome, Italy, 12–15 Oct 2021, Plinius17-69, https://doi.org/10.5194/egusphere-plinius17-69, 2021.

Plinius17-18 | Orals | PL1

On the influence of Ocean Mixed Layer depth and Sea Surface Temperature Anomaly in the genesis and evolution of the Mediterranean Tropical-Like cyclones “IANOS”

Antonio Ricchi, Giovanni Liguori, Leone Cavicchia, Mario Marcello Miglietta, Davide Bonaldo, Sandro Carniel, and Rossella Ferretti

Over the Mediterranean basin we can occasionally observe intense cyclones showing tropical characteristics and known as Mediterranean Tropical-Like Cyclones (TLC). Previous studies focusing on past TLCs events have found that SST anomalies play a fundamental role in modulating the intense air-sea exchange of latent and sensible heat fluxes, hence controlling both development and evolution of TLCs. However, given the connection between ocean mixed layer, ocean heat content and temperature, it is important to explore also the role of the mixed layer depth (MLD). In this study we investigated the role of both SST, SST anomaly and MLD profile on genesis and evolution of a recent record-breaking TLC. Specifically, we focus on TCL “IANOS”, a cyclone that originated over the southern Ionian Sea around 14 Sept 2020, moved over the Central Ionian Sea from south-west to North-East, and made landfall around 19 Sept 2020 over Greece mainland coast. It developed over a basin where a positive SST anomaly up to 4 °C was detected, which coincided with the sea area where it reached the maximum intensity. We conducted a series of experiments using an atmospheric model (WRF - Weather Research and Forecasting system) driven by underlying SST (standalone configuration) with daily update or coupled to a simple mixed-layer ocean model (SLAB ocean), with SST calculated at every time step using the SLAB ocean for a given value of the MLD. WRF was implemented with 3 km grid spacing, forced with ECMWF-IFS analysis (9 km resolution), while SST or MLD initialization, for standalone or coupled runs, respectively, are provided by the MFS-CMEMs Copernicus dataset at 4 km of horizontal resolution. For the studied TLC, the mean MLD is modified by increasing or decreasing its depth by 10 m, 30 m, 50 m, 75 m, 100 m, change the lapse rate ot MDL and studi the impacto of SST and anomaly present and estimated by climatological projections; the preliminary results show that the MLD influences not only the intensity of the cyclone but also the structure of the precipitation field both in terms of magnitude and location. At first  the MLD thickness was characterized  for the days in which the cyclone developed using ocean modeling data. Then we identified possible past and future climatological scenarios of MLD thickness. Starting from these data, we simulated the impact of the MLD, and consequently of the Ocean Heat Content, on the TLC. The preliminary results show that the MLD influences not only the intensity of the cyclone but also the structure of the precipitation field both in terms of magnitude and location. The results deserve further investigation in particular in the context of climate change scenarios.

How to cite: Ricchi, A., Liguori, G., Cavicchia, L., Miglietta, M. M., Bonaldo, D., Carniel, S., and Ferretti, R.: On the influence of Ocean Mixed Layer depth and Sea Surface Temperature Anomaly in the genesis and evolution of the Mediterranean Tropical-Like cyclones “IANOS”, 17th Plinius Conference on Mediterranean Risks, Frascati, Rome, Italy, 12–15 Oct 2021, Plinius17-18, https://doi.org/10.5194/egusphere-plinius17-18, 2021.

Plinius17-41 | Orals | PL1

Analysis of a subtropical cyclone in the North Atlantic Ocean by means of the HARMONIE-AROME model: evaluation against satellite data

Lara Quitián Hernández, Carlos Calvo-Sancho, Javier Díaz Fernández, Pedro Bolgiani, Daniel Santos-Muñoz, Juan Jesús Gonzalez-Alemán, Mariano Sastre, Francisco Valero, Jose Ignacio Farrán, and María Luisa Martín Pérez

Subtropical cyclones (STCs) are low-pressure atmospheric systems characterized by having a hybrid structure that shares tropical and extratropical features. Due to their rapid intensification and harmful impacts, sometimes similar to those generated by tropical storms or even hurricanes, the implementation of accurate simulations becomes key for improving their forecast. In this study, a particular STC developed in October 2014 near the Canary Islands is analyzed using the high-resolution HARMONIE-AROME model. This model is developed and operated at 2.5 km resolution through the collaboration of the 10 European National Meteorological Services (NMS) that are part of the international research program HIRLAM together with the 16 countries that comprise the ALADIN consortium. The HARMONIE-AROME model has a convection-permitting configuration and uses a non-hydrostatic spectral dynamical core with a semi-Lagrangian and semi-implicit discretization of the equations, which implies a lower computational cost. In order to evaluate the environment in which the cyclone was formed, several convective tools are used. In addition, the cyclone phase space diagrams (CPS) are used to thermodynamically categorize the STC as a hybrid system. Furthermore, considering the difficulty of obtaining observational data in the vicinity of this type of system, most of the time located in the middle of the ocean, the use of satellite data becomes key for the validation of the model’s simulations. Consequently, in this study, the simulated cloud top height is assessed for the October 2014 STC.

How to cite: Quitián Hernández, L., Calvo-Sancho, C., Díaz Fernández, J., Bolgiani, P., Santos-Muñoz, D., Gonzalez-Alemán, J. J., Sastre, M., Valero, F., Farrán, J. I., and Martín Pérez, M. L.: Analysis of a subtropical cyclone in the North Atlantic Ocean by means of the HARMONIE-AROME model: evaluation against satellite data, 17th Plinius Conference on Mediterranean Risks, Frascati, Rome, Italy, 12–15 Oct 2021, Plinius17-41, https://doi.org/10.5194/egusphere-plinius17-41, 2021.

Plinius17-3 | Orals | PL1

A high-impact meso-beta vortex in the Adriatic Sea

Mario Marcello Miglietta, Federico Buscemi, Stavros Dafis, Alvise Papa, Alessandro Tiesi, Dario Conte, Silvio Davolio, Emmanouil Flaounas, Vincenzo Levizzani, and Richard Rotunno

On the evening of November 12, 2019, an exceptional high tide hit the city of Venice and the central-southern area of its lagoon, damaging a large part of its historical center. The main cause of the event was a small warm-core mesoscale cyclone, which formed in the central Adriatic Sea and intensified during its northwestward movement. 

Simulations with different initialization times were carried out with the Weather Research and Forecasting (WRF) model, showing a strong sensitivity to the initial conditions, since the track (and strength) of the cyclone was determined by the exact position of an upper-level potential vorticity (PV) streamer. The factors responsible for the cyclone development are also investigated. The pre-existence of positive low-level cyclonic vorticity, associated with the convergence of the Sirocco and Bora winds in the Adriatic, made the environment favorable for cyclone development. Also, the interaction between the upper-level PV anomaly and the low-level baroclinicity, created by the advection of warm, humid air associated with the Sirocco, was responsible for the cyclone’s intensification, in a manner similar to a transitory (stable) baroclinic interaction at small horizontal scales.

Conversely, convection and sea surface fluxes did not play a significant role, thus the warm-core feature appears mainly as a characteristic of the environment in which the cyclone developed rather than a consequence of diabatic processes. The cyclone does not fall into any of the existing categories for Adriatic cyclones.

How to cite: Miglietta, M. M., Buscemi, F., Dafis, S., Papa, A., Tiesi, A., Conte, D., Davolio, S., Flaounas, E., Levizzani, V., and Rotunno, R.: A high-impact meso-beta vortex in the Adriatic Sea, 17th Plinius Conference on Mediterranean Risks, Frascati, Rome, Italy, 12–15 Oct 2021, Plinius17-3, https://doi.org/10.5194/egusphere-plinius17-3, 2021.

Plinius17-20 | Orals | PL1

Analysis and classification of severe cyclogenesis events over the western Mediterranean Sea in the last 40 years

Cosimo Enrico Carniel, Rossella Ferretti, Antonio Ricchi, Gabriele Curci, Piero Serafini, Evan David Wellmeyer, and Dino Zardi

The Mediterranean Sea is a mid-latitude fairly temperate marine basin, strongly influenced by the North-Atlantic atmospheric circulations. In this semi-enclosed basin, a wide variety of cyclogenesis mechanisms are known to develop, including baroclinic waves coming from the Atlantic, Mediterranean cyclogenesis originating from the cut-off of baroclinic waves, Tropical-Like Cyclones (TLC), Rapid-Cyclogenesis (RC) and Intense Mediterranean Cyclones (IMC). Depending on the cyclone type, the characteristic frequency of appearance can vary, ranging from tens per month to 1.5 per year, as in the TLC case. RCs are among the rarest and probably most intense and destructive cyclogenesis events that can develop within the Mediterranean basin; they usually originate at high latitudes, during wintertime, and mainly over the sea, preferring areas with high Sea Surface Temperature (SST) gradients. It is generally accepted that these events are determined by 12 different parameters, among which the most relevant one is the quick drop of pressure, close to 1hPa/hr for 24 hours, within the eye of the cyclone. RCs formation is an extremely complicated process, and in the Mediterranean basin it is mostly driven by air intrusions from the stratosphere and by the presence of Atmospheric Rivers. Using ERA5 dataset, we firstly conducted a physical and dynamical analysis of the most intense cyclogenesis events occurred in the Mediterranean basin in the period 1979-2020, identifying factors which triggered, generated cyclones and contributed to the intensification of such events. According also to Sanders’ and Gyakum’s definition of Bergeron, a parameter which describes RCs’ deepening rate and varies from 28mb (24h)-1 at the pole to 12 mb (24h)-1 at latitude 25°N, we were able to classify them in the three aforementioned categories. Further analysis has been undertaken to determine the cyclones’ phase and their main morphological characteristics, as well as their statistical distribution, seasonality and correlation with relevant indexes such as NAO, EA and SCAND, as well as  SST anomalies exhibited by the Central Mediterranean Basin.

How to cite: Carniel, C. E., Ferretti, R., Ricchi, A., Curci, G., Serafini, P., Wellmeyer, E. D., and Zardi, D.: Analysis and classification of severe cyclogenesis events over the western Mediterranean Sea in the last 40 years, 17th Plinius Conference on Mediterranean Risks, Frascati, Rome, Italy, 12–15 Oct 2021, Plinius17-20, https://doi.org/10.5194/egusphere-plinius17-20, 2021.

Plinius17-12 | Orals | PL1

Spatio-temporal nowcasting of local severe weather events with deep neural networks

Sandy Chkeir, Aikaterini Anesiadou, and Riccardo Biondi

In the last decades, the intensity and frequency of extreme weather events have increased in Europe. The climate change, through its impact on the atmospheric processes, is expected to lead to further increase of such severe phenomena which also affect the air traffic activities. Therefore, a continuous monitoring and understanding of convective and pre- convective environment is highly demanded and indeed several studies have been made towards this direction. However, there are still gaps and uncertainties, especially regarding extreme weather events that are locally developing in a short time range. The nowcasting of extreme weather is a difficult task due to the complex structures and non-linear relation between its features. The existing weather numerical models are computationally expensive and limited by the difficulty to transform the acquired knowledge into accurate mathematical equations. For these reasons, this topic has gradually gained attention in the artificial intelligence community which aims at establishing more accurate models than the existing well-known techniques.

Within the H2020 SESAR multi-hAzard monitoring and earLy wARning system (ALARM) project, we focus on nowcasting the rain and wind speed using different algorithm input configurations that account for convective and pre-convective environments using data from weather stations, lightning detectors, radar and GNSS receivers with 10-minute sampling rate. The selected areas are Milano Malpensa and Brussels Zaventem airports, where extreme weather events are highly active. With the good quality datasets available for 10 years, we built an end-to-end spatio-temporal nowcasting model that ensembles independent Long Short Term Memory based encoder decoder sub-models to predict rain and wind speed absolute values up to 1 hour ahead given 2 hours of past observations.

Following the regression analysis of the predicted features, we classify rain and wind speed extremes events and we present the assessment of the nowcasting model in terms of the probability of detection, false alarm ratio and the critical success index. For specific case studies we also showcase the potentials of the model as a useful tool for aviation management. The results show excellent wind speed nowcasting performances with probability of detection higher than 90% and false alarms ranging from 1% to 3%. The rain nowcasting model underestimates the observations but a post-processing adjustment allows to reach probability of detection higher than 80% and about 10% of false alarms.

How to cite: Chkeir, S., Anesiadou, A., and Biondi, R.: Spatio-temporal nowcasting of local severe weather events with deep neural networks, 17th Plinius Conference on Mediterranean Risks, Frascati, Rome, Italy, 12–15 Oct 2021, Plinius17-12, https://doi.org/10.5194/egusphere-plinius17-12, 2021.

Plinius17-55 | Orals | PL1

Attribution of the extreme heat wave of July-August, 2021, in Greece to human-induced climate change, employing a forecast-based storyline approach

Christos Giannaros, Stavros Dafis, Elissavet Galanaki, Vassiliki Kotroni, Konstantinos Lagouvardos, and Theodore M. Giannaros

Situated in the eastern Mediterranean basin, Greece is characterized by pronounced increasing trends in heat waves intensity, duration and frequency of occurrence. This evidence-based fact is associated with the human-induced climate change (CC). However, CC is not responsible for every single extreme temperature event. Attributing weather extremes to manmade climate change is necessary for putting CC effects in context. It is also of paramount importance for addressing societal needs and providing actionable knowledge to governance authorities with respect to the CC impact on humanity. The traditional attribution processes that are based on climate modeling are computationally demanding and very challenging in terms of uncertainty quantification. For this, in the current work, we present a forecast-based storyline methodology and demonstrate its application for the extreme nine-day (July 25-August 08) heat wave that affected Greece in summer 2021. The method is based on the Weather Research and Forecasting (WRF) model, which is operationally applied over Greece and neighboring countries at high spatial resolution (2 km) for supporting the NOA (National Observatory of Athens) weather forecasting activities. WRF has successfully predicted the event of interest, providing robustness in the attribution analysis. We first define and simulate analogues of the examined episode under hypothetical climate settings. For the past experiment, this corresponds to the simulation of the heat wave under pre-industrial global CO­ concentrations and historical simulated Sea Surface Temperature (SST). For the future experiment, the CO­ concentrations during the forecast simulations were set equal to those anticipated on 2050 based on the shared socioeconomic pathway 2 - 4.5 (SSP2-4.5), while SST was set based on future simulations. Then, we compare the 2021 extreme heat wave to the past and future scenarios, and investigate differences in the heat wave amplitude, attributed to the anthropogenic forcing.

How to cite: Giannaros, C., Dafis, S., Galanaki, E., Kotroni, V., Lagouvardos, K., and Giannaros, T. M.: Attribution of the extreme heat wave of July-August, 2021, in Greece to human-induced climate change, employing a forecast-based storyline approach, 17th Plinius Conference on Mediterranean Risks, Frascati, Rome, Italy, 12–15 Oct 2021, Plinius17-55, https://doi.org/10.5194/egusphere-plinius17-55, 2021.

Plinius17-86 | Orals | PL1

Extreme meteorological droughts from paleo-climatic reconstructions analyzed through non-asymptotic extreme-value distributions

Maria Francesca Caruso, David Johnny Peres, Antonino Cancelliere, and Marco Marani

Drought is a complex and multifaceted natural phenomenon whose effects may have serious environmental and socio-economic impacts on communities. Drought is a multi-year phenomenon and thus its probabilistic characterization needs long instrumental records. As a possible way to overcome the limitation posed by the paucity of long-term historical records of hydro-meteorological variables, in this work we aim at using paleo-climate reconstructions from tree-ring records, which are becoming increasingly available (International Tree-Ring Data Bank, ITRDB, accessible from the repositories of the NOAA's National Centers for Environmental Information). On the other side, we attempt to find the statistical link of paleo-climate data with drought characteristics identified on indices largely used in the literature, such as the self-calibrating Palmer Drought Severity Index (scPDSI). In particular, we determine drought events and their properties (severity, duration, and intensity) using threshold methods based on the statistical “theory of runs”. We then explore the potentialities of using the recently-proposed Metastatistical Extreme Value Distribution (MEVD) to estimate the probability of occurrence of extreme drought events of different severity, duration, or intensity at several European sites. Unlike the statistical approaches based on the traditional Extreme Value Theory, the MEVD framework minimizes estimation uncertainty by leveraging the information content of all the ordinary values (i.e., those in the main body of the probability distribution).

More in detail, in this work we focus on: (1) tests of the reliability of these paleo-climatic reconstructions in reproducing meteorological droughts in long observational records, (2) the statistical analysis approach affording minimal uncertainty in the estimation of extreme drought events with an assigned probability of exceedance, and (3) how the severity and timing of impacts vary across and within drought-affected areas.

How to cite: Caruso, M. F., Peres, D. J., Cancelliere, A., and Marani, M.: Extreme meteorological droughts from paleo-climatic reconstructions analyzed through non-asymptotic extreme-value distributions, 17th Plinius Conference on Mediterranean Risks, Frascati, Rome, Italy, 12–15 Oct 2021, Plinius17-86, https://doi.org/10.5194/egusphere-plinius17-86, 2021.

Plinius17-14 | Orals | PL1

The frequency of lightning super-bolts in winter thunderstorms associated with Mediterranean cyclones

Yoav Yair, Colin Price, Barry Lynn, Menahem Kurzets, and Yannai Namia-Cohen

The distribution of cloud-to-ground lightning energies is well established, and its most extreme values appear only in extremely rare flashes (< 0.0001%), defined as lightning "super-bolts". There are varying definitions of the specific energy values of super-bolts, depending on the detector or mode of observation. When using optical energy as viewed from a satellite, one usually refers to the brightest flashes (103 times brighter than average), while when relating to the electromagnetic radiation received by lightning detection networks, the definition revolves around the strongest signals in the VLF or ELF range, or the largest peak-current or charge-moment-change (CMC) inferred from the signal. These are all different metrics for evaluating the lightning's intensity, and they are inter-related and exhibit mutual dependence (e.g. extreme values of peak current positively correlate with extreme VLF amplitudes).

The global distribution of these extremely powerful lightning is remarkably different from that of normal lightning, which are concentrated in the 3 convective "chimneys" of tropical Africa, South America and the maritime continent in South-east Asia. Superbolts are found mostly over the oceans and near coastlines, such as Sea of Japan, the North Sea and in the Andes mountains (Holzworth et al., 2019). They are also discovered in maritime winter storms over the Mediterranean Sea, which is one of the most prolific regions, especially in the months November-January.

We present the climatology of east-Mediterranean super-bolts (peak current > 200 kA), and compare data obtained by various lightning detection networks (ENTLN, WWLLN and ILDN). Some storms exhibit a larger percentage of superbolts compared with the global average, up to 0.65% of total flashes. While the physical mechanisms producing these powerful flashes remains unknown, we suggest that such flashes are more common when large amounts of desert dust aerosols, coming from the Sahara Desert, are ingested into maritime winter cyclones and contribute to convective invigoration, enhanced freezing and efficient charge separation. Initial modelling results will be discussed.

How to cite: Yair, Y., Price, C., Lynn, B., Kurzets, M., and Namia-Cohen, Y.: The frequency of lightning super-bolts in winter thunderstorms associated with Mediterranean cyclones, 17th Plinius Conference on Mediterranean Risks, Frascati, Rome, Italy, 12–15 Oct 2021, Plinius17-14, https://doi.org/10.5194/egusphere-plinius17-14, 2021.

Plinius17-37 | Orals | PL1

A pan-Alpine climatology of lightning and convective initiation

Agostino Manzato, Stefano Serafin, Mario Marcello Miglietta, Daniel Kirshbaum, Wolfgang Schulz, and Gabriele Fasano

A new lightning-flash and convective initiation climatology is developed over the Alpine area, one of the hotspots for lightning activity in Europe. The climatology uses cloud-to-ground (CG) data from the European Cooperation for LIghtning Detection (EUCLID) network, occurring from 2005 to 2019.  The CG lightning data are gridded at a resolution of approximately 2km and 10min. A new and simple method of identifying convective initiation (CI) events applies a spatiotemporal mask to the CG data to determine CI timing and location.
Although the method depends on a few empirical thresholds, sensitivity  tests show the results to be robust. The maximum activity for both CG flashes and CI events is observed from mid-May to mid-September, with a peak at the end of July; the peak in the diurnal cycle occurs in the afternoon. CI is mainly concentrated over and around the Alps, particularly in northern and northeastern Italy. Since many thunderstorms follow the prevailing mid-latitude westerly flow, a peak of CG flashes extends from the mountains into the plains and coastal areas of northeastern Italy and Slovenia. CG flashes and CI events over the sea/coast occur less frequently than in plains and mountains, have a weaker diurnal cycle, and have a seasonal maximum in autumn instead of summer.

How to cite: Manzato, A., Serafin, S., Miglietta, M. M., Kirshbaum, D., Schulz, W., and Fasano, G.: A pan-Alpine climatology of lightning and convective initiation, 17th Plinius Conference on Mediterranean Risks, Frascati, Rome, Italy, 12–15 Oct 2021, Plinius17-37, https://doi.org/10.5194/egusphere-plinius17-37, 2021.

Plinius17-40 | Orals | PL1

Comparison of the characteristics of hailstones precipitated on one side and the other of the Pyrenees.

José Luis Marcos-Menéndez, José Luis Sánchez, Andrés Merino, Eduardo García-Ortega, Andrés Navarro, Claude Berthet, and Jean Dessens

Hailpads networks allow knowing the characteristics of the stones precipitated by hail storms. The province of Lleida (Spain) has an excellent network of hailpads (managed by the ADV Terres de Ponent and the Servei Meteorologic de Catalunya) which is located south of the Pyrenees. To the north of it and in French territory, there is another similar one (placed in Hautes Pyrénées and Midi Pyrénées), managed by ANELFA. A large part of the hail storms that affect this French area are formed in Spanish territory, crossing the mountainous barrier of the Pyrenees, so it is interesting to know their characteristics from one side to the other. In both cases, historical series of more than 20 years are available.

We have taken the database of all the days in which hail falls have been detected in one or another hailpads network and we have calculated the diameter and maximum energy of the precipitated stones. With the data obtained, we have found the corresponding statistical distributions.

Once we have obtained these four databases (ie two for each of the networks) we have analyzed the statistical parameters that characterize them. We have also studied the temporal trend of hail precipitation on both sides of the Pyrenees

Finally, we have studied the meteorological factors that intervene in the formation of hail and the dependence they have on the maximum diameter and the maximum expected energy.

The results show a greater severity in the stones precipitated on the South side of the Pyrenees and the meteorological factors involved in the formation of hailstorms.

How to cite: Marcos-Menéndez, J. L., Sánchez, J. L., Merino, A., García-Ortega, E., Navarro, A., Berthet, C., and Dessens, J.: Comparison of the characteristics of hailstones precipitated on one side and the other of the Pyrenees., 17th Plinius Conference on Mediterranean Risks, Frascati, Rome, Italy, 12–15 Oct 2021, Plinius17-40, https://doi.org/10.5194/egusphere-plinius17-40, 2021.

Plinius17-2 | Orals | PL1

A year-long total lightning forecast over Italy made with a dynamic lightning scheme using the WRF model

Stefano Federico, Rosa Claudia Torcasio, Martina Lagasio, Barry H. Lynn, Claudio Transerici, Silvia Puca, and Stefano Dietrich

Lightning is an important threat to life and properties and its forecast is important for practical applications. We show the performance of a dynamic lightning scheme for the next-day strokes forecast. The prediction is compared against the LINET network, and the forecast period spans one year. Specifically, a total of 162 case studies were selected between 1 March 2020 and 28 February 2021. The events span a wide range of lightning intensity; 69 cases occurred in summer, 46 in fall, 18 in winter, 29 in spring.

Three different settings of the lightning scheme are considered to test the sensitivity of the method to the key parameter of charge transferred in 1 second: 0.5*10-4 C (L50), 0.75*10-4 C (L75),  and 1.0*10-4 C(L100).

The meteorological driver is WRF. Each simulation lasts 36h and the first twelve hours are the spin-up time and are discarded from the analysis. The focus is on the next-day forecast (12-36 h). The horizontal resolution of the simulations is 3 km and 50 unevenly spaced vertical levels extend from the surface to 50 hPa.

Lightning is closely related to convection in the atmosphere and model errors in the lightning forecast have two main sources: errors in forecasting the convection and errors in the representation of the electric processes inside the clouds. This makes the lightning forecast a difficult task.

Results are discussed for the whole year and for different seasons. Moreover, statistics are presented for the land and sea. LINET strokes are remapped into the WRF 3km grid and then further elaborated for comparison with the strokes forecast.

Among the three configurations of the lightning scheme, L75 forecasts accurately the total number of strokes recorded for all the cases, L50 underestimates the strokes and L100 overestimates the strokes. The time-series correlation of daily observed and forecasted strokes is around 0.75 and depends on the season.

Qualitative scores (FBIAS, ETS, POD, FAR) computed for the 3km grid and different strokes thresholds have low values and upscaling the model output, by summing the forecast and observed strokes over grids with larger grid spaces (from 6 to 48 km), improves the results. Among the different configurations of the dynamic lightning scheme, L75 performs slightly better. However, L50, L75, and L100 show very similar spatial patterns of predicted strokes.

The analysis of the fraction skill score shows that the best lightning forecast is for summer, followed by fall, winter, and spring. This happens for all configurations L50, L75, L100.

The lightning forecast performance varies between sea and land; the analysis of the Taylor diagram shows better performance over the land than over the sea. This result shows that the convection is better simulated over the land than over the sea, where the effect of topography, partially represented by the model, may focus the convection on specific areas.

The result of this study shows that lightning forecast with the dynamic lightning scheme can be performed with success in Italy; nevertheless, a careful inspection of the forecast performance is necessary for tuning the scheme to the specific purpose.

How to cite: Federico, S., Torcasio, R. C., Lagasio, M., Lynn, B. H., Transerici, C., Puca, S., and Dietrich, S.: A year-long total lightning forecast over Italy made with a dynamic lightning scheme using the WRF model, 17th Plinius Conference on Mediterranean Risks, Frascati, Rome, Italy, 12–15 Oct 2021, Plinius17-2, https://doi.org/10.5194/egusphere-plinius17-2, 2021.

Plinius17-64 | Orals | PL1

Climatology of high-impact weather events in the Ligurian Sea

Dario Hourngir, Massimiliano Burlando, and Djordje Romanic

Extratropical cyclones are the main drivers of mid-latitude weather and they are the key synoptic phenomena that give rise to the areas of strong instability by the passage of their associated fronts. The importance of studying their characteristics in terms of development, trajectories and spatio-temporal distributions, has long been recognized over the last decades. Similarly, research of extreme events associated with extratropical cyclones has gained even more importance in the last years because of the increasing confidence that these weather systems are being affected by climate change. This relationship between extratropical cyclones and ongoing climate change might amplify their negative impacts on the largely populated midlatitude areas in the near future. To overcome time-consuming and subjective analyses of extratropical cyclones by manual analysis of synoptic maps, several numerical algorithms have been developed and used to identify and track cyclones. The procedures vary greatly with respect to computational details and the degree of sophistication involved. In many cases cyclonic cores are defined in terms of pressure minima at sea level, while in other cases they are alternatively defined in terms of maxima in low level vorticity. For this analysis, an algorithm originally developed for the identification and tracking of cyclones and pressure depressions in the Southern Hemisphere is applied to the Mediterranean region, which is considered as one of the major climatic hot spots in the world and one of the most prominent areas around the globe in terms of high-impact weather phenomena. The main goal of the current research is to derive a climatology of all cyclones and pressure depressions passing over the western Mediterranean that subsequently affect the Ligurian region and its surroundings. Several studies demonstrated that the specific geography of this area in the Mediterranean enhances the formation of intense cyclones associated with heavy rainfalls and windstorms. More precisely, the morphological characteristics of the area serve as a natural constraint to the air flows that blow from the southern quadrants and thereby creates convergence zones at low levels that affects the behaviour of meteorological structures at mesoscales. Our aim is to better understand the atmospheric conditions at larger scale that provide the necessary ingredients for the development of strong high-impact weather events. Moreover, we are interested in determining if these events have a trend in terms of their frequency and intensity, as well as a trend in the development of specific recurrent synoptic patterns that trigger mesoscale phenomena associated with high-impact weather in this area. In this sense, one of the goals of the present analysis will be to investigate the means by which the ongoing global warming causes variations of cyclonic properties and to what extent these variations affect the mesoscales associated with high-impact weather events in the region of interest.

How to cite: Hourngir, D., Burlando, M., and Romanic, D.: Climatology of high-impact weather events in the Ligurian Sea, 17th Plinius Conference on Mediterranean Risks, Frascati, Rome, Italy, 12–15 Oct 2021, Plinius17-64, https://doi.org/10.5194/egusphere-plinius17-64, 2021.

PL2 – Earth Observation data and techniques for the definition, characterization and monitoring of natural hazards

Plinius17-4 | Posters | PL2

Spatio-temporal evaluation of three rainfall prediction methods on French Riviera coastal catchments

Sarah Vigoureux, Pierre Brigode, Maria-Helena Ramos, Pierre Javelle, Julie Poggio, Stan Nomis, Raphaëlle Dreyfus, Olivier Delestre, Emmanuel Moreau, Christophe Laroche, and Emmanuel Tric

The French Riviera, located in the eastern part of the French Mediterranean coast, has experienced devastating flash floods, in particular during the last decade. These floods were generated by localized and intense or severe rainfall events, leading to significant material and human losses, especially on small coastal catchments. Flood forecasting is still challenging on those catchments  because they often have sparse rain gauge networks and are mostly ungauged in terms of streamflow. For example, the October 2015 event affected the Riou de l’Argentière, Frayère and Brague coastal catchments (respectively 47 km², 21 km² and 72 km²) with rain intensities (up to 200 mm in only two hours) characterized by a significant spatial variability (up to two times more precipitation on the downstream part of the catchments). This study investigates whether todays’ operational precipitation forecasts are effective on the French Riviera to accurately predict the episodes of intense Mediterranean precipitation.

We evaluate the performance of three rainfall prediction methods on 47 French Riviera coastal catchments. The NOVIMET method is based on a “simple” advection of observed radar rainfall fields and provide predictions at a horizontal resolution of 1 km and up to 2 hours of lead time. An “elaborated” advection method using a machine learning algorithm which applies radar image analysis to provide predictions up to six hours at the same spatial and temporal resolutions. Finally, we also evaluate predictions based on a blended product based on the aggregation of radar extrapolation and atmospheric numerical model predictions: PIAF. PIAF, provides forecasts at a horizontal resolution of 1 km and shorter lead times (0-3h). Rainfall forecasts are provided either as a single estimation or as an ensemble of equiprobable forecasts.

We evaluate the methods on their ability to reconstruct historical precipitation events. Forecasts are evaluated against the hourly, 1km x 1km gridded COMEPHORE radar precipitation product of Météo-France, available from 1997 to 2020. We calculate metrics of forecast quality that capture the spatio-temporal characteristics of the precipitation events. The results are discussed from the point of view of users, who assist municipalities in flood risk forecasting and mobilizes teams when it is needed to monitor events and take appropriate actions to anticipate the risk of flooding.

How to cite: Vigoureux, S., Brigode, P., Ramos, M.-H., Javelle, P., Poggio, J., Nomis, S., Dreyfus, R., Delestre, O., Moreau, E., Laroche, C., and Tric, E.: Spatio-temporal evaluation of three rainfall prediction methods on French Riviera coastal catchments, 17th Plinius Conference on Mediterranean Risks, Frascati, Rome, Italy, 12–15 Oct 2021, Plinius17-4, https://doi.org/10.5194/egusphere-plinius17-4, 2021.

Plinius17-60 | Posters | PL2

Combined ground and space-borne lightning detection over a mountainous region 

Alessandra Tiberia, Enrico Arnone, and Stefano Dietrich

Typical features of lightning distribution in the mountain area of Mt. Cimone (2165 m a.s.l. - Northern-Central Italy) have been studied through detections provided by the ground-based LIghtning NETwork data (LINET) and the Lightning Imaging Sensor (LIS) onboard the International Space Station (ISS-LIS).  The study was performed within the context of lightning implications as natural hazard, and its role in a changing climate. Of particular interest are mountain regions because of their orographic impact, which determine most lightning hotspots around the globe. LINET VLF/LF radio measurements allowed the characterization of both cloud-to-ground (CG) and intra-cloud (IC) strokes' geographical distribution and altitude of occurrence over 2012 through 2020. The lightning distribution showed a remarkable clustering of CGs at the mountain top in contrast to a homogeneous distribution of ICs, highlighting the likely impact of orography. IC strokes peaked around 4 to 6 km altitude, consistency with the observed typical cloud range. The joint exploitation of LIS-ISS optical observations of LINET detections extended the study to further features of flashes not seen in radio wavelengths and stands as cross-validation of the two detection methods over such a complex orography. These results give an example of mountain-driven changes in lightning occurrence. The clustering at the Cimone mountain top induced by the orography replicates a general feature of the dependence of global lightning hot-spots from elevation and is of great interest in the understanding of the lighting-climate relationship, considering known effects of elevation-depedent climate change.

How to cite: Tiberia, A., Arnone, E., and Dietrich, S.: Combined ground and space-borne lightning detection over a mountainous region , 17th Plinius Conference on Mediterranean Risks, Frascati, Rome, Italy, 12–15 Oct 2021, Plinius17-60, https://doi.org/10.5194/egusphere-plinius17-60, 2021.

Plinius17-56 | Orals | PL2

Satellite soil moisture-derived rainfall for flood modelling in italy

Luca Ciabatta, Stefania Camici, Paolo Filippucci, Christian Massari, Leo Pio D'Adderio, Giulia Panegrossi, Hamidreza Mosaffa, and Luca Brocca

Accurate precipitation estimates are paramount for the activities related to water management and risk assessment. Satellite-based rainfall estimates are generally obtained by an inversion of the atmospheric signals reflected or radiated by atmospheric hydrometeors, i.e., a “top-down” approach. The main drawback of this retrieval technique is related to the number of satellite overpasses, that may lead to a general underestimation of rainfall.

To overcome these issues, recently, some studies have investigated the possibility to integrate the state-of-the-art rainfall products with rainfall estimates obtained by a consolidated “bottom-up” approach, SM2RAIN (Brocca et al., 2014) exploiting satellite soil moisture observations for obtaining accumulated rainfall estimates. The integration between top-down and bottom-up estimates can produce a more reliable rainfall product for hydrological applications, characterized by better estimation of rainfall amounts and timing. 

On this basis, the Satellite Application Facility on Support to Operational Hydrology and Water Management (H SAF) has started the development and the sharing of integrated datasets of top-down satellite-based precipitation and soil moisture-derived rainfall estimates.

During the Continuous Development and Operational Phase (CDOP) 3 and 4, the H SAF consortium planned to develop and provide several integrated products to the users for hydrological applications, also by taking advantages of the next EPS-SG instruments with enhanced retrieval capabilities.

In this study, the usefulness of integrated products for river discharge simulation is assessed in Italy. More in details, the integrated product between SM2RAIN-derived estimates and Passive Microwave auxiliary product H67 (H64), the gauge corrected version (H84) and the SM2RAIN-only derived product (H87), along with the parent products will be use to force a semidistributed rainfall-runoff model (MISDc) during the period 2016-2019. The obtained river discharge timeseries have been compared with observed ones in order to evaluate the skill of the investigated products showing confirming the added value of using an integrated rainfall product for hydrological applications. Moreover, the results will provide useful insight that will help in improving the integrated products.

The analysis provided good results, confirming the added value of using an integrated rainfall product for hydrological applications, allowing to overcome some of the limitations of the state-of-the-art precipitation datasets.

How to cite: Ciabatta, L., Camici, S., Filippucci, P., Massari, C., D'Adderio, L. P., Panegrossi, G., Mosaffa, H., and Brocca, L.: Satellite soil moisture-derived rainfall for flood modelling in italy, 17th Plinius Conference on Mediterranean Risks, Frascati, Rome, Italy, 12–15 Oct 2021, Plinius17-56, https://doi.org/10.5194/egusphere-plinius17-56, 2021.

Pluvial floods (PFs) caused by extreme overland flow inland account for half of all flood damage claims each year, equally with fluvial floods (FFs). However, most remote sensing-based flood detection techniques only focus on the identification of degradations and/or water pixels in the close vicinity of overflowing streams. Geomatics hydrological models have been developed to easily and widely map susceptibility towards the occurrence of intense surface runoff without physics-based modelling. However, in order to increase confidence in such methods, they need to be comprehensively evaluated using PF observations from past events. For this, a generalized remote sensing fusion method called FuSVIPR (Fusion of Sentinel-2 & Very high resolution Imagery for Pluvial flood detection in Runoff prone areas) is developed. Based on 10 m change detection (from Sentinel-2) and sub-metric optical imagery (from Pléiades satellites and airborne sensors), machine learning (ML) and deep learning (DL) techniques are used to locate PF footprints on the ground at 0.5 m spatial resolution following heavy weather events. Post processing involving land use, soil type and topography allows accounting for runoff production processes to induce PFs downstream. In this work, six watersheds in the Aude and Alpes-Maritimes departments in the South of France are investigated over more than 3000 km2 of rural and periurban areas during three flash-flood events between 2018 and 2020. With a unique learning sample from the Aude flash-floods of October 2018, overall detection accuracies greater than 86% and false detection rates below 7% are reached independently on all three distinct events. These results emphasize the high generalization capability of this method to locate PFs at any time of the year and over diverse regions worldwide. The resulting damage proxy maps have high potential for helping precipitation downscaling and thorough evaluation and improvement of surface water inundation models at very high spatial resolution.

How to cite: Cerbelaud, A.: Multi-sensor optical remote sensing for generalized sub-metric detection of pluvial flood damages using U-net CNN and Random Forest., 17th Plinius Conference on Mediterranean Risks, Frascati, Rome, Italy, 12–15 Oct 2021, Plinius17-68, https://doi.org/10.5194/egusphere-plinius17-68, 2021.

Plinius17-1 | Orals | PL2

A multifractal framework to evaluate extreme rainfall trends across scales under a changing climate

Stergios Emmanouil, Andreas Langousis, Efthymios I. Nikolopoulos, and Emmanouil N. Anagnostou

The accurate quantification of hydroclimatic risk requires detailed knowledge on the spatiotemporal characteristics of extreme rainfall. In engineering design, Intensity-Duration-Frequency (IDF) curves are fundamental tools that encompass information on rare precipitation events over a wide range of characteristic temporal scales and exceedance probability levels. Inspired by physical evidence and laws of thermodynamics, researchers widely suggest that the rapidly changing climate instigates more frequent and intense precipitation-related natural hazards. Based on the foregoing implication, current protection standards may be systematically threatened in the upcoming years. Under this non-stationary setting, several IDF estimation approaches have been proposed that allow for distribution parameter estimates to vary (in most cases linearly) with time. Yet, the introduction of additional model parameters increases the estimation uncertainty of rainfall intensity quantiles, especially for rare events. As a potential solution to limitations related to non-stationarity, Emmanouil et al. (2022) proposed an elaborate parametric approach founded on multifractal (MF) scaling arguments (see Langousis et al., 2009), which assumes that the statistical structure of rainfall at interannual scales can be approximated by sequential realizations of a stationary multifractal process with parameters that vary slowly across (not within) realizations. The suggested framework is particularly robust when describing the intensity and frequency of extreme rain rates from small precipitation samples (i.e., down to 2 years; see Emmanouil et al., 2020) and, therefore, it can be effectively applied to adequately short sequential segments of data, allowing for climatic variations to be revealed. Given the above, we attempt to expand the analysis of Emmanouil et al. (2022) toward evaluating the effects of future climate pathways on extreme rainfall, under a wide spectrum of topographical and climatological conditions. To do so, we derive IDF curves based on statistically downscaled estimates of multiple climate model outputs (e.g., Mearns et al., 2017) that cover a 120-year period (i.e., from 1979 to 2099) over the Contiguous United States (CONUS). The yielded outcomes for both historical data and climate model hindcasts exhibit that, on average, extreme rainfall displays similar trends over the study domain. However, it is shown that the dependence structure and variability of rare precipitation events vary significantly across data sources, and should be scrupulously delineated when assessing how existing risk considerations could actually be affected.

References

  • Emmanouil, S., A. Langousis, E.I. Nikolopoulos, and E.N. Anagnostou (2020) Quantitative assessment of annual maxima, peaks-over-threshold (PoT) and multifractal parametric approaches in estimating intensity-duration-frequency (IDF) curves from short rainfall records, Journal of Hydrology, 589, 125151, doi: 10.1016/j.jhydrol.2020.125151.
  • Emmanouil, S., A. Langousis, E.I. Nikolopoulos, and E.N. Anagnostou (2022) The spatiotemporal evolution of rainfall extremes in a changing climate: A CONUS-wide assessment based on multifractal scaling arguments, Earth’s Future, 10 (3), e2021EF002539, doi: 10.1029/2021EF002539.
  • Langousis, A., D. Veneziano, P. Furcolo, and C. Lepore (2009) Multifractal rainfall extremes: Theoretical analysis and practical estimation, Chaos, Solitons and Fractals, 39 (3), 1182–1194, doi: 10.1016/j.chaos.2007.06.004.
  • Mearns, L.O., S. McGinnis, D. Korytina, R. Arritt, S. Biner, M. Bukovsky, et al. (2017) The NA-CORDEX dataset, version 1.0. NCAR Climate Data Gateway. Boulder (CO): The North American CORDEX Program, 10.

How to cite: Emmanouil, S., Langousis, A., Nikolopoulos, E. I., and Anagnostou, E. N.: A multifractal framework to evaluate extreme rainfall trends across scales under a changing climate, 17th Plinius Conference on Mediterranean Risks, Frascati, Rome, Italy, 12–15 Oct 2021, Plinius17-1, https://doi.org/10.5194/egusphere-plinius17-1, 2021.

Plinius17-27 | Orals | PL2

Satellite-based characterization of Medicanes in the GPM era

Leo Pio D'Adderio, Daniele Casella, Stefano Dietrich, Paolo Sanò, and Giulia Panegrossi

Mediterranean hurricanes (Medicanes) are meso-scale cyclones typical of the Mediterranean area which during their lifetime may show some dynamical features with tropical cyclones: the presence of a quasi-cloud-free calm eye, spiral-like cloud bands elongated from the center, strong winds close to the vortex centre and a warm core. They are often associated to heavy rainfall and flooding, intense wind, and high waves and storm surge, and can be serious threats to human life and infrastructure. Recent studies highlighted that extra-tropical and tropical-like cyclone (TLC) characteristics can alternate or even coexist in the same cyclonic system, and that only in some cases strong diabatic forcing leads to tropical-like transition (i.e., purely barotropic structure) associated to shallow or deep warm core. In this study a comparative analysis among the Medicanes occurred during the Global Precipitation Measurement (GPM) era (i.e. since March 2014), is carried out. The goal is to extract common features from passive MW measurements to identify and characterize the transition to TLC phase during the Medicane evolution. Passive microwave measurements from the GPM constellation radiometers are used to characterize the precipitation structure and warm core properties throughout the Medicane evolution. In particular, the NASA/JAXA GPM Core Observatory (GPM-CO) active and passive microwave (MW) sensors are used in conjunction with ground-based LIghtning NETwork (LINET) measurements to analyse the rainband structure and infer microphysics processes and convection strength. On the other hand, MW temperature sounding channels available from AMSU-A and ATMS radiometers are used to identify the warm core and infer its properties (e.g., depth and symmetry) around the cyclone center.  The most intense Medicane on record, named Ianos, which swept across the Ionian Sea between 14 and 18 September 2020, is anlaysed in detail. The GPM-CO Dual-frequency Precipitation Radar (DPR) overpass, available for the first time during a medicane TLC phase, provides key measurements and products to analyze the 3D precipitation structure in the rainbands, offering further evidence of the main precipitation microphysics processes inferred from the passive MW measurement analysis. Moreover, the GPM-CO overpasses highlight a significant change in deep convection features between Ianos development and mature phases, which explain the substantial drop in lightning activity during Ianos TLC phase. The study demonstrates the value of satellite MW measurements in the GPM era to provide evidence of Medicanes' transition to TLC phase and to characterize its precipitation structure and microphysics processes.

How to cite: D'Adderio, L. P., Casella, D., Dietrich, S., Sanò, P., and Panegrossi, G.: Satellite-based characterization of Medicanes in the GPM era, 17th Plinius Conference on Mediterranean Risks, Frascati, Rome, Italy, 12–15 Oct 2021, Plinius17-27, https://doi.org/10.5194/egusphere-plinius17-27, 2021.

Plinius17-6 | Orals | PL2

Analysis of a hail bearing Mediterranean supercell through weather radars

Mario Montopoli, Errico Picciotti, Luca Baldini, Saverio Di Fabio, Frank Marzano, Marcello M. Miglietta, Alessandro Tiesi, Simone Mazzà, and Gianfranco Vulpiani

In recent years, the Mediterranean area has been affected by a continuous and significant increase in the intensity of violent weather events resulting in floods, hailstorms and tornadoes and an increasing impact on human activities, infrastructure and agricultural production.

Among these extreme events, a particularly intense phenomenon occurred on July 10, 2019 affecting much of the central Adriatic coast. In particular, the Pescara area was affected by a supercell that produced heavy rainfall and an exceptional hailstorm, with hailstones even larger than 10 cm in diameter, causing extensive damage.

This contribution documents, for the first time in Italy, the dynamics, morphology and main characteristics of the Pescara supercell [1] which was simultaneously observed, by two C-band meteorological radars of the national Department of Civil Protection (DPC). The results obtained highlight the irreplaceable role of dual-polarization Doppler weather radars in monitoring the evolution of hail, identifying the mesocyclone initiation and the related updraft and downdraft zones as well as their vertical extension, and highlighting the current limitations in determining the size of hail particles from radar measurements. Numerical simulations with the WRF model, using the HAILCAST module to simulate the evolution of hail, were carried out in order to evaluate the capabilities of an operational model in the simulation of such a particular event.

In the context of the intensification of extreme events, this work is also a food for thought on the main aspects to be addressed in the near future to improve the chain of alerting and modelling of extreme events for prevention and civil protection.

[1] M.Montopoli, E.Picciotti, L.Baldini, S.Di Fabio, F.S.Marzano, G.Vulpiani, "Gazing inside a giant-hail-bearing Mediterranean supercell by dual-polarization Doppler weather radar", Atmospheric Research,  Vol. 264, 15 Dec. 2021, 105852, https://www.sciencedirect.com/science/article/pii/S0169809521004087?dgcid=author

How to cite: Montopoli, M., Picciotti, E., Baldini, L., Di Fabio, S., Marzano, F., Miglietta, M. M., Tiesi, A., Mazzà, S., and Vulpiani, G.: Analysis of a hail bearing Mediterranean supercell through weather radars, 17th Plinius Conference on Mediterranean Risks, Frascati, Rome, Italy, 12–15 Oct 2021, Plinius17-6, https://doi.org/10.5194/egusphere-plinius17-6, 2021.

Plinius17-73 | Orals | PL2

Heavy precipitation events where there’s no rain: Saharan rainfall climatology

Moshe Armon, Andries de-Vries, Francesco Marra, Nadav Peleg, and Heini Wernli

The scarcity of rainfall in the Sahara, the largest desert in the world, turns almost every rainstorm into an “extreme” event. The desert is situated to the south of the Mediterranean’s storm track and north of the equatorial-monsoonal rain belt, at the subsiding branch of both the Hadley and Walker circulation cells. The meager rainfall is observed by just a few rain gauges, recording few rainy days almost every year, occasionally triggering flash floods. Given the low amount of rainfall and the low number of observations, the characteristics of rainfall during such events were seldomly analyzed, especially at the scale of the whole Sahara. In this study, we (a) use high-resolution satellite remote sensing rainfall data (IMERG), to identify thousands of heavy precipitation events over the past 20 years, (b) characterize rainfall properties during these events, and (c) identify the governing atmospheric conditions on days of heavy precipitation using meteorological reanalysis (ERA5) data.

Heavy precipitation events occur throughout the Sahara, except for a small portion of its core. Southern Sahara events are the most frequent and happen mainly in summer. During winter, events occur primarily in the north and west parts of the desert. Preliminary analyses indicate that the events with the largest volume of rainfall (with volumes ≥ roughly the volume of Lake Chad) are characterized by much higher than normal upper-tropospheric temperatures over the eastern Mediterranean and lower temperatures over the southern Sahara.

The small number of events at each location is compensated in our analysis by the huge area of the desert with events occurring on average every second day. The high-resolution datasets we use enable us to characterize small-size events, with substantial implications at the local scale, which can help to cope with natural hazards.

How to cite: Armon, M., de-Vries, A., Marra, F., Peleg, N., and Wernli, H.: Heavy precipitation events where there’s no rain: Saharan rainfall climatology, 17th Plinius Conference on Mediterranean Risks, Frascati, Rome, Italy, 12–15 Oct 2021, Plinius17-73, https://doi.org/10.5194/egusphere-plinius17-73, 2021.

Plinius17-53 | Orals | PL2

Comparison of instantaneous satellite rainfall data and observations from rain gauges network in the Bouregreg-Chaouia region in Morocco

Imane EL Martili, Khalid Barkouki, Jihane Ahattab, and Najat Serhir

Over the last twenty years, remote monitoring of rainfall has become a fact. Thus, techniques to measure rainfall by analyzing satellite data is increasingly integrated in hydrology fields helping to tackle some of scientists’ biggest challenges such as the lack of rain gauges or the difficulty to access their data. 

This work is a study of the reliability and performance of precipitation observation products like PERSIANN-CCS (Precipitation Estimation from Remotely Sensed Information using Artificial Neural Networks-Cloud Classification System) with a temporal resolution of one hour (https://chrsdata.eng.uci.edu/) and like IMERG-GPMv6 (Integrated Multi-satellitE Retrievals for GPM version6) with a temporal resolution of 30 minutes (https://search.earthdata.nasa.gov/search) by using the programming language Python. These satellite-derived data are then compared to precipitation observed from rain gauges in the watershed Bouregreg-Chaouia in Morocco.   

The first procedure was to create a database of hourly rainfall collected from PERSIANN-CCS and IMERG-GPMv6 and based on measured rainfall events received from three rain gauges located in the study area. Afterwards, the comparison between the two data sources was executed through calculation of several statistical parameters such as the Pearson’s R correlation coefficient in addition to an analysis of the dimensionless values of rain (instantaneously observed precipitations from PERSIANN-CCS and IMERG-GPM).

Obtained results show a good correlation between values deduced from satellite imagery and those observed in rain gauges. Quantitively, the “R” correlation coefficients varied from 0.69 to 0.98 in the case of PERSIANN-CCS and from 0.86 to 0.99 in the case of IMERG-GPMv6. Furthermore, analysis of the dimensionless rainfall curves showed that they represent very comparable patterns, especially for the case of IMERG-GPMv6, it was also remarked that the latter dataset overestimated precipitation levels while the first underestimated them in comparison with ground station values. 

We concluded that, it’s possible to use instant rainfall data from satellites in contexts like hydrology for purposes like flood risk assessment. But, a correction of these products is necessary to improve the results and the quality of this data.

How to cite: EL Martili, I., Barkouki, K., Ahattab, J., and Serhir, N.: Comparison of instantaneous satellite rainfall data and observations from rain gauges network in the Bouregreg-Chaouia region in Morocco, 17th Plinius Conference on Mediterranean Risks, Frascati, Rome, Italy, 12–15 Oct 2021, Plinius17-53, https://doi.org/10.5194/egusphere-plinius17-53, 2021.

Plinius17-38 | Orals | PL2

Detection of extreme rainfall events by a network of microwave links in the area of Milan

Roberto Nebuloni, Greta Cazzaniga, Cristina Deidda, Michele D'Amico, and Carlo De Michele

The use of non-conventional rainfall sensors can help to close the gap on rainfall characterization, which is one weak link in the modelling of the Earth’s water cycle. This has been an hot topic in hydro-meteorology for the last decade. In this frame, the EU COST ACTION named OPENSENSE (Opportunistic precipitation sensing network) has been recently approved and is running since October 2021 [1].

Specifically, the point-to-point wireless links massively used by the cellular networks for backhauling, namely, commercial microwave links (CML) have some unique features that render them attractive for rainfall detection [2]. The ubiquitous deployment of CML, the relatively high density of sensors, especially in urbanized areas, and the availability of raw data as outputs of the link quality control process are a strong plus. On the other hand, CML data are owned by mobile operators, hence they are not of public domain, and they are usually not optimized for rainfall measurements. It is therefore important to assess the capability of CMLs to detect the temporal and spatial patterns of precipitation and to quantify precipitation intensity by validation against conventional rainfall sensors where the latter are present and sufficiently dense [3].

In this work, we investigate the capability of CMLs to detect extreme rainfall events analyzing a case study in a large area North of Milan, where a mesh of more than 200 links is present. The region is covered by an operational network of rain gauges owned by ARPA Lombardia and by MeteoSwiss weather radar. Due to the different spatial sampling of CML, rain gauge and radar observations, specific procedures must be envisaged to carry out a fair data comparison. Even though individual CMLs may return large discrepancies in rainfall intensity values with respect to nearby rain gauges, especially in the case of short high-frequency links, it is possible to obtain a good reconstruction of the rainfall patterns of extreme events, without an in-advance calibration through ground truth data.

References:

[1] OPENSENSE COST ACTION official site, https://www.cost.eu/actions/CA20136/ (last accessed on May 2, 2022)

[2] Messer, H. Rainfall monitoring using cellular networks [in the spotlight]. IEEE Signal Processing Magazine 2007, 24, 144–142.

[3] Nebuloni, R.; Cazzaniga, G.; D’Amico, M.; Deidda, C.; De Michele, C. Comparison of CML Rainfall Data against Rain Gauges and Disdrometers in a Mountainous Environment. Sensors 2022, 22, 3218. https://doi.org/10.3390/s22093218

How to cite: Nebuloni, R., Cazzaniga, G., Deidda, C., D'Amico, M., and De Michele, C.: Detection of extreme rainfall events by a network of microwave links in the area of Milan, 17th Plinius Conference on Mediterranean Risks, Frascati, Rome, Italy, 12–15 Oct 2021, Plinius17-38, https://doi.org/10.5194/egusphere-plinius17-38, 2021.

Plinius17-39 | Orals | PL2

GNSS-PWV time evolution in extreme weather events: comparison analysis with lightning and radar-VIL

Alessandra Mascitelli, Stefano Federico, Gianfranco Vulpiani, Mattia Crespi, and Stefano Dietrich

Over the years, there has been an increase in extreme weather events which encouraged the scientific community to employ ever more different techniques for their studies. In this context, GNSS (Global Navigation Satellite System) find its place. Over the last thirty years, this technique has shown increasing applicability and reliability in the field of weather forecasting and analysis. However, there are points that it is critical to continue to investigate; one of the most discussed and noteworthy is the behavior of the GNSS-PWV (Precipitable Water Vapor from GNSS) time course during severe weather events. The relation between GNSS-PWV pattern and weather event evolution appears to be non-constant, sometimes showing a PWV peak at maximum convection, sometimes an advance and sometimes a delay. In this study we try to identify the causes of this unevenness of behavior using the number of lightning as a reference for the trend of convection and the VIL (Vertical Integrated Liquid content) obtained from radar as a term of comparison for the validation of GNSS-PWV.

How to cite: Mascitelli, A., Federico, S., Vulpiani, G., Crespi, M., and Dietrich, S.: GNSS-PWV time evolution in extreme weather events: comparison analysis with lightning and radar-VIL, 17th Plinius Conference on Mediterranean Risks, Frascati, Rome, Italy, 12–15 Oct 2021, Plinius17-39, https://doi.org/10.5194/egusphere-plinius17-39, 2021.

Plinius17-49 | Orals | PL2

NASA MPLNET precipitation detection algorithm validation by ground-based disdrometers in the frame of future ESA Earthcare mission

Simone Lolli, Jasper R. Lewis, Gemine Vivone, Michael Sicard, Ali Tokay, and Ellsworth J. Welton

Lidar measurements can detect exceptionally light precipitation, such as drizzle or virga. This kind of precipitation is really hard to detect by other remote sensing techniques such as radars because a very short longwave (in the visible) is needed due to the small size of raindrops. For those reasons, lidar instruments are well suited to fill a gap in detecting light precipitation. In this study, we show the intercomparison results between the ground-based disdrometer observations and lidar precipitation algorithm detection at Goddard Space Flight center for future precipitation calibration/validation of the next European Space Agency (ESA) Earthcare mission, which is expected to be launched in 2023.

How to cite: Lolli, S., Lewis, J. R., Vivone, G., Sicard, M., Tokay, A., and Welton, E. J.: NASA MPLNET precipitation detection algorithm validation by ground-based disdrometers in the frame of future ESA Earthcare mission, 17th Plinius Conference on Mediterranean Risks, Frascati, Rome, Italy, 12–15 Oct 2021, Plinius17-49, https://doi.org/10.5194/egusphere-plinius17-49, 2021.

Plinius17-74 | Orals | PL2

The Potential of the W-band polarization diversity Doppler radar envisaged for the WIVERN mission for looking into the internal structures of Mediterranean cyclones

Alessandro Battaglia, Frederic Tridon, Antonio Parodi, Martina Lagasio, Vincenzo Mazzarella, and Anthony Illingworth

The WIVERN (WInd VElocity Radar Nephoscope, www.wivern.polito.it) mission, one of the four ESA Earth Explorer 11 mission candidates, currently in Phase-0, promises to complement the ADM-Eolus Doppler wind lidar measurements by globally observing, for the first time, vertical profiles of winds in cloudy areas. This work aims to determine the potential of the new cutting edge WIVERN W-band polarization-diversity Doppler radar for sampling Mediterranean hurricanes and monitoring their internal structure. It builds on the recently developed end to end simulator of the WIVERN dual-polarization Doppler conically scanning 94 GHz radar (Battaglia et al., Atmos. Meas. Tech., 15, 3011–3030, 2022, https://doi.org/10.5194/amt-15-3011-2022). The simulator is applied to: 1) the long-term CloudSat observation dataset of intense cyclones in the Mediterranean basin; 2) a Weather Research and Forecasting (WRF) Model very high horizontal resolution (333 m) run for Medicane Apollo occurred in October 2021. The analysis of the CloudSat results provides statistics for understanding which part of the cyclones can actually be seen by the W-band radar and where line of sight winds can be accurately measured. The high resolution WRF simulation provides insight into wind errors introduced by non-uniform beam filling and small-scale convective motions for the WIVERN observing system.

How to cite: Battaglia, A., Tridon, F., Parodi, A., Lagasio, M., Mazzarella, V., and Illingworth, A.: The Potential of the W-band polarization diversity Doppler radar envisaged for the WIVERN mission for looking into the internal structures of Mediterranean cyclones, 17th Plinius Conference on Mediterranean Risks, Frascati, Rome, Italy, 12–15 Oct 2021, Plinius17-74, https://doi.org/10.5194/egusphere-plinius17-74, 2021.

Plinius17-81 | Orals | PL2

Combined high-resolution rain/wind measurements over extreme wind events using Synthetic Aperture Radar 

Romain Husson, Alexis Mouche, Olivier Archer, Henrick Berger, Aurélien Colin, Charles Peureux, and Gaël Goimard

Spaceborne observations over extreme atmospheric events at global scale such as Tropical Cyclones, Extra-Tropical Cyclones, Polar Lows and Medicanes are a key component in extreme events monitoring and in anticipating appropriate risk mitigation and emergency response at landfall. In particular, meteorological forecasters and numerical modelers need to access various sources of conventional and specialized data/products including remote sensing observations to refine their analysis or adjust their models. 

Recent progresses in SAR processing have shown the potential of C-band SAR data acquired in dual-polarization for estimating at high-resolution (1 km) an ocean surface wind field [1, 2], including extreme events such as major hurricanes (category -3 to -5) [3]. Comparison with SFMR for yield to high correlation (R > 0.90), small bias ( < 0.5 m.s-1) and RMSE ( < 5 m.s-1) [4], including at highest wind speeds (80 m.s-1). 

C-band SAR signal can also be impact by non-wind related signatures. This is particularly true over Mediterranean Sea where strong convective events, associated with heavy precipitations are often met. These deep convections lead to SAR signatures through several processes, either surface and/or volume scattering and can significantly bias the wind estimates if not well delineated. A combined estimation of the wind vector and rain signature is therefore mandatory. 

The present work shows the ability of SAR measurements to provide accurate wind vector estimation, by providing independent wind speed and wind direction estimates [6] as well as a complementary rain rate regression based on Deep Neural Network architecture [5]. This is illustrated over several medicanes or extra-tropical storm use cases and described statistically. 

The provision of these measurements is made possible through CYMS project (Cyclone and Storm Monitoring Service based on Sentinel-1), an ESA funded project since 2020, aiming at monitoring ocean extremes with SAR, in view of its potential integration as part of a Copernicus Service.  

[1] Zhang, B. and W. Perrie, 2012: Cross-Polarized Synthetic Aperture Radar: A New Potential Measurement Technique for Hurricanes. Bulletin of the American Meteorological Society, 93 (4), 531–541 

[2] Mouche Alexis et al. Combined Co- and Cross-Polarized SAR Measurements Under Extreme Wind Conditions. IEEE Transactions On Geoscience And Remote Sensing, 55(12), 6746-6755.  (2017).  

[3] Mouche Alexis et al. Copolarized and Cross‐Polarized SAR Measurements for High‐Resolution Description of Major Hurricane Wind Structures: Application to Irma Category 5 Hurricane. Journal Of Geophysical Research-oceans, 124(6), 3905- 3922. 

[4] Combot Clement et al. “Extensive high-resolution Synthetic Aperture Radar (SAR) data analysis of Tropical Cyclones: comparisons with SFMR flights and BestTrack". Monthly Weather Review, 148(11), 4545–4563. (2020b). 

[5] A. Colin et al. ”Segmentation of rainfall regimes by machine learning on a colocalized Nexrad/Sentinel-1 Dataset”, Living Planet Symposium, May 2022 

[6] Husson R. et al. “Wind Direction Estimation and Accuracy Retrieval from Sentinel-1 SAR Images Under Thermal and Dynamical Unstable Conditions.” In 2021 IEEE International Geoscience and Remote Sensing Symposium IGARSS, 7588–91, 2021. 

How to cite: Husson, R., Mouche, A., Archer, O., Berger, H., Colin, A., Peureux, C., and Goimard, G.: Combined high-resolution rain/wind measurements over extreme wind events using Synthetic Aperture Radar , 17th Plinius Conference on Mediterranean Risks, Frascati, Rome, Italy, 12–15 Oct 2021, Plinius17-81, https://doi.org/10.5194/egusphere-plinius17-81, 2021.

Plinius17-52 | Orals | PL2

Measuring the urban heat island of Rome through a dense weather station network and imperviousness Copernicus Land Monitoring Service data

Andrea Cecilia, Giampietro Casasanta, Igor Petenko, Alessandro Conidi, and Stefania Argentini

Provided that the population living in cities is increasing, projected to reach 5.2 billion in 2030, and that heat waves are getting more intense and lasting as a consequence of the global warming, the urban heat island (UHI) phenomenon is leading increasingly to extremely high temperatures within cities. It is therefore important to find reliable and simple methods for estimating and characterizing at a high resolution the UHI.

In this work we characterize the urban heat island (UHI) of Rome, Italy, during summer, through a dense weather station network. Measurements were collected in summers 2019-2020. We calculate the UHI intensity using a method that relates the air temperature to imperviousness (IMP), which quantifies the presence of artificially sealed surface in a radius around each station using Copernicus Land Monitoring Service satellite data. To assess the reliability of this method we made a comparison with the LCZ-based approach, finding compatible daily trends of UHI intensity, with a fixed bias during night. Our method both simplifies the measurement area classification and allows to determine the UHI intensity even when measurements in totally urban and totally rural areas are not available. The correlation coefficient values between IMP and daily maximum, minimum and mean temperatures were 0.17, 0.81 and 0.82, respectively, evidencing the nighttime UHI peak observed in other cities. The UHI intensity diurnal cycle pattern showed, starting from its minimum of -0.1°C at 10:00 (CET), a progressive increase which intensifies after sunset, reaching a maximum of 3.4°C at midnight. During the night a slight decrease is observed, which exacerbates after sunrise. We did not find a relevant correlation between UHI and heat waves.

How to cite: Cecilia, A., Casasanta, G., Petenko, I., Conidi, A., and Argentini, S.: Measuring the urban heat island of Rome through a dense weather station network and imperviousness Copernicus Land Monitoring Service data, 17th Plinius Conference on Mediterranean Risks, Frascati, Rome, Italy, 12–15 Oct 2021, Plinius17-52, https://doi.org/10.5194/egusphere-plinius17-52, 2021.

Plinius17-57 | Orals | PL2

Atmospheric Precursor of fire hazard: development of a fire-sentinel index for risk management in Abruzzo Region (Central Italy).

Annalina Lombardi, Gabriele Pizzi, Valentina Colaiuda, Fabio Ferrante, Paolo Tuccella, Ludovico Di Antonio, Raffaele Lidori, Daniela Di Fazio, Thomas Malatesta, Jose Maria Costa Saura, Donatella Spano, Vincenzo Rizi, Frank Silvio Marzano, Francesco Luigi Rossi, Silvio Liberatore, Mauro Casinghini, Giuliano Rossi, and Barbara Tomassetti

About 10000 hectares of forest, corresponding to the 12% of the national forestry heritage, are lost each year in Italy due to arson or negligent fires. Consequences on ecosystem and natural equilibrium are relevant, since the time for the natural restoration process may take several decades. Climate extremes exacerbates Mediterranean area fire risk, due to prolonged drought conditions. On the other hand, hydrogeological risk is also expected to increase over burnt slopes, where surface runoff is incremented due vegetation loss. According to the current legislation, fire risk management is in charge of the Italian Regional Civil Protection, therefore the development of user-oriented tools, able to prevent the fire hazardous conditions, is key element to ensure the forest-fire risk management. In the proposed model, the atmospheric conditions preceding a forest fire are estimated thought the combination of air temperature and relative humidity, as reference of atmospheric parameters.The approach assesses how many times the observed air temperature and RH of the previous 12 days area above the critical conditions (i.e., >25°C and < 50%, respectively). The model validation is carried out by using a three-years dataset of forest fires, that hit the Abruzzo region from 2018 to 2020, combined with meteorological data from civil protection gauges’ network. The developed index identified fire-precursors in the 80% of selected case studies. The missing 20% is manly related to the meteorological uncertainty in poorly gauged areas. Starting from the index validation, a pre-operational tool forced with ECMWF analyses is also described.

How to cite: Lombardi, A., Pizzi, G., Colaiuda, V., Ferrante, F., Tuccella, P., Di Antonio, L., Lidori, R., Di Fazio, D., Malatesta, T., Costa Saura, J. M., Spano, D., Rizi, V., Marzano, F. S., Luigi Rossi, F., Liberatore, S., Casinghini, M., Rossi, G., and Tomassetti, B.: Atmospheric Precursor of fire hazard: development of a fire-sentinel index for risk management in Abruzzo Region (Central Italy)., 17th Plinius Conference on Mediterranean Risks, Frascati, Rome, Italy, 12–15 Oct 2021, Plinius17-57, https://doi.org/10.5194/egusphere-plinius17-57, 2021.

Plinius17-76 | Orals | PL2

Identification of the most fire susceptible areas in Portugal 

Patrícia Páscoa, Tiago Ermitão, and Célia M. Gouveia

Mediterranean European countries are considered fire-prone regions, being affected by fire events every summer, and Portugal is among these countries. Moreover, Portugal has been recording large burned areas over the last 20 years. Catastrophic fire season occurrence, associated with hot and dry conditions and high fuel availability in forests, has been recurrently destroying several ecosystems. Furthermore, the Mediterranean basin has been stated with high potential to be one of the most disturbed areas due to climate change, which strongly promotes the increase of fire weather conditions and fire risk and, thereby, the occurrence of more extreme fire seasons.

During the last years, Portugal has been implementing new effective policies regarding the prevention of fires during pre-fire season months, improving the investment in combat strategies. In this context, our study contributes to identify the regions with more potential to burn in a specific fire season. Through satellite-based data and reanalysis products, with large temporal extent and moderate to high spatial resolution, we combine a wide range of variables linked, directly or indirectly, with fire, in order to identify the most exposed regions to burn.

The application of Principal Component Analysis (PCA) to our range of climatological, ecological and biophysical parameters allowed to assess six different regions with more susceptibility to fire events. The central and the southernmost regions of the country presented a stronger signal on PCA analysis, indicating a higher exposure to future fire events. Fuel accumulation during several months, in conjunction with topography, land cover and fire weather conditions were the terms that explained the most variability of the first six PCAs. Therefore, with these results, our work addresses the key trigger parameters of fires, and the most susceptible areas to burn in Portugal, contributing to enhancing the effectiveness of fire prevention policies.

Acknowledgements: This study was supported by FCT (Fundação para a Ciência e Tecnologia, Portugal) through national funds (PIDDAC) – UIDB/50019/2020, and under the projects FlorestaLimpa (PCIF/MOG/0161/2019) and FIRECAST (PCIF/GRF/0204/2017).      

How to cite: Páscoa, P., Ermitão, T., and M. Gouveia, C.: Identification of the most fire susceptible areas in Portugal , 17th Plinius Conference on Mediterranean Risks, Frascati, Rome, Italy, 12–15 Oct 2021, Plinius17-76, https://doi.org/10.5194/egusphere-plinius17-76, 2021.

The damages generated by fire events on vegetation structure and its evolution and the economic impacts on human activity, life and infrastructures have led the scientific interest to develop tools and algorithms able to support the detection and monitoring of burned areas (BAs).

The possibility of monitoring the fire evolution and mapping the BAs has been strongly promoted in last decades by the opportunity to use a significant quantity of satellite observations. Earth observation (EO) data represent one of the key components in supporting both government agencies and local decision-makers in monitoring natural disasters such as wildfires. Among EO instruments, multispectral sensors have demonstrated their suitability for BA mapping, because fire has significant effects on vegetation reflectance. The Copernicus Sentinel-2 (S2) with 20-m spatial resolution and a 5-day return period is a good candidate for near real-time (NRT) monitoring of the fire situation throughout the fire season.

Pulvirenti et al. (2020) proposed an automatic NRT BA mapping approach based on S2 data. They developed the AUTOmatic Burned Areas Mapper (AUTOBAM) tool to respond the need of the Italian Department of Civil Protection in monitoring spatial distribution and numerousness of the BAs during the fire season (June- September) over the Italian territory. It is used, in pre-operational mode, since summer 2019. The atmospherically corrected Level-2A(L2A) surface reflectance products from S2 are used by AUTOBAM: the automatic chain downloads and processes the most updated L2A products available on Copernicus Open Access Hub over the studied area. Then, a change detection approach is applied to the three spectral indices chosen to map BA (Normalized Burn Ratio, the Normalized Burned Ratio 2, and the Mid-Infrared Burned Index). AUTOBAM compares the values of these indices acquired at current time with the values derived from the most recent cloud-free S2 data. The procedure for BA mapping is based on different sequential image processing techniques such as clustering, automatic thresholding, region growing that conduce to a final BA map with grid pixel size of 20m. Finally, a quality flag is included for each AUTOMAB BA to certify a temporal and spatial correspondence with ancillary data, such as active fire products derived from MODIS and VIIRS, as well as national fire notifications.

This processing chain has been tested for the fire seasons of years 2019-2021, and the AUTOBAM-derived BAs have been compared with the burned perimeters compiled by Carabinieri Command of Units for Forestry, Environmental and Agri-food protection. A validation procedure in fact has been realized to verify a-posteriori the ability of AUTOBAM to detect the actual BAs mapped by Carabinieri after local surveys. Timing and spatial criteria are adopted to validate AUTOBAM mapping, and a threshold of 20% overlapping is fixed to make an AUTOMBAM BA classified as a reliable detection. Results indicate that the proposed method has potential for NRT mapping of BAs.

How to cite: Fiori, E., Squicciarino, G., and Pulvirenti, L.: An automatic algorithm for near real-time burned area mapping from Sentinel-2 data: validation results for 2019-2021 fire seasons over Italy, 17th Plinius Conference on Mediterranean Risks, Frascati, Rome, Italy, 12–15 Oct 2021, Plinius17-43, https://doi.org/10.5194/egusphere-plinius17-43, 2021.

Plinius17-71 | Orals | PL2

costeLAB platform: a prototype collaborative environment for research and applications in support to coastal risk management

Laura Candela, Alessandro Coletta, Maria Girolamo Daraio, Ettore Lopinto, Deodato Tapete, Monica Palandri, Daniele Pellegrino, Massimo Zavagli, Angelo Amodio, Antonio Vecoli, Simone Mantovani, and Claudia Giardino

Coastal areas are increasingly becoming more vulnerable due to economic overexploitation and pollution. The Italian Space Agency (ASI) supports the research and development of technologies aimed at the use of multi-mission EO data, in particular of the national COSMO-SkyMed Synthetic Aperture Radar and PRISMA hyperspectral missions, as well as Copernicus Sentinels, through the development of algorithms and processing methodologies in order to generate products and services for coastal risk management.

In this context, ASI has promoted the development of the thematic platform costeLAB as a tool dedicated to monitoring, management and study of coastal areas (sea and land). This platform was developed in the frame of the “Progetto Premiale Rischi Naturali Indotti dalle Attività Umana - COSTE", n. 2017-I-E.0 (http://costelab.asi.it/en/homepage-en/), funded by the Italian Ministry of University and Research (MUR), coordinated by ASI and developed by e-GEOS and Planetek Italia with the participation of National Research Council of Italy (CNR), Meteorological Environmental Earth Observation (MEEO) and Geophysical Applications Processing (G.A.P.) s.r.l. The aim of the project was to define, develop and run in a pre-operational context, an integrated system that exploits Earth Observation data to support the management of coastal areas environmental processes and risks. The platform is addressed to the institutional, scientific and industrial users and allows the study, experimentation and demonstration of new downstream pre-operational services for the monitoring of the coastal area environment and in support to risk management.

The costeLAB platform provides a common entry point for several web-based EO data processing in the field of coastal zone monitoring and emergency management, to generate and visualize products by means of consolidated algorithms that users can utilize for their duty tasks.

The rationale of the platform is to “keep applications close to the data”, i.e. allowing users to access huge amount of EO data relieving them of demanding tasks for big data download and processing in local computers. Users are therefore able to generate reliable products by means of validated algorithms with reduced processing times.

Of the thirty consolidated products that users can generate through the platform (Candela et al., 2021), the paper will showcase in particular those of main relevance for coastal risk management: Coastline change map, Coastal subsidence rate, Landslide activities, Hydrocarbon beaching, Flooding maps, Flood exposure, Erosion exposure, Coastal pollution at national scale, Pollution at coastal scale, under different application scenarios.

Finally, the paper will present experimental scientific products that Researcher Users from CNR generated over selected Mediterranean sites via testing the “collaborative virtual laboratory” namely “Virtual Lab”, i.e. the ad hoc costeLAB facility for researchers and developers to share, test and demonstrate innovative algorithms in order to build new processing chains. These experiments within the platform followed on from dedicated research activities that were carried out on the various components of the marine-coastal environment (land-sea interface) during the costeLAB project. The breadth and novelty of these activities towards an improved understanding of Mediterranean coastal hazards will be presented.

How to cite: Candela, L., Coletta, A., Daraio, M. G., Lopinto, E., Tapete, D., Palandri, M., Pellegrino, D., Zavagli, M., Amodio, A., Vecoli, A., Mantovani, S., and Giardino, C.: costeLAB platform: a prototype collaborative environment for research and applications in support to coastal risk management, 17th Plinius Conference on Mediterranean Risks, Frascati, Rome, Italy, 12–15 Oct 2021, Plinius17-71, https://doi.org/10.5194/egusphere-plinius17-71, 2021.

Plinius17-23 | Orals | PL2

Assessing the Accuracy of Shoreline Evolution Trends Obtained by Using Copernicus Earth Observation Data. Case Study: Mediterranean Coastal Areas

Luca Cenci, Valerio Pampanoni, Giovanni Laneve, Carla Santella, Valentina Boccia, and Clément Albinet

Earth Observation (EO) data characterised by a spatial resolution in the range of 10-30 m (e.g., Sentinel 1 – S1, Sentinel 2 – S2, Landsat series), systematically acquired and freely distributed by national and international space agencies/institutions (e.g., ESA, EU, NASA), are a valuable tool for analysing shoreline evolution trends. These data can be used for supporting coastal erosion hazard and risk management strategies (Cenci et al., 2018). However, the accuracy of such trends is not often quantified because of the difficulties in finding systematic and freely available EO data at Very High Resolution (VHR) concurrently acquired over the same target areas to use as reference.

Within this context, this work was conceived for taking advantage of the Copernicus VHR optical datasets (spatial resolution: 2-4 m) to use as reference data to validate the shoreline evolution trends obtained by exploiting S1 and S2 images. The abovementioned analysis was carried out for a short-term scenario (i.e., 3 years: from 2015 to 2018) in an exemplifying littoral of the Mediterranean Sea characterised by both urbanised and natural coastal areas: i.e., Lido di Ostia (Rome, Italy). Importantly, the shoreline extraction method used in this case study was based on a methodological approach that allowed to map the shoreline positions with sub-pixel precision (Bishop-Taylor et al., 2019; Cenci et al., 2021).

Preliminary results showed that the shoreline evolution trends based on the S2 Visible Near-InfraRed (VNIR) spectral bands (spatial resolution: 10 m) retain an accuracy of 4.5 m (in term of Root Mean Squared Error - RMSE), if compared against the corresponding trends acquired by using Copernicus VHR data with a spatial resolution of 2 m. At the conference, the results of the analysis based on S1 data will be also presented, as well as a thorough interpretation and discussion of the S1 and S2 -based results that take into account the characteristics of the coastal area under assessment (e.g., presence or absence of defence structures) and the relationship between the magnitude of the shoreline advance/retreat trends and the corresponding accuracy. The overall objective of this work is to show the potentialities of the Copernicus EO data for the management of the coastal erosion hazard/risk in the Mediterranean area.

References:

  • Bishop-Taylor R., Sagar S., Lymburner L., Alam I. and Sixsmith J. Sub-Pixel Waterline Extraction: Characterising Accuracy and Sensitivity to Indices and Spectra. Remote Sensing. 2019; 11(24):2984. https://doi.org/10.3390/rs11242984
  • Cenci L., Disperati L., Persichillo M.G., Oliveira E.R., Alves F.L. and Michael Phillips. Integrating remote sensing and GIS techniques for monitoring and modeling shoreline evolution to support coastal risk management. GIScience & Remote Sensing. 2018. 55(3), pp. 355-375.https://doi.org/10.1080/15481603.2017.1376370
  • Cenci L., Pampanoni V., Laneve G., Santella C. and Boccia V. Evaluating the Potentialities of Copernicus Very High Resolution (VHR) Optical Datasets for Assessing the Shoreline Erosion Hazard in Microtidal Environments. AIT Series: Trends in earth observation. 2021. Volume 2, pp. 81-84. ISSN: 2612-7148. ISBN: 978-88-944687-0-0. Published on behalf of the Associazione Italiana di Telerilevamento (AIT) https://aitonline.org/wp-content/uploads/2021/10/PlanetCarefromSpace.pdf DOI: 10.978.88944687/00

How to cite: Cenci, L., Pampanoni, V., Laneve, G., Santella, C., Boccia, V., and Albinet, C.: Assessing the Accuracy of Shoreline Evolution Trends Obtained by Using Copernicus Earth Observation Data. Case Study: Mediterranean Coastal Areas, 17th Plinius Conference on Mediterranean Risks, Frascati, Rome, Italy, 12–15 Oct 2021, Plinius17-23, https://doi.org/10.5194/egusphere-plinius17-23, 2021.

Plinius17-78 | Orals | PL2

DInSAR-based monitoring services for ground deformation retrieval on active volcanoes and seismic regions through spaceborne and airborne radar sensors

Francesco Casu, Paolo Berardino, Manuela Bonano, Sabatino Buonanno, Federica Casamento, Claudio De Luca, Carmen Esposito, Adele Fusco, Riccardo Lanari, Michele Manunta, Mariarosaria Manzo, Fernando Monterroso, Antonio Natale, Giovanni Onorato, Stefano Perna, Yenni Roa, Pasquale Striano, Muhammad Yasir, Giovanni Zeni, and Ivana Zinno

Surface displacement is one of the main parameters to assess the natural hazard in volcanic and seismic regions, as well as in areas affected by landslides and subsidence.

Differential Synthetic Aperture Radar Interferometry (DInSAR) is becoming one of the key techniques to measure ground deformation in any atmospheric conditions, with continuous day and night imaging capabilities and a high accuracy level, thanks to its capability to provide dense measurements at large spatial scale and at relatively low cost.

The increasing diffusion of the use of DInSAR is also due to the large availability of huge and easily accessible SAR data archives, as those acquired, since late 2014, by the Copernicus Sentinel-1 constellation, which is globally and routinely providing C-band SAR data with a defined repeat-pass frequency. Therefore, with such a constant and reliable availability of data, it is possible to use the DInSAR technique for monitoring purposes, such as those related to the measurements of ground motion in natural hazard prone areas.

In this work, we present the operative services and tools that have been developed at CNR-IREA, in the framework of its cooperation with the Italian Department of Civil Protection (DPC), for detecting and monitoring large scale surface deformation through the use of the DInSAR technique.

A first service is focused on seismic areas and relies on the publicly accessible earthquake catalogues. Once an earthquake that likely produces ground deformation occurs, it triggers an automatic DInSAR processing that generates the co-seismic induced displacement maps, by retrieving the relevant pre- and post-seismic Sentinel-1 acquisitions. While being focused on the Mediterranean region the system works at global scale.

A second service is devoted to volcano displacement monitoring. The designed system is fully automatic and the process is triggered by the availability, for every monitored volcano site, of a new SAR data in the Sentinel-1 catalogues acquired from both ascending and descending passes. The data, per each orbit, are automatically ingested and then processed through the well-known Parallel Small BAseline Subset (P-SBAS) DInSAR technique that allows generating the corresponding displacement time series and mean displacement velocity maps. The so-retrieved Line of Sight (LOS) measurements are then combined to compute the Vertical and East-West components of the deformation, which are straightforward understandable by the end user. This service is currently operative for the main active Italian volcanoes (Campi Flegrei caldera, Mt. Vesuvius, Ischia, Mt. Etna, Stromboli and Vulcano), but it can be easily extended to include other volcanic areas on Earth.

Finally, a third tool is based on the use of an airborne platform which is equipped with a X-band and L-band SAR sensor, and that is used in conjunction with the already mentioned systems to provide further information on the areas under study.

Retrieved deformation results and their implication in the understanding of the analyzed phenomena will be discussed at the conference.

 

This work is supported by the CNR-IREA and Italian DPC agreement, the CNR-IREA/MiTE-DGISSEG agreement, the H2020 EPOS-SP (GA 871121), the ASI DInSAR-3M project, and the I-AMICA (PONa3_00363) project.

How to cite: Casu, F., Berardino, P., Bonano, M., Buonanno, S., Casamento, F., De Luca, C., Esposito, C., Fusco, A., Lanari, R., Manunta, M., Manzo, M., Monterroso, F., Natale, A., Onorato, G., Perna, S., Roa, Y., Striano, P., Yasir, M., Zeni, G., and Zinno, I.: DInSAR-based monitoring services for ground deformation retrieval on active volcanoes and seismic regions through spaceborne and airborne radar sensors, 17th Plinius Conference on Mediterranean Risks, Frascati, Rome, Italy, 12–15 Oct 2021, Plinius17-78, https://doi.org/10.5194/egusphere-plinius17-78, 2021.

Earth Observation (EO) data plays an important role in understanding how climate change impacts our environment. However, when considering the ensuing disaster as the result of heavy precipitation for instance, we observe that anthropogenic contributions such as urbanisation and land use change contribute significantly to the risk of a hazard influenced by external factors becoming a disaster (man-made disaster).

The H2020 EOPEN Project (https://eopen-project.eu/) demonstrated possibilities to fuse Sentinel data with multiple, heterogeneous, and big data sources, to improve the monitoring and analysis capabilities of the future EO downstream sector2. Additionally, the involvement of mature ICT solutions in the EO sector shall address major challenges in effectively handling and disseminating Copernicus-related information to the wider user community. A reasonable level of automation was achieved making it possible to establish workflows to implement systematic processing of multiple data sources.

EOPEN3 components are a framework core, a Dashboard environment, application specific extensions and three Pilot Use Cases which demonstrate its usage focused, respectively, on flood risk assessment and prevention, food security and climate change; moreover, the Crop Water Demand module implemented in the H2020 MOSES4 was run through the platform to demonstrate its interoperability.

Some achievements with regards to Mediterranean natural risks are:

PUC1 - Flood risk assessment and prevention - in this use case stakeholders, from offices, from local scale (municipality of Vicenza) to government scale, with specific roles during flood emergencies, have been involved to specify the needed information elements and presentation features to support their current operations; also, the early warning system (EWS) Flood Forecasting System to predict water level of the Bacchiglione river in Vicenza, implemented by the Eastern Alps River Basin District Authority (AAWA), was empowered through access to several additional input data for their hydrological model, such as those available from Copernicus Global Land Services (CGLS) as well as an additional weather forecast, provided by the Finnish Meteorological Service, and maps of the flooded areas generated in the platform.

PUC3 - Climate Change - this use case focused on challenges that climate change brings to the local reindeer herding livelihoods and to the infrastructure and transportation in Finland, which can be a reference for Mediterranean countries facing similar problems in mountainous areas.

While EOPEN achieved a level of processing autonomy, not all aspects of the operational workflow were included. Adding interconnection and feedback mechanisms would significantly reduce human intervention needed to compliment the data and connect the systems that eventually lead to delivering the service in support of decision makers, also interfacing currently used DSS. For example, in the case of PUC1, the system supported the preparedness and partly the response (weather forecast included) phases whereas recovery and prevention actions were not included.

Anticipating future Horizon calls, future EOPEN improvements will address the quality of modelling in particular risk assessment and compounding cascading events, and the connectivity of the various steps of operational workflows thus reducing the need for human intervention simply to create a continuum of the workflow to deliver services.

How to cite: Gale, L. and Scarpino, G.: Federated platforms in support of risk assessment and cascading effects: EOPEN1 - one step done, still more to go , 17th Plinius Conference on Mediterranean Risks, Frascati, Rome, Italy, 12–15 Oct 2021, Plinius17-98, https://doi.org/10.5194/egusphere-plinius17-98, 2021.

The susceptibility (S) of cloud radiative effect (CRE) to aerosols is approximated by satellite retrieval of the fractional change of CRE to a similar fractional change of ln(Nd), where Nd is the cloud drop number concentration [cm-3]. Larger S means larger aerosol cloud-mediated cooling effect with increasing aerosols that can serve as cloud drop condensation nuclei. The full record (2003-2021) of MODIS satellite observations was used to retrieve Nd, cloud fraction (CF), albedo (A) and CRE of boundary layer water clouds over all the world oceans. The susceptibility of CRE over the Mediterranean Sea is found to be exceptionally small compared to the oceans at the same latitude band. The causes for that are:

  • Small albedo susceptibility. It is caused by the large background of Nd, which is more than 200 cm-3 on average – 3 times compared to the oceans at the same latitude band.
  • Small cloud fraction susceptibility especially at the Eastern Mediterranean. It is also caused by the large background of Nd, which suppresses rainfall from shallow clouds that break them up.
  • Small occurrences of events of low clouds – less than half compared to the oceans at the same latitude band.
  • The occurrence of low clouds is only 1/3 of the occurrence over the oceans at the same latitude band.

The CRE susceptibility is the sum of the already small albedo and CF susceptibilities.

The total aerosol cloud-mediated cooling is very small because it is proportional to the CRE susceptibility multiplied by the very small occurrence of low clouds over the Mediterranean.

The probable root cause for all of this is the smallness of the Mediterranean Sea, which is dominant by advection of dry and polluted air from the adjacent continents all around it.

How to cite: Rosenfeld, D. and Cao, Y.: Exceptionally low susceptibility of aerosol cloud-mediated radiative forcing over the Mediterranean Sea, 17th Plinius Conference on Mediterranean Risks, Frascati, Rome, Italy, 12–15 Oct 2021, Plinius17-99, https://doi.org/10.5194/egusphere-plinius17-99, 2021.

PL3 – Hydro-geological effects of extreme events (e.g., floods, landslides, erosions, coastal dynamics, storm surges etc.)

Plinius17-54 | Posters | PL3

Are the effects of risk mitigation measures caught by Italian flood risk maps?

Margherita D'Ayala, Marcello Arosio, and Mario Martina

Flooding constitutes the most frequent and one of the most destructive natural disasters, and every year it affects millions of people worldwide causing loss of life, disruption of commerce and financial networks, loss of business continuity and essential services. Even in Italy, floods represent one of the most widespread extreme events, increasingly common and hazardous.

Data from recent Italian reports highlight that the amount of money spent for risk prevention are not at all comparable to 1.9 billion of euros per year for repair damage and recovery, causing 1:6 ratio between pre- and post-disasters costs.
Hence, the necessity of a deep analysis on the economic and technical criteria used to design mitigation measures for flood risk protection.

The ReNDiS database (Repertorio Nazionale degli interventi per la Difesa del Suolo – National Database of soil protection measures) offers the data for such an analysis and for a comparison between type of hydraulic measures and risk level area obtained from flood risk maps produced by the District Authority of Po Basin.

The results show that flood risk maps do not catch the effect of the risk mitigation measures in terms of benefit. From this, the necessity of new criteria with which maps are produced.

How to cite: D'Ayala, M., Arosio, M., and Martina, M.: Are the effects of risk mitigation measures caught by Italian flood risk maps?, 17th Plinius Conference on Mediterranean Risks, Frascati, Rome, Italy, 12–15 Oct 2021, Plinius17-54, https://doi.org/10.5194/egusphere-plinius17-54, 2021.

Plinius17-66 | Orals | PL3

How is the reverse orographic effect on hourly extreme precipitation reproduced by a high resolution climate model?

Eleonora Dallan, Francesco Marra, Giorgia Fosser, Giuseppe Formetta, Marco Marani, Christoph Schaer, and Marco Borga

Increasing extreme precipitation intensity at short duration is reported in recent literature and related to the global warming. For improving risk management and adaptation to changing climate, it is important to estimate the changes in hourly extremes, because they cause numerous hydro-geological hazards. High resolution climate models (Convection-permitting models, CPMs) resolve the scales at which convective processes occur, and can provide higher confidence in the future estimates of hourly precipitation than coarser resolution models. However, since actual CPM runs are available for short time slices (10–20 years), estimation of extremes by using classical Extreme Value approaches is difficult. Novel methods based on the concept of ordinary event have shown the capacity of deriving reliable frequency analyses from short data records, and they can be successfully applied to CPMs.

Recent literature reported distinct orographic effects on precipitation extremes. In particular, decreasing intensity with elevation for hourly extremes is found (“reverse orographic effect”) as contrasted with the orographic enhancement of precipitation for long durations. The reverse orographic effect was tentatively associated to orography-induced turbulence. These processes could be sub-grid even for CPMs, so it is crucial to understand whether and how CPMs can represent the orographic effect before using the simulations to project future extremes in mountainous areas.

We focus our study on an orographically complex area in the Eastern Italian Alps. Precipitation data comes from: i) ~170 5-min resolution rain gauges (our benchmark), ii) CPM simulations from COSMO model, run at 2.2 km spatial resolution and 1h time-resolution. The model is driven with ERA Interim re-analyses for the period 2000-2009. A storm-based statistical method is applied to both observed and simulated time series, and we use a Weibull distribution for modelling the upper tail of ordinary events. We derive the distribution parameters and extreme return levels up to 20-year return period for durations between 1 and 24 h. We look at their dependence on elevation, and we quantify the bias between observations and CPM, the dependence of the biases with elevation.

Spatial patterns in the CPM biases on the annual maxima and the modelled return levels emerge for short durations, while a general better agreement between model and observation is found at the daily duration. For the 1h return levels, the bias depends on elevation, with increasing overestimation with elevation, which implies a weak representation of the reverse orographic effect.

This work shows that we can have reliable estimates of high return levels from short CPM runs by using proper statistical methods. The results can improve our understanding of the changes in the meteorological processes underlying the changes in the precipitation extremes, and could help us develop adjustment approaches accounting for the role of orography at multiple durations.

How to cite: Dallan, E., Marra, F., Fosser, G., Formetta, G., Marani, M., Schaer, C., and Borga, M.: How is the reverse orographic effect on hourly extreme precipitation reproduced by a high resolution climate model?, 17th Plinius Conference on Mediterranean Risks, Frascati, Rome, Italy, 12–15 Oct 2021, Plinius17-66, https://doi.org/10.5194/egusphere-plinius17-66, 2021.

Plinius17-61 | Posters | PL3

Hydro-geological risk prediction: the operational activity in Abruzzo Region for the rainfall-induced landslides forecasting.

Barbara Tomassetti, Valentina Colaiuda, Giancarlo Boscaino, Paolo Tuccella, Raffaele Lidori, Ludovico Di Antonio, Francesco Luigi Rossi, Adelaide Memmo, Silvio Liberatore, and Annalina Lombardi

Hydrogeological hazard and its related risk prediction is becoming increasingly important in the context of climate change. Since extreme meteorological events, such as drought and intense rainfall, are expected to increase, the continuous update of the Early Warning Systems (EWSs) is particularly challenging, in the context of Civil Protection activities.  The new regulations concerning the organization of the Civil Protection distributed Service strongly reiterates the role of the collaboration with the scientific community, in order to ensure the EWS adaptation to deal with environmental changes. Scientists are called to convert up-do-date research findings to products available to end-users. On the other hand, civil protection should encourage scientific collaborations, with the aim of providing useful and user-friendly instruments to its operators, to increase the effectiveness of risk prediction and early intervention. In this context, the World Meteorological Organization recommends as sample products should be readily available for potential customers. From this conception, the rainfall-triggered landslides prediction system presented in this work was set-up by the Centre of Excellence CETEMPS for the Abruzzo Region Civil Protection institutional activities. The landslides forecasting system is based on the use of the Cetemps Hydrological Model (CHyM), coupled with different meteorological observations (gauges network, weather radar or satellites) and forecasts from limited area models. The landslide hazard is then given at hourly basis over the whole region, as well as, selected areas at risk, though the use of a stress index based on different thresholds.

How to cite: Tomassetti, B., Colaiuda, V., Boscaino, G., Tuccella, P., Lidori, R., Di Antonio, L., Rossi, F. L., Memmo, A., Liberatore, S., and Lombardi, A.: Hydro-geological risk prediction: the operational activity in Abruzzo Region for the rainfall-induced landslides forecasting., 17th Plinius Conference on Mediterranean Risks, Frascati, Rome, Italy, 12–15 Oct 2021, Plinius17-61, https://doi.org/10.5194/egusphere-plinius17-61, 2021.

Plinius17-65 | Posters | PL3

Evaluation of the impact of calibration period for distributed modelling of the hydrological cycle during droughts

Giulia Bruno, Doris Duethmann, Francesco Avanzi, Lorenzo Alfieri, Andrea Libertino, and Simone Gabellani

Drought risk will increase in the next decades due to anthropogenic warming, especially in the Mediterranean region. Therefore, robust hydrological models during droughts are essential tools for disaster risk reduction and climate change adaptation strategies. Yet, many studies showed drops in model performance when simulating periods with different climatic conditions from those of the calibration period, which poses challenges in properly simulating discharge (Q) during droughts. Some works also revealed that these issues may be related to the simulation of evapotranspiration (ET) and changes in terrestrial water storage (TWS) in the catchment, which has been shown to be highly sensitive to the calibration period too. Here, we analyzed how the simulation of Q, ET, and TWS differs according to the selected calibration period and during droughts, thus expanding on previous work on this matter that has mostly focused on Q. We compared two parameterizations of the distributed hydrological model Continuum for the Po river basin over 2009 – 2019. The northern Italian study area is characterized by a transition from continental to Mediterranean climates and experienced two major drought events during the study period (2012 and 2017). The two model parameterizations result from an iterative semi-automated calibration against Q data during a wet period for the first model variant (2018-2019), and during a dry period for the second model variant (2016-2017). We then evaluated the modelling skills in simulating Q, ET, and TWS for the whole river basin and 43 subcatchments in terms of both temporal and spatial variability, using ground-based and satellite-derived data as benchmark. Calibrating during a dry period improved the simulation of Q during low-flow conditions, as expected, though at the expense of model internal consistency, ET, and TWS representation. We also detected a general deterioration of modelling skills in reproducing Q and ET temporal dynamics, as well as ET and TWS spatial patterns, during droughts for both the model variants. Results call for (i) comprehensive evaluation of the output and states of hydrological models across the whole water balance, rather than only Q, to verify their internal consistency and (ii) the development of alternative calibration procedures to improve the distributed modelling of Q, ET, and TWS during dry periods. This is highly needed to properly predict water availability in the different compartments of the hydrological cycle in a changing climate.

How to cite: Bruno, G., Duethmann, D., Avanzi, F., Alfieri, L., Libertino, A., and Gabellani, S.: Evaluation of the impact of calibration period for distributed modelling of the hydrological cycle during droughts, 17th Plinius Conference on Mediterranean Risks, Frascati, Rome, Italy, 12–15 Oct 2021, Plinius17-65, https://doi.org/10.5194/egusphere-plinius17-65, 2021.

Plinius17-84 | Orals | PL3

RESILIENCE Project - Extreme Storms in the Italian North-East: frequency, impacts and projected changes

Eleonora Dallan, Marco Borga, Francesco Marra, Giorgia Fosser, Mario Martina, Marco Marani, Carlo Gregoretti, Emanuele Lingua, Antonio Canale, Massimiliano Massimiliano, Martino Bernard, Maximiliano Costa, Luigi Cesarini, Giorgio Dalmasso, Maria Francesca Caruso, Valentina Zanaga, and Mattia Zaramella

The RESILIENCE project aims at developing  an integrated methodology for assessing the impact of climatic variations and changes on the intense precipitation and wind regimes, and on the consequent triggering of flash floods, debris-flows and wind-related forest damages. A significant increase of short and intense precipitation is expected in the next future due to global warming, with consequent impacts on flash floods and hydro-geomorphic hazards such as shallow landslides and debris flows. Despite their societal importance, only few studies have explored potential climate change effects on these hydrological and hydro-geological processes. In fact, no accepted estimates of such changes to be used in engineering practice or environmental management planning exist so far, nationally or regionally.

The RESILIENCE project tries to address this specific knowledge gap. Two recent scientific advances are at the basis of the development of RESILIENCE. The first advance is the advent of high-resolution climate models, also called Convection-Permitting Climate Models (CPM), which improve the representation of both precipitation and wind field at the sub-daily scales compared to the standard coarser resolution Regional Climate Models. However, due to their computational costs, simulations are currently available for only short (typically ten years) time slices and few emission scenarios. These time series are too short to provide reliable statistics of extremes if analyzed using the classical extreme value methods. A second recent advance in the field of extreme value theory, the Metastatistical Extreme Value Distribution (MEVD), allows to overcome this limitation: it provides reliable extreme event probability estimates even from short time series, as in the case of CPM outputs, since it is based on all “ordinary events'' in the series instead of just yearly maxima or a few “peak-over-threshold” values per year as in the traditional methods.

Given this background, and focusing on the Veneto region in Italy as a study area, the specific objectives of RESILIENCE are 1) to quantify near (2041-2050) and far (2090-2099) future changes in precipitation and wind extremes probability at sub-daily temporal scales with respect to the baseline (1996-2005) using the MEVD approach  and high-resolution COSMO-CLM simulations, 2) to quantify the associated future impacts on flash floods, debris flows and forest damages, 3) to provide data and hazard models to support flood and forest risk management plans in the Italian North-East accounting for future climate changes.

RESILIENCE brings together an interdisciplinary group of scientists, from hydrologists, to climate modelers, to statisticians, to forest science experts, and is based on the interaction with three key Project Stakeholders. The project results will be communicated and disseminated to a wide audience of residents in the Veneto region and beyond, through collaborations with Museums, Academies and Local Authorities.

How to cite: Dallan, E., Borga, M., Marra, F., Fosser, G., Martina, M., Marani, M., Gregoretti, C., Lingua, E., Canale, A., Massimiliano, M., Bernard, M., Costa, M., Cesarini, L., Dalmasso, G., Caruso, M. F., Zanaga, V., and Zaramella, M.: RESILIENCE Project - Extreme Storms in the Italian North-East: frequency, impacts and projected changes, 17th Plinius Conference on Mediterranean Risks, Frascati, Rome, Italy, 12–15 Oct 2021, Plinius17-84, https://doi.org/10.5194/egusphere-plinius17-84, 2021.

Plinius17-88 | Orals | PL3

Statistical methodologies for biases correction of precipitation for a convection-permitting climate model and their spatio-temporal patterns in North-Eastern Italy

Massimiliano Schiavo, Eleonora Dallan, Giorgia Fosser, Francesco Marra, and Marco Borga

We investigate the spatial and temporal patterns of annual and seasonal biases in extreme precipitation simulated by a convection permitting climate model forced with reanalysis data (Era Interim driven COSMO-CLM model) across a 10-years period (2000-2009). Specifically, we aim at developing an adjustment procedure able to preserve extremes at different temporal and spatial scales, and which can be applied to future scenarios.

The biases are here defined as the ratio between simulated and observed rainfall at 130 rain gauges. The quantile-based analysis reveals a general overestimation for gauges located in foothill or mountain areas (elevation > 500 m asl), and a general underestimation over lowland sites. This behavior is recurrent for various investigated quantities, such as annual or seasonal biases, and their counterparts estimated upon Extreme precipitation Values (EV) or wet periods. We also observe a temporal heterogeneity of the biases estimated in different years or seasons. Dry years (e.g. 2003) are characterized by remarkably high biases, while those estimated upon springs and autumns data within the investigation period are generally overestimated and underestimated, respectively.

We explore two preliminary adjustment approaches: Quantile Mapping (QM) and Linear Scaling (LS) adjustments. QM corrects simulated rainfall series but can affect the rainfall temporal autocorrelation. Conversely, LS preserves the autocorrelation but fails in the correction of seasonal and annual biases. EV-related biases are not properly corrected, and further statistical methods need to be formulated to correct EV simulated rainfall while both respecting their ACF and taking into account orographic effects.

How to cite: Schiavo, M., Dallan, E., Fosser, G., Marra, F., and Borga, M.: Statistical methodologies for biases correction of precipitation for a convection-permitting climate model and their spatio-temporal patterns in North-Eastern Italy, 17th Plinius Conference on Mediterranean Risks, Frascati, Rome, Italy, 12–15 Oct 2021, Plinius17-88, https://doi.org/10.5194/egusphere-plinius17-88, 2021.

Liguria region is historically affected by severe hydro-meteorological events often resulting in dramatic death tolls and large socio-economic impacts. On 7-8 October 1970, Genoa, region capital city, was struck by the most catastrophic flood event of its history. On the evening of 7 October pre-frontal storms affected the western side of the city (Voltri, Prà and Pegli municipalities), while on 8 October 1970 an anticyclone block generated recurring convective systems that hit Genoa city and above all the Bisagno Valley. The heavy rainfall continued more than 24 h with highs at Bolzaneto rain gauge (Polcevera Valley, northwest of Genoa city center) where over 950 mm of rainfall in 24 hours was measured. Over the city center and the Bisagno Valley, 400 mm in 24 h was recorded. The Bisagno stream channels overflowed, submerging the city center. The 1970 event in Genoa City was also the most dramatic in terms of damage: 44 fatalities occurred and over 2000 individuals were evacuated.

This study hindcasts the meteorological evolution of this event at high spatial resolution (1.5 km) and temporal one (1 hour) using the Weather and Research Forecasting (WRF) model by downscaling the ERA5 climatology developed by European Center for Medium-Range Weather Forecast (ECMWF). The weather hindcast scenario is compared with available meteorological observations as well as with recorded geomorphological impacts on Genoa city center and municipalities.

How to cite: Parodi, A., Boni, G., Faccini, F., and Paliaga, G.: Hindcast high-resolution simulation of the most catastrophic rainfall event in Genoa City (7-8 October 1970): hydro-meteorological and geomorphological analysis, 17th Plinius Conference on Mediterranean Risks, Frascati, Rome, Italy, 12–15 Oct 2021, Plinius17-89, https://doi.org/10.5194/egusphere-plinius17-89, 2021.

Plinius17-26 | Orals | PL3

Temperature and slope stability in temperate climate

Gianvito Scaringi, Marco Loche, Saeed Tourchi, and Luigi Lombardo

Changes in slope stability can arise from hydro-mechanical processes driven by atmosphere-soil interaction, and these processes are affected by the temperature at which they occur. This is well studied in cold climates, but even at temperatures well above freezing, experiments show significant changes in soil parameters upon comparatively small variations in temperature. These effects are typically neglected in geomechanical models, as their formulations do not typically include temperature or, if they do, they relate it to soil hydrology and not soil mechanics. Therefore, by only focusing on extremes in hydrological forcing, we may be underestimating the role of climate change in landsliding in temperate regions. Within ongoing projects, we are exploring the relationship between temperature and slope stability with various approaches and at various scales. In the laboratory, we are conducting temperature-controlled oedometer tests and ring-shear tests on saturated soils, observing patterns of strengthening or weakening in relation to both the mineralogy and shear rate. We also are evaluating correlations between basic and mechanical properties on the basis of the soil’s response to heating and cooling. We are using such correlations in the field to obtain insights on slope stability, particularly of rock bodies. Focusing on soils, we are developing thermo-hydro-mechanical model formulations for slope stability under climate change. At the catchment scale, we are using statistical tools to find whether a temperature-related variable (such as the land surface temperature) can inform landslide susceptibility models. Insights from debris flow-yielding steep mountain catchments and gentle clay slopes with slow creep processes suggest the significance of temperature and its fluctuations in influencing/controlling gravitational processes also independently of its influence on vegetation and hydrological forcing.

How to cite: Scaringi, G., Loche, M., Tourchi, S., and Lombardo, L.: Temperature and slope stability in temperate climate, 17th Plinius Conference on Mediterranean Risks, Frascati, Rome, Italy, 12–15 Oct 2021, Plinius17-26, https://doi.org/10.5194/egusphere-plinius17-26, 2021.

Plinius17-80 | Orals | PL3

Extreme rainfall estimation in orographically complex ungauged locations

Giuseppe Formetta, Francesco Marra, Eleonora Dallan, and Marco Borga

Quantifying rainfall volumes at varying duration and frequencies (e.g. design rainfall) and their uncertainty is crucial for a reliable design of water related infrastructures, such as flood retention reservoirs, urban drainage systems, spillways, culverts. This is of particular relevance in orographically complex area where extreme rainfall could trigger hydro-geological hazards.

Estimate of the design rainfall and its uncertainty is usually done at-site, i.e. at the position where the rain gauge is located and regionalization methods are required to provide estimates in ungauged locations. 

In this work we exploit the potential of the Simplified Metastatistical Extreme Value (SMEV) statistical framework for the analysis of extreme rainfall based on ordinary events and not only the annual maxima and we evaluated the performances of two different regionalization methods (namely, regionalization of extreme rainfall quantiles and of the distribution function parameters). The performance of the two selected approaches is evaluated by leave one out cross-validation and traditional goodness of fit measures (i.e. percent bias, percent root mean square error, and Kling Gupta efficiency).

The study area is the Alto Adige Region located in the Italian Alps, where 57 rain gauges at sub-hourly and hourly time steps are analyzed.

Preliminary results show that accounting for elevation in the regionalization (Kriging) methods provides better performances and reduce the design rainfall uncertainty in ungauged locations.

How to cite: Formetta, G., Marra, F., Dallan, E., and Borga, M.: Extreme rainfall estimation in orographically complex ungauged locations, 17th Plinius Conference on Mediterranean Risks, Frascati, Rome, Italy, 12–15 Oct 2021, Plinius17-80, https://doi.org/10.5194/egusphere-plinius17-80, 2021.

This work analyses the spatial structure of some extra-ordinary extreme rainfall events (EEEs) in Liguria (NW of Italy). The EEEs affecting the region are often caused by Mediterranean Back-building MCS events which are usually characterized by a very small spatial extent. EEEs produce the annual maximums of precipitation for short durations, commonly used for the probabilistic analysis of rainfall and flood hazard.

The characteristic spatial scale of the EEE analyzed, represented by the cross-sectional dimension of the peak structures, compared with the average rain gauge density shows that the former is often less than or of the same order as the latter.

Rain gauge data are used to obtain statistics of extreme rainfall, usually expressed by rainfall depth-duration-frequency (DDF) curves. This statistical approach relies on the assumption that the maxima observed by the raingauges are matching with the local maxima of the actual event. The lower is the average rain gauge density compared to the characteristic spatial scale of EEEs, the less valid is the aforementioned hypothesis.

The spatial analysis of some recent EEEs in the region underlines that the mismatch between the characteristic spatial scale of the rainfall field and the average rain gauge density can be extremely significant.

This impacts the probability of observing the actual peak rainfall and can lead to an overestimation of the return period associated with the most intense events, which are of interest for the design of hydraulic structures and risk planning.

The dramatic underestimation of the rainfall depth at very high return periods due to the application of traditional statistical methods has been already highlighted as a criticality in the literature, focusing on daily rainfall. This work presents a first attempt to set up a framework to quantify the underestimation of the precipitation peak (or the overestimation of the return period) at sub daily scale as a function of the ratio between the raingauge density and the transversal dimension of the precipitation events.

How to cite: Boni, G., De Angeli, S., Lagasio, M., and Parodi, A.: How the spatial structure of extreme rainfall observed by meteo-radars can impact the estimation of the return period of extra-ordinary events?, 17th Plinius Conference on Mediterranean Risks, Frascati, Rome, Italy, 12–15 Oct 2021, Plinius17-95, https://doi.org/10.5194/egusphere-plinius17-95, 2021.

Plinius17-59 | Orals | PL3

User-oriented indices for rainfall-related hydrogeological hazards prediction at regional scale: validation in Central Italy

Annalina Lombardi, Valentina Colaiuda, Davide Gallicchio, Giancarlo Boscaino, Edoardo Raparelli, Paolo Tuccella, Raffaele Lidori, Francesco Luigi Rossi, Silvio Liberatore, and Barbara Tomassetti

Italy is one of the countries most exposed to hydrogeological risk in Europe. From the hydrological point of view, alluvial phenomena and rainfall-induced landslides have a common origin, since both of them are caused by intense surface runoff causing slope instability or water overflow in the drainage network. In particular, the territory of central Italy has a complex orography, where heterogeneous basins with different areas co-exist. Vast basins such as that of the Tiber, are found in geographical areas contiguous to minor hydrographic basins, which are mainly located along the eastern slope of the Apennines. Due to this complexity of the landscape, the territorial response to precipitation can be different and alluvial phenomena can be the result of different processes, with the precipitation as a common denominator. Floods or flash floods, but also rainfall-triggered landslides represent the main effects at the ground, due to intense or persistent rains. In general, river floods are considered more predictable than flash floods, since the latter are linked to very localized rain events, concentrated over a short period of time. The predictability of landslides is associated with attentive monitoring, based on the definition of rainfall thresholds.In this work, the hydrological model developed by Cetemps (CHyM) is applied for the simulation and detection of areas subjected to hydrological stress of a large geographical domain, which includes all of Central Italy, during diverse severe weather event impacting Central Italy in the recent years. We propose the validation of three different stress indices on a geographical area of ​​about 65 500 km2, including basins of very different sizes and characterized by heterogeneous substrates. The main purpose is to present a unique tool for the forecast on a regional scale of hydrogeological stresses induced by precipitation. The identification of stress conditions is given through the use of indices, able to detect areas affected by floods, flash floods and landslides, also providing a key to discriminate and classify these three different phenomena.

How to cite: Lombardi, A., Colaiuda, V., Gallicchio, D., Boscaino, G., Raparelli, E., Tuccella, P., Lidori, R., Rossi, F. L., Liberatore, S., and Tomassetti, B.: User-oriented indices for rainfall-related hydrogeological hazards prediction at regional scale: validation in Central Italy, 17th Plinius Conference on Mediterranean Risks, Frascati, Rome, Italy, 12–15 Oct 2021, Plinius17-59, https://doi.org/10.5194/egusphere-plinius17-59, 2021.

Plinius17-62 | Orals | PL3

Early Warning System for hydrogeological risk forecasting in mountain environments: The Rio Croso case study.

Barbara Tomassetti, Silvia Ferrarese, Alessio Golzio, Valentina Colaiuda, Marco Luciani, Paolo Tuccella, and Annalina Lombardi

The Italian peninsula has one of the highest hydrogeological risk levels in Europe, characterised by a geomorphologically varied and geologically complex territory. In particular, mountainous areas are characterized by fragile environments that are frequently affected by floods and instability.

The weather events that have struck our country in recent decades have often triggered/reactivated natural instability processes that have been particularly damaging in terms of structures and infrastructure. In mountainous and hilly areas, both muddy-debris flows and surface landslides are particularly widespread. The former is triggered within secondary basins, often fed by surface landslides, and are particularly evident on alluvial conoids, affecting population centers. There are many variables, both meteorological and territorial, that make forecasting these phenomena very difficult.

In view of the intensification of these severe weather events, it is important to set up an advanced hazard forecasting system in mountain locations that allows geological analyses to be integrated with atmospheric and hydrological modelling. In this context, the identification of areas susceptible to landslides cannot be performed using a conventional approach, since hydrological-hydraulic methods have a poor or poor calibration.

In response to the need of fast communication to make the Early Warning System more effective, allowing an immediate assessment of the risk and its spatial and temporal location, we propose the use of specially designed indices that, although deduced from the predicted physical fields, allow warning messages to be provided both on the basis of observed and predicted rainfall, and on the basis of the flow forecasts of the monitored rivers and their main tributaries.

We therefore propose a new approach, based on a forecasting chain that brings together geomorphological information, reliable high-resolution weather forecasts and hydrological models.

In this work, a pre-operational chain was set up, coupling off-line the high-resolution Weather Research and Forecasting (WRF) meteorological model and the Cetemps Hydrological Model (CHyM). Different stress indices were calculated useful to identify the debris flows of the Croso river and possible criticalities on the other river basins.

How to cite: Tomassetti, B., Ferrarese, S., Golzio, A., Colaiuda, V., Luciani, M., Tuccella, P., and Lombardi, A.: Early Warning System for hydrogeological risk forecasting in mountain environments: The Rio Croso case study., 17th Plinius Conference on Mediterranean Risks, Frascati, Rome, Italy, 12–15 Oct 2021, Plinius17-62, https://doi.org/10.5194/egusphere-plinius17-62, 2021.

Plinius17-75 | Orals | PL3

Water-Age Accounting, Fully Distributed Watershed Modeling for Flood Forecasting

Fabio Castelli and Chiara Arrighi

Water-age accounting, and its stable isotopic signature due to fractionation, is becoming a powerful tool in gaining further insights in several science questions related to watershed hydrologic response in extreme weather events and its sensitivity to land and climate changes. Experience is quite limited on fully distributed watershed models capable of explicitly tracking water age and stable isotopes variations along the modelled fluxes. Most of these models rely on a full-mixing simplifying hypothesis inside each model conceptual reservoir, e.g. a soil layer in a computational pixel or a river reach. This hypothesis is known to seriously affect the capability of matching model results with isotope data, especially at time scales much shorter than the seasonal one, hence preventing efficient data assimilation to improve model calibration ad state estimation. We propose here a water age-and-isotope tracking version of the fully distributed watershed model MOBIDIC, which in its standard operational version includes surface energy-mass balance, snowpack dynamics, hydraulic river and reservoir routing, surface-groundwater interactions. An augmented EnKF isotope and river discharge data assimilation framework is also presented based on such a model, aimed at both estimating key model parameters and improving the estimation of river water partitioning among different sources during floods. While input hydrometeorological data used in the experiments refer to real high-flow events on a mid-size mountain basin, synthetic data are generated (with an ideally ‘unknown’ set of model parameters) for river flows and isotopes in a first assimilation efficiency assessment presented here.

How to cite: Castelli, F. and Arrighi, C.: Water-Age Accounting, Fully Distributed Watershed Modeling for Flood Forecasting, 17th Plinius Conference on Mediterranean Risks, Frascati, Rome, Italy, 12–15 Oct 2021, Plinius17-75, https://doi.org/10.5194/egusphere-plinius17-75, 2021.

Plinius17-87 | Orals | PL3

Changes in flood hazards in North Africa and implications for flood frequency analysis

Yves Tramblay, El Mahdi El Khalki, Lahcen Benaabidate, Tayeb Boulmaiz, Hamouda Boutaghane, Hamouda Dakhlaoui, Lahoucine Hanich, Wolfgang Ludwig, Mohamed Meddi, Mahrez Sadaoui, Mohamed El Mehdi Saidi, and Gil Mahé

Maghreb countries are strongly impacted by floods, causing twice as many deaths as in southern European countries in recent decades. However, due to the lack of data accessibility, there are no studies to analyze whether the frequency or intensity of floods are changing at the regional scale. In this work, a recent database of daily river discharge data from 58 basins located in Algeria, Morocco and Tunisia with on average 32 years of complete records over the time period 1970-2017 is considered to analyze the evolution of floods. A peaks-over-threshold sampling of flood events is considered, to detect trends on the annual frequency and the magnitude of floods. The results illustrate the complexity of conducting trend detection in a context of high inter-annual variability, with spurious trends detected in several cases due to isolated extreme events. Overall, few statistically significant trends are detected on the intensity of floods but an increase in flood frequency is detected in one-third of the basins. The results are interpreted in relation to land-use change, river regulation by dams and reservoirs, and climatic change. Recommendations concerning the use of frequency analysis approaches on floods in this region are given.

How to cite: Tramblay, Y., El Khalki, E. M., Benaabidate, L., Boulmaiz, T., Boutaghane, H., Dakhlaoui, H., Hanich, L., Ludwig, W., Meddi, M., Sadaoui, M., El Mehdi Saidi, M., and Mahé, G.: Changes in flood hazards in North Africa and implications for flood frequency analysis, 17th Plinius Conference on Mediterranean Risks, Frascati, Rome, Italy, 12–15 Oct 2021, Plinius17-87, https://doi.org/10.5194/egusphere-plinius17-87, 2021.

PL4 – Socio-economic impacts: exposure, vulnerability, prospectives, and adaptation

Plinius17-13 | Orals | PL4

From scientific knowledge to individual change of habits: the Barcelona Living Lab on extreme events 

Maria Carmen Llasat, Montserrat Llasat-Botija, Raul Marcos, Laura Esbrí, Sandra Racionero, Tomeu Rigo, Joan Gilabert, and Jordi Corbera

Barcelona constitutes a good example of a Mediterranean coastal megacity that can be severely affected by climate change impacts. The urban heat island effect, which is particularly important in Barcelona could magnify direct impacts on health produced by the frequency and intensity increase in heat waves and tropical nights. If we consider the Metropolitan Area of Barcelona (AMB) where 52.8% of its surface area is urban, is possible to see maximum temperatures higher than 35 °C in the city center, with minimum nighttime temperatures above 23°C, while coastal peri-urban areas register 4°C less than in the city. Besides this, in a warmer climate, the risk of floods might also increase. Floods are relatively frequent in the AMB with more than 3 pluvial flood episodes per year and over 7 Million €2015 paid for flood damages between 1996 and 2014 by the national insurance company “Consorcio de Compensación de Seguros”.

Nevertheless, the impacts of these events across the city are heterogeneous and highly dependent on its urban planning, socioeconomic distribution, topography, and the characteristics of the meteorological systems affecting it. As a result, Barcelona resilience has a strong dependence on local factors that must be accounted for in the design of any management plan or adaptation strategy that must be adopted by the municipality, its citizens or socioeconomic actors. In this context of hydrometeorological risks that are going to worsen over time, and with the goal of improving resilience in a sustainable way, the Barcelona Living Lab on Extreme Events (Barcelona LLEE) was born under the auspices of the I-Change (Individual Change of HAbits Needed for Green European transition) project and in collaboration with the C3-RiskMed project.

This communication begins with the knowledge about intense rains, floods, and extreme temperatures in AMB, continues with the strategy that will govern the Living Lab, and ends with the methodological proposal that will govern the experiment. The first part is based in the application of the Local Climate Zones to do a classification of the different land covers and land uses of AMB and obtaining the spatial distribution of temperature at high resolution in present and future scenarios as well as its impact in the risk mortality (Gilabert et al., 2021).  On the other hand, flood events have a heterogeneous effect across the city due to differences in the urban planning, its topography, the distinct socioeconomic distribution, and the intrinsic characteristics of these precipitation systems that have been analysed through the meteorological radar and considering information provided by the company responsible of the drainage system (Esbrí et al., 2021). The second part shows the seven points of the strategy that governs the Barcelona LLEE and pretends to engage citizens and stakeholders in the project for Green European transition.  Finally, the methodology includes the use of the App FLOODUP in the framework of citizen science.

This project has received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement 101037193, and the “Ministerio de Ciencia e Información” (project PID2020-113638RB-C22).

How to cite: Llasat, M. C., Llasat-Botija, M., Marcos, R., Esbrí, L., Racionero, S., Rigo, T., Gilabert, J., and Corbera, J.: From scientific knowledge to individual change of habits: the Barcelona Living Lab on extreme events , 17th Plinius Conference on Mediterranean Risks, Frascati, Rome, Italy, 12–15 Oct 2021, Plinius17-13, https://doi.org/10.5194/egusphere-plinius17-13, 2021.

Plinius17-8 | Orals | PL4

Examining flood damage occurrence at the local level as a function of rainfall, based on insurance claims across an urban Mediterranean region

Katerina Papagiannaki, Vassiliki Kotroni, Kostas Lagouvardos, Antonis Bezes, Vasileios Vafeiadis, Ioanna Messini, Efstathios Kroustallis, and Ioannis Totos

Flood-producing rainfall events often lead to material damage to buildings, vehicles, and infrastructure with a significant cumulative economic impact. Especially in urban areas, vulnerability to floods may vary at the local level, and so are the rainfall amounts likely to trigger flood damages. Insurance claims for flood damages can accurately indicate when and where these occurred. In the frame of the YANTAS project (project code:T2EDK-01108), a detailed insurance claims dataset of one of Greece's most important private insurance companies was used, combined with the dense surface weather station data provided by the METEO unit of the National Observatory of Athens. The aim was to model flood damage occurrence and identify the triggering rainfall thresholds at the local level across the Athens Metropolitan Area. Namely, we used eight-year rainfall observations from 66 meteorological stations and insurance claims on the postal code segmentation for the analysis. Logistic regression was applied to statistically model flood damage occurrence. We further applied the ROC curves to assess the performance of the binary response models and define optimal 24-h rainfall thresholds. The method is performed at the municipal level, as municipalities are the first administration level where decision-making to address the local risks for the citizens is needed. The rainfall thresholds were further classified to estimate and map the local risk of flood damages. The applicability of the detected thresholds in early-warning systems is also discussed.

How to cite: Papagiannaki, K., Kotroni, V., Lagouvardos, K., Bezes, A., Vafeiadis, V., Messini, I., Kroustallis, E., and Totos, I.: Examining flood damage occurrence at the local level as a function of rainfall, based on insurance claims across an urban Mediterranean region, 17th Plinius Conference on Mediterranean Risks, Frascati, Rome, Italy, 12–15 Oct 2021, Plinius17-8, https://doi.org/10.5194/egusphere-plinius17-8, 2021.

Plinius17-97 | Orals | PL4

Challenges related to Climate Change and Identification of Risks and Impacts  in Jerusalem

pinhas Alpert, yoav rubin, and Yitzhaq yosef

Jerusalem City is unique in its diversity of populations with a
total of 936,000 inhabitants (end of 2018) with 62% Jewish and 38% Arabs,
and is located exactly at the border of Mediterranean climate with a significant
variability between the coastal area, including Jerusalem City (annual rainfall
~600 mm) and the most arid zone of the Dead Sea, 20-30 km east of the city
(annual rainfall ~50 mm). The spatial-temporal variation of rainfall
intensity is the main and not well-known driver that generates the majority of flash floods in the nearby Judean Desert. Hence, its monitoring is crucial in this area as in other remote arid areas worldwide.

Recently, extensive research was performed related to global warming potential risks and their effects on rainfall and temperature over the East Mediterranean. Several major risks were pointed out including extreme temperatures, heat waves, colder nights and heavy rainfall. Important to notice is our first super-high-resolution global climate model projections that the ancient “Fertile Crescent” in the Middle East (considered as the cradle of civilization), will nearly disappear during this century by the year 2100 (Kitoh et al. 2008).

Jerusalem temperatures both maximum and minimum show that significant increases occurred during 1950-2020 (based on homogenized dataset, Yosef et al., 2019). Furthermore, enhanced increases are shown to have occurred from the 1980s of the temperature trends which are even more than double of the global average ones. A fact that led to definition of the Mediterranean as a “Hot Spot” of global warming. Comparison of Jerusalem temperatures increasing trends to the coastal upstream Bet Dagan station, at ~40 km to the west does show similar patterns of statistically most significant increases in the region as well as large inter-annual variabilities.

A general reduction in the annual amount was observed in the last four decades over Jerusalem. This tendency is expected to continue and become more pronounced under the "business as usual" scenario of RCP8.5. Some potential socioeconomic impacts will be presented.

How to cite: Alpert, P., rubin, Y., and yosef, Y.: Challenges related to Climate Change and Identification of Risks and Impacts  in Jerusalem, 17th Plinius Conference on Mediterranean Risks, Frascati, Rome, Italy, 12–15 Oct 2021, Plinius17-97, https://doi.org/10.5194/egusphere-plinius17-97, 2021.

Plinius17-77 | Orals | PL4

Exploring space and time dimensions of indirect impacts of floods

Chiara Arrighi and Fabio Castelli

Models for the assessment of direct flood impacts are widely applied, while models for indirect impacts and cascading effects are still in a theoretic and demonstration phase. The division of damage into direct and indirect is commonplace, but interpretations and delineations of what is considered a direct and indirect impact differ. Direct damages are usually associated with the physical contact with flood water, thus almost instantaneous, and generally estimated by stage-damage functions. All the consequences beyond the physical damage are considered indirect impacts and include effects occurring outside the inundated area in space and time. This work presents two modelling frameworks capable of describing the space and time dimensions of indirect flood impacts. The first model simulates the water supply system (WSS) of a metropolitan area and the effect of the service disruption for users in case of floods. The second model simulates the recovery after a flood and it is specifically tailored for describing resilience of art cities, where cultural heritage makes the difference in socio-economic impacts. Both models are applied to the metropolitan area of Firenze (Italy) as a proof of concept. The results show how significant space and time extents of indirect impacts are, when compared to direct ones and this drive the need for a better understanding of system perspectives in flood risk management.

How to cite: Arrighi, C. and Castelli, F.: Exploring space and time dimensions of indirect impacts of floods, 17th Plinius Conference on Mediterranean Risks, Frascati, Rome, Italy, 12–15 Oct 2021, Plinius17-77, https://doi.org/10.5194/egusphere-plinius17-77, 2021.

Plinius17-30 | Orals | PL4

Flood risk to society in Italy: a national scale approach

Paola Salvati, Mauro Rossi, Cinzia Bianchi, Mina Yazdani, and Fausto Guzzetti

Floods are a common type of hazard that globally cause significant economic and societal damage. According to the European Environment Agency (2020) Europe has experienced a large number of catastrophic floods in recent decades, with numerous lives lost. In Italy, a country for which detailed information on the number of flood fatalities is available, in the last decade 2011-2020, 150 deaths, 7 missing people and 68 injured persons were recorded. These figures indicate the severity of the risk posed by flood to people in Italy.  The risk posed by a hazard on the population is assessed using the societal risk, and is typically sized constructing frequency-consequences curves that relate the frequency of the fatal events to the magnitude of the consequences. The latter is measured by the number of the fatalities (the sum of deaths and missing people). Using the historical catalogue of flood fatalities available for Italy, here we propose an approach, tested for all the Italian country and previously used for other natural hazards, such as landslides and earthquakes, to evaluate the spatial and the temporal distribution of societal flood risk from historical point information. The historical catalogue was divided in different time subsets, respectively used to calibrate and validate the model results. The empirical distributions of the frequency of fatal flood events was modelled adopting the Zipf distribution, defined for a population of finite size. The model variables, can be defined as: (i) the largest number of flood fatalities F, (ii) the number of fatal flood events E, and (iii) the scaling exponent of the Zipf distribution s, which controls the relative proportion of low vs. large magnitude floods. To obtain a homogeneous risk assessment across the Italian territory we partitioned the entire Italian territory in a regular square grid and for each grid cell, we selected from the record of historical fatal floods all the events within a circular kernel of variable radius r, (in km). For each sub-set, selected inside the kernel, the Probability Mass Function (PMF) was computed to estimate the value of the Zipf distribution s parameter. Therefore, for each grid cell, the three model variables (F, E, s) are calculated, producing maps to visualize the model results which revealed the complexity of flood risk in Italy for the exposed population.

Despite the difficulty in modelling sparse datasets, the approach provided a coherent representation of societal flood risk in Italy.  We therefore expect the approach to be used to model societal flood risk in other geographical areas for which adequate information on flood events and their fatal consequences is available.

How to cite: Salvati, P., Rossi, M., Bianchi, C., Yazdani, M., and Guzzetti, F.: Flood risk to society in Italy: a national scale approach, 17th Plinius Conference on Mediterranean Risks, Frascati, Rome, Italy, 12–15 Oct 2021, Plinius17-30, https://doi.org/10.5194/egusphere-plinius17-30, 2021.

In spite of substantial improvements in managing flood risk and a large number of governmental initiatives on a different scale, floods still represent a threat to human life. The July 2021 catastrophic flood that affected Germany and neighboring countries, killing more than 200 people, witnesses that citizens can be massively killed by floods in developed countries attentive to flood risk management. Beyond the local factors leading to each death, specific circumstances and individual behaviors are shown to be comparable among different flood fatalities. The collection of these data allows researchers and flood risk managers to explore demographic, behavioral, and situational factors and environmental features of flood-related mortality to promote Disaster Risk Reduction. To answer the lack of standardized data collection on flood fatalities on the European scale, we created FFEM-DB, the multinational Database of Flood Fatalities from the Euro-Mediterranean region. Currently, FFFEM-DB hosts 2,875 flood fatalities from 12 territories (nine of which represent entire countries) in Europe and the broader Mediterranean region from 1980 to 2020 and provides data on fatalities’ profiles, location, and circumstances contributing to the fatal accident. The FFEM-DB is expandable, regularly updated, publicly available, and with anonymized data. Compared to existing disaster datasets containing spare data on flood fatalities, the key advantages are FFEM-DB's high level of detail, data accuracy, record completeness, and the large sample size from an extended area. The present contribution proposes future developments of the FFEM-DB in terms of a) the spatial expansion, covering more regions; b) data sharing by means of a dedicated webgis platform, planned to both support actions of civil protection agencies and promote data diffusion among citizens to raise risk awareness. 

How to cite: Petrucci, O. and the FFEM-DB Team: FFEM-DB: the multinational Database of Flood Fatalities from the Euro-Mediterranean region. Planning a public webgis platform to promote risk awareness and support risk reduction strategies, 17th Plinius Conference on Mediterranean Risks, Frascati, Rome, Italy, 12–15 Oct 2021, Plinius17-11, https://doi.org/10.5194/egusphere-plinius17-11, 2021.

Plinius17-21 | Orals | PL4

I-CHANGE (Individual Change of HAbits Needed for Green European transition) project

Antonio Parodi, Silvana Di Sabatino, Francesca Munerol, Erika Brattich, Pinhas Alpert, Paolo Mazzetti, Francesco Pilla, Maria Carmen Llasat, Gert-Jan Steeneveld, Muhammad Adnan, Fredrik Wetterhall, Katriina Soini, Eskil Welan, Katja Firus, Milan Kalas, Carlo Trozzi, Ephraim Broschkowski, and Seyni Salack

Climate change phenomena represent the most serious threats to human well-being and sustainable development. This affects several dimensions of human life from individual health issues to economic growth, passing through civil protection, with strong impacts on European territories and in several other world regions. The I-CHANGE (Individual Change of HAbits Needed for Green European transition, 2021-2025) project faces the challenge of engaging and promoting the active participation of citizens for addressing climate change, sustainable development and environmental protection in the framework of the European Green Deal , the European Climate Pact and the European Biodiversity Strategy for 2030. The overall driving concept is that citizens and civil society have a central role in the definition of environmental protection and climate action and their direct involvement is essential to drive a true shift and promotion of changes of behaviors towards more sustainable patterns. I-CHANGE represents a change of paradigm achievable through a multi-disciplinary and participatory approach: improvement of data usability - citizen awareness raises through the observation of the environmental impacts of human activities; active participation of citizens - the active involvement of citizens through a set of Living Labs (LLs) located in different socio-economic contexts (Europe, Middle-East and Africa); climate change awareness - the development of clear understanding for citizens of the scientific processes underlying climate change and environmental protections. First year of I-CHANGE activities will be presented and discussed.

How to cite: Parodi, A., Di Sabatino, S., Munerol, F., Brattich, E., Alpert, P., Mazzetti, P., Pilla, F., Llasat, M. C., Steeneveld, G.-J., Adnan, M., Wetterhall, F., Soini, K., Welan, E., Firus, K., Kalas, M., Trozzi, C., Broschkowski, E., and Salack, S.: I-CHANGE (Individual Change of HAbits Needed for Green European transition) project, 17th Plinius Conference on Mediterranean Risks, Frascati, Rome, Italy, 12–15 Oct 2021, Plinius17-21, https://doi.org/10.5194/egusphere-plinius17-21, 2021.

Plinius17-22 | Orals | PL4

Deciphering the impact of hydro-geological hazards on Italian firms: a nation-wide assessment

Samuele Segoni, Stefano Clò, and Francesco David

Landslides and floods are responsible for causalties and economic losses worlwide and Italy is one of the most affected countries. However, despite the relevant damages, little is known on the indirect effects that such hazards exert on the local and national economy.  

In this nation-wide study, the indirect effects od hydro-geological phenomena on Italian firms are assessed by coupling variables concerning Italian firms' competitiviness with a dataset of flood and landslide events. Econometic indicators were defined starting from data provided by organizations such as INPS, ISTAT, CERVED, Tax Registry and Bank of Italy. A geodatabase providig the timing and location of harmful hydro-geological events was compiled by an automated web datamining procedure based on a semantic algorithm scanning internet news. The datasets covers all italian municiaplites in the timespan ranging from 2010 to 2020.

A statistical analysis highlighted that hydro-geological disasters, even the non-extreme ones, may negatively affect the future development of local economies: firms located in municipalities hit by a relevant event face on average a 4.8% increase in the probability of exiting the market with respect to non-impaired firms. Moreover, surviving firms seem to be slightly affected by natural disasters, in particular on the revenue side (-3.5%) and, to a lesser extent, on employment (-1.7%). Acros Italy, these effects are very eterogeneus, depending on the location and the characteristics of th affected firms. The most evident effects are observed in case of micro and small businesses, for those active in services and those located in rural and suburban areas.

How to cite: Segoni, S., Clò, S., and David, F.: Deciphering the impact of hydro-geological hazards on Italian firms: a nation-wide assessment, 17th Plinius Conference on Mediterranean Risks, Frascati, Rome, Italy, 12–15 Oct 2021, Plinius17-22, https://doi.org/10.5194/egusphere-plinius17-22, 2021.

Plinius17-24 | Orals | PL4

A bottom-up approach to forecast and manage water crises in the Turin area

Elisa Brussolo, Christian Ronchi, Alessio Salandin, Roberto Cremonini, and Secondo Barbero

In the last twenty years, the Italian territory has been affected by different water crises, which have affected the main sectors of water use, exacerbating conflicts in different territories between these sectors (concerning the priority use of the resource), and requiring the implementation of emergency procedures for impacts management. The recent drought events of 2017, 2021, and winter 2022 saw areas of the country not typically prone to this type of phenomenon, such as north-western Italy, go into crisis.
The term “water crisis” identifies the phenomenon for which the water shortage (a condition resulting from a demand for a resource exceeding the natural availability of renewable resources) reaches a severity demanding a series of management procedures for the phenomenon.
Future water security will depend on the magnitude, rate, and regional details of meteo-climatic changes and non-climatic factors such as agricultural practices, water demand, and governance: improving aspects of water management will be a key to winning adaptation measures. Since drought can be defined in several ways, there are potentially different responses under a warming climate depending on the drought type. Beyond a lack of precipitation, changes in evapotranspiration are critical components of drought, because these can lead to soil moisture declines. Under very dry soil conditions, evapotranspiration becomes restricted and plants experience water stress in response to increased atmospheric demand. Human activities and decision-making have a critical impact on drought severity. The discrepancy between water shortage and the unavailability of the water resource to meet water demand is a function of socio-economic vulnerabilities and gaps in water governance.
In this framework, uncertainty in future water scarcity forecasting and projections makes water security risk assessment and adaptation strategies a top priority scientific challenge: a bottom-up approach for forecasting and managing water crises is particularly advantageous.
Considering the Turin area, Italy, after identifying the events that moved the drinking water supply sources towards crisis, meteorological data and appropriate drought indexes have been analyzed. Critical thresholds and parameters have been identified as a function of water supply sources and response time.
A first forecasting chain was tested to provide monthly forecasts to assess the overcoming of these thresholds for operational purposes.

How to cite: Brussolo, E., Ronchi, C., Salandin, A., Cremonini, R., and Barbero, S.: A bottom-up approach to forecast and manage water crises in the Turin area, 17th Plinius Conference on Mediterranean Risks, Frascati, Rome, Italy, 12–15 Oct 2021, Plinius17-24, https://doi.org/10.5194/egusphere-plinius17-24, 2021.

Plinius17-45 | Orals | PL4

Vulnerability of maize, barley, and wheat yields to growing season temperature and socioeconomic indicators in Morocco

Soumia Achli, Terence Epule Eplule, Driss Dhiba, Abdelghani Chehbouni, Salah Er-Raki, and Wiam Salih

Africa's agricultural growth will be complicated by climate change, which is expected to worsen already difficult conditions. In many cases, agricultural yields are becoming more volatile due to deteriorating weather conditions. Climate change is likely to exacerbate severe extreme events by increasing temperatures and further altering rainfall patterns. In Morocco, the historical record depicts a situation characterized by increasing temperatures and diminishing precipitation, which often ends up in severe drought episodes and affects crop production. This study investigates the vulnerability of wheat, barley, and maize to fluctuations in growing season temperature as well as socioeconomic proxies of adaptation capacity such as literacy and poverty rates in Morocco at both national and sub-national scales. A composite vulnerability index is adopted in this research; it posits that vulnerability is a function of the exposure index, sensitivity index, and adaptive capacity index. FAOSTAT and the yield gaps Atlas provided the national and sub-national crop yield data required to compute the sensitivity index. The world bank climate portal is utilized to obtain mean annual growing season temperature data at both national and subnational scales and is used to calculate the exposure index. Finally, the world bank, figshare, and MPR archives are used to acquire proxy data on adaptive capacity in the form of literacy and poverty rates. The results indicate that wheat has the lowest vulnerability index and the highest adaptive capacity index, while barley has the highest vulnerability index and the lowest adaptive capacity index. Maize falls somewhere in the middle with median indexes. Another notable observation is that the coefficient of determination R2 for all crops is generally very low, indicating that temperature during the growing season is a very strong yield determinant. Sub-nationally, Vulnerability indexes and normalized growing season temperature decrease as one moves northwards, whereas the adaptive capacity index increases. Also, at each latitude northward wheat records the lowest vulnerability index and the highest adaptive capacity index as well as, the second-highest normalized growing season temperature after maize. Furthermore, these findings have significance for establishing climate change adaptation or coping techniques, cereal responses, and adaptation to variation in temperatures, as well as the mechanisms underlying heat tolerance development and socioeconomic indicators for key crops that should be included in the Moroccan Agricultural Transformation Agenda.

How to cite: Achli, S., Epule Eplule, T., Dhiba, D., Chehbouni, A., Er-Raki, S., and Salih, W.: Vulnerability of maize, barley, and wheat yields to growing season temperature and socioeconomic indicators in Morocco, 17th Plinius Conference on Mediterranean Risks, Frascati, Rome, Italy, 12–15 Oct 2021, Plinius17-45, https://doi.org/10.5194/egusphere-plinius17-45, 2021.

Plinius17-58 | Orals | PL4

A combined flood-seismic resilience-based planning framework to improve the recoverability of urban settlements

Soheil Mohammadi, Serena Cattari, Francesca Pirlone, Giorgio Boni, and Silvia De Angeli

According to UNDRR terminology, resilience is the ability of a system, community, or society exposed to hazards to resist, absorb, accommodate, adapt to, transform, and recover from the effects of a hazard in a timely and efficient manner, including through the preservation and restoration of its essential basic structures and functions through risk management. Damages to urban physical structures caused by consequent and/or interacting natural hazards create a complex and challenging post-disaster environment. Many functions provided by the affected structures are disrupted and consequently, systemic processes, including recovery, are impaired and delayed. Despite its criticality, recovery is the less explored phase in the disaster management framework, specifically from a pre-disaster perspective, in terms of planning and actions for better recovery before disasters occur.

This work presents a modeling framework to determine which infrastructures and with what level of functionality in an urban system, after a disaster, can ensure that the system can efficiently go through the path of the recovery process. The final goal is to increase the overall resilience of the urban settlements from multiple hazards. This research question is addressed considering (i) multiple functionalities (e.g. economic, social, health, etc.) of the territorial elements; (ii) the potential interactions and interdependencies among them as well as the overall functionality of the system; (iii) a multi-hazard risk perspective, considering both flood and seismic hazard scenarios; (iv) pathway and goal of the recovery process able to ensure not only the prioritization of recovery interventions but also the improvement of system resilience according to a ‘build back better’ perspective.

First, the main results of a critical review of existing literature and guidelines on disaster recovery are provided with the twofold aim of identifying current gaps and providing the layout to develop a multi-hazard framework for decision-making and investments optimization in pre-disaster recovery planning. As a first step of the framework definition, the essential urban structures that contribute to economic, social, cultural, demographic, environmental, governmental, and community functions, and their interdependencies are identified. Then, the contribution of each structure to the overall functionality of the urban system is determined using quantitative data and qualitative data. Stakeholders’ priorities and needs for going through a good recovery are also integrated into the approach thanks to structured stakeholder-engagement activities based on a participatory approach. The influence of the hazards on the system is evaluated by imposing multi-hazard risk scenarios of floods and earthquakes, considering various levels of interaction between them (hazard, exposure, vulnerability, risk, DRR measures).

The developed modeling framework represents the basis for the implementation of a quantitative tool for decision-makers to find and plan the optimal investment alternatives to increase the system’s resilience under a limited budget.

 

How to cite: Mohammadi, S., Cattari, S., Pirlone, F., Boni, G., and De Angeli, S.: A combined flood-seismic resilience-based planning framework to improve the recoverability of urban settlements, 17th Plinius Conference on Mediterranean Risks, Frascati, Rome, Italy, 12–15 Oct 2021, Plinius17-58, https://doi.org/10.5194/egusphere-plinius17-58, 2021.

PL5 – Safeguarding and management of cultural and natural heritage at risk from climate extreme events

Plinius17-44 | Orals | PL5

Safeguarding of the Villa Romana del Casale UNESCO site from severe weather events: the case study of Apollo medicane occurred in October 2021

Fernanda Prestileo, Alessandra Mascitelli, Guido Meli, Marco Petracca, Claudio Giorgi, Davide Melfi, Silvia Puca, and Stefano Dietrich

In response to damage resulting from the natural phenomena of aging and decay but also from the occurrence of disasters (earthquakes, floods, fires, etc.), the conservation strategies of cultural heritage (whether it is movable or immovable) inevitably require a methodological approach aimed at planned conservation and preparedness for the risk event of the cultural site. Between 2007 and 2012, in this context, the intervention of recovery and conservation of the archaeological site of Villa Romana del Casale in Piazza Armerina (Sicily, Italy), UNESCO World Heritage Site (since 1997), was realized.

The project, directed by the Centro Regionale per la Progettazione e il Restauro, Regione Siciliana, was aimed not only at performing the conservative intervention of the monumental site and its decorative apparatus, but also at drawing up a protocol for preventive maintenance. This protocol concerned the new covering system of the archaeological site, its protection and fruition, as well as the hydrogeological asset of the territory on which it rises. In this frame, since the early Middle Ages the fonts document serious floods that interested the area on which the Villa del Casale is located. These floods inevitably interacted with its conservation history, even influencing its existence. The damages caused by the flood of October 1991 are documented, when the archaeological area was already excavated thanks to the archaeological campaign directed by the archaeologist Gino Vinicio Gentili. These excavations were themselves influenced by the flood of 1951 that covered the area still partially explored. In this study, after considering the damage caused by the previous weather event of October 1991 on the UNESCO site, the occurrence of October 2021 and the construction’s positive response to the stress caused by the meteorological phenomenon are analysed.

The investigation was carried out using ground-based and satellite-based measurements, to provide a detailed overview of the extreme event that occurred, to identify the pressures that insisted on the studied site. The analysis highlights the effectiveness of recovery and conservation project carried out on the monumental complex and completed in 2012.

Keywords: UNESCO site, Archaeological area, Meteorology, Extreme weathers, Flooding, Safeguarding

References

- Meli, G. (Ed.) (2007). Progetto di recupero e conservazione della Villa Romana del Casale di Piazza Armerina, Palermo, Collana I Quaderni di Palazzo Montalbo. I Grandi Restauri, 12/1, C.R.P.R., Palermo.

- Coletta, V., Mascitelli, A., Bonazza, A., Ciarravano, A., Federico, S., Prestileo, F., Torcasio, R.C. & Dietrich, S. (2021). Multi-instrumental Analysis of the Extreme Meteorological Event Occurred in Matera (Italy) on November 2019. In International Conference on Computational Science and Its Applications (pp.140-154). Springer, Cham.

- Prestileo, F., Mascitelli, A., Meli, G., Petracca, M., Giorgi, C., Melfi, D., Puca, S. & Dietrich, S. (2022). Resilience of cultural heritage in extreme weather conditions: the case of the UNESCO Villa Romana del Casale archaeological site’s response to the Apollo Medicane in October 2021. In International Conference on Computational Science and Its Applications (In Press). Springer, Cham.

How to cite: Prestileo, F., Mascitelli, A., Meli, G., Petracca, M., Giorgi, C., Melfi, D., Puca, S., and Dietrich, S.: Safeguarding of the Villa Romana del Casale UNESCO site from severe weather events: the case study of Apollo medicane occurred in October 2021, 17th Plinius Conference on Mediterranean Risks, Frascati, Rome, Italy, 12–15 Oct 2021, Plinius17-44, https://doi.org/10.5194/egusphere-plinius17-44, 2021.

Plinius17-48 | Orals | PL5

Data, product and service from Copernicus program to support Cultural and Natural Heritage monitoring, protection and management. 

Nico Bonora, Alessandra Bonazza, Daniele Spizzichino, and Andrea Taramelli

During the last decades, there has been quickly increasing awareness of the need for efficient, science-based tools, to be used to monitor and protect cultural and natural heritage. Indeed heritage assets are increasingly at risk because of the impact of natural and anthropogenic hazards, the frequency and intensity of which continue to be amplified and worsened by climate change. The protection of archaeological sites and monumental complexes in the age of mass tourism and climate change represents a growing challenge that can only be addressed by integrating management models and best practices. In this context, the innovative application of remote sensing technologies and Copernicus data and information could certainly constitute a turning point as demonstrated in other transversal areas. Sites and monuments are affected by various anthropogenic environmental pressures, acting in synergy, that impact them with varying frequency and intensity both in space and time. Therefore, long-term monitoring of prioritised environmental and climate parameters and indicators, at proper spatial and temporal resolution, is a key requirement for setting up action plans and strategies of sustainable management. This monitoring should rely on the integration of data from remote sensing and in situ measurements, along with climate modeling and forecasting outputs.  The present paper aims to summarize the work and outcomes conducted by the Task Force Copernicus Cultural Heritage (CCHTF) to evaluate the uptake extent in the field of Cultural Heritage management by the Copernicus Committee. The objective of CCHTF was to assess the current and future potential of Copernicus data, services and products uptake by users, and identify the possible Copernicus architectural solutions to support data and/or information access. The CCHTF was composed by the Member States’ (MS) national experts, from both the Cultural Heritage and Earth Observation domains, officially coordinated by Italy and chaired by the Italian Ministry of Culture. The CCHTF included an extended range of stakeholders (research and business communities, public authorities, policy and decision makers, operational bodies and social players), who provided a set of users’ needs, extending across the different cultural heritage disciplines.

The interaction with the Copernicus Entrusted Entities responsible for the Service, Space and in-situ component developments resulted in the identification of a number of further Copernicus products, suitable for support of CH users’ activities; these mostly stem from the Global Land Component, Atmosphere, Climate Change and Marine monitoring Services, as well as Emergency and Security. At the end of the users consultation phase, 41 specific requirements were identified. After that, the matching of the identified requirements with the Copernicus capacity was addressed, identifying 31 requirements partially or completely satisfiable by the current Copernicus products. As general outcome we can say that cultural heritage sector stands to benefit greatly from an increased use of remote sensing technologies. It is also expect that the use of Copernicus capabilities by cultural heritage stakeholders will produce innovative new methods and approaches to cultural heritage protection and management. This importance must urgently be reflected by substantial and sustainable investment into all of the EU’s relevant technological programs.

How to cite: Bonora, N., Bonazza, A., Spizzichino, D., and Taramelli, A.: Data, product and service from Copernicus program to support Cultural and Natural Heritage monitoring, protection and management. , 17th Plinius Conference on Mediterranean Risks, Frascati, Rome, Italy, 12–15 Oct 2021, Plinius17-48, https://doi.org/10.5194/egusphere-plinius17-48, 2021.

Due to heavy anthropogenic pressure suffered by large areas of our countries, extreme climate events such as heavy rainfalls, potentially followed by flooding, are having a growing impact on the environment. Historic towns are particularly exposed to these threats, which are becoming increasingly frequent and, in some cases, may have a devastating effect on the territories and population. Such critical occurrences, with reference to the catastrophes they can lead to and how fast they can occur, are referred to as Slow-Onset Disasters (SODs), and Rapid Onset Disasters (RODs). In this context, GNSS observations can help to develop new tools aimed at tackling the effects of these events on the built environment and their users. With this aim, a Continuously Operating Reference Station (CORS), based on GNSS observations, named SNIK, was installed by the research group Applied Geomatics Laboratory (AGlab) at the Polytechnic University of Bari, with the support of Stonex Italy, while an integrated test field, consisting of four GNSS rover receivers was planned to be implemented on the new Rectorate building, currently under construction. The SNIK CORS is based on a high-precision Stonex SC2200 GNSS receiver equipped with a SA1500 choke-ring antenna. The test field is set up to be upgraded with additional sensors, such as SAR corner reflectors, accelerometers, and weather stations. The availability of a continuous stream of GNSS observations wants to help and facilitate the development of integrated approaches aimed at the early detection of the occurrence of potentially catastrophic events over the short and long-term period and the implementation of strategies for the mitigation of their impact on the safety and the healthiness of the built environment and cultural heritage, which is intrinsically more prone to be damaged.

How to cite: Sonnessa, A. and Tarantino, E.: GNSS observation for reducing the impact of Slow and Rapid Onset Disasters on cultural heritage – the SNIK CORS, 17th Plinius Conference on Mediterranean Risks, Frascati, Rome, Italy, 12–15 Oct 2021, Plinius17-51, https://doi.org/10.5194/egusphere-plinius17-51, 2021.

Plinius17-91 | Orals | PL5

The extraordinary plan for monitoring and conservation of Italian cultural heritage

Daniele Spizzichino, Marica Mercalli, Paolo Iannelli, Carlo Cacace, Antonia Pasqua Recchia, Alessandra Bonazza, Paolo Mazzanti, and Claudio Modena

The present paper illustrates and summarizes the activities carried out so far for the implementation of the first “Extraordinary National plan for monitoring and conservation of Italian cultural heritage”. This initiative is part of the wider context of the institutional activities of the Ministry of Culture - General Directorate for the Safety of Cultural Heritage, aimed at the conservation and protection of cultural heritage, and specifically on its safeguarding towards the impacts from different risk factors, including climate-induced extreme events. This two-year plan has 2 fundamental pillars and targets: 1) to carry out both remote and in situ integrated monitoring systems of the most vulnerable monuments and sites (e.g. bell towers, monumental complexes, archaeological areas in urban, coastal and remote areas) in relation to their structural and environmental level of different risks; 2) to provide a decision support tool (e.g. an integrated monitoring system, DSS) for supporting owners and managers of immovable Cultural Heritage to activate the necessary procedures and any subsequent conservation and preventive intervention and measure. With reference to the satellite downstream services, to be provided in the context of the National Mirror Copernicus Program, the implementation of the aforementioned Plan is therefore useful for updating the knowledge resources, already available in the various information systems and repositories of the Ministry (e.g. Carta del Rischio and SecurArt projects), as well as the main data aimed at the architectural and structural characterization of the whole CH. In this first year, the technical committee purposely set up by the General Directorate for the Safety of Cultural Heritage, implemented and initiated the following activities through 10 work tasks which include: 1) agreements with research bodies and governmental institutions; 2) general plan management and technical support; 3) sensor installation for on-site monitoring activities; 4) integration of different monitoring technologies and calibration by use of satellite monitoring techniques; 5) implementation and filling of specific datasheet for the vulnerability assessment; 6) creation of an IT dashboard for the development DSS, data management and interoperability between systems; 7) adaptation of existing IT structures and purchase of those necessary for local sites managements, satellite data management and post-processing services; 8) evolution of a unique information system (new dashboard) integrated with the Carta del Rischio and SecurArt, also by the use and implementation of satellite data and in situ monitoring; 9) general implementation of national monitoring plan integrated by and in situ sensors; 10) test validation in different areas at diverse scales: identification of sites, monuments and buildings differentiated by typologies, risk, relevance, installation of systems for monitoring, degradation and potential damage. As part of the plan, at least 18 test areas have already been identified throughout the whole country. At the same time, the filling survey and the implementation of the IT dashboard were launched

How to cite: Spizzichino, D., Mercalli, M., Iannelli, P., Cacace, C., Recchia, A. P., Bonazza, A., Mazzanti, P., and Modena, C.: The extraordinary plan for monitoring and conservation of Italian cultural heritage, 17th Plinius Conference on Mediterranean Risks, Frascati, Rome, Italy, 12–15 Oct 2021, Plinius17-91, https://doi.org/10.5194/egusphere-plinius17-91, 2021.

Plinius17-93 | Orals | PL5

Risk assessment and vulnerability evaluation of cultural landscapes exposed to extreme events linked to climate change: the Wachau case study

Alessandro Sardella, Linda Canesi, Riccardo Cacciotti, Anna Kaiser, and Alessandra Bonazza

It is widely recognized that climate change is creating continuous and new challenges for the protection and conservation of cultural heritage and it is foreseen that the frequency and intensity of extreme events such as heavy rain, flooding, prolonged drought periods, are likely to increase in the near and far future throughout Europe.

The present contribution aims to study the Wachau valley in Austria, taken as example of cultural terraced landscape exposed to climate change related challenges, and especially to its risk assessment and vulnerability evaluation. In order to do that, methodologies and tools developed within the Interreg Central Europe project STRENCH (STRENgthening resilience of Cultural Heritage at risk in a changing environment) were exploited, particularly the “Risk mapping tool for cultural heritage protection, WebGIS tool”. Methodology for vulnerability ranking, time series based on earth observation data (e.g. Copernicus C3S reanalysis products) and future hazard maps at territorial level based on outputs from regional and global climate models (EURO Cordex experiment) available within the WebGIS Tool were mainly applied and exploited.

Outcomes include a numerical quantification of the vulnerability for two dry-stone wall terraced areas taken into consideration and climate projections of the changes of the extreme indices R20mm, R95pTOT and Rx5day with spatial resolution of 12x12 km for the near (2021-2050) and far (2071-2100) future, under stabilizing (RCP 4.5) and pessimistic (RCP 8.5) scenarios. A general increase of the three indices in the two investigated areas in the far future under the pessimistic scenario is foreseen, highlighting a high likelihood of heavy rain and flooding risk. The results obtained could therefore support policy and decision-makers in defining strategies for the protection of cultural heritage, assisting local stakeholders in improving their know-how on the process of defining priorities of intervention (preparedness / emergency / recovery).

How to cite: Sardella, A., Canesi, L., Cacciotti, R., Kaiser, A., and Bonazza, A.: Risk assessment and vulnerability evaluation of cultural landscapes exposed to extreme events linked to climate change: the Wachau case study, 17th Plinius Conference on Mediterranean Risks, Frascati, Rome, Italy, 12–15 Oct 2021, Plinius17-93, https://doi.org/10.5194/egusphere-plinius17-93, 2021.

PL6 – Impacts of climate change and extremes on ecosystems and agriculture

Desertification processes affect ground surface properties and soil-water availability, thus impacting vegetation dynamics and ecosystem functioning. Semiarid areas – encompassing the major part of grazing lands and providing a wide range of ecosystem services – are subjected to both ‘natural’ and anthropogenic degradation processes. Afforestation has been widely accepted as an effective means of halting land degradation and adapting to climate change. However, recent studies have shown that dryland afforestation might adversely affect geo-ecosystem functioning.

Across the Israeli drylands, afforestation projects have been implemented by the Keren Kayemet Le’Israel (KKL) to restore degraded lands. These projects rely on harvesting water overland flow and are designed to accumulate runon water, sediments, and nutrients from runoff contributing source areas. Such systems have been established both in hillslopes and valleys, allowing the support of woody vegetation, such as trees and shrubs.    The most common runoff harvesting systems in the northern Negev region are contour bench terraces (in hillslopes) and limans (in valleys). In the hillslope-afforestation systems, the woody canopy coverage area varies from 0.1% in the youngest planting areas to ~1.0% in the eldest areas.

In this study, we analyzed the temporal development of different planted sites in the Ambassador’s afforestation land. The area has been under afforestation since 2005. For this study, we selected four sites within the afforestation area, including (1) undisturbed, control hillslopes, where no water harvesting systems nor tree planting have been conducted; (2) hillslopes that were planted just before the hydrological year of 2005; (3) hillslopes that were planted just before the hydrological year of 2009; and (4) hillslope that were planted just before the hydrological year of 2016.

Long-term analysis of meteorological trends revealed that the area had been subjected to substantial climatic change. A decadal rate increase of 0.45°C was observed in air temperature, while a 1.3% decrease in (minimal) relative humidity. Although a long-term change in evapotranspiration has not been detected, summer values have been significantly increased.

For each of the afforestation sites (2005, 2009, and 2016), a significant reduction in seasonal Normalized Difference Vegetation Index (NDVI) values were recorded compared to the undisturbed slopes, a trend that took place until the establishment of runoff harvesting systems. However, in the 2005 and 2009 sites, the NDVI seasonal average was significantly higher after the establishment of runoff harvesting systems than that in the prior seasonal values, as well higher than that in the undisturbed hillslopes. At the same time, in the newly disturbed sites planted in 2016, the average seasonal values were substantially lower after the establishment of runoff harvesting systems than those in the prior year.

How to cite: Argaman, E., Borow, N., and Stavi, I.: Long-term effects of water harvesting systems on soil and vegetation dynamics in a semiarid region, Israel, 17th Plinius Conference on Mediterranean Risks, Frascati, Rome, Italy, 12–15 Oct 2021, Plinius17-17, https://doi.org/10.5194/egusphere-plinius17-17, 2021.

Plinius17-94 | Posters | PL6

Climate suitability analysis in the context of EFSA Pest Risk Assessment. Amyelois transitella, the navel-orange worm, as a case study

Caterina Campese, Ewelina Czwienczek, Giuseppe Stancanelli, Wopke van der Werf, and Andrea Maiorano

The European Food Safety Authority (EFSA) conducts plant pest risk assessment (PRA) under the mandate of the European Commission, the European Parliament and the Member States. The analysis of potential pest establishment is a key element of PRA and it is based on the presence of suitable hosts in the area under assessment and on the analysis of climate suitability for the pest. We aim to elucidate the climate suitability analysis process in the context of EFSA PRA, from literature search on pest distribution data and eco-physiology, to data extraction, data analysis, and application of climate suitability models. We detail the full process, applied to the polyphagous pest navel-orange worm Amyelois transitella (Lepidoptera: Pyralidae). Following two mandates of the European Commission, EFSA completed a pest categorisation of the navel-orange worm (EFSA, 2021) and it is currently conducting a PRA. For this case study, 771 scientific documents were collected and screened at title – abstract level, out of these 191 were screened as full-text. Ninety-seven studies were then selected for data extraction (out of which 69 containing information on the pest distribution and 51 on eco-physiology). Information on distribution included 160 geographical records, out of which 91 related to specific points with geographical coordinates and 69 related to different level of administrative units. Based on this information, climate suitability analysis was conducted applying a methodology based on the Köppen–Geiger climate classification, and the Climex model. A. transitella is currently present in North and South America, but absent from the EU territory. Preliminary results showed that, if the insect enters in the EU territory, it is more likely to establish in Southern and Mediterranean areas of the EU, where it could cause an impact on susceptible EU crops.

How to cite: Campese, C., Czwienczek, E., Stancanelli, G., van der Werf, W., and Maiorano, A.: Climate suitability analysis in the context of EFSA Pest Risk Assessment. Amyelois transitella, the navel-orange worm, as a case study, 17th Plinius Conference on Mediterranean Risks, Frascati, Rome, Italy, 12–15 Oct 2021, Plinius17-94, https://doi.org/10.5194/egusphere-plinius17-94, 2021.

Plinius17-25 | Orals | PL6

Adaptation strategies to address irrigation demand in the Mediterranean under climate change

Nikolaos Nikolaidis, Dionissis Efstathiou, and Maria Lilli

Irrigation in the Mediterranean region consumes at least 80% of the total water consumption. This is expected to increase due to the impacts of climate change. There is a lack of data regarding the irrigation needs of agricultural plants especially in the Mediterranean region.  To address this issue, the Water Use Efficiency of an Avocado plantation in Crete, Greece is being assessed in systematic way in order to minimize the environmental footprint and impact of the operation while maximizing the benefits for the farmer and the environment. A hydrologic and plant monitoring station have been established in an avocado plantation to determine optimal irrigation schemes, the water use efficiency of the trees and ways to improve plant productivity. The station consists of a precipitation and meteorological station, soil moisture profilers near and away from the tree, irrigation flow monitoring, NDVI and PRI cameras for the estimation of the above ground biomass changes.  These data that are collected every 15 minutes, together with expert knowledge were used to determine optimal irrigation schemes such as deficit irrigation that will conserve the use of water as well as maximize plant production.  The plants were irrigated the amount estimated by their evapotranspiration needs.  In addition, drip irrigation was not applied in a linear fashion in the field, but in a circle with one-meter diameter from the root of the tree.  In this way, the amount of irrigation used was only 30% of the typically prescribed irrigation needs for the plants on an areal basis. Irrigation was applied every 3-4 days based on soil moisture changes in a constant fashion.  It has been observed the over-irrigation stresses the plant. Biomass production was monitored with the NDVI and PRI cameras in order to estimate the above ground production as well as to identify the conditions that plants were stressed. No tilling was practiced in order not to disturb the formation of water stable aggregates and thus the productivity of the soil. Finally, soil organic matter was added by cutting the grass grown in between the trees and leaving the clippings on site and also by not removing the leaves from the avocado. The addition of organic matter in the soil promotes the below ground biodiversity as well as the productivity of the plants and it improves the soil water retention capacity. The results of this study illustrate that we can reduce the amount of irrigation significantly (60-70% of suggested irrigation annual rates) by both increasing the soil organic matter and by irrigating the tree and not the field. Reducing irrigation rates as well increasing the soil water retention capacity can be the two main adaptation strategies that can address effectively the increases or irrigation demand due to climate change.

How to cite: Nikolaidis, N., Efstathiou, D., and Lilli, M.: Adaptation strategies to address irrigation demand in the Mediterranean under climate change, 17th Plinius Conference on Mediterranean Risks, Frascati, Rome, Italy, 12–15 Oct 2021, Plinius17-25, https://doi.org/10.5194/egusphere-plinius17-25, 2021.

Plinius17-28 | Orals | PL6

Impact of drought events on plant Water Use Efficiency 

Nikolaos Nikolaidis, Maria Lilli, Dionissis Efstathiou, Christian Poppe, and Harry Vereecken

One of the research topics in the eLTER-PLUS project is to study the impact of drought events on ecosystem water-use efficiency (WUE) and resilience, and the relationships between WUE, soil structure, plant productivity and ecosystem resilience. Data from 10 well-instrumented eLTER sites across a range of climatic, geological and socio-ecological regions are being used to test resilience indicators, such as WUE, nutrient use efficiency, soil structure and function. Outputs from integrated models that consider the whole water-soil-plant system are being analysed to a) assess the impact of drought events on the WUE of ecosystems, b) determine the resilience of the ecosystems with respect to their ability to recover from impacts of single & multiple droughts, and c) understand the relationship between WUE, soil structure, plant productivity and ecosystem resilience. We also develop mitigation measures for drought adverse impacts. First, we did a time series analysis of CO2 and H2O fluxes from long term Flux tower Eddy Covariance measurements and calculated the evolution of WUE in time and assessed the impact of hydrologic and meteorological droughts on WUE. Second, we conducted modeling simulations of the plant-soil-water system at selected sites and assessed the relationship between WUE and soil structure, plant productivity and ecosystem resilience using the 1D-ICZ and the CLM5.0 models. The presentation will provide an overview of the results across Europe with a specific focus on the Mediterranean sites.

How to cite: Nikolaidis, N., Lilli, M., Efstathiou, D., Poppe, C., and Vereecken, H.: Impact of drought events on plant Water Use Efficiency , 17th Plinius Conference on Mediterranean Risks, Frascati, Rome, Italy, 12–15 Oct 2021, Plinius17-28, https://doi.org/10.5194/egusphere-plinius17-28, 2021.

Plinius17-35 | Orals | PL6

Evaluating agricultural risks in Central Italy by coupling drought risk assessment and agro-hydrological modelling

Lorenzo Villani, Giulio Castelli, Estifanos Addisu Yimer, Luigi Piemontese, Ann van Griensven, Daniele Penna, and Elena Bresci

Higher temperatures, less reliable precipitation patterns, and increased occurrence of extreme events such as drought will significantly affect the sustainability of agricultural systems in the Mediterranean region. A multidisciplinary, participatory approach and a large amount of data are required to unravel the complexity of climate change and properly evaluate the impacts and the possible adaptation strategies. The European countries of the Mediterranean are interesting case studies for these processes since there are numerous institutions active on these topics, collecting a high amount of information. The study area selected for this research is composed of coastal watersheds of Central and Southern Tuscany, Italy. The main objective was to study the impacts of climate change and possible adaptation strategies, with a particular focus on drought. Therefore, a drought risk assessment was performed as a preliminary study to assess the hazard, exposure, vulnerability, and risk of agricultural systems. Free, ready- and easy-to-use data were obtained from public databases to calculate the forty-two indicators that were selected to estimate the various components of risk. Finally, archetype analysis, an emerging approach for identifying recurrent patterns within cases and supporting a context-specific generalization of insights, was used to link the study's results with possible adaptation strategies. Then, the hydrological model SWAT+ was applied to the Ombrone watershed, the largest and most representative of the study area, to estimate impacts on both hydrology and crop production and to evaluate possible agronomic adaptation strategies. By using a hydrological model that includes a module to simulate plant growth, it is possible to study these dynamics at a larger scale than the field scale; this is convenient, especially when dealing with the water resource which is better studied at the watershed level. Data from various public databases were used to set up the model; after that, it was calibrated with monthly streamflow and crop yield of the most representative crops of the area. The future risks for agricultural systems were then analysed by using a multi-model ensemble of EURO-CORDEX projections. The impacts related to the water resource were estimated by evaluating the components of the water balance, while those on agriculture by considering crop yield. Then, possible adaptation strategies such as conservation agriculture and supplemental irrigation were simulated. The presented research demonstrates the importance of integrating multiple data sources and methodologies for the study of climate risks in agricultural systems.

How to cite: Villani, L., Castelli, G., Addisu Yimer, E., Piemontese, L., van Griensven, A., Penna, D., and Bresci, E.: Evaluating agricultural risks in Central Italy by coupling drought risk assessment and agro-hydrological modelling, 17th Plinius Conference on Mediterranean Risks, Frascati, Rome, Italy, 12–15 Oct 2021, Plinius17-35, https://doi.org/10.5194/egusphere-plinius17-35, 2021.

Plinius17-70 | Orals | PL6

Compound impact of anomalous vegetation activity and hot/dry conditions during the 2017 extreme fire season in Portugal

Tiago Ermitão, Célia Gouveia, Ana Bastos, and Ana Russo

Fires are a natural part of many ecosystems, constituting nonetheless a serious threat to ecosystems and humans. Portugal is recurrently affected by wildfires, being considered a fire-prone region within the Mediterranean basin. However, during the last twenty years, several fire seasons recorded a large extension of burned areas, and the catastrophic fire season of 2017 stands out by recording more than 450,000 hectares of burned area and causing the death of more than 100 people.

Hot and dry fuel conditions were pinpointed as the main drivers of the widespread propagation of wildfires. Therefore, this work aims to assess the impact of the compound or cascading extreme events on vegetation, and also if there was a selectivity of fires for more stressed vegetation. We analyse the climatological and ecological conditions during the pre-fire season, in order to understand its effects on fire season burned areas through fuel accumulation and dryness.

The study highlights the importance of fuel accumulation during the growing season in fire-prone regions like Portugal. Moreover, anomalous hot and dry conditions during summer, in conjunction with strong fuel accumulation during the months preceding fire season, enabled to clarify why the 2017 fire season were so outstanding. Additionally, under the context of climate change, fire seasons as the one occurred in 2017 in Portugal can be more frequent. Therefore, our results highlight that fuel management can be an effective way to mitigate extreme fire seasons and point to the need of implementation of fire prevention policies, especially regarding biomass accumulation control during pre-fire season.

This study was supported by national funds through FCT (Fundação para a Ciência e Tecnologia, Portugal) under the project FIRECAST (PCIF/GRF/0204/2017) and by the 2021 FirEUrisk project funded by European Union’s Horizon 2020 research and innovation programme under the Grant Agreement no. 101003890.

How to cite: Ermitão, T., Gouveia, C., Bastos, A., and Russo, A.: Compound impact of anomalous vegetation activity and hot/dry conditions during the 2017 extreme fire season in Portugal, 17th Plinius Conference on Mediterranean Risks, Frascati, Rome, Italy, 12–15 Oct 2021, Plinius17-70, https://doi.org/10.5194/egusphere-plinius17-70, 2021.

Plinius17-90 | Orals | PL6

Reforestation efforts and impact on climate change

Pau Benetó, Hassane Moutahir, and Samira Khodayar

The Mediterranean basin is strongly affected by global warming leading to important changes in the hydrological cycle and ecosystems. Mean precipitation decrease in the western Mediterranean reduces water availability in the region yielding, together with air temperature increase, loss of forests and desertification. Besides, extreme conditions linked to climate change play an important role in the occurrence of fires enhancing the loss of forest areas. Forests provide an important amount of water vapor to the atmosphere, can help decrease air temperature, and they are crucial in carbon dioxide fixation. In these terms, Mediterranean countries such as Spain, strongly affected by climate change, started reforestation efforts at local-to-regional scales to adapt and mitigate its effects. However, it is key to investigate to what extent these land-use changes influence main hydrometeorological variables and atmospheric dynamics.

In this study, the Weather Research and Forecasting (WRF) model is used to conduct sensitivity analyses regarding the impact of increasing forest mass on the hydrological cycle and atmospheric conditions over the Iberian Peninsula and particularly the Mediterranean coast. To this end, land-use categories have been modified over a control simulation to describe different scenarios. These scenarios are selected regarding the extension of reforested areas, as well as the type of vegetation planted, which are defined with respect to climatological parameters such as mean annual precipitation. The scenarios considered are as follows (i) reforestation with pine forest of bare soils, grasslands and shrublands (PINE1), (ii) same as PINE1 but also reforesting mixed cropland/natural areas (PINE2), (iii) same as PINE2 but with heterogeneous forest (MIXED) and (iv) same as MIXED but with 50% decrease in tree density (MIXED50%). Simulations are conducted at horizontal resolutions of 9 and 3 km for the period 2015-2020 covering the Iberian Peninsula and the Hydrographic Confederations of the Júcar and Segura (CHJS) located in the south-eastern part of the Iberian Peninsula, respectively. The study focuses on the analysis of the spatio-temporal patterns of the main hydrometeorological variables (e.g., precipitation, soil moisture, evapotranspiration and atmospheric water vapor), and the examination of the variability on the chain of processes leading to precipitation.

Preliminary results indicate a generalized increase in annual mean precipitation over the Iberian Peninsula (up to 1% for MIXED), more marked along the Mediterranean coast, together with changes in the distribution of atmospheric water vapor. Main precipitation variations occur during summer, with areas receiving up to three times more precipitation than in the control runs during autumn, some areas near the Mediterranean coast present an increase in seasonal precipitation up to 70% with respect to the control run.

How to cite: Benetó, P., Moutahir, H., and Khodayar, S.: Reforestation efforts and impact on climate change, 17th Plinius Conference on Mediterranean Risks, Frascati, Rome, Italy, 12–15 Oct 2021, Plinius17-90, https://doi.org/10.5194/egusphere-plinius17-90, 2021.

Plinius17-92 | Orals | PL6

Climate stressors' interplays modulating interannual olive and grapevine yields in Italy: a composite index approach 

Arianna Di Paola, Edmondo Di Giuseppe, and Massimiliano Pasqui

Even though a large part of the Italian peninsula is characterized by a Mediterranean climate intrinsically highly suitable for olive and grapevine cultivation, farmers may experience variable agronomic and management costs due to interannual yield variability. A synoptic picture of major climate stressors and their ongoing impacts on olive and grapevine yield variability at a broad spatio-temporal scale are scarce, but, if identified, could enhance the development of actionable services to alert stakeholders of potential climate risks. We analyzed Italian olive and grapevine yield data from the Italian National Statistics Institute (ISTAT), aggregated at the provincial level, during 2006-2021, and several climatic variables from Reanalysis v5 (ERA5) of the European Centre for Medium-Range Weather Forecasts (ECMWR) to i) explore yields trends and inter-annual variations over the whole peninsula; ii) identify major climate stressors likely responsible for the largest drops in yield; iii) build a composite index that summarizes the risk of having exceptionally low yields due to the occurrence of multiple climate stressors. To this end, we defined two major classes of yield, namely exceptionally low and high yields (LY and HY, respectively), and explored the climatic variables, aggregated on a monthly (grapevine) and bimonthly (olive) time scale, determining yield in outcomes. It is worth noting that the use of monthly or bimonthly periods provides a means of examining the seasonal effects of stressors while providing the basis for near-real-time forecasting. Selected years, characterized by a conspicuous number of both LY and HY, were focused to examine whether the composite risk index has application at more local scales. Results are discussed and some possible explanations based on the current knowledge of olive and grapevine physiological developmental. We suggest our approach as a promising yet still in-progress work that could pave the way to an integrated meteorological seasonal forecast system to provide timely insight on factors affecting within-season yield development.   

How to cite: Di Paola, A., Di Giuseppe, E., and Pasqui, M.: Climate stressors' interplays modulating interannual olive and grapevine yields in Italy: a composite index approach , 17th Plinius Conference on Mediterranean Risks, Frascati, Rome, Italy, 12–15 Oct 2021, Plinius17-92, https://doi.org/10.5194/egusphere-plinius17-92, 2021.

PL7 – Air quality and Health in the Mediterranean

Plinius17-63 | Orals | PL7

On the Redox‐Activity and Health‐Effects of Atmospheric Primary and Secondary Aerosol

Francesca Costabile and the RHAPS team

The RHAPS (Redox‐Activity And Health‐Effects Of Atmospheric Primary And Secondary Aerosol) project was launched in 2019 with the major objective of identifying specific properties of the fine atmospheric aerosol from combustion sources that are responsible for toxicological effects and can be used as new metrics for health‐related outdoor pollution studies. Here, we will present the overall methodology of RHAPS, we introduce the phenomenology and the first data observed. A comprehensive physico‐chemical aerosol characterization has been achieved by means of high‐time resolution measurements (e.g., number size distributions, refractory chemical components, elemental composition) and low‐time resolution analyses (e.g., oxidative potential, toxicological assays, chemical composition). Preliminary results indicate that, at the real atmospheric conditions observed (i.e., daily PM1 from less than 4 to more than 50 μg m−3), high/low mass concentrations of PM1, as well as black carbon (BC) and water soluble Oxidative Potential (WSOP,) do not necessarily translate into high/low toxicity. Notably, these findings were observed during a variety of atmospheric conditions and aerosol properties and with different toxicological assessments. Findings suggest a higher complexity in the relations observed between atmospheric aerosol and toxicological endpoints that go beyond the currently used PM1 metrics. Finally, we provide an outlook to companion papers where data will be analyzed in more detail, with the focus on source apportionment of PM1 and the role of source emissions on aerosol toxicity, the OP as a predictive variable for PM1 toxicity, and the related role of SOA possessing redox‐active capacity, exposure‐response relationships for PM1, and air quality models to forecast PM1 toxicity.

How to cite: Costabile, F. and the RHAPS team: On the Redox‐Activity and Health‐Effects of Atmospheric Primary and Secondary Aerosol, 17th Plinius Conference on Mediterranean Risks, Frascati, Rome, Italy, 12–15 Oct 2021, Plinius17-63, https://doi.org/10.5194/egusphere-plinius17-63, 2021.

Plinius17-47 | Orals | PL7

Past and future health burden: the impact of climate change and air pollution on mortality risk for Rome and Milan.

Melania Michetti, Maurizio Gualtieri, Alessandro Anav, Mario Adani, Barbara Benassi, Claudia Dalmastri, Ilaria D'Elia, Antonio Piersanti, Gianmaria Sannino, Gabriele Zanini, and Raffaella Uccelli

Climate change is expected to raise the threats to human health. The effects of temperatures on excess of mortality, for exposed populations, can be amplified by the simultaneous presence of air pollution.

Using Distributed Lag Nonlinear Models with delayed effects, we assess the combined short-term impact of temperature and air pollution (PM10, O3) for Milan and Rome, the latter located at the center of the Mediterranean basin. Relative mortality risks (RRs) are estimated for the city population as a whole and the most vulnerable group of people (over the age of 85), for the historical decade 2004-2015 and for the future (2050), assuming climate and air pollution scenarios consistent with the representative concentration pathways RCP2.6 and RCP8.5. The daily mean temperature (T) and the daily apparent mean temperature (AT) exposure variables are used to proxy the effects of climate change; the MDA8 (maximum daily 8-hour average concentration) indicator for O3 and the daily mean of PM10 characterize, instead, past and future air pollution effects. The minimum mortality temperature (Tmm), which is city specific due to human adaptability to the local climate, is defined and inferred for both cities and age groups, together with exposure-response functions for each exposure variable.

Results on past mortality show lower RRs for Rome along the whole year and a larger influence of temperature rather than air pollutant on short-term mortality. Specifically, attributable deaths are mainly associated with low temperature conditions (T<Tmm) and increase when considering the older age group. As regard of air pollutants, their combined influence sum up to those of temperature with a seasonal connotation: while PM10 affects the risk values mainly in association with low temperatures, O3 exerts its greatest effect especially in conjunction with high temperatures.

RRs projections to 2050 confirm that Rome is the least affected city with a smaller fraction of total deaths attributable to climate change and air pollution. The effects of global warming is captured by a double-sided effect: a decrease in the cold-related mortality burden and a rise in the attributable mortality due to increasing temperatures. However, the latter effect partially offsets the relief in the health burden achieved from the former one. This substitution effect between cold- and warm-related mortality is more evident in the RCP8.5 scenario and for the 85+ age group.

Concluding, the results suggest that a more rigorous and internationally coordinated climate action, implying more stringency in related policies, can lead to significant co-benefits: in addition to reducing the future health burden, containing the air pollution implications, and achieving climate objectives, health costs and loss of life can be also reduced. Indeed, when the effects of climate change and air pollution are contained with climate policy action (RCP2.6) the number of fatalities could decrease by 8 times in Rome and 1.4 in Milan, compared to historical values.

How to cite: Michetti, M., Gualtieri, M., Anav, A., Adani, M., Benassi, B., Dalmastri, C., D'Elia, I., Piersanti, A., Sannino, G., Zanini, G., and Uccelli, R.: Past and future health burden: the impact of climate change and air pollution on mortality risk for Rome and Milan., 17th Plinius Conference on Mediterranean Risks, Frascati, Rome, Italy, 12–15 Oct 2021, Plinius17-47, https://doi.org/10.5194/egusphere-plinius17-47, 2021.

Exposure to potentially toxic trace elements (PTTEs) in inhalable airborne particulate matter (PM10) is associated with an increased risk of developing cardiovascular and respiratory diseases. In urban settings, there are generally multiple emission sources of natural and anthropogenic origin, and each source releases particles with different concentrations of PTTEs. Therefore, a geo-referenced assessment of the carcinogenic and non-carcinogenic risk associated with exposure to trace elements in PM10 is essential to identify major sources of PTTEs and critical source areas. However, although some studies have been conducted to spatially assess the health risk of PTTEs in road dust, a high spatial resolution risk assessment of trace elements in PM10 has never been undertaken so far due to the lack of appropriate instrumentation.
In this study, we propose the use of an innovative experimental approach for a geo-referenced assessment of health risks associated with exposure to PTTEs in PM10 released from spatially disaggregated sources. A very-low volume device for high spatial resolution sampling and analysis of PM10 was employed in Terni, an urban and industrial area in Central Italy characterized by the presence of multiple anthropogenic sources, high concentrations of airborne elemental pollutants, and an associated increase in morbidity and mortality from the onset of cardiorespiratory diseases. The vey-low volume sampler was employed in a large and dense network (23 sampling sites, approximately 1 km of distance from each other) during a 15-month monitoring campaign to collect PM10 and analyze, by chemical fractionation, the soluble and insoluble fraction of 33 elements to increase their selectivity as source tracers. The carcinogenic and non-carcinogenic risk to adults and children due to concentrations of PTTEs in PM10 was calculated and the contribution of different emission sources to the risk was assessed by positive matrix factorization (PMF) applied to the high spatial resolution elemental concentration data. Finally, risk values associated with PTTEs released from the different emission sources at the 23 sites were interpolated and mapped to geo-reference their possible health impacts across the study area.

How to cite: Massimi, L., Pietrantonio, E., Astolfi, M. L., and Canepari, S.: A new approach for spatial mapping of source-specific contributions to carcinogenic and non-carcinogenic risk of potentially toxic trace elements in PM10, 17th Plinius Conference on Mediterranean Risks, Frascati, Rome, Italy, 12–15 Oct 2021, Plinius17-9, https://doi.org/10.5194/egusphere-plinius17-9, 2021.

The Mediterranean Basin, which is considered an hot-spot region in term of air-quality and climate change, frequently experiences surface ozone (O3) exceedances to European legislated values for human health protection. Indeed, its peculiar meteorological conditions, such as frequent clear sky and high solar radiation in summer, as well as the availability of natural and anthropogenic precursors, enhance the formation of photochemical ozone so increasing the risk of O3 pollution events in the area.

O3 is one of the air pollutants of most concern for public health, as it can damage the respiratory and circulatory systems. O3 can also deteriorate the vegetation, ecosystems, and building materials. Moreover, it is also one of the most important greenhouse gases as a so-called short-lived climate factor. Being a secondary pollutant, the variability of O3 is strongly dependent on the precursors, the meteorological parameters and the interactions among them through a series of complex and non-linear functions. Such complexity makes the definition of the O3 control strategies not immediate; this is why the improvement of the extensive networks of continuous O3 measurements as well as of appropriate methods to analyze O3 levels and to predict future changes is required.

The abrupt and unplanned anthropogenic emission reductions determined by the COVID-19 lockdown in 2020 produced an extraordinary real-world opportunity to assess the air quality response to changes in emissions. Taking advantage of this circumstance, the present study aims to characterize the influence of both the precursor emissions and the local meteorological conditions during 2020 on the surface ozone concentrations measured in the Basilicata region, (Southern Italy), which is located in the center of the Mediterranean basin.

To these ends, eXtreme Gradient Boosting (XGBoost) machine learning (ML) models were built to provide both the business-as-usual (BAU) and the meteorological normalized O3 time series. The former allows the estimates of the impact of the lockdown restrictive measures on O3 by means of the comparison with the observed concentrations, the latter accounts for the meteorological variability and other time features for more reliable assessment of O3 trend/changes. Moreover, thanks to the non-black box nature of the developed ML models, the partial dependence of the observed O3 concentrations on each explanatory variables used in the models can be analysed, shedding light on the role of local meteorological processes in the observed O3 variability.

The results obtained made it possible to evaluate the different contribution of emissions and meteorology on the detected changes in the levels of O3 and to provide deeper insights of major drivers of surface ozone concentrations in the studied area. This knowledge could help in defining strategies effective in reducing the negative impacts associated with O3 exposure as well as in optimizing the potential synergies between O3 reduction policies and climate change policies.

 

 

How to cite: Gagliardi, R. V. and Andenna, C.: Evaluation of the effects of the COVID-19 lockdown and the meteorology on surface ozone variability with machine learning techniques.  , 17th Plinius Conference on Mediterranean Risks, Frascati, Rome, Italy, 12–15 Oct 2021, Plinius17-16, https://doi.org/10.5194/egusphere-plinius17-16, 2021.

Plinius17-82 | Orals | PL7

Impact of wildfire emissions of PM2.5 and Black Carbon in southern Italy

Jessica Castagna, Alfonso Senatore, Mariantonia Bencardino, Guido Pellis, Marina Vitullo, and Giuseppe Mendicino

The climate change induced-events are affecting the Mediterranean Sea through ever-increasing frequent and severe heatwaves and droughts, which are primary drivers for wildfires diffusion. This study aims to comprehensively investigate the wildfires' impact on emissions of PM2.5 and Black Carbon during fire seasons in southern Italy.  As a first step, the Lagrangian transport of emissions produced by wildfires and impacting two National Parks of the Calabria region, placed in the middle of the Mediterranean Sea, was estimated for a particularly severe fire season. PM2.5 and Black Carbon observations were taken from the Sila National Park at the Monte Curcio Global Atmosphere Watch (GAW) regional station and the Aspromonte National Park at the Mammola rural-regional background station. These observations were integrated with remote-sensing fire detections and the high-resolution WRF-HYSPLIT back-trajectories, which improved the model accuracy in the orographically complex region of Calabria. Moreover, we evaluated the wildfire impact on human health in terms of passively smoked cigarettes (PSC), related to PM2.5 and Black carbon measurements. Finally, we estimated the PM2.5 and Black Carbon emissions released during the whole analyzed fire season and assessed the uncertainties of remote sensing-based inventories by comparing the temporal and spatial behavior of the last version of the satellite-based Global Fire Emissions Database (GFED4s) with the more accurate ground-based wildfire emissions inventory produced by ISPRA (Institute for Environmental Protection and Research).

How to cite: Castagna, J., Senatore, A., Bencardino, M., Pellis, G., Vitullo, M., and Mendicino, G.: Impact of wildfire emissions of PM2.5 and Black Carbon in southern Italy, 17th Plinius Conference on Mediterranean Risks, Frascati, Rome, Italy, 12–15 Oct 2021, Plinius17-82, https://doi.org/10.5194/egusphere-plinius17-82, 2021.

CC BY 4.0