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Located in a highly sensitive climate area, according to the IPCC reports, Lake Kinneret is exposed to extreme changes in the next few decades. Lake Kinneret is a warm monomictic lake, located between subtropical and arid climatic belts. It is thermally stratified throughout most of the year and mixes thoroughly each winter when the epilimnion water temperature reaches equilibrium with the hypolimnion water temperature by surface cooling and turbulence. Using high-resolution atmospheric projections obtained from COSMO-CLM simulation to force a 3D hydrodynamical model, we show significant changes in the stratification and circulation of the lake over the next five decades. As air temperature is expected to rise by up to 2.5oC in winter and autumn by 2070, the water column full mixing is expected to be suppressed. Unmixed years are expected to appear more often and full mixing will be re-activated just when cold enough winter conditions allow a full water column turnover. The lack of mixing between the epilimnion and the hypolimnion may create an environment that is oxygen depleted in which very few organisms can live, hence, might strongly affect the lake's present ecological system, its sustainability, and its water quality. Stratification Index analysis results show that Lake Kinneret will remain stratified throughout the year 20%-30% of the time in 2030-2070 under the moderate climate change scenario RCP4.5. However, abrupt cooling of the lake surface due to enhanced latent heat loss is identified, around the year 2065, in the model results, and is expected to restrain the dramatic change in the lake stratification.

In 2021, a group of seven Italian institutions decided to bring together their know-how, experience, and instruments for measuring the drop size distribution (DSD) of atmospheric precipitation, giving birth to the Italian Group of Disdrometry (in Italian named Gruppo Italiano Disdrometria, GID, https://www.gid-net.it/, last access: 16 May 2023). GID has made freely available a database of 1 min records of DSD collected by the disdrometer network along the Italian peninsula. At the time of writing, the disdrometer network was composed of eight laser disdrometers belonging to six different Italian institutions (including research centres, universities, and environmental regional agencies). This work aims to document the technical aspects of the Italian DSD database consisting of 1 min sampling data from 2012 to 2021 in a uniform standard format defined within GID. Although not all the disdrometers have the same data record length, the DSD data collection effort is the first of its kind in Italy, and from here onwards, it opens up new opportunities in the surface characterization of microphysical properties of precipitation in the perspective of climate records and beyond. The Version 01 GID database can be downloaded at https://doi.org/10.5281/zenodo.6875801 (Adirosi et al., 2022), while Version 02 can be downloaded at https://doi.org/10.5281/zenodo.7708563 (Adirosi et al., 2023). The difference among the two versions is the diameter–fall velocity relation used for the DSD computation.

In the last few decades there has been increasing interest in the commercial usage of the stratosphere, especially for Earth observation systems. Stratospheric platforms allow Earth monitoring at a regional scale with persistency toward a limited area. For this reason, accurate meteorological forecasts are needed in order to guarantee stationarity. The main aim of this work is to provide a review of wind prediction techniques in the stratosphere, achieved by the most popular global models, such as ECMWF IFS, NCEP GFS and ICON. Then, the capabilities of the COSMO limited area model to reproduce the wind speed in the stratosphere are evaluated considering a model configuration with very high resolution (about 1 km) over a domain located in Southern Italy, assuming the radio sounding data at Pratica di Mare airport as the reference. Vertical profiles were analyzed for selected days, highlighting good performances, though improvements can be achieved by adopting a fifth-order interpolation of the model data. Finally, monthly wind speed time series for selected heights were post-processed by means of fast Fourier transform, revealing the existence of main frequencies and the presence of a scaling regime and a power law of the form f−β over a broad range of time scales, in the Fourier space. The exponent spectral β is close to the exact 5/3 Kolmogorov value for all the datasets.

A new urban canopy scheme for the ICON atmospheric model is presented. Increasing the resolution of atmospheric models for numerical weather prediction (NWP) or climate simulations allows, among others, for a more realistic description of the processes at the land surface. Here, one field of growing interest are the processes in urban areas. Beside their relevance for the meteorological modelling, there is a general trend in most countries that the number of people living in towns is significantly increasing. During the recent years, an urban canopy parameterization was developed for the multi-layer land surface scheme TERRA of the Consortium for Small-scale Modeling (COSMO) mesoscale atmospheric model. This parameterisation, TERRA_URB, originally developed for the climate version of COSMO and then ported to the NWP version, was shown to be able to reproduce the key urban meteorological features for different European cities. In the framework of the transition of the COSMO Consortium to the ICON model, TERRA_URB needs to be implemented in ICON. Furthermore, an updated set of urban canopy parameters needs to be provided, for describing the urban characteristics down to a mesh size of 1 km, and below. For these purposes, the COSMO Consortium organises the dedicated Priority Project CITTA’. First results are presented for TERRA_URB in the ICON limited-area model ICON-LAM for different cities of interest of the CITTA’ partners. The preliminary results indicate already that urban features like the urban heat island effect are well represented. This is in agreement with the experiences with TERRA_URB in the COSMO model, both the climate as well as the NWP version.

The ICON (ICOsahedral Nonhydrostatic) is a joint project between the Deutscher Wetterdienst (DWD) and the Max-Planck-Institute for Meteorology (MPI-M) for the development of a unified global numerical weather prediction system. In 2018, COSMO (COnsortium for Small-scale Modeling) started the migration from the COSMO-LM to the ICON-LAM (ICON Limited Area Model) as the operational model. The main aim of this work is the presentation of a sensitivity study performed over a domain located in southern Italy (including the northern part of the Campania region and the southern part of Lazio) aimed to provide a contribution to the definition of a model configuration suitable for accurate weather forecasts over this area. Following the work performed by the authors with COSMO on a similar domain, the week 19-25 November 2018 has been selected as test case, when a low-pressure system coming from Western Mediterranean determined intense storms and gusts.A computational grid R2B11, characterized by a very high resolution (about 1.2 km), has been adopted. Initial and boundary conditions are provided by the ECMWF IFS model at a spatial resolution of about 8.5 km. The sensitivity was carried out starting from a model configuration optimized by the authors (in a joint effort with the CMCC Foundation, Italy) over the whole Italian area, employing a grid with different resolution (R2B10, about 2.5 km). The reference configuration assumes that the shallow convection parameterization is active whereas the parts treating deep and mid-level convection are switched off. Moreover, a single moment cloud microphysics scheme and a diagnostic Kohler cloud cover scheme are employed.A first sensitivity was performed with respect to the domain size, considering a reference domain (11.38° – 15.38° E; 40.25° - 42.25° N) and two additional domains respectively larger (in both directions) than 50% and 100% with respect to the original one. Then, a sensitivity to the numerical parameters, which have been shown to play a significant role in determining model response, has been carried out, e.g tkhmin (minimal diffusion coefficient for heat), rlam_heat (factor for laminar resistance for heat) and v0snow (factor for vertical velocity of snow).Model evaluation has been conducted against ground observation data provided by CIRA instrumentation and by the SCIA system developed by ISPRA (Italy). Moreover, a comparison with forecasts provided by the COSMO model at 0.009° (about 1 km resolution) forced by the same driving data has been performed, in order to highlight the differences between the performances of the two models.

Remote sensing measurements provided by satellite-borne radars play a fundamental role in estimating precipitation distribution worldwide. However, they are subjected to a variety of potential errors and need continuous validation with ground-based measurements. Validating satellite products using measurements collected by sensors at the ground has been addressed in the literature, but it is still challenging due to intrinsic differences in the measuring principle and viewing geometries of the instrument being compared each other. To date, the Dual-frequency Precipitation Radar (DPR) aboard the Core Satellite of the Global Precipitation Measurement (GPM) mission is the only active sensor able to provide, at the global scale, vertical profiles of rainfall rate, radar reflectivity, and Drop Size Distribution (DSD) parameters from space. After the launch of the GPM Core Satellite, on February 2014, an extensive Ground Validation (GV) program was established with the aim of evaluating the performance of the retrieval algorithms, over long periods and in different climatic regions across the world. Since the free availability of GPM data, many studies have been conducted to compare and validate the available version of satellite precipitation products with data collected by ground-based instrumentations such as radars and rain gauges, however very few published studies used networked disdrometers data on national scale.For the first time, we used disdrometers to evaluate near surface GPM-DPR products (Version V06A) against long time series of measurements collected by seven laser disdrometers dislocated along the Italian peninsula and networked thanks to a cooperation effort of seven institutions (including research centers, universities and environmental regional agencies). The comparison was made in terms of rainfall and DSD parameters: rainfall rate, radar reflectivity, mass-weighted mean diameter (Dm), and normalized gamma DSD intercept (Nw). The comparison showed limited differences between single- or dual-frequency GPM algorithms, although the former presents better performance in most cases. The conclusions suggest that the agreement was good for rain rate, reflectivity factor, and Dm, while Nw satellite estimates need to be improved. Same method is used for evaluating current V07A of precipitation products.Given the collaborative nature that has allowed the validation analysis presented, this study also represents an opportunity to consolidate cooperation between Institutions managing disdrometers in Italy and set the stage for future plans aimed at improving the use of disdrometer data in Italy.

One of the most severe weather hazards to aviation is in-flight airframe icing, i.e. the accretion of ice on airplane’s surfaces during flight. In order to increase margins of aviation safety, the early detection of regions affected by icing conditions is a challenging and desirable goal. In the framework of the H2020 EU project SENS4ICE (SENSors and certifiable hybrid architectures for safer aviation in ICing Environment), CIRA has developed a remote detection tool of icing conditions based on satellite data. Specifically, high-resolution satellite products, based on Meteosat Second Generation (MSG) data, have been considered, with spatial and temporal resolutions of about 3 km and 15 minutes respectively. The aim of this tool is to identify areas potentially affected by in-flight icing hazard, giving information about the severity of the phenomenon (light, moderate or severe) and an estimate of the altitude at which this hazard can occur. The developed algorithm also takes into account supercooled large droplets (SLD), which pose a serious threat to aviation and have been the cause of tragic accidents over the last decades. The tool relies on satellite data, to remotely infer the properties of clouds, and a set of experimental curves and envelopes that describe the interrelationship of cloud liquid water content, mean effective diameter of the cloud droplets and ambient air temperature. These curves, provided by the Federal Aviation Administration (FAA), define the atmospheric icing conditions and represent the reference legislation in this field. Furthermore, a nowcasting algorithm based on the extrapolation in time of the current icing conditions has been implemented, in order to perform a forecast over a short period ahead, responding to the great need for timely and location-specific forecasts that are relevant for aviation, e.g. for safety reasons or for planning and routing air traffic. This presentation will provide a preliminary analysis of the performance of the implemented tools, which will be evaluated in relevant icing conditions in the framework of SENS4ICE flight campaigns, planned for 2023.Acknowledgment: This project has received funding from the European Union's Horizon 2020 research and innovation programme under grant agreement N° 824253 (SENS4ICE project).

Nature-based Solutions function as an umbrella concept for ecosystem-based approaches that are an alternative to traditional engineering solutions for Disaster Risk Reduction. Their rising popularity is explained partly by their entailing additional benefits (so called co-benefits) for the environment, society, and economy. The few existing frameworks for assessing co-benefits are lacking guidance on co-benefit pre-assessment that is required for the NBS selection and permission process. Going beyond these, this paper develops a comprehensive guidance on quantitative pre-assessment of potential co-benefits and disbenefits of NBS tackling Disaster Risk Reduction. It is based on methods and frameworks from existing literature around NBS and related disciplines. Furthermore, this paper discusses the evaluation of the quantified results of the pre-assessment. In particular, the evaluation focuses on the significance of change of the estimated co-benefits and disbenefits as well as the sustainability of the NBS. This paper will support decision-making in planning processes on suitability and sustainability of Nature-based Solutions and assist in the preparation of Environmental Impact Assessments of projects.

The objective calibration method originally performed on regional climate models is applied to a fine horizontal resolution Numerical Weather Prediction (NWP) model over a mainly continental domain covering the Alpine Arc. The method was implemented on the MeteoSwiss COSMO (consortium for a small-scale modeling) model with a resolution of 0.01° (approximately 1 km). For the model calibration, five tuning parameters of the parameterization schemes affecting turbulence, soil-surface exchange and radiation were chosen. A full year was simulated, with the history of the soil included (hindcast) to find the optimal parameter value. A different year has been used to give an independent assessment of the impact of the optimization process. Although the operational MeteoSwiss model is already a well-tuned configuration, the results showed that a slight model performance gain is obtained by using the Calibration of COSMO (CALMO) methodology.

Nowadays, cities are the preferred location for more than half of the human population and the places where major human-perceived climate change impacts occur. In an increasingly urbanized world, it is essential to represent such areas adequately in Numerical Weather Prediction (NWP) models, not only to correctly forecast air temperature, but also the human heat stress and the micro-climate phenomena induced by the cities. Among them, the best known is the Urban Heat Island (UHI) effect, which refers to the significantly higher temperatures experienced by a metropolitan area than its rural surroundings. Currently, the COSMO model employs a zero-order urban description, which is unable to correctly reproduce the UHI effect: cities are simply represented as natural lands with increased surface roughness length and reduced vegetation cover. However, the reproduction of the urban climate features in NWP and regional climate models is possible with the use of the so-called urban canopy models, that are able to parameterize the interaction between the urbanized surface and the overlying atmosphere. In this context, a new bulk parameterization scheme, TERRA_URB (TU), has been developed within the COSMO Consortium. TU offers an intrinsic representation of urban physics: the effect of buildings, streets and other man-made layers on the surface-atmosphere interaction is described by parameterizing the impervious water balance, translating the 3D urban-canopy parameters into bulk parameters with the Semi-empirical Urban canopy parameterization (SURY) and using the externally calculated anthropogenic heat flux as additional heat source. In this work, we present high-resolution simulations with the TU scheme, for different European cities, Turin, Naples and Moscow. An in-depth evaluation and verification of the performances of the recent COSMO version with TU scheme and new implemented physical parameterizations, such the ICON-like surface-layer turbulence scheme and the new formulation of the surface temperature, have been carried out. The validation concerned the 2-meter temperature and was performed for 1- or 2-week selected periods over the 3 European cities characterized by different environment and climate, namely the Moscow megacity in Russia and Turin and Naples in Italy. Even if the three domains are morphologically different, the results follow a common behavior. In particular, the activation of TERRA_URB provides a substantial improvement in capturing the UHI intensity and improving air temperature forecasts in urban areas. Potential benefits in the model performance also arise from a new turbulence scheme and the representation of skin-layer temperature (for vegetation). Our model framework provides promising perspectives for enhancing urban climate modelling, although further investigations are needed.

Nature-based solutions are increasingly implemented to tackle disaster risk reduction and climate change adaptation. Their rising popularity over grey solutions is partially explained by their number of additional benefits (so called co-benefits) for the socio-ecological system (SES). Frameworks are available to monitor and assess co-benefits, however, these frameworks are lacking clear guidance and ex-ante quantification of co-benefits and potential disbenefits of NBS. Another limitation is the accessibility and quality (representativeness) of data for computing indicators, especially, going towards larger scales (regional, pan-European). To develop a comprehensive framework and method for assessing and estimating possible side effects in advance, this paper aligns to existing frameworks but goes beyond those by providing practical guidance on data sourcing (including possible proxy variables) and quantification of both co-benefits and disbenefits. The resulting framework will support decision-making on area specific suitability of NBS for disaster risk reduction. Furthermore, it will enhance the planners’ knowledge and understanding of linked processes which can lead to potential positive and negative side effects; thus, this guidance will build a base for selecting suitable locations and NBS interventions.

Karst aquifers provided 9.2 % of the world’s population with fresh water in 2016 (Stevanović, 2019), but due to their dual flow behavior they are highly vulnerable to anthropogenic impacts and shifts in climate. In the near future, 52 out of 356 Mediterranean aquifers will be exposed to more extreme climatic conditions, which will enhance their water stress if the water usage is not adapted to available water resources (Nußbaum, 2020). Therefore, accurate and high resolution numerical - and empirical models are essential to calculate the groundwater recharge and water availability in complex karst aquifers that cover ~ 14 % of the earth’s ice free land (Stevanovic, 2019).During the last decades, several empirical equations have been developed to calculate the recharge for Israel´s most important source of freshwater, the Western Mountain Aquifer (WMA). These equations calculate annual groundwater recharge of the entire 1.812 km2 recharge area based on annual or monthly precipitation data. We analyzed the applicability of several new methods, such as Soil & Water Assessment Tool (SWAT), HydroGeoSphere (HGS) and Hydro- / Pedo- Transfer Functions (HPTF) to estimate groundwater recharge with a higher resolution as this is essential to calculate proper water fluxes though the vadose zone of karstic aquifers when precipitation is affected by a high variability in space and time.The hydrologic balance models, e.g. SWAT (Neitsch et al., 2009), calculate the water balance on a daily basis for specified Hydrologic Response Units (HRUs), while generalized HPTFs (Wessolek et al., 2009) use soil-, land cover- and climate data to calculate annual percolation rates on a coarse grid, in our case 500 m grid size. The dual continuum model using the code HGS (Brunner et al., 2011) is able to simulated based on Richards’s flow equation down- and upward water fluxes in the unsaturated zone accounting for both, a rapid flow component though the high permeable conduit and a slow flow component through the rock matrix.The comparison of these empirical and new methods for groundwater recharge estimation show significant differences for hydrological extreme years, while results are similar during years with precipitation rates near the average value. For example, the empirical equation of Guttman & Zukerman (1995) gives highest recharge values of all approaches during wet years, while the equation of Abusaada (2011) and the SWAT-model calculates highest recharge values of all approaches during dry years. Overall, the mean recharge ranges from 120 to 177 mm/a which equals 25 – 37 % of the average precipitation between 1990 – 2018.These recharge rates are calculated based on IMS climate data. However, for recharge values used in water resources management regional climate projections are needed. For Israel a high resolution CORDEX-MENA climate projection (Hochman et al., 2018) is available for RCP4.5, showing an increase in temperature and decrease of precipitation during the winter of 2.5 °C and 40 %, respectively. Based on these climate projections the SWAT-model estimates, that the average groundwater recharge for 2050 – 2070 will be 16 % lower than the reference period between 1980 – 2000.

The OPERANDUM project is designed to address major hydro-meteorological risks through the deployment and assessment of Nature-Based Solution (NBS). The project pursues a co-creation approach and sets up 7 Open Air Laboratories (OAL) in which a user-centric method, characterized by the active participation of the stakeholders, is promoted. Stakeholder engagement in co-designing, co-developing, and co-deploying NBS is becoming a prominent practice in environmental projects and a crucial part of the process is monitoring and impact evaluation of the engagement strategy and actions. Monitoring aims at providing information about the stakeholder engagement processes throughout the project and should not be seen as a separate part of the stakeholder engagement processes or an aim in itself but as a continuous and integral element of the co-creation process. The poster shows the results of preliminary empirical research conducted among the OALs in order to propose some key indicators useful to evaluate the process and the impact generated by the OPERANDUM co-creative approach. Starting from a theoretical framework, the research selected and discussed some crucial indicators in order to propose an action plan for the monitoring and impact evaluation of OPERANDUM strategy to involve and support the participation of stakeholders, with a specific focus on the tools used so far and those that are in the pilot phases (i.e Stakeholder Forum experimented in OAL Italy). Both qualitative and quantitative methods have been included in the evaluation for the engagement strategy outcome of the projects to be fully understood and, not secondarily, to identify a sustainability strategy beyond the conclusion of OPERANDUM to reinforce the social acceptance, the shared knowledge, and the upscaling of NBS at local, national and global level.

In the last decade, the Climate Limited-area Modeling (CLM) Community has contributed to the Coordinated Re- gional Climate Downscaling Experiment (CORDEX) with an extensive set of regional climate simulations. Using several versions of the COSMO-CLM community model, ERA-Interim reanalysis and eight Global Climate Models from phase 5 of the Coupled Model Intercomparison Project (CMIP5) were dynamically downscaled with horizontal grid spacings of 0.44° (∼50 km), 0.22° (∼25 km) and 0.11° (∼12 km) over the CORDEX domains Europe, South Asia, East Asia, Australasia and Africa. This major effort resulted in 80 regional climate simulations publicly available through the Earth System Grid Fed- eration (ESGF) web portals for use in impact studies and climate scenario assessments. Here we review the production of these simulations and assess their results in terms of mean near-surface temperature and precipitation to aid the future design of the COSMO-CLM model simulations. It is found that a domain-specific parameter tuning is beneficial, while increasing horizontal model resolution (from 50 to 25 or 12 km grid spacing) alone does not always improve the performance of the simulation. Moreover, the COSMO-CLM performance depends on the driving data. This is generally more important than the dependence on horizontal resolution, model version and configuration. Our results emphasize the importance of performing regional climate projections in a coordinated way, where guidance from both the global (GCM) and regional (RCM) climate modelling communities is needed to increase the reliability of the GCM-RCM modelling chain.

Nature-Based Solutions (NBS) refer to the sustainable management, protection and use of nature to preserve the ecosystem and prevent the loss of biodiversity. Given the multiple environmental, social, and economic benefits they provide to society, NBS have been increasingly promoted and implemented in cities, especially for air pollution mitigation and the improving of human thermal comfort and well-being. Several databases and web platforms already exist, which document these beneficial impacts of NBS in our cities by collecting and exposing existing NBS case studies and projects from around globe. However, the effort of cataloging and storing NBS data according to common and harmonized principles and standards seems yet sporadic and uncoordinated at the global and European level, especially in the context of natural hazard-related disasters. Nature-based solutions have been indeed recently emerged as viable and effective measures to mitigate the impacts of hydro-meteorological phenomena such as floods, landslide, etc. in both urban and rural environments, an aspect not often emphasized in the existing databases.Driven by the ambition of overcoming these two main gaps, an innovative geo-catalogue of existing NBS has been developed within the framework of GeoIKP, the NBS web-platform newly created by the EU H2020 project OPERANDUM.The geo-catalogue represents a comprehensive, geo-referenced, database of NBS case studies which are specifically designed to mitigate the risk and impacts of hydro-meteorological hazards, under a variety of environmental setting and hazard categories. It therefore represents a novel and open-access data source to learn about, and explore, the usability of NBS in fulfilling climate mitigation and adaptation objectives over a wide range of hydro-meteorological hazards.Case studies collected from various resources (NBS platforms, scientific literature, technical reports, OPERANDUM living labs, etc.) are revised, classified and harmonized according to internationally recognized standard and classification schemes (e.g., INSPIRE legislation, MAES classification, etc.) which allow to characterize each NBS through a comprehensive set of parameters, including the type of hazard and ecosystem, the societal challenges and driving policies linked to it, the type of intervention and its spatial coverage, among many others.The highly structured and comprehensive data model adopted here enables to query the database and/or filter the results based on a multitude of individual parameters which encompass all different dimensions of NBS (e.g. geophysical, societal, environmental, etc.). This not only allows for a straightforward and automatic association to one or more thematic aspects of NBS, but also enhances standardization, discoverability and interoperability of NBS data.

Global warming is likely to cause a progressive drought increase in some regions, but how population and natural resources will be affected is still underexplored. This study focuses on global population, forests, croplands and pastures exposure to meteorological drought hazard in the 21st century, expressed as frequency and severity of drought events. As input, we use a large ensemble of climate simulations from the Coordinated Regional Climate Downscaling Experiment (CORDEX), population projections from the NASA-SEDAC dataset and land-use projections from the Land-Use Harmonization 2 project for 1981–2100. The exposure to drought hazard is presented for five Shared Socioeconomic Pathways (SSP1-SSP5) at four Global Warming Levels (GWLs: 1.5°C to 4°C). Results show that considering only Standardized Precipitation Index (SPI; based on precipitation), the SSP3 at GWL4 projects the largest fraction of the global population (14%) to experience an increase in drought frequency and severity (versus 1981–2010), with this value increasing to 60% if temperature is considered (indirectly included in the Standardized Precipitation-Evapotranspiration Index, SPEI). With SPEI, considering the highest GWL for each SSP, 8 (for SSP2, SSP4, SSP5) and 11 (SSP3) billion people, that is, more than 90%, will be affected by at least one unprecedented drought. For SSP5 at GWL4, approximately 2 × 10$^{6}$ km$^{2}$ of forests and croplands (respectively, 6% and 11%) and 1.5 × 10$^{6}$ km$^{2}$ of pastures (19%) will be exposed to increased drought frequency and severity according to SPI, but for SPEI this extent will rise to 17 × 10$^{6}$ km$^{2}$ of forests (49%), 6 × 10$^{6}$ km$^{2}$ of pastures (78%) and 12 × 10$^{6}$ km$^{2}$ of croplands (67%), being mid-latitudes the most affected. The projected likely increase of drought frequency and severity significantly increases population and land-use exposure to drought, even at low GWLs, thus extensive mitigation and adaptation efforts are needed to avoid the most severe impacts of climate change.

Karstified aquifers respond rapidly to hydrological events, such as heavy rain storms or draughts. Our ability to predict the response of the aquifer after such events strongly depends on i) temporal and spatial resolution of the available monitoring data and ii) suitable modelling approaches to assess recharge at the respective level of detail. The study catchment, the Western Aquifer Basin (WAB), is Israel´s most important source for freshwater supply. The recharge area of the WAB has an area of 1,812 km2. Recharge is characterized by high spatial variability in topography and a high variability in precipitation and temperature, land use, and vegetation. Precipitation also shows a seasonal variability: while annual precipitation mainly occurs during the winter months accompanied by floods in the otherwise dry wadis (October to March, ca. 90 %), summer periods (April to September) are hot and dry, and precipitation decreases to nearly zero.We employ SWAT to simulate the large-scale hydrological water balance (evapotranspiration, recharge, run-off) in the recharge area of the WAB on a daily and monthly temporal resolution. The SWAT model uses a SRTM DEM from NASA, soil maps from FAO, soil properties of the Harmonized World Soil Database, and land use maps from the ESA CCI project covering the time period from 1992 to 2015. These datasets are merged in SWAT into 361 Hydrologic Response Units with unique characteristics in soil, land use, and slope, respectively. The calibration of soil water balance model with SWAT-CUP employs monthly actual evapotranspiration and daily surface runoff data. Run-off was measured in hydrometric stations between 2004 – 2015. Evapotranspiration with a spatial resolution of 500 m x 500 m is obtained from the MODIS satellite mission and covers a period between 2001 and 2013 with individual time steps of 8 days. Calculated long-term groundwater recharge is compared with spring discharge measured during the period 1990 – 2013. Climate projections have been obtained with the RCM COSMO-CLM at resolution of 8km, under the IPCC RCP4.5 scenario, nested into the MENA-CORDEX domain.The calibrated water balance model allows for scenario analysis for predicted shifts in climate until 2050 to address the impact of climate change on groundwater recharge. In addition to an increase in temperature, fewer but more extreme rainfall events are to be expected. Furthermore, the effect of future land use changes, such as expansion of farm land or urban areas, on recharge depth are analyzed. Finally, simulated high-resolution recharge provides an updated estimate for the currently developed groundwater flow model of the aquifer system. SWAT provides daily recharge for the equivalent porous medium model of the WAB, simulated by MODFLOW. One of our challenges is the calculation of recharge in the hilly region i) characterized by steep slopes and ii) vadose zones of several 100 meters of thickness. Our investigations are expected to provide information on the impact of shifts in climate and global changes on recharge processes and to illustrate the effect of short-term hydrologic events on water resources in large carbonate aquifers under Mediterranean climate.

Groundwater recharge is an important variable for sustainable groundwater resources management in regions affected by water scarcity. The specifics of the Mediterranean require adapted techniques to also account for climate change implying a higher frequency of extreme events. Appropriate techniques are highly relevant for recharge with low rates. We compare three methods for the Western Mountain Aquifer, a karst in Israel: soil moisture budget calculations at basin scale, empirical functions, and machine learning algorithms. Resulting recharge are compared with measured spring discharge.Neural networks have the advantage of not requiring much knowledge about physical processes or hydrogeological and hydrological conditions, nor about model parameters. This data-driven machine learning algorithms learn the non-linear relationship between precipitation events and spring water discharge given a sufficient amount of training data is available. After training, the neural network could be used as a nonlinear function to model recharge of any predicted precipitation time series. However, this approach does not allow for any quantitative analysis of external forcing, such as land use, or internal parameter, such as soil characteristics, nor does it account for any expected future change in precipitation pattern.Hydro-pedotransfer functions (HPTF) are based on empirical relationships between precipitation and recharge. HPTFs account for potential evapotranspiration, annual precipitation, land cover, and a critical water supply (a threshold when actual evapotranspiration depends only on atmospheric conditions). Resulting percolation rates consider i) vegetation types, ii) precipitation during the vegetation growth period, iii) runoff, iv) plant available soil water, and v) capillary rise. The application of HPTF to a karst aquifer has the advantage that only limited input data are required. However, our results indicate that HPTFs are not able to capture the rapid recharge component observed in karst systems and thus underestimate recharge.The Soil Water Assessment Tool (SWAT) employs a hydrological and soil moisture budget calculations. Objective functions are actual evapotranspiration and surface runoff. Evapotranspiration is obtained from MODIS remote sensing data. Calibration of actual evapotranspiration is especially challenging for summer periods due to the impact of vegetation and irrigation. However, the most relevant parameter determining daily recharge rates are water loss by surface-runoff and surface water storage in wadi beds generating episodic recharge.Impact of shifts in climate is considered by climate projections obtained with the RCM COSMO-CLM at resolution of 3 km, under the IPCC RCP4.5 scenario, nested into the MENA-CORDEX domain. However, we believe that changes in land use from natural vegetation (trees, grass-, and shrublands) to rain-fed agricultural area could possibly shift the water budget from deficit to surplus conditions (recharge dominated). During the period 1992 to 2015 natural vegetation decreased by 8% and urban areas increased by up to 6%, while (rain-fed) agricultural areas remained almost constant. We investigate if land use changes might have (a much) larger impact on percolation rates than the predicted climate change effect. Thus, in future recharge may be controlled and enhanced in regions with water scarcity by better management of land use employing an optimized combination between precipitation, irrigation, and crop type.

Weather conditions and Air Traffic Management (ATM) operations are strongly related, due to the relevant influence that the observed and forecasted weather conditions into assigned airspace have on the operational conditions that are therefore possible for such airspace. In the framework of the SESAR JU funded project CREATE (Innovative operations and climate and weather models to improve ATM resilience and reduce impacts), therefore, a dedicated study has been carried out in order to investigate the relation between weather and ATM. Such study both investigated the consequences that adverse weather conditions can have on ATM and, on the other side, addressed the currently and future available tools that can support ATM in the prediction and management of weather conditions from the aeronautical operations point of view. In this paper, the results of such literature study are outlined. More in details, in the paper first the main outcomes of the study are summarized, in terms of identification of the most relevant weather phenomena that affect the ATM operations, indication of their main impacts on them in terms of operational disruptions and, finally, identification of the associated level of severity. In particular, the above indicated aspects are addressed by taking into specific consideration the enroute and the TMA (Terminal Manoeuvring Area) flight phases and, for each of them, the main affecting weather phenomena and the main affected operations are identified. Then, in the paper the results of the study are summarized about the identification of the most relevant meteo tools that are expressed by state-of-the-art technologies to support the ATM operations in order to properly take into account the weather conditions in a precise and timely manner. This study addresses both the review of available and perspective tools for weather reporting and of the available and perspective numerical models supporting ATM in terms of weather models and air quality models.

Nature-based solutions (NBS) are being promoted as adaptive measures against predicted increasing hydrometeorological hazards (HMHs), such as heatwaves and floods which have already caused significant loss of life andeconomic damage across the globe. However, the underpinning factors such as policy framework, end-users' interestsand participation for NBS design and operationalisation are yet to be established. We discuss theoperationalisation and implementation processes of NBS by means of a novel concept of Open-Air Laboratories(OAL) for its wider acceptance. The design and implementation of environmentally, economically, technicallyand socio-culturally sustainable NBS require inter- and transdisciplinary approaches which could be achievedby fostering co-creation processes by engaging stakeholders across various sectors and levels, inspiring more effective use of skills, diverse knowledge, manpower and resources, and connecting and harmonising the adaptationaims. The OAL serves as a benchmark for NBS upscaling, replication and exploitation in policy-makingprocess through monitoring by field measurement, evaluation by key performance indicators and buildingsolid evidence on their short- and long-term multiple benefits in different climatic, environmental and socioeconomicconditions, thereby alleviating the challenges of political resistance, financial barriers and lack ofknowledge.We conclude that holistic management of HMHs by effective use of NBS can be achieved with standard compliant data for replicating and monitoringNBS inOALs, knowledge about policy silos and interaction betweenresearch communities and end-users. Further research is needed for multi-risk analysis of HMHs andinclusion of NBS into policy frameworks, adaptable at local, regional and national scales leading to modificationin the prevalent guidelines related to HMHs. The findings of this work can be used for developing synergies betweencurrent policy frameworks, scientific research and practical implementation of NBS in Europe and beyondfor its wider acceptance.

Wave climate projections at global scales are often of little direct use for local or regional coastal applications, where bathymetric gradients and coastal geometry dominate onshore wave propagation and transformation. In such systems, and even more in the case of semi-enclosed basins where coastal orography can play a major role in wind modulation, wave climate assessments require a specific effort, with particularly strict prescriptions in terms of model resolution and quality of the wind forcing. In this work, we provide a numerical modelling estimate of the expected variations of wave regime in the Adriatic Sea (a semi-enclosed basin of the Mediterranean Sea) under an IPCC RCP 8.5 climate change scenario at the end of the current century, focusing on the implications for energy modulation in the coastal regions. Results tend to confirm the evolution towards an overall decrease of wave storminess in the basin, as suggested by previous studies, but show that some regions might experience a local increase in the severity of the sea states impacting the coast. The model resolution and the unprecedented directional skills of the climatological wind forcings allow to ascribe this behaviour to a shift in the directional wind regime that can be related to a northward translation of the Mediterranean cyclones trajectory. Although in the absence of a quantitative assessment of the uncertainty associated with the choice of the climate model, our results give an account of the possible extent of the spatial variability of the response of coastal dynamics to mid-latitude storm tracks modification induced by climate change.