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An enhanced understanding of Climate Change related implications in the maritime domain is needed in order to improve coastal infrastructure resilience and possible future operations, also in terms of climate security. Although the Mediterranean Sea is a relatively mild basin, it is however characterized by high geopolitical and economic relevance, occasionally showing intense cyclones with tropical-like characteristics known as Tropical-Like Cyclones (TLC). Many studies have highlighted that sea surface temperature (SST) distribution and anomalies play a crucial role in modulating the intense air-sea exchange, hence controlling both development and evolution of TLCs. However, given the complex interplay among ocean mixed layer, heat content and temperature, the role of the mixed layer depth (MLD) is of paramount importance. In this study we investigated the role of both SST anomaly, horizontal gradients and MLD profile on the origin and evolution of a recent record-breaking TLC (named IANOS). This cyclone originated over the southern Ionian Sea from 14 Sept 2020 to 19 Sept 2020, moving over the Central Ionian Sea from south-west to North-East, and made landfall 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 intensification and strength. We conducted a series of experiments using an atmospheric model (WRF - Weather Research and Forecasting system) driven by underlying SST (standalone configuration), either 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. Sensitivity tests were performed increasing or decreasing MLD depth by 10 m, 30 m, 50 m, 75 m, 100 m, removing the horizontal gradients, removing the SST anomaly. Then, possible past and future climatological scenarios of MLD thickness were identified and tested. 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 fundamental role of the SST anomaly was also found to be essential to provide intense characteristics to IANOS. Results deserve further investigation in particular in the context of climate change scenarios that can provide useful insights into impact on coastal civil and military infrastructures in the whole Mediterranean region.

Recent studies exhibit a considerable reduction of summer season precipitation frequency in the new generation of convection-permitting (CP) climate simulations. This seems to over-correct non-CP wet biases with a knock-on effect on summer temperatures via soil moisture-atmosphere feedbacks. However, it is difficult to elucidate which part of the warmth/dryness in CP simulations can be ascribed to land-atmosphere coupling and/or "atmosphere-only" processes. Another layer of uncertainty belongs to the still crude representation of land surface/sub-surface processes that become especially relevant when approaching such high resolution.In this study we explore the modulation of land-atmosphere coupling when moving from a non-CP to a CP-scale climate modeling, considering increasingly sophisticated land surface model configurations. We perform a two-step dynamical downscaling at ~15 km (convection-parameterized) and ~ 3km (convection-permitting) resolutions with the WRF-4.2.1 regional climate model driven by ECMWF-ERA5 reanalysis. The greater alpine region and the extended summer season (May to September) of 2003 are the spatial and temporal domains of interest. A mini multi-physics ensemble is generated with four Noah-MP land-surface model configurations to examine if, and how, including crucial land processes (e.g., vertical soil water transport) modifies hot-temperature forcing mechanisms in the two resolutions. Moreover, each ensemble member is run according to three different initial soil moisture levels, defining reference, anomalously dry- and wet-initialization experiments.Preliminary results show an improved representation of precipitation statistics (seasonal cumulative, frequency, and 99th percentile) from CP simulations, particularly over complex orography. Generally, maximum temperature reproduction benefits from the CP scale. However, localized warm biases persist over flat terrains regardless of the land surface model configuration. Finally, the two resolutions show a substantially different decay of the initial soil moisture state. At CP scale all three runs converge to similar soil moisture at the end of the integration. Conversely, non-CP runs preserve large soil moisture differences until the end of the summer season, signaling longer soil moisture memory and different soil moisture-precipitation feedback.These factors might significantly affect the reproduction and predictability of environmental and societal relevant hydroclimatic extremes on a wide-ranging temporal scale, from seasonal climate predictions to long-term climate projections.

Climate change is deeply affecting oceanographic, biogeochemical, and hydrological processes and consequently influencing the ecological patterns of ecosystems. Indeed, marine habitats and species are facing many alterations in their structure, functioning, and in their capacity of providing ecosystem services. To investigate and explore the distribution and potential variation of habitats and species under future climate change scenarios, Habitat Suitability Models (HSMs) have been widely applied during the last years for their recognized ability in predicting the suitability of a location for species and habitats in correlation with the environmental conditions.With the application of two of the best-known HSMs (Random Forest and MaxEnt), this research intends to investigate the distribution of the coralligenous, a widespread habitat in the Northern Adriatic Sea threatened by the effects of climate change, and identify its potential variation in a severe future scenario. The analysis consisted in examining the correlation between the habitat distribution with environmental parameters obtained from online databases and a set of dedicated ocean model simulations applied in recent past conditions and under RCP 8.5 climate change scenario. Furthermore, to explore the potential uncertainty of the environmental variables in future conditions, a sensitivity analysis has been implemented by running additional HSMs simulations set up with variables' increments and decrements resulting from projections modeled by other research.The models perform very well in predicting habitat distributions. The prediction under the climate change scenario shows that opportunistic species (e.g. turf-dominant algae) find more suitable conditions in the area being more tolerant to stressful conditions and alterations of the environmental variables. As a result, calcareous macroalgae appear to be more vulnerable to climate change effects, including increases in temperature, nutrient concentrations, salinity, and velocity. Overall, the results of the sensitivity analysis confirmed the results predicted by models; however, Random Forest also shows a higher sensitivity to uncertainty than MaxEnt.In conclusion, this study gives a sight of the likely ecological behavior in correlation with past environmental conditions and future alterations due to climate change. Besides, HSMs confirm to be very useful tools to develop adequate conservation strategies and/or identify priority areas to protect. Thanks to the sensitivity analysis, additional hints about the models’ behavior according to the environmental uncertainties are extrapolated, allowing to consider with consciousness the results and understanding of the potentialities of the models according to the data in possession.

In the semi-enclosed basin of the Mediterranean Sea, a wide variety of cyclone mechanisms are known to develop, including baroclinic waves coming from the Atlantic, Mediterranean cyclones originating from the cut-off of baroclinic waves, Warm Seclusions, Tropical-Like Cyclones (TLC), Rapid-Cyclogeneses (RC) and Intense Mediterranean Cyclones (IMC). Depending on the cyclone's type, the characteristic frequency of appearance can vary, ranging from tens per month to around 1-1.5 per year, as in the TLC case. RCs are among the rarest and probably most intense and destructive cyclone events that can develop in nature; 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 described by quick drop of pressure, close to 1hPa/hr for 24 hours, within the eye of the cyclone. Several recent studies investigated the formation of RC’s over Mediterranean Basin (MB). RCs formation is an extremely complicated process, and in the MB it is mostly driven by dry air intrusions from the stratosphere and by the trigger of Atmospheric Rivers.Using ERA5 dataset, we firstly conducted a physical and dynamical analysis of the most intense cyclone events occurred in the Mediterranean basin in the period 1979-2020, identifying factors which triggered, generated and contributed to the intensification of such events. According to Sanders’ and Gyakum’s definition of Bergeron, a parameter which describes RCs’ deepening rate and varies from 28mb/(24h) at the pole to 12 mb/(24h) at latitude 25°N, we were able to classify them in the three aforementioned categories. With the help of EOF analysis, we outlined synoptic configuration more likely to drive the phenomena, highlighting the role of SCAND index and NAO-. Moreover, we have investigated the deepening with a new promising approach involving the use of 6 hours timespans, in order to single out the cyclones with higher gradients of pressure and faster evolution in semi enclosed basins. Further analysis is being undertaken to determine the cyclones’ phase and their main morphological characteristics, as well as their correlation with atmospheric rivers and SST anomalies exhibited by the Central Mediterranean Basin.

We propose a new point-prediction DEep Learning WAVe Emulating model (DELWAVE) which successfully emulates the behaviour of a numerical surface ocean wave model (SWAN) at a sparse set of locations, thus enabling numerically cheap large-ensemble prediction over synoptic to climate timescales. DELWAVE training inputs consist of 6-hourly surface COSMO-CLM wind fields during period 1971–1998, while its targets are significant wave height, mean wave period and mean wave direction. Testing input set consists of surface winds during 1998–2000 and cross-validation period is the far-future climate timewindow of 2071–2100. DELWAVE is constructed to have a convolution-based atmospheric encoder block, followed by a temporal collapse block and finally a regression block. Random importance-sampling was performed to better model underpopulated tails of variable data distributions. Detailed ablation studies were performed to determine optimal performance regarding input fields, temporal horizon of the training set and network architecture. DELWAVE reproduces SWAN model significant wave heights with a mean absolute error (MAE) between 5 and 10 cm, mean wave directions with a MAE of 10°–25° and mean wave period with a MAE of 0.2 s. DELWAVE is able to accurately emulate multi-modal mean wave direction distributions, related to dominant wind regimes in the basin. We use wave power analysis from linearized wave theory to explain prediction errors in the long-period limit during southeasterly conditions, indicating, as expected, that non-local generation of swell poses a more difficult challenge during long-fetched Scirocco than during cross-basin Bora flow. We present a storm analysis of DELWAVE, employing threshold-based metrics of precision and recall to show that DELWAVE reaches a very high score (both metrics over 95 %) of storm detection. SWAN and DELWAVE time series are compared against each other in the end-of-century scenario (2071–2100), and compared to the control conditions in the 1971–2000 period. Good agreement between DELWAVE and SWAN is found when considering climatological statistics, with a small (≤5 %), though systematic, underestimate of 99th percentile values. Compared to control climatology over all wind directions, the mismatch between DELWAVE and SWAN is generally small compared to the difference between scenario and control conditions, suggesting that the noise introduced by surrogate modeling is substantially weaker than the climate change signal.

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. The preliminary results show that the topography and in particular the interaction with the peaks of the Apennine range plays a fundamental role in the dynamics of the cold pool that trigger the convective system. Also, the SST anomaly is found to play an important role in the development of the supercell. In particular, we observed that the simulations forced with MFS-CMEMS SST and the COAWST model runs produce a very realistic SST, in terms of spatial and temporal distribution, but colder by about 1.5 °C in absolute value if compared to observed satellite data. This difference generates lower heat fluxes, less evaporation, weaker precipitations and smaller hail than using warmer SSTs.

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.

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.

Mediterranean basin could be occasionally it can be affected by tropical-like cyclonic phenomena. These are called out Mediterranean Tropical-Like Cyclones (TLC) or Medicanes. Their frequency is about 1.5 per year and they can reach category 1 intensities. Previous studies focusing could beon past TLCs events have found that SST 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 and MLD on genesis, intensification and evolution of a recent record-breaking TLC “IANOS”. IANOS cyclone it 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, reaching atmospheric pressure values of 984 hpa and wind intensity of over 120-130 km/h. 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, IFS Analysis (at 9km 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, 70 m, 100 m. 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 content of climate change scenarios.

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 30 most intense cyclogenesis events occurred in the Mediterranean basin in the period 1979-2020, identifying factors which triggered and generated cyclones and contributed to the intensification of such events; this allowed to classify them as TLC, RC or IMC. 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.

The aim of this work is to study the triggering mechanism and the other factors involved in the development of the Medicane ‘Ianos’ over the Ionian Sea, occurred during 15-20 September 2020. Ianos was one of the most intense Tropical-Like cyclones(TLC) observed on the Mediterranean. It was characterized by a minimum pressure of 984 hPa and generated winds of over 120 km/h and up to 5 meters of significant waves height. It also caused massive flooding along the Greek coast and rain accumulations of more than 500 mm in inland areas. The triggering and the physical process for intensifying the cyclone has been studied using satellite and the convection permitting numerical simulation at 1 km resolution. Factors such as dry air intrusion due to the stratosphere-troposphere exchange partially helped in the formation and stabilization of the eye of the cyclone. Moreover, convection was initially triggered by the cold north-easterly advection that de-stabilized the atmosphere in Gulf of Sidra, helping in the deep convection and rainfall in the region during 15 September. Further, the formation of the low pressure system in Libya that later interacted with this convective system along with the dry air intrusion led to the formation of the cyclone. The latent heat release mostly sustains and intensified the storm processes. This can also be deduced (in conjunction with the marine phenomena of mixing, waves, etc.) from the decrease in Sea Surface Temperature along the TLC track. Understanding the mechanism of the storm initiation process is an important task for improving the forecast in the future in order to improve forecasts but also to limit the impacts of these extreme phenomena, in a complex context of climate change.

Heatwaves (HWs) is high-impact phenomena that may have devastating impacts on societies and ecosystems. In the context of numerical modeling, despite driving synoptic scale dynamics are generally well caught, local-scale forcing representation is still challenging, embodying a source of uncertainty and errors. In this work we study two HWs occurring in 2021 summer season (02-05 Aug and 11-14 Aug), on the Italian territory. The first event, is characterized by strong South-Westerly winds and albeit without high geopotential and 850 hPa temperature caused 2 m temperatures above 40 °C in the central Italy east cost (e.g., in the urban area of Pescara), mainly driven by katabatic winds (i.e., Fhoen dynamics). The second HW, has been triggered by a strong advection of hot air from the North African territory and with a major impact on the western coasts of the Italian territory. Here, we leverage a WRF (Weather Research and Forecasting system) numerical model at 1 km resolution over central Italy multi-physics ensemble, including various Planetary Boundary Layer (PBL), land-surface-model (LSM), radiative and surface numerical schemes. The simulations are performed using an approach that takes into account the evolution of sea surface temperature and Marine Mixed Layer Depth (at high resolution, 4.5 km), according to the OML numerical scheme, in order to represent the air-sea interactions more realistically. The preliminary results show a relevant impact exerted by numerical parameterizations, in the prediction of the maximum temperature and humidity, especially in the urban areas. A notable impact is also observed for the simulation of the minimum temperature values. The greatest modulation of HWs reproduction results from the choice of LSMand PBL schemes, and their combinations. These results highlight that the multi-physics approach is also useful to highlight most relevant processes driving local-scale modulation and related uncertainty representing a valuable tool to foster local-scale HWs-related risk mitigation.

The Mediterranean Sea is a semi-enclosed, fairly temperate, mid-latitude marine basin, strongly influenced by the North-Atlantic atmospheric circulations. A wide variety of cyclogenesis mechanisms are known to develop within this basin, including baroclinic waves coming from the Atlantic, Mediterranean cyclogenesis originating from the cut-off of baroclinic waves, Tropical-Like Cyclones (TLC) and explosive-cyclogenesis (EC). Depending on the cyclone type, the frequency of appearance can vary, ranging from tens per month to 1.5 per year, as in the TLC case. ECs 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. These events are determined by 12 different parameters, among which the main one is the quick drop of pressure, close to 1hPa/hr for 24 hours, within the eye of the cyclone. ECs formation is an extremely complicated process, and in the Mediterranean basin it is probably driven by air intrusions from the stratosphere and by the presence of Atmospheric Rivers. Starting from the analysis of the EC event called “Vaia Storm”, occurred in the Central Mediterranean Basin on October 29th 2018, and using ERA5 dataset, we firstly conducted a physical and dynamical analysis of the event, by pointing out some recurring characteristics previously highlighted in other works, on both local and synoptic scale. Secondly, we analyzed the results given by the reanalysis model ERA5 regarding the period January 1st 1950 – January 1st 2020, identifying other cyclogeneses with the same features, such as the event on November 4th 1966. On the basis of these information, the return period of the EC events was defined, as well as its statistical distribution and seasonality and correlation with NAO and EA indexes (both strongly negative). Further analysis are currently undertaken to determine correlations with SCAND index and possible SST anomalies in the Central Mediterranean Basin.

We present a numerically cheap machine-learning model which accurately emulates the performances of the surface wave model Simulating WAves Near Shore (SWAN) in the Adriatic basin (north-east Mediterranean Sea).A ResNet50 inspired deep network architecture with customized spatio-temporal attention layers was used, the network being trained on a 1970-1997 dataset of time-dependent features based on wind fields retrieved from the COSMO-CLM regional climate model (The authors acknowledge Dr. Edoardo Bucchignani (Meteorology Laboratory, Centro Italiano Ricerche Aerospaziali -CIRA-, Capua, Italy), for providing the COSMO-CLM wind fields). SWAN surface wave model outputs for the period of 1970-1997 are used as labels. The period 1998-2000 is used to cross-validate that the network very accurately reproduces SWAN surface wave features (i.e. significant wave height, mean wave period, mean wave direction) at several locations in the Adriatic basin. After successful cross validation, a series of projections of ocean surface wave properties based on climate model projections for the end of 21st century (under RCP 8.5 scenario) are performed, and shifts in the emulated wave field properties are discussed.

Issue sup1: Copernicus Marine Service Ocean State Report, Issue 5 Supplement.-- Karina von Schuckmann (Editor), Pierre-Yves Le Traon (Editor), Neville Smith (Chair) (Review Editor), Ananda Pascual (Review Editor), Samuel Djavidnia (Review Editor), Jean-Pierre Gattuso (Review Editor), Marilaure Grégoire (Review Editor), The work was supported by the Copernicus Marine Environment Monitoring Service (CMEMS) LATEMAR project. CMEMS is implemented by Mercator Ocean in the framework of a delegation agreement with the European Union. This work has also been conducted as part of the bilateral project EOLO-1 (“Extreme Oceanic waves during tropical, tropical-like, and bomb cyclones”) between CNR-ISMAR and the University of Tokyo (Japan; Prof. Takuji Waseda). Antonio Ricchi funding have been provided via the PON “AIM” - Attraction and international mobility program AIM1858058. Joanna Staneva acknowledges H2020 IMMERSE Project, Arno Behrens was supported by CMEMS Waveflow project and G. Gayer by ESA Black Sea and Danube Regional Initiative (EO4BS).

The Mediterranean basin is the formation site of a vast number and type of cyclones. Among these, we can occasionally identify intense vortices showing tropical characteristics, called Tropical-Like Cyclones (TLC). Their development has been studied in several case studies, showing the influence of synoptic scale upper level forcings and mesoscale features, such as the sea surface temperature and the characteristics of the air masses on the formation area. The importance of Sea Surface Temperature (SST) consists in modulating the intense latent and sensible heat fluxes, which control the development of the TLC. For tropical cyclones, one of the most studied factors in recent years is the ocean heat content in the formation basin of these storms. We plan here to extend this analysis to TLC. Besides innovative studies with coupled atmosphere-waves-ocean numerical models, a simpler approach for investigating the sole effect of the ocean heat content consists of adopting a simplified ocean description by varying the local characteristics of the Ocean Mixed Layer (OML). In this work we use the WRF (Weather Research and Forecasting system) model, in standalone (atmospheric) mode, with 3 km grid spacing, forced with GFS-GDAL (0.25°x0.25° horizontal resolution) and SST initialization provided by the MFS-CMEMs Copernicus dataset. Two case studies of TLC are examined here, namely ROLF (06-09/11/2011) and IANOS (14-19/09/2020). The ocean is simulated with an OML approach, with SST updated at each iteration as a function of the atmospheric heat fluxes and with an average mixed layer deph (MDL) provided by the MFS-CMEMS dataset. For each TLC studied, the MDL is modified by increasing and decreasing its depth by 10 mt, 30 mt, 50 mt . The preliminary results show how the structure of the MDL influences the intensity of the cyclone but also the structure and precipitation both in terms of quantity and location.

During the night between 9 and 10 September 2017, multiple flash floods associated with a heavy-precipitation event affected the town of Livorno, located in Tuscany, Italy. Accumulated precipitation exceeding 200 mm in two hours was recorded. This rainfall intensity is associated with a return period of higher than 200 years. As a consequence, all the largest streams of the Livorno municipality flooded several areas of the town. We used the limited-area weather research and forecasting (WRF) model, in a convection-permitting setup, to reconstruct the extreme event leading to the flash floods. We evaluated possible forecasting improvements emerging from the assimilation of local ground stations and X- and S-band radar data into the WRF, using the configuration operational at the meteorological center of Tuscany region (LaMMA) at the time of the event. Simulations were verified against weather station observations, through an innovative method aimed at disentangling the positioning and intensity errors of precipitation forecasts. A more accurate description of the low-level flows and a better assessment of the atmospheric water vapor field showed how the assimilation of radar data can improve quantitative precipitation forecasts.

Reliable wave forecasts and hindcasts, together with long-term statistical analysis of extreme conditions, are of utmost importance for monitoring marine areas. Indeed, there is general consensus that high-quality predictions of extreme events during marine storms can substantially contribute to avoiding or minimizing human and material damage, especially in busy waterways such as the Mediterranean and Black Seas. So far, however, the wave climate characterization (average and anomaly relative to the average) has focused on the bulk characterization of the significant wave height Hs, and it has lacked a description of the individual waves, such as the maximum ones that may occur at a given location in the sea. To fill this gap, we provide the intensity and geographical distribution of the maximum waves in the Mediterranean and Black Seas over 27 years (1993-2019), by representing the average annual (1993-2018) and anomaly for 2019 relative to the average of the 99th percentile of the expected maximum wave height Hm and crest height Cm. The analysis combines wave model hindcasts available through CMEMS model setup and the wave model WAVEWATCH III®, both forced with ECMWF ERA5 reanalysis winds. Results show that in 2019 maximum waves were smaller than usual in the Black Sea (anomalies of Hm up to -1.5 m), while in the Mediterranean Sea a markedly positive anomaly (+2.5 m for Hm) was found in the southern part of the basin. The peculiar 2019 configuration seems to be caused by a widespread atmospheric stability over the Black Sea and by depressions that rapidly passed over the Mediterranean Sea.

The model initialization with high-resolution SAR wind data provided by the Sentinel-1 mission and its impact on the meteorological model WRF-ARW simulations is discussed. The activity is performed within the Horizon 2020 CEASELESS project, focusing on one of the target areas, the northern Adriatic Sea (northern-central Mediterranean). The Sentinel-1 SAR wind is ingested into LAPS, a numerical system developed at NOAA, specifically designed for data analysis and nowcasting issues, since it has the advantage of being faster and less computational demanding than advanced data assimilation methods. Here, LAPS analyses are used to perform a smarter initialization of the WRF-ARW model simulations than using simply global model fields. The impact of the Sentinel-1 SAR wind on the model simulations is evaluated for twenty cases, ranging through several atmospheric conditions occurring in different seasons of the years 2014–2018. For each case study, a reference WRF-ARW simulation is forced with GFS analysis and forecasts used as initial and boundary conditions, respectively. Additional model runs are initialized with the LAPS analyses, which include the information of Sentinel-1 SAR wind, METAR data and the SEVIRI/MSG (Eumetsat) brightness temperature. A statistical evaluation of the WRF-ARW simulations is performed versus an independent set of surface records, provided by the Friuli Venezia Giulia regional station network (northeastern Italy), and METAR data. The comparison is performed for 10 m wind, 2 m air and dew point temperature. The results show a positive, albeit modest, impact on the WRF model simulations initialized with the LAPS analyses. The initialization with the Sentinel-1 SAR wind show benefits for all surface variables. Finally, a Mediterranean tropical-like cyclone (Medicane), occurred in the Ionian Sea in November 2017, is considered in order to show how the use of Sentinel wind data can contribute to a better analysis and simulation of severe weather episodes in the Mediterranean. The improvement in the simulation of the pressure minimum location is remarkable.

The Mediterranean basin is the formation site of a vast number and type of cyclones. Among these, we can occasionally identify intense vortices showing tropical characteristics, called Tropical-Like Cyclones (TLC) or MEDIcanes (Mediterranean Hurricane). Their development has been studied in several case studies, showing the influence of synoptic scale upper level forcings and mesoscale features, such as the sea surface temperature and the characteristics of the air masses on the formation area. The importance of Sea Surface Temperature (SST) consists in modulating the intense latent and sensible heat fluxes, which control the development of the TLC. For tropical cyclones, one of the most studied factors in recent years is the ocean heat content in the formation basin of these storms. We plan here to extend this analysis to TLC. Besides innovative studies with coupled atmosphere-waves-ocean numerical models, a simpler approach for investigating the sole effect of the ocean heat content consists of adopting a simplified ocean (1-Dimensional) description by varying the local characteristics of the Ocean Mixed Layer (OML). In this work we use the WRF (Weather Research and Forecasting system) model, in standalone (atmospheric) mode, with 3 km grid spacing, forced with GFS-GDAL (0.25°x0.25° horizontal resolution) and SST initialization provided by the MFS-CMEMs Copernicus dataset. Three case studies of TLC are examined here, namely ROLF (06-09/11/2011), ILONA (19-21/01/2014) and NUMA (11-20/11/2017). The ocean is simulated with an OML approach, with SST updated at each iteration as a function of the atmospheric heat fluxes and with an average mixed layer deph (MDL) provided by the MFS-CMEMS dataset. For each TLC studied, the MDL is modified by increasing and decreasing its depth by 50% and increasing and decreasing its lapse rate by 50%. The results show how the structure of the MDL influences not only the intensity of the cyclone but also the structure and precipitation both in terms of quantity and location. These outcomes suggest that, as for hurricanes, also for MEDICANES the heat content of the mass of seawater plays a fundamental role in their intensification, suggesting further studies also in a climate change perspective.

Seasonal Climate Predictions (SCPs) represent a challenging intermediate field where aspects typical of the short-term weather forecasts and long-term climate projections interact. Skillful SCPs represent an essential tool to reduce societal vulnerabilities to the inter-annual climate fluctuation through short-term (i.e., next season) climate impact mitigation measures. This is especially true over areas characterized by large climate inter-annual variability as the Mediterranean basin, which is also traditionally characterized by a poor seasonal predictability.The primary research question of present study is to assess the capability of two dynamical downscaling approaches to improve the seasonal inter-annual variability signal coming from the global-scale driving SCP system on the Mediterranean basin.In this work the Weather Research and Forecasting model (WRF3.9.1.1) and the Regional Climatic Model (RegCM4.1) were nested into NCEP’s operational seasonal forecast model Climate Forecast System version 2 (CFSv2) to dynamically downscale seasonal predictions over Mediterranean basin.Using the initial and boundary conditions of an ensemble of the CFSv2 we compare the capability of the two downscaling approaches on improving the large scale CFSv2 prediction of a climatological period of 22-cold seasons (December–February) during 1982–2002.The SCP systems (WRF- and RegCM-based) consist on a double dynamical downscaling where a height-member lagged ensemble of 3-month CFSv2 climate predictions represent the common driving fields. Both the nested models dynamically downscales CFSv2 climate prediction from the original 100 km resolution to 60 km over a domain covering the Mediterranean basin and Central Europe. The first downscaling feeds a second downscaling performed over a domain centered over Central Italy with a resolution of 12 km.Climate variables considered are: 2 m temperature, precipitation, geopotential height at different pressure levels and mean sea level pressure. Results will be discussed by means of mean bias spatial distribution, inter-annual anomaly variability reproduction and probabilistic hit-rate of anomalous seasons, through tercile plots and reliability diagrams of the above mentioned variables.Preliminary results, considering the RegCM, identify temperature variability reproduction benefiting from the downscaling. At the same time, precipitation shows an improved spatial distribution patterns but not improved inter-annual variability representation if compared to the driving CFSv2 reference period climate predictions.

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.

Between 19 and 22 January 2014, a baroclinic wave moving eastward from the Atlantic Ocean generated a cut-off low over the Strait of Gibraltar and was responsible for the subsequent intensification of an extra-tropical cyclone. This system exhibited tropical-like features in the following stages of its life cycle and remained active for approximately 80 h, moving along the Mediterranean Sea from west to east, eventually reaching the Adriatic Sea. Two different modeling approaches, which are comparable in terms of computational cost, are analyzed here to represent the cyclone evolution. First, a multi-physics ensemble using different microphysics and turbulence parameterization schemes available in the WRF (weather research and forecasting) model is employed. Second, the COAWST (coupled ocean&ndash, atmosphere wave sediment transport modeling system) suite, including WRF as an atmospheric model, ROMS (regional ocean modeling system) as an ocean model, and SWAN (simulating waves in nearshore) as a wave model, is used. The advantage of using a coupled modeling system is evaluated taking into account air&ndash, sea interaction processes at growing levels of complexity. First, a high-resolution sea surface temperature (SST) field, updated every 6 h, is used to force a WRF model stand-alone atmospheric simulation. Later, a two-way atmosphere&ndash, ocean coupled configuration is employed using COAWST, where SST is updated using consistent sea surface fluxes in the atmospheric and ocean models. Results show that a 1D ocean model is able to reproduce the evolution of the cyclone rather well, given a high-resolution initial SST field produced by ROMS after a long spin-up time. Additionally, coupled simulations reproduce more accurate (less intense) sea surface heat fluxes and a cyclone track and intensity, compared with a multi-physics ensemble of standalone atmospheric simulations.

The evolution of coastal and transitional environments depends upon the interplay of human activities and natural drivers, two factors that are strongly connected and many times conflicting. The urge for efficient tools for characterising and predicting the behaviour of such systems is nowadays particularly pressing, especially under the effects of a changing climate, and requires a deeper understanding of the connections among different drivers and different scales. To this aim, the present paper reviews the results of a set of interdisciplinary and coordinated experiences carried out in the Adriatic Sea (north-eastern Mediterranean region), discussing state-of-the art methods for coastal dynamics assessment and monitoring, and suggests strategies towards a more efficient coastal management. Coupled with detailed geomorphological information, the methodologies currently available for evaluating the different components of relative sea level rise facilitate a first identification of the flooding hazard in coastal areas, providing a fundamental element for the prioritization and identification of the sustainability of possible interventions and policies. In addition, hydro- and morpho-dynamic models are achieving significant advances in terms of spatial resolution and physical insight, also in a climatological context, improving the description of the interactions between meteo-oceanographic processes at the regional scale to coastal dynamics at the local scale. We point out that a coordinated use of the described tools should be promptly promoted in the design of survey and monitoring activities as well as in the exploitation of already collected data. Moreover, expected benefits from this strategy include the production of services and infrastructures for coastal protection with a focus on short-term forecast and rapid response, enabling the implementation of an event-oriented sampling strategy.

On the morning of September 26, 2007, a heavy precipitation event (HPE) affected the Venice lagoon and the neighbouring coastal zone of the Adriatic Sea, with 6-h accumulated rainfall summing up to about 360 mm in the area between the Venetian mainland, Padua and Chioggia. The event was triggered and maintained by the uplift over a convergence line between northeasterly flow from the Alps and southeasterly winds from the Adriatic Sea. Hindcast modelling experiments, using standalone atmospheric models, failed to capture the spatial distribution, maximum intensity and timing of the HPE. Here we analyze the event by means of an atmosphere-wave-ocean coupled numerical approach. The combined use of convection permitting models with grid spacing of 1 km, high-resolution sea surface temperature (SST) fields, and the consistent treatment of marine boundary layer fluxes in all the numerical model components are crucial to provide a realistic simulation of the event. Inaccurate representations of the SST affect the wind magnitude and, through this, the intensity, location and time evolution of the convergence zone, thus affecting the HPE prediction.

Cyclones with characteristics similar to tropical cyclones, although smaller in size, are sometimes observed in the Mediterranean Sea. Several studies have analyzed their genesis, evolution, and decay, shedding some light on the mechanisms responsible for their development. However, some of these cyclones were not properly reproduced in terms of track and intensity by neither real-time simulations nor hindcasts, emphasizing the delicate role of small-scale upper level features in the development of these cyclones. Also, the cyclone intensity is very sensitive to the intense fluxes between the ocean and atmosphere in the high-wind core. The importance to reproduce properly the air-sea interaction has been recently investigated by means of a coupled atmosphere-wave-ocean model (COAWST), which exchanges consistently the sea surface fluxes between the atmospheric model (WRF) and the ocean circulation model (ROMS), including also the effect of waves (SWAN). Finally, considering the importance of sea spray droplets in the air-sea exchange, an integrated numerical study has been undertaken, using the wave model SWAN two-way coupled with WRF-CHEM (the WRF model integrated with the chemistry package). A new sea spray generation function under severe wind condition is proposed in WRF-CHEM, in particular in the GOCART aerosol module, which explicitly considers the emission and transport of sea spray aerosol.

Several studies show how very high resolution can improve the simulation of wind speed in term of variability and intensity. In this work, we study an intense Bora event using the WRF (Weather Research and Forecasting) model with very high horizontal resolution. The Bora is a katabatic wind mainly associated to two different atmospheric configurations: 1) Cold Air Outbreak events (CAO) triggered by thermal continental anticyclones that transport cold and dry air masses from Siberia to the central Mediterranean sea, and 2) the displacement of a low pressure minimum from the Tyrrhenian Sea towards the Slovenian and Croatian coast. The first case activates a dry and cold air flow from the Dinaric Alps to the Adriatic Sea that extract a large quantity of heat and moisture fluxes from the sea (Adriatic Lake Effect). In the second case, Bora winds are activated by local dynamics and amplified by topography. Many papers have already studied the Bora dynamics, but the present work is one of the first with very-high resolution that adopts a 2-way coupling between atmosphere and waves. In this work, we study a Bora event caused by CAO, using a WRF model with 600 m grid spacing and 60 vertical terrain-following levels. Initial and boundary conditions are taken from ERA-interim dataset. SWAN (Simulating Waves in Nearshore) model is used for simulating wave generation and evolution, and its coupling to WRF is carried out via the COAWST system. In the coupled run, WRF and SWAN exchange data every 600 second. Model results are compared with data recorded every 10 minutes from three stations located inside a Bora jet, namely Vida Buoy (Piran), Paloma Buoy (Trieste) and the "Acqua Alta" tower (close to the Venice coast). Results show that the use of very high resolution increases the model performances both in terms of wind speed (in particular during the peak), and in terms of variability as well; moreover, it reduces bias and RMSE in all stations. The use of coupled atmospheric-wave models, at least for this specific case when winds are larger than 20 m/s, generates larger surface roughness due to waves and, as a consequence, a larger heat and moisture extraction from the sea.

Due to the twofold face of the Adriatic Sea as a shallow coastal sea and as a dense water formation site, the interplay between Bora (a north-easterly wind blowing from the Dinaric alps toward the Italian Adriatic coast, eastern Mediterranean basin) jets and the sea is crucial in conditioning ocean dynamics from the scale of the very coastal processes up to the deep water circulation at the basin scale. In this work we analyse the metocean dynamics associated with Bora jets in the northern Adriatic Sea and in the surrounding coastal regions, with reference to a cold spell event that hit the eastern Europe in January 2017 bringing significant snow falls also in southern Italy and Greece. To this aim, the observational information from in-situ and remote sensing measurements is complemented by a set of numerical model runs carried out within the COAWST system in which different coupling configurations among atmosphere (WRF), ocean (ROMS) and surface waves (SWAN) models are explored, aiming at assessing the potential and the upcoming challenges for model coupling with reference to these events. Preliminary results describe the impact of the explicit description of atmosphere-ocean interactions, and of the waves modulating interface processes, in terms of ocean dynamics (especially concerning evidence from surface quantities), snowfall, and small-scale wind field features. In particular, attention is dedicated to the implications of model coupling with respect to the description of the sharp gradients characterising the coastal zones, where shortcomings in satellite products and numerical models most usually arise. This study was funded by the UE H2020 programme under grant agreement No. 730030 (CEASELESS Project, Coordinator Agustin Sanchez-Arcilla).

Occasionally, storms that share many features with tropical cyclones, including the presence of a quasi-circular &ldquo, eye&rdquo, a warm core and strong winds, are observed in the Mediterranean. Generally, they are known as Medicanes, or tropical-like cyclones (TLC). Due to the intense wind forcings and the consequent development of high wind waves, a large number of sea spray droplets&mdash, both from bubble bursting and spume tearing processes&mdash, are likely to be produced at the sea surface. In order to take into account this process, we implemented an additional Sea Spray Source Function (SSSF) in WRF-Chem, model version 3.6.1, using the GOCART (Goddard Chemistry Aerosol Radiation and Transport) aerosol sectional module. Traditionally, air-sea momentum fluxes are computed through the classical Charnock relation that does not consider the wave-state and sea spray effects on the sea surface roughness explicitly. In order to take into account these forcing, we implemented a more recent parameterization of the sea surface aerodynamic roughness within the WRF surface layer model, which may be applicable to both moderate and high wind conditions. The implemented SSSF and sea surface roughness parameterization have been tested using an operative model sequence based on COAWST (Coupled Ocean Atmosphere Wave Sediment Transport) and WRF-Chem. The third-generation wave model SWAN (Simulating Waves Nearshore), two-way coupled with the WRF atmospheric model in the COAWST framework, provided wave field parameters. Numerical simulations have been integrated with the WRF-Chem chemistry package, with the aim of calculating the sea spray generated by the waves and to include its effect in the Charnock roughness parametrization together with the sea state effect. A single case study is performed, considering the Medicane that affected south-eastern Italy on 26 September 2006. Since this Medicane is one of the most deeply analysed in literature, its investigation can easily shed some light on the feedbacks between sea spray and drag coefficients.

Occasionally, storm that shares many features with tropical cyclones, including the presence of a warm core, are observed in the Mediterranean. Sometimes, they are called Medicanes. Due to the intense wind forcing and the consequent development of high wind waves, a large number of sea spray droplets are likely to be produced at the sea surface. In this work, sea spray droplets refer to film, jet and spume droplets. The typical radii at formation of bubble-mediated film and jet droplets are typically less than 5 and 20 ?m, respectively. Spume droplets, which torn off from the crest of breaking waves, are larger, with minimum radius at formation generally about 20 ?m, and a maximum one around 500 ?m. The spray droplets with radii between 10 and 300 ?m (Zhao et al., 2006) contribute most to the air-sea exchange processes of momentum and heat. At this purpose we implemented the Sea Spray Source Function (SSSF) of Wan et al. (2017) in WRF-Chem model version 3.6.1 using the GOCART aerosol sectional module. This SSSF simulates the emission of spume droplets in addition to film and jet droplets, only these last ones are taken into account by still commonly used SSSFs. Traditionally, air-sea momentum flux is computed through the classical Charnock relation (1955) that does not explicitly consider the wave-state and sea spray effects on sea surface roughness. In order to take into account both effects, we implemented the Liu et al. (2011) parameterization of sea surface aerodynamic roughness within the WRF surface layer model (sf_sfclay_physics). It is based on the Volkov (2001) and Makin (2005) parametrizations and may be applicable to both moderate and high wind conditions. This work represents an integrated numerical study utilising the third-generation wave model (SWAN) two-way coupled with the Weather Research and Forecasting Model, running in both stand-alone configuration (WRF) and integrated with the chemistry package (WRF-Chem, modified as described above). The latter is configured using GOCART aerosol module, which explicitly consider the emission and transport of sea spray aerosol. The operative sequence is performed considering first the offline coupling SWAN with WRF, and then the two-way coupling SWAN with WRF-Chem. With this sequence, there is a full consistency between the wind field and wave geometry. A test is performed considering the Medicane occurred in South-Eastern Italy on September 26, 2006. This Medicane is one of the most deeply analyzed in literature, so that an intensive investigation of the feedbacks between sea-spray, drag coefficients and latent heat flux may be made considering our integrated approach in comparison with its known features.

A novel implementation of parameters estimating the space-time wave extremes within the spectral wave modelWAVEWATCH III (WW3) is presented. The new output parameters, available in WW3 version 5.16, rely on the theoretical model of Fedele (J Phys Oceanogr 42( 9): 1601-1615, 2012) extended by Benetazzo et al. (J Phys Oceanogr 45( 9): 2261-2275, 2015) to estimate the maximum secondorder nonlinear crest height over a given space-time region. In order to assess the wave height associated to the maximum crest height and the maximum wave height (generally different in a broad-band stormy sea state), the linear quasi-determinism theory of Boccotti (2000) is considered. The new WW3 implementation is tested by simulating sea states and space-time extremes over the Mediterranean Sea ( forced by the wind fields produced by the COSMO-ME atmospheric model). Model simulations are compared to space-time wave maxima observed on March 10th, 2014, in the northern Adriatic Sea (Italy), by a stereo camera system installed on-board the "Acqua Alta" oceanographic tower. Results show that modeled space-time extremes are in general agreement with observations. Differences are mostly ascribed to the accuracy of the wind forcing and, to a lesser extent, to the approximations introduced in the space-time extremes parameterizations. Model estimates are expected to be even more accurate over areas larger than the mean wavelength (for instance, the model grid size).

In this work we assess the quality of the wind fields provided over the Adriatic Sea by the Regional Climate Model COSMO-CLM with reference to a control (CTR) period from 1971 to 2000 and to a future period from 2071 to 2100 under IPCC RCP 8.5 scenario (SCE), focusing on the implications for wave climate characterisation. Model skills have been assessed by comparing CTR results in terms of gross statistical properties and storm features against wind data from coastal observatories along the whole Italian Adriatic coast, showing a satisfactory capability of capturing the main features of mean observed seasonal variability. Significant achievements with reference to existing climatological models have been observed especially in terms of wind directionality, with unprecedented performances in reproducing the bimodal dominance of Bora (from northeast) and Sirocco (from southeast) in the northern basin, and the typical patterns of Bora jets flowing from the mountain ridges enclosing the Adriatic Sea on its eastern side. Future projections generally confirm the tendency to a decreasing energy trend envisaged by previous studies, with a more marked effect for extreme events in the northern basin. Based on the comparison between climatological wind fields and the results of a SWAN wave model run forced by COSMO-CLM, we also define and test a criterion for a rapid identification of some relevant case studies for dedicated wave modelling experiments, without the need of running entire climatological wave simulations. This permits to focus the analysis of climatological oceanographic extreme events to a limited number of selected cases, allowing remarkable saving of computational effort especially if an ensemble approach is desired.

Between 19-22 January 2014 a baroclinic wave from the Atlantic region goes in cutoff over the Strait of Gibraltar. The resulting depression remains active for approximately 80 hours, passing off shore of the north African coast, crossing the Tyrrhenian Sea and the Adriatic Sea, before turning south. During the first phase (close to the Balearic islands) and when passing over the Adriatic, the depression assumes the characteristics of a TLC (Tropical Like Cyclones). Sea Surface Temperature (SST) is a very important factor for a proper numerical simulation of these events hence we chose to model this TLC event using the COAWST suite (Coupled Ocean Atmosphere Wave Sediment Transport Modelling System). In the first phase of our work we identified the best model configuration to reproduce the phenomenon, extensively testing different microphysics and PBL (Planetary Boundary Layer) schemes available in the numerical model WRF (Weather Research for Forecasting). In the second phase, in order to evaluate the impact of SST, we used the best physical set-up that reproduces the phenomenon in terms of intensity, trajectory and timing, using four different methods of implementation of the SST in the model: i)from a spectrum-radiometer at 8.3 km resolution and updated every six hours; ii) from a dataset provided by "MyOcean" at 1 km resolution and updated every 6 hours; iii) from COAWST suite run in coupled atmosphere-ocean configuration; iv) from COAWST suite in fully coupled atmosphere-ocean- wave configuration). Results show the importance of the selected microphysics scheme in order to correctly reproduce the TLC trajectory, and of the use of high-resolution and high-frequency SST fields, updated every hour in order to reproduce the diurnal cycles. Coupled numerical runs produce less intense heat fluxes which on turn result in better TLC trajectories, more realistic timing and intensity when compared with standalone simulations, even if the latter use a high resolution SST. Last, a temporary increase of the mixed layer depth along the trajectory of the TLC was exhibited by the fully coupled run during the two phases of maximum intensity of the phenomenon, when the wave field is more developed and acts more intensely on the vertical mixing. We will discuss how these results can be improved or further validated in proximity of land by using satellite information that will be available within the framework of H2020 CEASELESS project.

In this work we assess the quality of the wind fields provided over the Adriatic Sea by the Regional Climate Model COSMO-CLM with reference to a control (CTR) period from 1971 to 2000 and to a future period from 2071 to 2100 under IPCC RCP 8.5 scenario (SCE), focusing on the implications for wave climate characterisation. Model skills have been assessed by comparing CTR results in terms of gross statistical properties and storm features against wind data from coastal observatories along the whole Italian Adriatic coast, showing a satisfactory capability of capturing the main features of mean observed seasonal variability. Significant achievements with reference to existing climatological models have been observed especially in terms of wind directionality, with unprecedented performances in reproducing the bimodal dominance of Bora (from northeast) and Sirocco (from southeast) in the northern basin, and the typical patterns of Bora jets flowing from the mountain ridges enclosing the Adriatic Sea on its eastern side. Future projections generally confirm the tendency to a decreasing energy trend envisaged by previous studies, with a more marked effect for extreme events in the northern basin. Based on the comparison between climatological wind fields and the results of a SWAN wave model run forced by COSMO-CLM, we also define and test a criterion for a rapid identification of some relevant case studies for dedicated wave modelling experiments, without the need of running entire climatological wave simulations. This permits to focus the analysis of climatological oceanographic extreme events to a limited number of selected cases, allowing remarkable saving of computational effort especially if an ensemble approach is desired., U ovom radu ocjenjujemo kvalitetu polja vjetra nad Jadranskim morem dobivenog primjenom Regionalnog klimatskog modela COSMO-CLM za kontrolno razdoblje (CTR) od 1971. do 2000. i za buduće razdoblje od 2071. do 2100. uz pretpostavku klimatskog scenarija IPCC RCP 8.5 (SCE), s posebnim osvrtom na posljedice za valnu klimu. Kvaliteta modela procijenjena je usporedbom njegovih rezultata za CTR-a s podacima vjetra s obalnih opservatorija duž cijelog talijanskog dijela jadranske obale na temelju ukupnih statističkih i olujnih svojstava. Usporedba je pokazala zadovoljavajuće rezultate modela pri reproduciranju glavnih obilježja srednje opažene sezonske varijabilnosti. Značajna unapređenja u odnosu na postojeće klimatske modele dobivena su posebice u reproduciranju smjera vjetra, kao i pri uspješnoj reprodukciji bimodalne dominacije bure (sa sjeveroistoka) i juga (s jugoistoka) u sjevernom bazenu, te tipičnim obrascima bure s jakim intenzitetima ispred planinskih prijevoja duž istočne obale Jadranskoga mora. Buduće projekcije općenito potvrđuju negativni trend energije predviđen i prethodnim studijama, s izrazitijim učinkom na ekstremne događaje u sjevernom bazenu. Na temelju usporedbe klimatoloških valnih polja i rezultata valnog modela SWAN forsiranog izlaznim poljima COSMO-CLM modela, definirani i testirani su kriteriji za brzu identifikaciju relevantnih situacija u modeliranju valova bez potrebe za izvođenjem cijele klimatološke simulacije valova. To dozvoljava da se analiza klimatoloških oceanografskih ekstremnih događaja usredotoči na ograničeni broj odabranih slučajeva, čime se omogućava značajna ušteda računalnih resursa pogotovo ako se želi primjeniti ansambl modela.

An intense cold air outbreak affected the northern Adriatic Sea during winter 2012, determining an exceptional persistence of northeasterly Bora wind over the basin, which lasted for about 3 weeks. The cold air coming from the Balkans produced icing in the Venice lagoon and very intense snowfall in the Apennines Mountains and even near the coasts. In order to understand the importance and role of air–sea interactions for the evolution of the atmospheric fields, simulations with the Weather Research and Forecasting (WRF) model encompassing the whole period have been performed using sea surface temperature (SST) fields with an increasing level of complexity. Starting from a large-scale static sea temperature, the SST in the initial and boundary conditions has been progressively made more realistic. First, a more refined field, retrieved from a satellite radiometer was used; then, the same field was updated every 6 h. Next, the effect of including a simplified 1D ocean model reproducing the Oceanic Mixed Layer (OML) evolution has been tested. Finally, the potential improvements coming from a coupled description of atmosphere–ocean and atmosphere–ocean–waves interactions have been explored within the Coupled Ocean–Atmosphere–Wave Sediment Transport (COAWST) modeling system. Results highlight that the energy exchange between air and sea does not significantly impact the atmospheric fields, in particular 10 m wind and 2 m temperature, also because of the geography of the basin and the predominance of synoptic-scale flow in intense events of Bora, in the northern Adriatic. However, when sensible and latent heat fluxes, which are dependent on atmospheric and oceanic variables, are analyzed, the more realistic representation of SST drastically improves the model performances.

In November 2011, an Atlantic depression affected the Mediterranean basin, eventually evolving into a Tropical-Like Cyclone (TLC or Mediterranean Hurricane, usually designated as Medicane). In the region affected by the Medicane, mean sea level pressures down to 990 hPa, wind speeds of hurricane intensity close to the eye (around 115 km/h) and intense rainfall in the prefrontal zone were reported. The intensity of this event, together with its long permanence over the sea, suggested its suitability as a paradigmatic case for investigating the sensitivity of a numerical modeling system to different configurations, air-sea interface parameterizations and coupling approaches. Toward this aim, a set of numerical experiments with different parameterization schemes and levels of coupling complexity was carried out within the Coupled Ocean Atmosphere Wave Sediment Transport System (COAWST), which allows the description of air-sea dynamics by coupling an atmospheric model (WRF), an ocean circulation model (ROMS), and a wave model (SWAN). The sensitivity to different initialization times and Planetary Boundary Layer (PBL) parameterizations was firstly investigated by running a set of WRF standalone (atmospheric-only) simulations. In order to better understand the effect of coupling on the TLC formation, intensification and trajectory, different configurations of atmosphere-ocean coupling were subsequently tested, eventually including the full coupling among atmosphere, ocean and waves, also changing the PBL parameterization and the formulation of the surface roughness. Results show a strong sensitivity of both the trajectory and the intensity of this TLC to the initial conditions, while the tracks and intensities provided by the coupled modeling approaches explored in this study do not introduce drastic modifications with respect to those resulting from a fine-tuned standalone atmospheric run, though they provide by definition a better physical and energetic consistency. Nevertheless; the use of different schemes for the calculation of the surface roughness from wave motion, which reflects the description of air-sea interface processes, can significantly affect the results in the fully coupled runs.

We present a study on expected wind wave severity changes in the Adriatic Sea for the period 2070–2099 and their impact on extremes. To do so, the phase-averaged spectral wave model SWAN is forced using wind fields computed by the high-resolution regional climate model COSMO-CLM, the climate version of the COSMO meteorological model downscaled from a global climate model running under the IPCC-A1B emission scenario. Namely, the adopted wind fields are given with a horizontal resolution of 14 km and 40 vertical levels, and they are prepared by the Italian Aerospace Research Centre (CIRA). Firstly, in order to infer the wave model accuracy in predicting seasonal variability and extreme events, SWAN results are validated against a control simulation, which covers the period 1965–1994. In particular, numerical predictions of the significant wave height Hs are compared against available in-situ data. Further, a statistical analysis is carried out to estimate changes on wave storms and extremes during the simulated periods (control and future scenario simulations). In particular, the generalized Pareto distribution is used to predict changes of storm peak Hs for frequent and rare storms in the Adriatic Sea. Finally, Borgman's theory is applied to estimate the spatial pattern of the expected maximum wave height Hmax during a storm, both for the present climate and that of the future scenario. Results show a future wave climate in the Adriatic Sea milder than the present climate, even though increases of wave severity can occur locally.

ObjectivesWe sought to describe the sequence of molecular events during ischemia and reperfusion of the human heart and to determine the activation of stress kinases and deoxyribonucleic acid (DNA) damage response elements on apoptosis in ischemia or reperfusion of the human heart.BackgroundBrief ischemia is tolerated by cardiac myocytes, but it determines immediate metabolic changes and block of contraction. Prompt restoration of coronary blood flow is inexorably associated with a slow recovery of myocardial contractile function. The prolonged, postischemic contractile dysfunction in the viable tissue is called myocardial stunning. The molecular mechanisms underlying myocardial stunning and ischemia-reperfusion injury are still poorly understood. Their elucidation would be valuable in order to identify novel therapeutic strategies.MethodsWe examined human left ventricular samples taken from 20 patients undergoing elective valve surgery before aortic cross-clamping, 20 ± 2 min (brief ischemia), 58 ± 5 min after the cross-clamping period (prolonged ischemia), and 21 ± 4 min after reconstitution of coronary blood flow (reperfusion). Stress kinases and DNA damage sensor proteins (ATM, H2AX, p53) were determined by immunoblotting with specific antibodies. Electron microscopy analysis was carried out on ischemic and reperfused samples. ATP content, reactive oxygen species (ROS) levels, and cytochrome oxidase activity were determined by biochemical assays.ResultsIschemia caused accumulation of ROS, reduction of cytochrome C oxidase and ATP, and activation of stress kinases p38 and Jun terminal kinase. Electron microscopy showed significant mitochondrial swelling in the majority of cells, but no appreciable apoptosis of cardiomyocytes. During ischemia, myocytes were intensely stained by TUNEL, and many cells showed proliferative cell nuclear antigen-positive nuclei. Finally, we found in ischemic tissues increased p53/p21WAFlevels and phosphorylation of histone H2AX, a substrate of ATM kinase, which marks double-strand DNA breaks. Reperfusion caused a robust extracellular signal-regulated kinase-1/2 activation, a marked reduction of TUNEL staining, and persistent activation of ATM checkpoint.ConclusionsThese data indicate that ischemia induces extensive DNA damage and activation of ATM checkpoint. Reperfusion allows the repair of the DNA lesions and salvage of ischemic cells.