Search

Croatian Adriatic coast is often affected by extreme precipitation that leads to flash-floods with severe damage, both human and material. The added value of high-resolution regional climate model (RCM) simulations of mean and extreme precipitation has already been proven, but RCMs' skill over complex terrain, such as coastal mountains in Croatia, still poses some challenges and open questions. We evaluate the daily precipitation simulations of high-resolution (0.11°) RCM ALADIN-Climate versions 5.2 (ALD5) and 6.3 (ALD6) driven by the ERA-Interim reanalysis over the Med-CORDEX domain. The spectral nudging technique (SN) was applied on both model versions (AD5SN, ALD6SN). Reference datasets used are precipitation analysis system MESCAN, available on 5.5 km resolution every 6 h, and 24 h accumulated precipitation data from the Croatian raingauge network. To assess the agreement between model and reference we perform statistical analysis in terms of multi year spatial bias for the mean annual and seasonal precipitation, the number of wet days, the 99.9th quantile, and the quantile-quantile plots for the period 1979-2012. ALD6SN outperforms the previous versions by diminishing the drizzling effect, with notably less wet days than ALD5 and ALD5SN, and with significantly improved lower precipitation quantiles. All model versions show an underestimation of higher-order quantiles. The spectral nudging in ALD5SN causes an overestimation of the lower quantiles, with minimum difference in higher quantiles compared to ALD5. [ABSTRACT FROM AUTHOR]

The Mediterranean region of France are regularly affected by extreme precipitation that often lead to devastating flash-floods, often associated with both human and material damages. The evolution of such events in terms of occurrence and severity with climate change remains an open question.The purpose of the current study is to characterize the future evolution of these heavy precipitating events in terms of occurrence and intensity. A historical simulation (1976 – 2005) will be compare to a future simulation (2071 – 2100) for the RCP8,5 scenario. The CNRM-CM5 global climate is used as driver model. The study also compare climate change simulations from a convection parametrized convection model (ALADIN-Climate) and a convection permitting reginal climate model (AROME-Climate). These simulations were carried out on the domain defined by the CORDEX Flagship Pilot Study "Convective phenomena at high resolution over Europe and the Mediterranean". It is centered on the Alps. This domain allows a good representation of the large scale circulation over the Mediterranean sea that causes convective phenomena in the Southeastern France. The study of changes in spatial distribution and cumulative precipitation will be based on daily and hourly averages and quantiles of precipitation.I would like to share my knowledge on convection permitting regional climate model with interested people. This workshop would be a great opportunity and I hope, I will have the opportunity to exchange with people from this community. [ABSTRACT FROM AUTHOR]

The evolution of different renewable energy resources under different climate change scenarios is a key factor for the energy industry and for the energy transition. The possible changes with respect to present conditions for the operating plants and the projected resources can affect the financial frame and viability of the projects.Over Europe, climate models give a robust answer in terms of global warming and other important climate variables. However, GCMs and RCMs disagree in the projected changes of surface solar radiation (SSR) over Europe. Whereas global climate models, GCMs, present a clear positive signal for the end of XXI century, some studies show a negative anomaly for the same period in RCMs from EURO-CORDEX ensemble. This discrepancy is of special interest for photovoltaic (PV) power plants, whose resource is precisely solar radiation reaching earth's surface.In this work, which is a contribution to the CORDEX FPS-aerosols, we try to explain the reasons of the difference in anomalies focusing on the representation of aerosols in the scenario simulations of RCMs. We use regional climate models simulations from the EURO-CORDEX ensemble grouped together by its forcing GCM. Different families of runs are analysed with only one simulation with evolving aerosols per group. We focus on RCP8.5 emissions scenario. In addition, a detailed PV model is used to estimate future PV potential over Europe, which has not been considered in previous approaches.Results of this study will lead to the obtention of more accurate PV projections over Europe, demanded by policymakers and the energy sector. [ABSTRACT FROM AUTHOR]

Aerosols are known to interact with shortwave and longwave radiation, provoking a negative radiative forcing at the surface with ensuing cooling. They have therefore an important role in the Mediterranean climate system. In order to estimate the impact of aerosols on future climate, we use the ALADIN-Climat regional climate model which incorporates a prognostic aerosol scheme (TACTIC). It includes desert dust, sea salt, organic, black carbon, sulphate, ammonium and nitrate particles (Drugé et al., ACPD, 2018). The aim of this work is to study the future evolution of the different aerosols over the Euro-Mediterranean area, as well as the future climate sensitivity of this region to anthropogenic/natural aerosols. We realised a historical simulation (1971-2000) and two CMIP6 scenarios (SSP 5-8.5; 2021-2050), one using evolutive aerosols and the other constant anthropogenic emissions. This protocol allows us to identify the role of aerosols in the scenarios. First results show an additional increase in surface radiation and temperature over the future period due to aerosols, more precisely due to the drop in anthropogenic (notably sulfate) emissions. The future evolution of aerosols has also consequences on atmospheric circulation, precipitations and cloud cover that will be discussed in this presentation. [ABSTRACT FROM AUTHOR]

For more than five decades, the Mediterranean Sea has been identified as a region of so-called thermohaline circulation, namely of basin-scale overturning driven by surface heat and freshwater exchanges. The commonly accepted view is that of an interaction of zonal and meridional "conveyor belts" that sink at intermediate or deep convection sites. However, the connection between convection and sinking in the overturning circulation remains unclear. Here we use multi-decadal physical and biogeochemical simulations of the Mediterranean Sea and glider transport measurements to diagnose the location and physical drivers of this sinking. We find that most of the net sinking occurs within 50km of the boundary, away from open-sea convection sites. We also diagnose significant vertical biogeochemical fluxes near the boundary associated with this downwelling. We relate this sinking near the boundary to vorticity dynamic and the role of the Earth's rotation in suppressing net vertical motions in the open ocean. These findings corroborate previous idealized studies and conceptually replace the historical offshore "conveyor belts" by boundary "sinking rings". They challenge the respective roles of convection and sinking in shaping the oceanic overturning circulation and confirm the key role of boundary currents in ventilating the interior ocean. [ABSTRACT FROM AUTHOR]