Dry spells analysis over the Mediterranean basin for present climate and climate change conditions using ENSEMBLES regional climate models

The hydrological stresses and specially the dry spells are one of the main climatic features of the Mediterranean regions and it can affect and lead to relevant impacts on ecosystems, agriculture and population. It is proposed the analysis of the annual mean dry spells length (DSML) from a group of Regional Climate Model (RCM) simulations of 25km horizontal resolution from ENSEMBLES European project. The capability of these RCMs to reproduce the DSML compared with ECAv6 gridded observational database is first studied in the baseline period (1961-2000). Then percentage change of the DSML from these RCMs forced by different Global Climate Models (GCMs) for future conditions (2021-2050) under A1B emission scenario respect to historical (1951-1980) climate conditions is evaluated. The results show the success of RCMs to reproduce the overall observed dry spells characteristics. A North-to-South gradient of DSML index along the Mediterranean basin is obtained in the baseline and historical periods, with the maximum length values located over Sahara desert and minimum over the mountain ranges on the northern part of the basin. High values also can be observed in the southern half of the Iberian Peninsula, western and southern coast of the Mediterranean Sea. The climate change analysis indicates a common increase of the DSML over the Mediterranean basin for all the GCM-forced RCM simulations.