Climate model validation and selection for hydrological applications in representative Mediterranean catchments.

This paper discusses the relative performance of several climate models in providing reliable forcing for hydrological modeling in six representative catchments in the Mediterranean region. We consider 14 Regional Climate Models (RCMs), from the EU-FP6 ENSEMBLES project, run for the A1B emission scenario on a common 0.22- degree (about 24 km) rotated grid over Europe and the Mediterranean. In the validation period (1951 to 2010) we consider daily precipitation and surface temperatures from the E-OBS dataset, available from the ENSEMBLES project and the data providers in the ECA&D project. Our primary objective is to rank the 14 RCMs for each catchment and select the four best performing ones to use as common forcing for hydrological models in the six Mediterranean basins considered in the EU-FP7 CLIMB project. Using a common suite of 4 RCMs for all studied catchments reduces the (epistemic) uncertainty when evaluating trends and climate change impacts in the XXI century. We present and discuss the validation setting, as well as the obtained results and, to some detail, the difficulties we experienced when processing the data. In doing so we also provide useful information and hint for an audience of researchers not directly involved in climate modeling, but interested in the use of climate model outputs for hydrological modeling and, more in general, climate change impact studies in the Mediterranean. [ABSTRACT FROM AUTHOR]