This workpackage aims primarily at producing high resolution (10 km) 30-year time slices over four target areas. The model responses are to be compared with coarser results from existing simulations to assess the gain of a higher resolution. The daily data from the simulations will be put in a common database.

A secondary objective is high resolution model improvement for future scenarios.

The first step consists of selecting the RCM and its integration domain. Two models will be used, ALADIN and RegCM. ALADIN is currently used at 10 km resolution by CHMI, NIMH and OMSZ for numerical weather prediction. RegCM is currently used at 25 km for climate studies by CUNI, NMA and ELU. In both cases one needs an adaptation to 10 km climate simulations (improved parameterizations).

Four areas will be considered by the WP: Central Europe (CHMI, CUNI), Carpathian Basin (OMSZ, ELU), Romania and Black Sea (NMA) and Bulgaria (NIMH). For the first two areas, both models will be run on the same grid.

Once the RCM and domains identified, with observed boundary conditions (ERA40) shorter runs will be performed for adaptation of parameterization for maximum benefit from the high resolution and a 30- year simulation (1961-1990) will be performed with each model for validation purpose. The work on new parameterizations will be continued in parallel for RegCM with focus on convection (AUTH, CUNI), surface scheme (BOKU), boundary layer (WUT). The sensitivity to integration domain size will be studied (DMI). This will contribute to maintain the technical level of the partners on very high resolution climate simulation at the top.

In order to produce scenarios of the 21st century, boundary conditions from a global version of ALADIN at 50 km resolution (ARPEGE) and a European version at 25 km of RegCM will be prepared for the four above domains and three time slices: 1961-1990, 2021-2050 and 2071-2100. For the first two time slices, simulations are available at month 6, so that high resolution simulations can start at month 12. The last one is delivered at month 18 by WP1. This work is done by CNRM and ICTP. The four time slices will be archived on a daily basis by DMI according to the standard of the previous PRUDENCE project. ENSEMBLES database is compatible with this standard. To accelerate the data delivery to the other WPs, a peer to peer exchange between RCM modelers and impact modelers will be activated.

Along with the production of time-slices, the high-resolution RCM partners (CUNI, CHMI, ELU, OMSZ, NMA and NIMH) will compare, with assistance of DMI, ICTP and CNRM who are involved in both PRUDENCE and ENSEMBLES, the mean climate features of the 2021-2050 (resp. 2071-2100) response with results from ENSEMBLES (resp. PRUDENCE). The aim of this analysis is to evaluate the gain, from an atmospheric point of view, of a 10 km resolution in producing local features. The comparison with station observation of ERA40 driven time-slices is in charge of WP3, and the validation and response of extreme events is in charge of WP4.

M2.1 Month 6: The integration domains and RCM parameterizations are defined
M2.2 Month 18: The observation driven simulations are ready for other WPs
M2.3 Month 24: The scenarios and references RCM simulations are ready for other Wps
M2.4 Month 24: The sensitivity experiments to improved physical parameterizations are analyzed
M2.5 Month 26: The database is ready for access inside the project
M2.6 Month 36: The database is in public access and a report on the gain of high resolution in the local description of climate responses is available