The predominance of either dynamical or physical processes varies in different regions of the globe. Therefore, regional models have been developed for different regions. As the regional simulation of the water- and energy cycle is very sensitive to how physical processes are represented within a regional model, transferability studies are a suitable approach to validate the performance of a regional model under different meteorological conditions.

The main goal of this study is to evaluate the RSM simulated energy- and water budget by transferability studies. This will be achieved by transferring the RSM to seven different domains all over the globe taken from the Continental Scale Experiments (CSE). The data used for the validation are taken from the Coordinated Enhanced Observation Period (CEOP). Thus, the model runs are carried out during CEOP, from 1 July 2001 until 31 December 2004. The RSM is run at 50 km horizontal resolution using NCEP reanalyses as initialization and boundary conditions. As equilibration of the land surface is necessary the runs begin July 1, 1999.

Comparisons of the RSM simulations over the seven CSE domains with ISCCP data in July 1986 illustrated already the benefit of transferability studies: Evaluating the model performance under the different meteorological prerequisites of the various model domains showed that the two diagnostic cloud schemes used within RSM have different strengths connected with different dynamical and physical processes. This indicates that transferring the model to different domains leads to a more sophisticated validation than doing comparisons only over one domain.