Flow-field simulations with GRAMM-SCI in challenging topographical conditions in Switzerland

In this study highly-resolved wind-field simulations utilizing the newly developed mesoscale model GRAMM-SCI with a horizontal resolution of 200 m have been carried out for a part of Switzerland. Two periods of several days in winter and summer 2014 which were characterized by dynamic synoptic conditions have been selected. The modelling domain covers the main alpine ridge with peaks over 4,000 m, extremely steep faces like the famous Eiger North- face as well as the Swiss Midland. Despite the challenging framework for the modelling regarding weather and topographical conditions generally good agreement between simulations and observations was found. The complex interplay between thermally-induced local wind systems and synoptic- scale flows which was evident from the observations at different sea levels (480 to 3,571 m) has been modelled satisfactory by GRAMM-SCI. Further research is primarily planned regarding the influence of different turbulence models.