The diurnal circulation of Zugspitzplatt: observations and modeling

Abstract

Zugspitzplatt is a gently sloping plateau in the Wetterstein massif with a steep eastward oriented slope which leads down to the narrow and deep Reintal. Such combinations of plateaus and valleys are ubiquitous in the Alps. A e eld campaign has been conducted and a surface station has been installed to observe the diurnal circulation of this plateau. Nocturnal oute ow as well as an ine ow of a few hundred meters depth during the day are found at the eastern edge of the plateau on fair weather days. A rather extreme decrease of the dew point tends to occur during oute ow late in the night. This indicates that air from relatively large heights descends down to the plateau to e ow over the edge. Simulations with a mesoscale model have been performed for the days of the e eld campaign. The model is capable of simulating successfully the trajectories of the pilot balloons released near the edge. The model calculations suggest that the ine ow towards the plateau during the day ascends from Reintal and includes air from outside the Wetterstein massif. This ine ow normally reaches the western end of Zugspitzplatt. Zusammenfassung