Case studies of frontal passages in the Bavarian-Alps - Results from the IFU moutain stations during the German front experiment 1987

The Fraunhofer-Institut für Atmosphärische Umweltforschung (IFU) participated in the German Front Experiment 1987 in order to investigate the spatial and temporal structure of cold fronts in mountainous terrain. The observing systems of the IFU includes I) 6 meteorological/airchemical stations located along the northern rim of the Bavarian Alps, II) two temporary radiosonde stations in the Loisach River Valley at Garmisch (VIZ rawinsondes) and Farchant (structure sondes), and III) several mobile air pressure stations (electronic sensors) in the Alpine foreland. The discussion is mainly focussed on the frontal passages in the Garmisch area based on the recordings at the stations (valley floor: 700 m, Wank peak: 1780 m, Zugspitze peak: 2960 m) and the aerological data. Results from the frontal events A (October 8, 1987) and B (November 12, 1987) - similar cases with prefrontal foehn - clearly show some orographically induced frontal phenomena.