Objective mesoscale analyses in complex terrain: application to foehn cases during MAP

Abstract

A very dense surface network consisting of 38 stations was operated in the Rhine Valley and its tributaries during the MAP-SOP. The data was used to investigate foehn on the meso-scale. The "Vienna Enhanced Resolution Analysis" (VERA) is a model-independent analysis approach and was adapted to interpolate meteorological data in individual valleys. Minimizing different spatial derivatives as a cost function and taking the topography into account made it possible to get reasonably low level meteorological fields of pressure and potential temperature on a 2 km grid. The data of the surface stations used in the analyses were carefully quality-controlled. The examination of different foehn cases throughout the autumn of 1999 yields interesting and detailed features in the fields of pressure and potential temperature.