EFFECT OF BAROCLINICITY ON WIND PROFILES AND THE GEOSTROPHIC DRAG LAW FOR THE CONVECTIVE PLANETARY BOUNDARY LAYER.

Abstract

By using a simple physical model of the baroclinic convective planetary boundary layer, the similarity functions of the geostrophic drag law are expressed as sums of a barotropic part, dependent only on the stability and boundary layer height parameters, and a baroclinicity dependent part. These drag laws are confirmed by the results of a more sophisticated higher-order closure model, which also predict the magnitude of actual wind shears in the bulk of the mixed layer remaining much smaller than the magnitude of imposed geostrophic shear. The results are shown to be supported by some observations from the recent Wangara and ATEX experiments.