Role of Moist Baroclinic Instability in the Development of Polar Lows and Comma Clouds

摘要

The Mak parameterization of latent heat release is discussed using a finite difference version of a quasi-geostrophic beta-plane model. It is found that his analytical results can be well reproduced with 20-layer vertical resolution. This finite difference version can be used for observed (arbitrary) zonal wind and static stability vertical profiles with more realistic heating. This model with Chang profiles of heating is applied to the North Pacific polar lows studied by Mullen and to a subsynoptic scale (inverted) comma cloud system observed over Central South America. The principal features of these disturbances are reproduced by the model. Thus the generation mechanism of polar lows and comma clouds seems to be the baroclinic instability modified by the latent heat release.