CONDITIONS OF FORMATION OF TROPICAL CYCLONES IN GEOSTROPHIC FLOW

摘要

Conditions of occurrence of a closed cyclonic circulation in the area of positive heat anomalies are studied on the basis of a simple model of interaction between the convective boundary layer and the upper atmosphere against the background of the easterly geostrophic flow. It is shown that such conditions are determined by the ratio of dimensionless parameters that characterize a relative role of convection and background flow, stratification and buoyancy due to heating, and the friction and Coriolis forces. Under some conditions, the horizontally nonuniform heating and friction convergence in the boundary layer result in the formation of a closed circulation and its spread upward. This is accompanied by the generation of a cold core in the upper atmosphere.