Motion and structure of atmospheric mesoscale baroclinic vortices: dry air and weak environmental shear

Abstract

By matched asymptotic expansions we analyze the simplified three-dimensional atmospheric flow regime of a nearly axisymmetric vortex in dry air that is in gradient wind balance and embedded in a quasi-geostrophic background wind with weak vertical shear. A description of the vortex' overall motion, its vertical tilt, and of the evolution of its leading-order axisymmetric core structure are developed. The analysis includes the influence of diabatic source terms in the vortex core as a first step towards an asymptotic theory for the structure and motion of hurricanes. The theory is closed except for the solution of a regularized quasi-geostrophic outer flow problem, the formulation of which is outlined here but whose detailed description and numerical integration are deferred to future work.