Tropical Cyclone Evolution via Potential Vorticity Anomalies in a Three-Dimensional Balance Model

Abstract

Abstract A new mechanism of vortex intensification by convectively forced vortex Rossby waves was proposed by Montgomery and Kallenbach. As demonstrated by them, the axisymmetrization process is described by vortex Rossby waves that eventually propagate outward before their symmetrization. Montgomery and Kallenbach were able to relate these waves to intensity changes in barotropic hurricane-like vortices. In the present work these ideas are applied to better understand structure change and intensification of hurricanes in a baroclinic setting. The work of Moller and Montgomery, who examined the wave kinematics and wave–mean flow interaction of vortex Rossby waves in a barotropic model, is extended here to three dimensions. The model is based on the asymmetric balance theory of Shapiro and Montgomery. A nonlinear prognostic model is used to examine the effect of convectively generated potential vorticity (PV) disturbances on the evolution of a hurricane-like vortex on an f plane. This investigation general...