Vortex Rossby Waves in a Numerically Simulated Tropical Cyclone. Part II: The Role in Tropical Cyclone Structure and Intensity Changes*

Abstract

Abstract In Part I, the author analyzed the asymmetric structure in the inner core of a numerically simulated tropical cyclone and found that the asymmetry near the eyewall in the mid–lower troposphere is dominated by wavenumber-1 and -2 vortex Rossby waves. These waves are found to be well coupled with asymmetries in eyewall convection and thus may play an important role in the life cycle of a tropical cyclone. In this paper, analyses are extended to include the role of these vortex Rossby waves in tropical cyclone structure and intensity changes. The waves are found to transport angular momentum from the eyewall to the eye, accelerating tangential winds in the eye at the expense of decelerating the tangential wind in the eyewall, and thus they play an important role in the inner core dynamics of the tropical cyclone. Convection in the eyewall is enhanced between the downstream trough and upstream ridge in the vortex Rossby waves but suppressed between the downstream ridge and upstream trough. This close...