STUDY OF SPIRAL BANDS IN A LINEAR MODEL OF A CYCLONIC VORTEX.

Abstract

This paper investigates the generation and propagation of spiral bands on an axisymmetric base-state vortex. A linear model is used to study the formation of bands from internal gravity-inertia waves in a barotropic atmosphere. Spiral bands form from random perturbations placed on a vortex with unstable static stability that is equal for ascending and descending motion. This growing mode assumes the characteristics of pseudoadiabatic motion in a conditionally unstable atmosphere due to the coarse vertical resolution of the linear model. Inertial instability and the Coriolis parameter are unimportant for band formation in these linear experiments.