The atmospheric circulation around Antarctica: linear stability and finite-amplitude interactions with migrating cyclones.

Abstract

Available observations of the atmospheric circulation over the coast of Antarctica indicate the presence of a core of westerly winds in the upper troposphere. The linear stability of these westerlies is studied by using a semi-spectral numerical model with which the linearized, shallow, anelastic hydrostatic equations are integrated. The results obtained for several basic flows taken as idealizations of possible mean states indicate that although the topography exerts a somewhat stabilizing influence, the doubling times for the unstable perturbations are less than 2 days in all cases.-from Author