Stability properties of cylindrically curved mean flows

Abstract

This article describes results from numerical experiments which isolate the influence of horizontal curvature upon various linear properties of growing baroclinic eddies. Cylindrically symmetric mean flows on an f-plane are studied; they have either strong or weak curvature. The radius of curvature is twice as large for weak as it is for strong curvature. Strong curvature reduces the growth rates and this is most evident only for the short waves. The baroclinic energy conversion is positive (from mean flow to eddy) and little influenced by curvature. The barotropic conversion is made more negative by stronger curvature; it is responsible for the growth rate reductions. The regions of positive and negative barotropic conversion are distributed about the mean flow jet in such a way that the eddies are tending to straighten out that jet. These results compare favorably with some previous analyses of long-wave flows by others.