On the Role of Ozone in the Stability of Rossby Normal Modes

Abstract

The role of ozone in the linear stability of Rossby normal modes is examined in a continuously stratified, extratropical baroclinic atmosphere. The flow is described by coupled equations for the quasi-geostrophic potential vorticity and ozone volume mixing ratio. A perturbation analysis is carded out under the assumption of weak diabatic heating, which is generated by Newtonian cooling and dynamics?ozone interaction. An expression for the propagation and growth characteristics is obtained analytically in terms of the vertically averaged wave activity, which depends explicitly on the wave spatial structure, photochemistry, and basic state distributions of wind, temperature, and ozone mixing ratio. Calculations show that stationary internal modes, whose amplitudes are largest in the stratosphere, are destabilized by dynamics?ozone interaction and Newtonian cooling, with e-folding times on the order of 20?40 days.