Stratospheric ozone and the morphology of the northern hemisphere planetary waveguide

Abstract

A middle atmosphere general circulation model is used to examine the effects of zonally asymmetric ozone (ZAO) on the Northern Hemisphere planetary waveguide (PWG) during winter (December-February). The morphology of the PWG is measured by a refractive index, Eliassen-Palm flux vectors, the latitude of the subtropical zero wind line, and the latitude of the subtropical jet. ZAO causes the PWG to contract meridionally in the upper stratosphere, expand meridionally in the lower stratosphere, and expand vertically in the upper stratosphere and lower mesosphere. The ZAO-induced changes in the PWG are the result of increased upward and poleward flux of planetary wave activity into the extratropical stratosphere and lower mesosphere. These changes cause an increase in the Eliassen-Palm flux convergence at high latitudes, which produces a warmer and weaker stratospheric polar vortex and an increase in the frequency of stratospheric sudden warmings. The ability of ZAO to alter the flux of planetary wave activity into the polar vortex has important implications for accurately modeling wave-modulated and wave-driven phenomena in the middle atmosphere, including the 11-year solar cycle, stratospheric sudden warmings, and the phase of the Northern Hemisphere annular mode. © 2012. American Geophysical Union.