A Dynamical Explanation for the Asymmetry in Zonally Averaged Column Abundances of Ozone between Northern and Southern Springs

Abstract

The observed zonally averaged column ozone shows a maximum at 90°N during the northern winter and spring and at 60°S throughout the southern winter and spring. This asymmetry is explained in the context of a zonally averaged model with coupled radiation, dynamics, and chemistry, together with consistently parameterized planetary wave driving and wave transport. It is shown that in the presence of weak wave driving, the penetration of the tropospheric circulation into the lower stratosphere and the characteristics of ozone chemistry are such that they produce a column ozone maximum at subpolar latitudes. The effect of increased wave driving is to intensify the residual circulation and extend it farther poleward, resulting in an ozone maximum at the pole. The role of the mesospheric drag is to further enhance these column ozone maxima. Model calculations show that the positions of the observed column ozone maxima are consistent with intensities of wave driving in the two hemispheres derived from data.