CROSS-TROPOPAUSE MIXING OF OZONE THROUGH GRAVITY-WAVE BREAKING - OBSERVATION AND MODELING

In the companion paper [Langford et al., this issue] clear signatures of ozone modulation by gravity waves in the lower and middle troposphe re have been described from lidar observations over Fritz Peak Observa tory (39.9 degrees N, 105.3 degrees W) during September 3-4, 1993, and analyzed using a linear model. It is emphasized in that paper that th e linear analysis breaks down at the tropopause level. The purpose of this paper is to interpret the ozone observation in the upper troposph ere using a high-resolution mesoscale model and analyze the physical p rocesses responsible for the structures in the upper troposphere and l ower stratosphere. In particular, it is shown that topographically exc ited gravity waves that break at the tropopause level are responsible for an irreversible exchange of ozone from the stratosphere to the tro posphere.