TOMS TOTAL OZONE TRENDS IN POTENTIAL VORTICITY COORDINATES

Global total ozone measurements from the Nimbus 7 Total Ozone Mapping Spectrometer (TOMS) are analyzed using potential vorticity (PV) as an approximate vortex-following coordinate. We analyze the time period No vember 1978-May 1991, prior to the volcanic eruption of Mt. Pinatubo. The TOMS data are remapped into PV coordinates and trends are calculat ed, thereby characterizing ozone losses inside and outside the winter polar vortices. These analyses show large regions of ozone loss outsid e of the vortex in both hemispheres. Furthermore, these data suggest t hat midlatitude losses in the NH during winter-spring do not result so lely from the transport of ozone depleted air from inside to outside t he vortex.