LONGITUDINAL DISTRIBUTION OF TOTAL OZONE CONTENT IN EDGE REGION OF ANTARCTIC STRATOSPHERIC VORTEX

Longitudinal distribution of total ozone content (TOC) in the edge region of the Antarctic stratospheric vortex is analyzed using the TOMS satellite data (version 8) of 1979 to 2004. The five-month time interval of August-December covering the late Antarctic winter, spring, and early summer is considered. The five-month mean TOC zonal distributions at latitudes of 65 degrees S and 70 degrees S are obtained from the daily TOMS data. Zonal wave number 1 is dominated. It forms a zonal asymmetry with the quasi-stationary wave minimum and maximum placed in the opposite longitudinal sectors. Our results show that during the last 26 years the TOC asymmetry increased and in the last years it reaches 70-90 Dobson Units, or about 30 % relative to the zonal mean. Interannual variations of the longitude of the TOC maximum are observed near the stable position of 162 degrees E and 172 degrees E at latitudes of 65 degrees S and 70 degrees S, respectively. Besides the interannual variations, the longitude of the TOC minimum during 1979-2004 shows a systematic displacement to the east in the longitudinal sector of 45 degrees W to 10 degrees E. A spectral analysis shows that this tendency is caused by an interaction between the quasi-stationary components of the zonal wave number 1 and 2. In the last decades they have the opposite longitudinal drift of the phase of the maximum amplitude.