Summary
We examine the cause of seasonal trends in the zonal asymmetry of the total ozone column (TOC) at high southern latitudes. Grystai et al. [2007] demonstrated that the quasi‐stationary component of TOC in the collar region outside the Antarctic Ozone Hole in Sept-Oct‐Nov rotated by as much as 45 degrees eastward during 1979-2005, with differences in the zonal and meridional displacements of the minima and maxima of the pattern. We have extended and updated the analysis of Grystai et al. [2007] to include the other 3 seasons and the period 1979‐ 2011 using version 8.6 of the NASA/GSFC Merged Ozone Dataset, and find that the Sept-Oct-Nov trends have continued post-2005 and that weaker long-term shifts are also apparent over the time period in Dec-Jan-Feb and Mar-April-May. Using ERA-Interim assimilated meteorological data, we examine characteristics of extra-tropical Rossby waves, the location of the stratospheric polar vortex and metrics of the Ozone Hole, and their relationship with observed trends in the TOC distribution at high southern latitudes. We find that the TOC trends are consistent with long-term changes in the phase and amplitude of quasi-stationary Rossby waves, which show seasonal differences that suggest separate influences from springtime ozone depletion and other climate processes.
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