Summary
The ozone hole over Antarctica is formed inside polar stratospheric vortex, which is under influence of large-scale planetary waves. The Quasi-stationary wave (QSW) in the spring Southern Hemisphere (SH) stratosphere is mainly contributed by zonal wave number 1 which in turn determines location of the total ozone extremes in spring: QSW minimum (maximum) is located in the South Atlantic (Australian) sector. Our previous studies have revealed decadal eastern drift in the longitudinal location of the total ozone minimum. This drift was considered as possible consequence of ozone hole formation in the 1980s: polar SH stratosphere cooling due to ozone losses increases meridional temperature contrast and strengthens the stratospheric polar vortex that modifies the planetary wave propagation and stationary wave structure. Therefore, predicted ozone recovery over Antarctica could possibly lead to change in the longitudinal drift tendency. Antarctic ozone recovery is observed since approximately mid-1990s, and, by models, pre-ozone hole levels are expected to about 2050–2070. Using TOMS/OMI data 1979–2012 we have analyzed the monthly mean locations of the total ozone minimum in September–November over the latitudes 50–80S. By polynomial fit (order 3), the ozone minimum was the farthest east (near 0E) in early 2000s and it exhibits reverse (westward) motion later. The eastward shift tendency undergoes clearly observed change in early 2000s that generally agrees with Antarctic total ozone leveling off since mid-1990s and supports the mentioned above idea that ozone loss is partly responsible for the stationary wave structure in the Antarctic stratosphere. Persistent Antarctic ozone losses during 1980s–1990s are known to be associated not only with strengthening of the zonal circulation in the SH stratosphere and longitudinal trends in total ozone zonal extremes, but also with delay in the breakdown of the SH polar vortex, summer surface warming in the Antarctic Peninsula region, and many other combined/competing effects. Model studies indicate that ozone recovery over Antarctica may reverse/delay/cancel these tendencies and our results could be possible evidence of such changes in the QSW. Acknowledgements. This work contributes to Project 4012 of the Australian Antarctic Science program.
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