Antarctic Ozone Hole 2011
The Antarctic Ozone Hole during 2011
The Antarctic ozone hole of 2011 is reviewed from a variety of perspectives, making use of various data and analyses. The ozone hole of 2011was relatively large in terms of maximum area, minimum ozone level and total ozone deficit, being ranked amongst the top 10 in terms of severity of the 32 ozone holes adequately characterised since 1979. In particular, the estimated integrated ozone mass effectively removed within the ozone hole of 2011 was 2.12 Gt, which is the 7th largest deficit on record and 82% of the peak value observed in 2006. The key factors in promoting the extent of Antarctic ozone loss in 2011 were the relatively low temperatures that occurred in the lower stratosphere of the polar cap region over most of the year, and the fact that the stratospheric vortex was relatively strong and stable, at least up to mid-spring. Dynamical disturbance of the polar vortex from mid-spring provided some improvement to Antarctic ozone levels in the latter part of the ozone hole’s evolution and helped to limit the overall severity of depletion. Meteorological factors continue to largely dictate the in year-to-year variability of Antarctic ozone loss, but, through examination of regression of various ozone metrics against expected levels of equivalent effective stratospheric chlorine, we suggest that recent changes in averaged ozone levels over Antarctica show some evidence of the recovery expected due to international controls on the manufacture of ozone depleting chemicals.