12th Conference on Middle Atmosphere

Tuesday, 5 November 2002
What controls the size of the Antarctic ozone hole?
Paul A. Newman, NASA/GSFC, Greenbelt, MD; and E. R. Nash and S. R. Kawa
The Antarctic ozone hole is a region of extremely large ozone depletion that is roughly centered over the South Pole. Since 1979, the area coverage of the ozone hole has grown from near zero size to over 24 Million km2. In the 8-year period from 1981 to 1989, the area expanded by 18 Million km2. During the last 5 years, the hole has been observed to exceed 25 Million km2 over brief periods. We will review these size observations, the size trends, and the interannual variability of the size. The area is derived from the area enclosed by the 220 DU total ozone contour. We will discuss the rationale for the choice of 220 DU: 1) it is located near the steep gradient between southern mid-latitudes and the polar region, and 2) 220 DU is a value that is lower than the pre-1979 ozone observations over Antarctica during the spring period. The phenomenal growth of the ozone hole was directly caused by the increases of chlorine and bromine compounds in the stratosphere. In this talk, we will show the relationship of the ozone hole’s size to the interannual variability of Antarctic spring temperatures. In addition, we will show the relationship of these same temperatures to planetary-scale wave forcings.

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