Antarctic Ozone Depletion

Average vertical temperature structure of atmosphere FIGURE 1.11 Layers of the atmosphere as related to the average profile of air temperature above the earth’s surface. The heavy line illustrates how the average temperature varies in each layer.

Ozone Measurement in Dobson Units (DUs)

http://ozonewatch.gsfc.nasa.gov/

Antarctic Ozone Seasonality

Sources of Stratospheric Chlorine About 80% anthropogenic About 20% natural (but some natural HCl from human-induced biomass burning) Based on early 1990s estimates (UNEP/WMO)