Characteristics of the ozone decline over both hemispheres

Abstract

The ozone decline in both hemispheres accelerated up to the 1990s. A number of interesting facts are presented that use objective characteristics, such as ozone mass deficiencies (O₃MD) from the pre-1976 averages. In the mid-1990s the major decline in the lower stratosphere was better understood and the essential role of the stratospheric temperature and dynamics affecting the Arctic ozone decline was confirmed. In 1993 and 1995 in the northern latitudes (>35°N) the cumulative winter–spring O₃MD was surpassing the deficiencies over Antarctica for the corresponding season. Total ozone deficiencies of 4–6% from pre-1976 averages continue to be observed over extra-tropical latitudes. There is no decline in the tropics only (25°N–25°S). The decline is much stronger in winter–spring than in the summer season and is very much influenced by the meteorological conditions at nearly equal concentrations of ozone depleting substances. The largest spring O₃MD over Antarctica was in 2006; the intensity of the loss per unit surface within <220 DU area increased during the past decade and there are no signs of reduction of the ozone losses there.

Acknowledgments

This study has been partially funded by the European Commission under the EC Integrated Project SCOUT-O3 (505390-GOCE-CT-2004).