POAM III observations of the anomalous 2002 Antarctic ozone hole

Abstract

The 2002 southern hemisphere winter was marked by unusually large wave activity, culminating with an unprecedented major warming in late September. This led to an ∼250 DU increase in column ozone near the pole as measured by the Polar Ozone and Aerosol Measurement (POAM) III instrument. POAM measurements of unusually high ozone mixing ratio throughout most of the stratosphere resulted primarily from air from outside the polar vortex being transported to the POAM measurement latitude. In the altitude region where chemical ozone loss from chlorine catalyzed chemistry occurs (below 600 K potential temperature) the 2002 ozone loss was similar to previous years up to the time of the major warming. The ozone loss diminished after this time (about 1 week earlier than usual), resulting in up to 20% less chemical ozone loss within the vortex than in previous winters. This corresponds to partial column ozone values below 600 K inside the polar vortex that were ∼25 DU larger in 2002 than in previous years.