Abstract

New evidence conclusively demonstrates the existence of a broad cohesive region of air at the edge of the Antarctic stratospheric vortex, which is only weakly mixed with the core of the vortex. This new evidence greatly strengthens our earlier work suggesting the existence of this edge region of the vortex. It is from analyses, ozone measurements and models, and observed balloon trajectories:

• Calculations of effective diffusivity for 2003 and 2005 show similarly weak mixing in the edge region of the vortex to earlier calculations for 1996.

• Comprehensive measurements by Antarctic ozonesondes in 2003 show quite different evolution in the edge region of the vortex from the vortex core, in agreement with model calculations.

• With one exception, long duration balloons launched from Antarctica in spring 2005 remained confined either to the edge region of the vortex or to the vortex core.

This new evidence again shows that the edge region is up to half the area of the ozone hole. The importance of the edge region’s existence is that because it is unmixed with the vortex core, it can contain more polar stratospheric clouds as increased greenhouse gases cool the stratosphere during the 21st Century, thereby delaying the expected recovery of the ozone hole.