Transport and mixing processes during the Antarctic ozone increase

The 44th Japanese Antarctic Research Expedition (JARE-44) performed intensive ozonesonde observations at Syowa Station (69.0゜S, 39.6゜E) from June 2003 through January 2004 to clarify the time evolution and mechanism of the Antarctic ozone hole dissipation as well as its formation. From analysis of the ozonesonde and satellite observational data, it was found that ozone concentration inside the Antarctic ozone hole began to increase due to the Brewer-Dobson circulation and the lateral mixing between inside and outside the polar vortex even before its breakup. In addition, the ozone increase was dependent on longitude because of the zonal wavenumber 1 quasi-stationary planetary waves. It is also reported that the ozone enhanced layers frequently observed inside the Antarctic ozone hole mostly originated from the vortex boundary region.