Study of the interannual ozone loss and the permeability of the Antarctic polar vortex from aerosol and ozone lidar measurements in Dumont d'Urville (66.4°S, 140°E)

Abstract

Systematic ground‐based measurements of the ozone and aerosol stratospheric profile performed in the Dumont d'Urville (66.4°S, 140°E) Antarctic station are used to study the air subsidence in fall, the springtime ozone loss, and the vortex confinement on an interannual basis. The data obtained mostly from March to October in the 1992–1998 time period are analyzed as a function of equivalent latitude in order to discriminate the measurements performed inside, at the edge or outside the vortex. The subsidence rate derived from the ozone measurements in the lower stratosphere prior to the destruction period and from the volcanic aerosol measurements in 1992 is in good agreement with the estimation provided by radiative transfer models. The analysis of the ozone seasonal variation shows that the ozone destruction starts in the beginning of August and affects essentially the inner vortex or inner edge regions. The destruction lasts up to the end of September and low ozone values are found up to the end of October, confirming the isolation of the polar vortex above 400 K. Ozone destruction rates of the order of 3%/d in the 400–475 K region and 1.5%/d around 550 K are derived from the data obtained inside the vortex. The ozone measurements obtained in October allow to study the vortex confinement which shows the increase of the ozone meridional gradient through the vortex edge from 400 to 650 K. A fine view of the vortex edge is provided by a near daily series of aerosol lidar measurements performed in October 1992, a period when the vortex was deformed by planetary waves and slanted with respect to the vertical direction.