Estimation of the Chemical Loss of Ozone in the Antarctic Stratosphere in the 1999 Winter-Spring Season from Direct Measurements and Simulations

Ulanovskii A.E., A.N.Lukyanov, V.A.Yushkov, N.M.Sitnikov, M.Volk, E.V.Ivanova, and F.Ravegnani,

Central Aerological Observatory, Russia

Izvestiya, Atmospheric and Oceanic Physics, Vol. 40, No. 6, p. 695-703, 2004

Abstract

Estimates of the chemical loss of ozone in the Antarctic circumpolar cyclone when there is an "ozone hole" are given. The ozone, water-vapor, and nitrous oxide concentrations were measured from aboard the Russian M-55 Geofizika high-altitude aircraft in September-October 1999 in the framework of the APE-GAIA (Airborne Polar Experiment-Geophysical Aircraft in Antarctica) field campaign. The cross- correlation relationships between the O3 and N2O concentrations were used to calculate the ozone mixing ratio in the absence of ozone chemical destruction at the level of the aircraft. The behavior of the O3, N2O, and H2O mixing ratios in the chemically disturbed region (CDR) and at its boundaries was analyzed. On September 23, 1999, the ozone and water-vapor concentrations at the CDR boundary located at the height level corresponding to a potential temperature of 450 K decreased by more than 80 and 50%, respectively. In all flights, it was found that the maximum magnitude of ozone loss increased with height to 4 ppm at the height level corresponding to 450 K, while the maximum relative loss was constant and equal to 98-100% at height levels corresponding to the temperature range 370-450 K. It was shown that the loss of ozone in the CDR was predominantly caused by chemical processes. On the basis of a trajectory chemical model, the chemical destruction of ozone during the winter-spring season under consideration was estimated for the region of the polar stratospheric vortex. These estimates correlate well with the data measured in the CDR