Comparison of measured and modeled ozone above McMurdo Station, Antarctica, 1989-2003, during austral winter/spring

Abstract

Fifteen years of ozonesonde measurements at McMurdo Station, Antarctica (78°S), are used to test the ability of the SLIMCAT off-line 3-D chemical transport model to reproduce Antarctic stratospheric ozone in the period of August-October over many annual cycles. Two versions of SLIMCAT, both previously used in Arctic studies, are used in a detailed quantitative comparison for total column ozone and ozone mixing ratios (O 3 MR) at the vertical resolution of SLIMCAT. The newer model run, EC, forced by ERA-40 ECMWF meteorological (re)analyses, uses a general circulation model (GCM) radiation scheme to derive vertical transport and has improved chemistry and denitrification. The older run, UK, uses UKMO analyses and the MIDRAD scheme. Run EC shows good agreement with measured total column ozone (within ±10%). Run UK has similar agreement except during the annual ozone depletion period when run UK overestimates total column ozone by ∼20% in many years. Linear regression of O 3 MR shows run EC is in excellent agreement with measurements, R 2 = 0.89. Run UK does not agree as well at higher altitudes in late winter. Overall, the newer version of SLIMCAT, with improved vertical velocity due to the use of the GCM radiation scheme and improved vertical and temporal resolution due to the use of ERA-40 ECMWF (re) analyses, does well in reproducing variations in Antarctic ozone concentrations over many annual cycles, indicating SLIMCAT can make useful contributions to chemistry climate models (CCM). Copyright 2007 by the American Geophysical Union.