Atmospheric Chemistry and Physics Discussions www.atmos-chem-phys-discuss.net 1680-7367 1680-7375 4 6 2004 10.5194/acpd-4-7011-2004 http://www.atmos-chem-phys-discuss.net/4/7011/2004/ http://www.atmos-chem-phys-discuss.net/4/7011/2004/acpd-4-7011-2004.html http://www.atmos-chem-phys-discuss.net/4/7011/2004/acpd-4-7011-2004.pdf 7011 7045 2004-11-01 2002–2003 Arctic ozone loss deduced from POAM III satellite observations and the SLIMCAT chemical transport model C. S. Singleton shaw@lasp.colorado.edu C. E. Randall M. P. Chipperfield S. Davies W. Feng R. M. Bevilacqua K. W. Hoppel M. D. Fromm G. L. Manney V. L. Harvey Laboratory for Atmospheric and Space Physics, UCB 392, University of Colorado, Boulder, CO 80309-0392, USA Institute for Atmospheric Science, School of the Environment, University of Leeds, Leeds LS2 9JT, UK Naval Research Laboratory, Remote Sensing Physics Branch, Naval Research Laboratory, Washington, D.C., 20375-5351, USA Computational Physics, Inc., Springfield, VA 22151, USA Jet Propulsion Laboratory, California Institute of Technology, USA Department of Natural Sciences, New Mexico Highlands University, Department of Natural Resources Management, New Mexico Highlands University, Las Vegas, NM, 87701, USA The SLIMCAT three-dimensional chemical transport model (CTM) is used to infer chemical ozone loss from Polar Ozone and Aerosol Measurement (POAM) III observations of stratospheric ozone during the Arctic winter of 2002–2003. Inferring chemical ozone loss from satellite data requires quantifying ozone variations due to dynamical processes. To accomplish this, the SLIMCAT model was run in a "passive" mode from early December until the middle of March. In these runs, ozone is treated as an inert, dynamical tracer. Chemical ozone loss is inferred by subtracting the model passive ozone, evaluated at the time and location of the POAM observations, from the POAM measurements themselves. This "CTM Passive Subtraction" technique relies on accurate initialization of the CTM and a realistic description of vertical/horizontal transport, both of which are explored in this work. The analysis suggests that chemical ozone loss during the 2002–2003 winter began in late December. This loss followed a prolonged period in which many polar stratospheric clouds were detected, and during which vortex air had been transported to sunlit latitudes. A series of stratospheric warming events starting in January hindered chemical ozone loss later in the winter of 2003. Nevertheless, by 15 March, the final date of the analysis, ozone loss maximized at 425 K at a value of about 1.2 ppmv, a moderate amount of loss compared to loss during the unusually cold winters in the late-1990s. SLIMCAT was also run with a detailed stratospheric chemistry scheme to obtain the model-predicted loss. The SLIMCAT model simulation also shows a maximum ozone loss of 1.2 ppmv at 425 K, and the morphology of the loss calculated by SLIMCAT was similar to that inferred from the POAM data. These results from the recently updated version of SLIMCAT therefore give a much better quantitative description of polar chemical ozone loss than older versions of the same model. Both the inferred and modeled loss calculations show the early destruction in late December and the region of maximum loss descending in altitude through the remainder of the winter and early spring.