HR: 1340h
AN: A13D-0962    [Abstracts]
TI: Comparison of Measured and Modeled Ozone Above McMurdo Station, Antarctica, 1989-2003, During Austral Winter/Spring
AU: * Deshler, T
EM: deshler@uwyo.edu
AF: Department of Atmospheric Science, University of Wyoming, Laramie, WY 82071 United States
AU: Mercer, J L
EM: mercer@uwyo.edu
AF: Department of Atmospheric Science, University of Wyoming, Laramie, WY 82071 United States
AU: Kroger, C
EM: C.Kroger@gns.cri.nz
AF: Institute of Geological and Nuclear Sciences, 69 Gracefield Rd., Lower Hutt, 6007 New Zealand
AU: Nardi, B
EM: nardi@ucar.edu
AF: UCAR, P.O. Box 3000, Boulder, CO 80307 United States
AU: Johnson, B J
EM: Bryan.Johnson@noaa.gov
AF: CMDL, NOAA, 325 Broadway, Boulder, CO 80305 United States
AU: Chipperfield, M P
EM: martyn@env.leeds.ac.uk
AF: School of Earth and Environment, University of Leeds, Leeds, LS2 9JT United Kingdom
AU: Wood, S
EM: s.wood@niwa.co.nz
AF: NIWA, PB 50061, Lauder, 50061 New Zealand
AU: Nichol, S
EM: s.nichol@niwa.co.nz
AF: NIWA, PB 14901, Wellington, 14901 New Zealand
AU: Santee, M L
EM: mls@mls.jpl.nasa.gov
AF: JPL, 4800 Oak Grove, Pasadena, CA 91109 United States
AB: 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 ozone depletion over many annual cycles. Two versions of the model are used, both previously used in Arctic studies, to perform a detailed comparison for total column ozone and ozone mixing ratios (OMR) at the vertical resolution of SLIMCAT. The newer model run, EC, was forced by ECMWF meteorological (re-) analyses while the older run, UK, used UKMO analyses. In both cases, modeled total ozone and OMR agree (within ±10%) with sonde measurements during the annual period of ozone depletion (15-Sept to 1-Nov). However, during Austral winter (prior to 15-Sept), run UK underestimates total column ozone (by ~20%), while run EC shows agreement (within ±10%) in half of the years studied, but underestimates total ozone (by > 10%) in the other half. Linear regression of winter-time modeled and measured OMR for run UK indicates SLIMCAT systematically overestimates OMR below ~3.5 ppmv and underestimates OMR between ~3.5-5.0 ppmv. Run EC does not show the same systematic over/underestimations. Agreement improves significantly after 15-Sept for both runs. Overall, the newer model performs better through better representation of transport, as seen through the ozone seasonal cycle and magnitude of chemical loss. Therefore, we conclude that, overall, SLIMCAT accurately reproduces Antarctic ozone loss. However, long-term analysis shows that the model, and therefore the meteorological analyses, does not fully capture year-to-year dynamical variability of processes that contribute to ozone depletion.
DE: 0300 ATMOSPHERIC COMPOSITION AND STRUCTURE
DE: 0340 Middle atmosphere: composition and chemistry
SC: Atmospheric Sciences [A]
MN: Fall Meeting 2005