Studies of Stratospheric NOy Chemistry with Three-Dimensional Chemical Transport Model Wuhu Feng1, Martyn Chipperfield1, Stewart Davies1,B. Sen2, G. Toon2, J.F. Blavier2 , W. Kouker3, G.P. Stiller3, R. Ruhnke3, TOPOZ and VINTERSOL Scientists 1. School of the Environment, University of Leeds, U.K 2. NASA Jet Propulsion Laboratory, Pasadena, CA, U.S.A. 3. IMK, Forschungzentrum Karlsruhe, Germany firstname.lastname@example.org , email@example.com 1. Introduction NOy (N, NO, NO2, NO3, HNO3, ClONO2, N2O5, HNO4, ..) species play an important role in the chemistry of stratospheric O3. Within the European Union TOPOZ III project we are comparing current CTM models with a range of NOy observations to test our understanding of NOy chemistry under different conditions. In this poster, the SLIMCAT model results are compared with MIPAS during the Antarctic sudden warming event in 2000. We also compared with measurements (MK IV balloon and geophysic M55 aircraft data) in 2002/03 Arctic winter during the SOLVE/VINTERSOL campaigns. 2. SLIMCAT 3D CTM • 3D off-line chemical transport model. • - vertical coordinate • Detailed chemical scheme (see Chipperfield ). 3. Antarctic sudden warming in 2002: Comparison with MIPAS 4.1 2002/03 Arctic winter: Comparison with MK IV balloon Fig1. Comparison of N2O, O3, NOy between SLIMCAT and MIPAS observations at 20Km on Sep. 18 and 26, 2002 Fig 4. Correlation of NOy v N2O on December 16, 2002 for Mk IV data (triangles) and SLIMCAT model (+). Also shown is calculated NOy* v N2O from a third-order polynomial [Popp, et al., 2001] using Mk IV and model N2O Fig2. As Fig 1., but for HNO3 and ClONO2. • SLIMCAT successful produce the evolution of Antarctic polar vortex and vortex split in 2002, and also gives a good simulation of NOy and its components structure above 20Km. However, modelled N2O5 is still poor. Fig3. Profile comparison of NOy and its components for four select locations: right of top profile is outside the vortex on 26/09/2002 Fig 5. Mk IV-Observed (solid lines) and SLIMCAT-modelled (dashed lines) profiles of NOy species on December 16, 2002 4.2 2002/03 Arctic winter: Comparison with Geophysic M55 aircraft Fig 6. As Fig 5, but for ratios of the individual species with respect to total NOy. Fig 8. Comparison of modelled O3 with sondes at Ny-Alesund station using CCM and MIDRAD radiation schemes. Fig 7. Comparison of modelled NOy, N2O and O3 using different radiation schemes with in-situ observations on the selected three EUPLUX flights • SLIMCAT captures denitrification and renitrification signal remarkably well and major features of the NOy species based on an ice sedimentation scheme • SLIMCAT gives good simulation of NOy for the cold region while the model overestimates denitrification at T>200K due to equilibrium scheme; Model with CCM radiation scheme gives better descent of airmasses and succesfful reproduce the 2002/03 Arctic polar O3 loss AcknowledgmentsWe are grateful to all TOPOZ and VINTERSOL scientists. The work is supported by TOPOZ III project and U.K. NERC UTLS OZONE Programme.Meteorological analyses have been provided by the ECMWF via British Atmospheric Data Centre (BADC). References Chipperfield, M.P. , JGR, 104, 1781-1805, 1999. Feng W, et al, JAS, (in poress) Popp, P,J., et al., GRL, 28, 2875-2878, 2001.