Atmos. Chem. Phys. Discuss., 11, 33419-33463, 2011
© Author(s) 2011. This work is distributed
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This discussion paper has been under review for the journal Atmospheric Chemistry and Physics (ACP). Please refer to the corresponding final paper in ACP.
Stratosphere-troposphere ozone exchange from high resolution MLS ozone analyses
J. Barré1, V.-H. Peuch1, J.-L. Attié1,2, L. El Amraoui1, W. A. Lahoz1,3, B. Josse1, M. Claeyman1,2, and P. Nédélec2
1CNRM-GAME, Météo-France and CNRS URA1357, Toulouse, France
2Laboratoire d'Aérologie, Université de Toulouse, CNRS/INSU, Toulouse, France
3NILU, 2027 Kjeller, Norway

Abstract. We assimilate stratospheric ozone profiles from MLS (Microwave Limb Sounder) into the MOCAGE CTM model in order to study Stratosphere-Troposphere Exchange (STE). This study uses two horizontal grid resolution of 2° and 0.2°. The combined impacts of MLS ozone assimilation and high horizontal resolution are illustrated in two case studies where STE events occurred (23 June 2009 and 17 July 2009). At high resolution the fine filamentary structures of stratospheric air which characterise STE events are captured by the model. To test the impact of the assimilation and the resolution, we compare model outputs from different experiments (high resolution and low resolution; MLS assimilation run and free run) with independent data (MOZAIC aircraft ozone data; WOUDC ozone sonde network data) not used in the assimilation. MLS ozone analyses show a better description of the UTLS region and the stratospheric intrusions than the free model run. In particular, at high horizontal resolution the high resolution MLS ozone analyses presents fine filamentary ozone structures at the UTLS and laminae structures in the tropospheric ozone profile. By using MLS ozone analyses and high resolution, ozone fluxes through the tropopause show a range of results that lie within the range of similar previous studies. Results from backward trajectories and forecasts results show that assimilation at high horizontal resolution of MLS ozone profiles between 10 hPa and 215 hPa has an impact on tropospheric ozone.

Citation: Barré, J., Peuch, V.-H., Attié, J.-L., El Amraoui, L., Lahoz, W. A., Josse, B., Claeyman, M., and Nédélec, P.: Stratosphere-troposphere ozone exchange from high resolution MLS ozone analyses, Atmos. Chem. Phys. Discuss., 11, 33419-33463, doi:10.5194/acpd-11-33419-2011, 2011.
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