Atmospheric Chemistry and Physics www.atmos-chem-phys.net 1680-7316 1680-7324 9 23 2009 10.5194/acp-9-9197-2009 http://www.atmos-chem-phys.net/9/9197/2009/ http://www.atmos-chem-phys.net/9/9197/2009/acp-9-9197-2009.html http://www.atmos-chem-phys.net/9/9197/2009/acp-9-9197-2009.pdf 9197 9207 2009-12-07 Influence of scintillation on quality of ozone monitoring by GOMOS V. F. Sofieva viktoria.sofieva@fmi.fi V. Kan F. Dalaudier E. Kyrölä J. Tamminen J.-L. Bertaux A. Hauchecorne D. Fussen F. Vanhellemont Earth observation, Finnish Meteorological Institute, Helsinki, Finland Organization of Russian Academy of Sciences A.M. Obukhov Institute of Atmospheric Physics RAS, Moscow, Russia LATMOS, Université Versailles Saint-Quentin; CNRS/INSU, Verrières-le-Buisson, France Institut d'Aeronomie Spatiale de Belgique, Brussels, Belgium Stellar light passing through the Earth atmosphere is affected by refractive effects, which should be taken into account in retrievals from stellar occultation measurements. Scintillation caused by air density irregularities is a nuisance for retrievals of atmospheric composition. In this paper, we consider the influence of scintillation on stellar occultation measurements and on the quality of ozone retrievals from these measurements, based on experience of the GOMOS (Global Ozone Monitoring by Occultation of Stars) instrument on board the Envisat satellite. <br><br> In GOMOS retrievals, the scintillation effect is corrected using scintillation measurements by the fast photometer. We present quantitative estimates of the current scintillation correction quality and of the impact of scintillation on ozone retrievals by GOMOS. The analysis has shown that the present scintillation correction efficiently removes the distortion of transmission spectra caused by scintillations, which are generated by anisotropic irregularities of air density. The impact of errors of dilution and anisotropic scintillation correction on the quality of ozone retrievals is negligible. However, the current scintillation correction is not able to remove the wavelength-dependent distortion of transmission spectra caused by isotropic scintillations, which can be present in off-orbital-plane occultations. This distortion may result in ozone retrieval errors of 0.5–1.5% at altitudes 20–40 km. This contribution constitutes a significant percentage of the total error for bright stars. 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