Atmospheric Chemistry and Physics Discussions www.atmos-chem-phys-discuss.net 1680-7367 1680-7375 5 4 2005 10.5194/acpd-5-4893-2005 http://www.atmos-chem-phys-discuss.net/5/4893/2005/ http://www.atmos-chem-phys-discuss.net/5/4893/2005/acpd-5-4893-2005.html http://www.atmos-chem-phys-discuss.net/5/4893/2005/acpd-5-4893-2005.pdf 4893 4928 2005-07-14 Geophysical validation of SCIAMACHY Limb Ozone Profiles E. J. Brinksma A. Bracher D. E. Lolkema A. J. Segers I. S. Boyd K. Bramstedt H. Claude S. Godin-Beekmann G. Hansen G. Kopp T. Leblanc I. S. McDermid Y. J. Meijer H. Nakane A. Parrish C. von Savigny K. Stebel D. P. J. Swart G. Taha A. J. M. Piters KNMI, Postbus 201, 3730 AE De Bilt, The Netherlands Institute of Environmental Physics (IFE), University of Bremen, PO Box 330440, D-28334 Bremen, Germany National Institute for Public Health and the Environment (RIVM), Bilthoven, The Netherlands NIWA, Environmental Research Institute, Ann-Arbor, MI 48108, USA Deutscher Wetterdienst, Meteorologisches Observatorium, Albin SchwaigerWeg 10, 82383 Hohenpeissenberg, Germany Service d’Aéronomie – CNRS, Institut Pierre Simon Laplace, 4 Place Jussieu, 75252 Paris Cedex 05, France Norwegian Institute for Air Research (NILU), Polar Environmental Centre, Tromsoe, Norway IMK, Forschungszentrum Karlsruhe and Universität Karlsruhe, Germany NASA-JPL, Wrightwood (CA), USA Atmospheric Environment Division, National Institute for Environmental Studies, 16-2, Onogawa, Tsukuba, Ibaraki 305-8506, Japan University of Massachusetts, USA Science and Application International Corporation, Hampton (VA), USA NASA-Langley Research Center, MS 475, Hampton (VA), 23681, USA We discuss the quality of the two available SCIAMACHY limb ozone profile products. They were retrieved with the University of Bremen IFE's algorithm version 1.61 (hereafter IFE), and the official ESA offline algorithm (hereafter OL) versions 2.4 and 2.5. The ozone profiles were compared to a suite of correlative measurements from ground-based lidar and microwave, sondes, SAGE&nbsp;II and SAGE&nbsp;III (Stratospheric Aerosol and Gas Experiment). <br><br> To correct for the expected Envisat pointing errors, which have not been corrected implicitly in either of the algorithms, we applied a constant altitude shift of &minus;1.5 km to the SCIAMACHY ozone profiles. <br><br> The IFE ozone profile data between 16 and 40 km are biased low by 3&ndash;6%. The average difference profiles show a characteristic zigzag shape with a wavelength of approximately 8 km. The standard deviation of the differences is typically 10% between 20&nbsp;and 35 km. <br><br> We show that more than 20% of the SCIAMACHY official ESA offline (OL) ozone profiles version 2.4 and 2.5 have unrealistic ozone values, most of these are north of 15&deg; S. The remaining OL profiles compare well to correlative instruments above 24 km. Between 20&nbsp;and 24 km, they underestimate ozone by 15&plusmn;5%.