Atmospheric Chemistry and Physics www.atmos-chem-phys.net 1680-7316 1680-7324 8 13 2008 10.5194/acp-8-3671-2008 http://www.atmos-chem-phys.net/8/3671/2008/ http://www.atmos-chem-phys.net/8/3671/2008/acp-8-3671-2008.html http://www.atmos-chem-phys.net/8/3671/2008/acp-8-3671-2008.pdf 3671 3688 2008-07-10 Envisat MIPAS measurements of CFC-11: retrieval, validation, and climatology L. Hoffmann l.hoffmann@fz-juelich.de M. Kaufmann R. Spang R. Müller J. J. Remedios D. P. Moore C. M. Volk T. von Clarmann M. Riese Forschungszentrum Jülich, Institut für Chemie und Dynamik der Geosphäre (ICG-1), Jülich, Germany EOS, Space Research Centre, Department of Physics and Astronomy, University of Leicester, Leicester, UK J. W. Goethe-Universität Frankfurt, Institut für Atmosphäre und Umwelt, Frankfurt, Germany Forschungszentrum Karlsruhe, Institut für Meteorologie and Klimaforschung, Karlsruhe, Germany From July 2002 to March 2004 the Michelson Interferometer for Passive Atmospheric Sounding (MIPAS) aboard the European Space Agency's Environmental Satellite (Envisat) measured nearly continuously mid infrared limb radiance spectra. These measurements are utilised to retrieve the global distribution of the chlorofluorocarbon CFC-11 by applying a new fast forward model for Envisat MIPAS and an accompanying optimal estimation retrieval processor. A detailed analysis shows that the total retrieval errors of the individual CFC-11 volume mixing ratios are typically below 10% in the altitude range 10 to 25 km and that the systematic components dominate. Contribution of a priori information to the retrieval results are less than 5 to 10% and the vertical resolution of the observations is about 3 to 4 km in the same vertical range. The data are successfully validated by comparison with several other space experiments, an air-borne in-situ instrument, measurements from ground-based networks, and independent Envisat MIPAS analyses. The retrieval results from 425 000 Envisat MIPAS limb scans are compiled to provide a new climatological data set of CFC-11. The climatology shows significantly lower CFC-11 abundances in the lower stratosphere compared with the Reference Atmospheres for MIPAS (RAMstan V3.1) climatology. Depending on the atmospheric conditions the differences between the climatologies are up to 30 to 110 ppt (45 to 150%) at 19 to 27 km altitude. Additionally, time series of CFC-11 mean abundance and variability for five latitudinal bands are presented. 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