ACP Atmospheric Chemistry and Physics ACP 1680-7324 Copernicus GmbH Göttingen, Germany 10.5194/acp-6-1953-2006 Comparisons between SCIAMACHY and ground-based FTIR data for total columns of CO, CH<sub>4</sub>, CO<sub>2</sub> and N<sub>2</sub>O Dils B. 1 De Mazière M. 1 Müller J. F. 1 Blumenstock T. 2 Buchwitz M. 11 de Beek R. 11 Demoulin P. 5 Duchatelet P. 5 Fast H. 3 Frankenberg C. 7 Gloudemans A. 12 Griffith D. 4 Jones N. 4 Kerzenmacher T. 10 Kramer I. 2 Mahieu E. 5 Mellqvist J. 6 Mittermeier R. L. 3 Notholt J. 11 Rinsland C. P. 13 Schrijver H. 12 Smale D. 8 Strandberg A. 6 Straume A. G. 12 Stremme W. 9 Strong K. 10 Sussmann R. 9 Taylor J. 10 van den Broek M. 12 Velazco V. 11 Wagner T. 7 Warneke T. 11 Wiacek A. 10 Wood S. 8 Belgian Institute for Space Aeronomy, Brussels, Belgium Forschungszentrum Karlsruhe and University Karlsruhe, IMK-ASF, Karlsruhe, Germany Environment Canada, Downsview, Ontario, Canada University of Wollongong, New South Wales, Australia Institut d’Astrophysique et de Géophysique, Liège, Belgium Chalmers University of Technology, Radio & Space Science, Göteborg, Sweden Institute of Environmental Physics, University of Heidelberg, Heidelberg, Germany National Institute for Water and Air Research (NIWA), New Zealand Forschungszentrum Karlsruhe, IMK-IFU, Garmisch-Partenkirchen, Germany Department of Physics, University of Toronto, Toronto, Ontario, Canada Institute of Environmental Physics, University of Bremen, FB1, Germany Netherlands Institute for Space Research (SRON), Utrecht, The Netherlands NASA Langley Research Center, Hampton, VA, USA 08 06 2006 6 7 1953 1976 This is an open-access article ditributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. This article is available from http://www.atmos-chem-phys.net/6/1953/2006/acp-6-1953-2006.html The full text article is available as a PDF file from http://www.atmos-chem-phys.net/6/1953/2006/acp-6-1953-2006.pdf

Total column amounts of CO, CH<sub>4</sub>, CO<sub>2</sub> and N<sub>2</sub>O retrieved from SCIAMACHY nadir observations in its near-infrared channels have been compared to data from a ground-based quasi-global network of Fourier-transform infrared (FTIR) spectrometers. The SCIAMACHY data considered here have been produced by three different retrieval algorithms, WFM-DOAS (version 0.5 for CO and CH<sub>4</sub> and version 0.4 for CO<sub>2</sub> and N<sub>2</sub>O), IMAP-DOAS (version 1.1 and 0.9 (for CO)) and IMLM (version 6.3) and cover the January to December 2003 time period. Comparisons have been made for individual data, as well as for monthly averages. To maximize the number of reliable coincidences that satisfy the temporal and spatial collocation criteria, the SCIAMACHY data have been compared with a temporal 3rd order polynomial interpolation of the ground-based data. Particular attention has been given to the question whether SCIAMACHY observes correctly the seasonal and latitudinal variability of the target species. The present results indicate that the individual SCIAMACHY data obtained with the actual versions of the algorithms have been significantly improved, but that the quality requirements, for estimating emissions on regional scales, are not yet met. Nevertheless, possible directions for further algorithm upgrades have been identified which should result in more reliable data products in a near future.