ACP Atmospheric Chemistry and Physics ACP 1680-7324 Copernicus GmbH Göttingen, Germany 10.5194/acp-5-2029-2005 Shipborne solar absorption measurements of CO<sub>2</sub>, CH<sub>4</sub>, N<sub>2</sub>O and CO and comparison with SCIAMACHY WFM-DOAS retrievals Warneke T. 1 de Beek R. 1 Buchwitz M. 1 Notholt J. 1 Schulz A. 2 Velazco V. 1 Schrems O. 3 Institute of Environmental Physics, University of Bremen, Bremen, Germany Alfred Wegener Institute for Polar and Marine Research, Potsdam, Germany Alfred Wegener Institute for Polar and Marine Research, Bremerhaven, Germany 05 08 2005 5 8 2029 2034 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/5/2029/2005/acp-5-2029-2005.html The full text article is available as a PDF file from http://www.atmos-chem-phys.net/5/2029/2005/acp-5-2029-2005.pdf

CO, CH<sub>4</sub>, N<sub>2</sub>O and CO<sub>2</sub> were retrieved from high resolution solar absorption spectra obtained during a ship cruise from Capetown to Bremerhaven in January/February 2003 by Fourier Transform Infrared (FTIR) spectroscopy. Precisions of better than 0.5% for the column averaged volume mixing ratios (VMR) of CH<sub>4</sub> and CO<sub>2</sub> are achieved using of O<sub>2</sub> as a reference gas. Shipborne FTIR-measurements of CO and data from SCIAMACHY/ENVISAT retrieved by the Weighting Function Modified Differential Optical Absorption Spectroscopy (WFM-DOAS) retrieval algorithm show qualitatively the same latitudinal variations. WFM-DOAS data of CH<sub>4</sub>, N<sub>2</sub>O and CO<sub>2</sub> measured over sea exhibit a great spread. The spread is significantly reduced for satellite measurements over land and a reasonable agreement can be obtained if the shipborne data are compared with the closest SCIAMACHY measurements over land. The number of comparisons is too small to draw conclusions. However, by including only WFM-DOAS data with small errors the shipborne and WFM-DOAS data compare within 5% for CH<sub>4</sub> and CO<sub>2</sub> and within 30% for N<sub>2</sub>O.