Comparisons between SCIAMACHY Scientific Products and Ground-Based FTIR Data for Total Columns of CO, CH4 and N2O

Total column amounts of CO, CH4 and N2O retrieved from SCIAMACHY nadir observations in its near-infrared channels have been compared to data from a ground-based network of Fourier-transform infrared (FTIR) spectrometers as well as to data obtained with an FTIR instrument during a ship cruise in January-February 2003, along the African West Coast. The SCIAMACHY data considered here have been produced by two different scientific retrieval algorithms, wfm-doas (version 4.0) and IMLM (version 5.1), and cover different time periods, making the number of reliable coincidences that satisfy the temporal and spatial collocation criteria rather limited and different for both. Also the quality of the SCIAMACHY Level 1 data, and thus of the Level 2 data for the different time periods is very different. Still the comparisons demonstrate the capability of SCIAMACHY, using one of both algorithms, to deliver geophysically valuable products for the target species under consideration, on a global scale