Retrieval of Co, H2o, Ch4, Co2, and N2o Columns from Sciamachy/envisat by Wfm-doas: Current Status

The spectra measured by SCIAMACHY contain information on a number of important atmospheric trace gases. The near-infrared nadir spectra enable the retrieval of total column amounts of CO, H2O, CH4, CO2, and N2O. We are developing a modified DOAS algorithm (WFM-DOAS) to accomplish this task. Here we give an overview about the current status of this activity (using WFM-DOAS Version 0.4). We show that encouraging higher level data products can be obtained despite the preliminary calibration of the operational spectra. For example, accurate water vapour columns can been retrieved over ocean and land, plumes of CO can be detected, the relatively small (few percent) interhemispheric difference of the methane mixing ratio is visible in single day data, and there are strong indications that for the first time a CO2 source/sink region has been identified from space. We highlight a number of issues that need further study and, if solved, are expected to result in improved data products.