Monitoring Nitrogen Oxides with Satellite Instruments: High Resolution Maps from Gome Narrow Swath Mode and Sciamachy

The Global Ozone Monitoring Experiment (GOME) allows to retrieve tropospheric vertical column densities (TVCDs) of NO2. Mean maps of the global distribution of NO2 TVCDs reveal a clear fingerprint of anthropogenic sources due to fossil fuel combustion. However, GOME data suffer from the rather large footprint size of 320 km east-west, leading to a smearing out of the NO2 peaks in the retrieved maps. A better spatial resolution is achieved by the GOME measurements in the “narrow swath mode” (NSM) (80*40 km) and especially by SCIAMACHY on ENVISAT (60*30 km). Here we present first mean composites of SCIAMACHY and compare them to GOME results. We demonstrate the benefit of the improved spatial resolution of GOME NSM and SCIAMACHY, i.e. a more precise knowledge of the global distribution of NO2, allowing to localize and assign enhanced NO2 levels directly to sources like cities, and to separate different source types. We furthermore analyze the effect of the pixel size on the retrieved TVCDs quantitatively.