DOAS RETRIEVAL OF GLYOXAL FROM SPACE

Glyoxal (C2H2O2) is formed by the oxidation of several VOCs and hence serves as an indicator for fast VOC chemistry. C2H2O2 has characteristic absorption bands in the blue spectral range, allowing remote sensing by DOAS. From space, the detection of enhanced Glyoxal column densities has recently been reported from OMI and SCIAMACHY data. Here we present the results of our Glyoxal retrieval from SCIAMACHY spectra. In the resulting mean maps, photochemical hot spots due to anthropogenic activities can clearly be identified, for instance Hong Kong or Los Angeles. Also strong biomass burning events lead to enhanced Glyoxal levels. Generally, the detected C2H2O2 column densities are high over the tropical rain forest, indicating biogenic emissions. Also over some bioactive oceanic regions enhanced Glyoxal levels are found, possibly indicating VOC emissions over ocean.