Troposphere

Nadir measurements in the troposphere

Preliminary methane total column amounts retrieved from orbit 2338 (11 August 2002) using the Weighting Function Modified (WFM) DOAS algorithm. Ground pixels colored grey are cloud contaminated as identified using SCIAMACHYs high resolution PMD measurements (see Figure "PMD 1 (320-380 nm)"). As methane is relatively well mixed in the atmosphere the surface topography should be clearly visible in the total column field (see Figure "Surface Elevation" for comparison). The spatial resolution is approximately 30x120 km2. Details can be found in "Retrieval of trace gas vertical column amounts from SCIAMACHY/ENVISAT near-infrared nadir spectra: First preliminary results", poster presented at Cospar 2002, corresponding paper submitted to Advances in Space Research, Buchwitz et al., 2002 (a draft version of the paper can be obtained from Michael.Buchwitz@iup.physik.uni-bremen.de).

Signal of SCIAMACHYs Polarisation Measurement Device (PMD) number 1 (ultra-violet) Color code: low signal level = dark blue, high signal level = light blue or white). High signal levels are assumed to result mainly from clouds. The spatial resolution is approximately 30x7 km2. The signal has been divided by the cosine of the solar zenith angle.

Earths surface elevation corresponding to orbit 2338 (grid: 1 deg x 1 deg).

Preliminary total columns of nitrogen dioxide over Europe derived from SCIAMACHY Nadir measurements as compared to GOME data (Dr. A. Richter). It can clearly be seen that the improved horizontal resolution of SCIAMACHY facilitates the detection of the high spatial variability of tropospheric NO2. The plumes of the metropolitan areas in the UK and of cities such as Vienna or Rome can readily be identified. The good spatial resolution and the high data quality of SCIAMACHY NO2 measurements will enable us to quantify global emissions of NO2 in the near future.

Detection of nitrogen dioxide total columns over the north-eastern part of the United States of America from SCIAMACHY nadir measurements compared with GOME (Dr. A. Richter).