Retrieval of CO from SCIAMACHY onboard ENVISAT: detection of strongly polluted areas and seasonal patterns in global CO abundances C. Frankenberg, U. Platt, and T. Wagner Institute of Environmental Physics, Heidelberg, Germany
Abstract. SCIAMACHY onboard the European environmental research satellite
ENVISAT is an UV/visible/near-infrared spectrometer providing 3
near infrared channels covering wavelengths from 1-1.75 µm,
1.94-2.04 µm and 2.26-2.38 µm with moderate spectral
resolution (0.22-1.5nm). From their structured absorption in these
spectral regions, we can quantitatively determine the total column
densities of the greenhouse gases CO2, CH4,
N2O and H2O as well as of CO. A
modified DOAS algorithm based on optimal estimation (IMAP-DOAS) has
been developed at the University of Heidelberg to account for the
peculiarities of these absorbers. CO is a relatively weak absorber
whose spectral signature is overlapped by strong CH4 and
H2O absorptions. Hence, retrieval of CO from SCIAMACHY
spectra (within 2.26-2.38 µm) is a challenging task.
Therefore, the calibration of the raw spectra with respect to dark
current issues and nonlinearity were analysed in detail and
substantially improved to enable reasonable retrieval of CO. This
paper focusses on first results of the CO retrieval where various
sources like biomass burning events and their seasonal variability
can be clearly identified.
Citation: Frankenberg, C., Platt, U., and Wagner, T.: Retrieval of CO from SCIAMACHY onboard ENVISAT: detection of strongly polluted areas and seasonal patterns in global CO abundances, Atmos. Chem. Phys., 5, 1639-1644, doi:10.5194/acp-5-1639-2005, 2005.