Carbon monoxide, methane and carbon dioxide columns retrieved from SCIAMACHY by WFM-DOAS: year 2003 initial data set M. Buchwitz1, R. de Beek1, S. Noël1, J. P. Burrows1, H. Bovensmann1, H. Bremer1, P. Bergamaschi2, S. Körner3, and M. Heimann3 1Institute of Environmental Physics (IUP), University of Bremen FB1, Bremen, Germany 2Institute for Environment and Sustainability, Joint Research Centre (EC-JRC-IES), Ispra, Italy 3Max Planck Institute for Biogeochemistry (MPI-BGC), Jena, Germany
Abstract. The near-infrared
nadir spectra measured by
ENVISAT contain information on
the vertical columns of important atmospheric trace
gases such as
carbon monoxide (CO), methane (CH4),
and carbon dioxide (CO2).
The scientific algorithm
WFM-DOAS has been used to retrieve
CH4 and CO2 also column averaged mixing ratios
(XCH4 and XCO2) have been determined
by simultaneous measurements of the dry air mass.
spectra of the year 2003
have been processed.
We describe the algorithm versions used to
generate the data (v0.4; for methane
also v0.41) and show comparisons of monthly averaged data
over land with global measurements (CO from MOPITT)
and models (for CH4 and CO2).
We show that elevated concentrations of CO resulting from biomass burning
have been detected in reasonable agreement with
MOPITT. The measured XCH4 is enhanced over
India, south-east Asia, and
central Africa in September/October 2003 in line with model
simulations, where they result from surface sources of
methane such as rice fields and wetlands.
The CO2 measurements over the Northern Hemisphere show the lowest
mixing ratios around July in qualitative agreement with model simulations
indicating that the large scale pattern of CO2 uptake
by the growing vegetation can be detected with SCIAMACHY.
We also identified potential problems such as a too low inter-hemispheric
gradient for CO, a time dependent bias of the methane
columns on the order of a few percent,
and a few percent too high CO2 over parts of the Sahara.
Citation: Buchwitz, M., de Beek, R., Noël, S., Burrows, J. P., Bovensmann, H., Bremer, H., Bergamaschi, P., Körner, S., and Heimann, M.: Carbon monoxide, methane and carbon dioxide columns retrieved from SCIAMACHY by WFM-DOAS: year 2003 initial data set, Atmos. Chem. Phys., 5, 3313-3329, doi:10.5194/acp-5-3313-2005, 2005.