Methane and carbon dioxide column-averaged mixing ratios from SCIAMACHY on ENVISAT
Oliver Schneising(1), Michael Buchwitz(1), Maximilian Reuter(1), Heinrich Bovensmann(1) and John P. Burrows(1)
(1) University of Bremen FB1, Otto Hahn Allee 1, 28334 Bremen, Germany
Methane (CH4) and carbon dioxide (CO2) are the two most important
anthropogenic greenhouse gases contributing to global climate change.
Despite their importance our knowledge about their variable
natural and anthropogenic sources and sinks has significant gaps.
Satellite observations can add important global scale information
on greenhouse gas sources and sinks provided the data are accurate and
precise enough and are sensitive to the lowest atmospheric layers
where the variability due to regional greenhouse gas sources
and sinks are largest. SCIAMACHY onboard ENVISAT is the first satellite
instrument which covers important absorption bands of both gases in the
near-infrared/shortwave-infrared (NIR/SWIR) spectral region.
In nadir mode SCIAMACHY observes reflected and backscattered solar radiation.
The daytime measurements are therefore very sensitive to near-surface
greenhouse gas concentration changes except in case of significant
cloud cover. At the Institute of Environmental Physics (IUP) of the
University of Bremen, Germany, the Weighting Function Modified Differential
Optical Absorption Spectroscopy (WFM-DOAS or WFMD) algorithm
has been developed and is continuously improved to extract the
atmospheric greenhouse gas information from the SCIAMACHY spectra.
Retrieval and analysis focussed on the
first three full years of the ENVISAT mission (2003-2005) but recently we started to also analyse
the data after 2005.
The status of this ongoing retrieval activity will be presented
focussing on discussion of the SCIAMACHY greenhouse gas data sets
over interesting source regions and first results from
analysing SCIAMACHY data after 2005.