Carbon Monoxide and Methane Retrievals from SCIAMACHY Infrared Channels
Sebastián Gimeno García(1), Franz Schreier(1), Günter Lichtenberg(1), Sander Slijkhuis(1) and Bernd Aberle(1)
(1) DLR, Münchenerstr. 20, 82234 Oberpfaffenhofen, Germany
The Beer InfraRed Retrieval Algorithm (BIRRA) is designed to retrieve
vertical column densities (VCDs) of atmospheric gases in the near
infrared (NIR) region of the electromagnetic spectrum. Recently, it
has been successfully incorporated into the operational SCIAMACHY
processor for retrieval of carbon monoxide (CO) VCDs from nadir
observations in channel 8 (validation is still ongoing). Furthermore,
BIRRA can be used to gain information on other gases absorbing in the
SCIAMACHY NIR channels, the most important among them being CH4 and CO2.
During its lifetime, SCIAMACHY NIR channels have been degrading,
with the number of bad and/or dead pixels continuously increasing with
time. Further, it has been shown that retrieval results vary
considerably with the omission (or inclusion) of one single spectral
pixel. For this reason, an accurate bad dead pixel mask is crucial for
the quality of the SCIAMACHY NIR retrievals. Additionally, the
post-processing (nb. filtering of good results) is not straightforward
and special care has to be taken.
In this work, we present results of carbon monoxide and methane
retrievals using BIRRA in SCIAMACHY channels 6 and 8.