Three years of global carbon monoxide from SCIAMACHY: comparison with MOPITT and first results related to the detection of enhanced CO over cities M. Buchwitz, I. Khlystova, H. Bovensmann, and J. P. Burrows Institute of Environmental Physics (IUP), University of Bremen FB1, Bremen, Germany
Abstract. Carbon monoxide (CO) is an important atmospheric constituent
affecting air quality and climate.
SCIAMACHY on ENVISAT is currently the only satellite instrument
that can measure the vertical column of CO with nearly
equal sensitivity at all altitudes
down to the Earth's surface because
of its near-infrared nadir observations of reflected solar radiation.
Here we present three years' (2003–2005)
of SCIAMACHY CO columns consistently retrieved with the latest version
of our retrieval algorithm (WFMDv0.6). We describe the retrieval
method and discuss the multi-year global CO data set focusing on a
comparison with the operational CO column data product of MOPITT.
We found reasonable to good agreement (~20%) with MOPITT,
with the best agreement for 2004. We present detailed results for
various regions (Europe, Middle East, India, China)
and discuss to what extent enhanced levels of CO can be detected
over populated areas including individual cities.
The expected CO signal from cities is close to or even below
the detection limit of individual measurements. We show
that cities can be identified when averaging long time series.
Citation: Buchwitz, M., Khlystova, I., Bovensmann, H., and Burrows, J. P.: Three years of global carbon monoxide from SCIAMACHY: comparison with MOPITT and first results related to the detection of enhanced CO over cities, Atmos. Chem. Phys., 7, 2399-2411, doi:10.5194/acp-7-2399-2007, 2007.