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Titel |
Application of SCIAMACHY and MOPITT CO total column measurements to evaluate model results over biomass burning regions and Eastern China |
VerfasserIn |
C. Liu, S. Beirle, T. Butler, J. Liu, P. Hoor, P. Jöckel, M. Penning de Vries, A. Pozzer, C. Frankenberg, M. G. Lawrence, J. Lelieveld , U. Platt, T. Wagner |
Medientyp |
Artikel
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Sprache |
Englisch
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ISSN |
1680-7316
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Digitales Dokument |
URL |
Erschienen |
In: Atmospheric Chemistry and Physics ; 11, no. 12 ; Nr. 11, no. 12 (2011-06-29), S.6083-6114 |
Datensatznummer |
250009875
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Publikation (Nr.) |
copernicus.org/acp-11-6083-2011.pdf |
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Zusammenfassung |
We developed a new CO vertical column density product from near IR
observations of the SCIAMACHY instrument onboard ENVISAT. For the correction
of a temporally and spatially variable offset of the CO vertical column
densities we apply a normalisation procedure based on coincident MOPITT
(version 4) observations over the oceans. The resulting normalised SCIAMACHY
CO data is well suited for the investigation of the CO distribution over
continents, where important emission sources are located. We use only
SCIAMACHY observations for effective cloud fractions below 20 %. Since the
remaining effects of clouds can still be large (up to 100 %), we applied a
cloud correction scheme which explicitly considers the cloud fraction, cloud
top height and surface albedo of individual observations. The normalisation
procedure using MOPITT data and the cloud correction substantially improve
the agreement with independent data sets. We compared our new SCIAMACHY CO
data set, and also observations from the MOPITT instrument, to the results
from three global atmospheric chemistry models (MATCH, EMAC at low and high
resolution, and GEOS-Chem); the focus of this comparison is on regions with
strong CO emissions (from biomass burning or anthropogenic sources). The
comparison indicates that over most of these regions the seasonal cycle is
generally captured well but the simulated CO vertical column densities are
systematically smaller than those from the satellite observations, in
particular with respect to SCIAMACHY observations. Because SCIAMACHY is more
sensitive to the lowest part of the atmosphere compared to MOPITT, this
indicates that especially close to the surface the model simulations
systematically underestimate the true atmospheric CO concentrations,
probably caused by an underestimation of CO emissions by current emission
inventories. For some biomass burning regions, however, such as Central
Africa in July–August, model results are also found to be higher than the
satellite observations. |
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