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Titel |
The ACOS CO2 retrieval algorithm – Part 1: Description and validation against synthetic observations |
VerfasserIn |
C. W. O'Dell, B. Connor, H. Bösch, D. O'Brien, C. Frankenberg, R. Castano, M. Christi, D. Eldering, B. Fisher, M. Gunson, J. McDuffie, C. E. Miller, V. Natraj, F. Oyafuso, I. Polonsky, M. Smyth, T. Taylor, G. C. Toon, P. O. Wennberg, D. Wunch |
Medientyp |
Artikel
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Sprache |
Englisch
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ISSN |
1867-1381
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Digitales Dokument |
URL |
Erschienen |
In: Atmospheric Measurement Techniques ; 5, no. 1 ; Nr. 5, no. 1 (2012-01-11), S.99-121 |
Datensatznummer |
250002310
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Publikation (Nr.) |
copernicus.org/amt-5-99-2012.pdf |
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Zusammenfassung |
This work describes the NASA Atmospheric CO2 Observations
from Space (ACOS) XCO2 retrieval algorithm, and its
performance on highly realistic, simulated observations. These
tests, restricted to observations over land, are used to
evaluate retrieval errors in the face of realistic clouds and
aerosols, polarized non-Lambertian surfaces, imperfect
meteorology, and uncorrelated instrument noise. We find that
post-retrieval filters are essential to eliminate the poorest
retrievals, which arise primarily due to imperfect cloud
screening. The remaining retrievals have RMS errors of
approximately 1 ppm. Modeled instrument noise, based on the
Greenhouse Gases Observing SATellite (GOSAT) in-flight
performance, accounts for less than half the total error in
these retrievals. A small fraction of unfiltered clouds,
particularly thin cirrus, lead to a small positive bias of
~0.3 ppm. Overall, systematic errors due to imperfect
characterization of clouds and aerosols dominate the error
budget, while errors due to other simplifying assumptions, in
particular those related to the prior meteorological fields,
appear small. |
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