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The ACOS CO_2 retrieval algorithm – Part 1: Description and validation against synthetic observations

O'Dell, C. W. and Connor, B. and Bösch, H. and O'Brien, D. and Frankenberg, C. and Castano, R. and Christi, M. and Crisp, D. and Eldering, A. and Fisher, B. and Gunson, M. and McDuffie, J. and Miller, C. E. and Natraj, V. and Oyafuso, F. and Polonsky, I. and Smyth, M. and Taylor, T. and Toon, G. C. and Wennberg, P. O. and Wunch, D. (2012) The ACOS CO_2 retrieval algorithm – Part 1: Description and validation against synthetic observations. Atmospheric Measurement Techniques, 5 (1). pp. 99-121. ISSN 1867-1381.

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This work describes the NASA Atmospheric CO_2 Observations from Space (ACOS) X_(CO_2) 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.

Item Type:Article
Related URLs:
URLURL TypeDescription
Bösch, H.0000-0003-3944-9879
Frankenberg, C.0000-0002-0546-5857
Crisp, D.0000-0002-4573-9998
Eldering, A.0000-0003-1080-9922
Miller, C. E.0000-0002-9380-4838
Natraj, V.0000-0003-3154-9429
Oyafuso, F.0000-0002-8862-8737
Toon, G. C.0000-0003-4174-7541
Wennberg, P. O.0000-0002-6126-3854
Wunch, D.0000-0002-4924-0377
Alternate Title:The ACOS CO2 retrieval algorithm – Part 1: Description and validation against synthetic observations
Additional Information:© 2012 Author(s). This work is distributed under the Creative Commons Attribution 3.0 License. Published by Copernicus Publications on behalf of the European Geosciences Union. The authors wish to thank two anonymous reviewers for their constructive suggestions and insightful comments. We would like to thank several colleagues for work they have done that has helped this project: Bashwar Sen for early algorithm management, Linda Brown for spectroscopy development, Rob Spurr for help with the radiative transfer, Lukas Mandrake for GOSAT data analysis, and Ross Salawitch for many useful discussions. A portion of the research described in this paper was carried out at the Jet Propulsion Laboratory, California Institute of Technology, under a contract with the National Aeronautics and Space Administration. The Colorado State University contributions to this work were carried out under NASA contract 1380533.
Errata:We would like to inform you that there were two mistakes in the author list of this manuscript. The initial of the author Eldering was wrong and the author Crisp was missing in the author list. Above you will find the correct author list.
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Record Number:CaltechAUTHORS:20140716-141221563
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Official Citation:O'Dell, C. W., Connor, B., Bösch, H., O'Brien, D., Frankenberg, C., Castano, R., . . . Wunch, D. (2012). The ACOS CO2 retrieval algorithm – Part 1: Description and validation against synthetic observations. Atmos. Meas. Tech., 5(1), 99-121. doi: 10.5194/amt-5-99-2012
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:47269
Deposited By: Joanne McCole
Deposited On:16 Jul 2014 23:31
Last Modified:28 May 2020 22:36

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