Authors

D Wunch, California Institute of Technology
P O. Wennberg, California Institute of Technology
G C. Toon, California Institute of Technology
B J. Connor, BC Consulting
B Fisher, California Institute of Technology
G B. Osterman, California Institute of Technology
C Frankenberg, California Institute of Technology
L Mandrake, California Institute of Technology
C O'Dell, Colorado State University
P Ahonen, Finnish Meteorological Institute
S C. Biraud, Lawrence Berkeley National Laboratories, Berkeley
R Castano, California Institute of Technology
Noel Cressie, University of WollongongFollow
D Crisp, California Institute of Technology
N M. Deutscher, University of WollongongFollow
A Eldering, California Institute of Technology
M L. Fisher, Lawrence Berkeley National Laboratories, Berkeley
David W. Griffith, University of WollongongFollow
M Gunson, California Institute of Technology
P Heikkinen, Arctic Research Centre of the Finnish Meteorological Institute
G Keppel-Aleks, California Institute of Technology
E Kyro, Arctic Research Centre of the Finnish Meteorological Institute
R Lindemaier, University of Toronto
Ronald Macatangay, University of WollongongFollow
J Mendonca, University of Toronto
J Messerschmidt, University of Bremen
C E. Miller, California Institute of Technology
I Morino, National Institute for Environmental Studies, Tsukuba, Japan
J Notholt, University of Bremen
F A. Oyafuso, California Institute of Technology
M Rettinger, Karlsruhe Institute of Technology
J Robinson, National Institute of Water & Atmospheric Research, Wellington, New Zealand
C M. Roehl, California Institute of Technology
R J. Salawitch, University of Maryland
V Sherlock, National Institute of Water & Atmospheric Research, Wellington, New Zealand
K Strong, University of Toronto
R Sussmann, IMK-IFU, Germany
T Tanaka, National Institute for Environmental Studies, Tsukuba, Japan
D R. Thompson, California Institute of Technology
O Uchino, National Institute for Environmental Studies, Tsukuba, Japan
Thorsten Warneke, University of Bremen
Steven C. Wofsy, Harvard University

RIS ID

46330

Publication Details

Wunch, D., Wennberg, P. O., Toon, G. C., Connor, B. J., Fisher, B., Osterman, G. B., Frankenberg, C., Mandrake, L., O'Dell, C., Ahonen, P., Biraud, S. C., Castano, R., Cressie, N., Crisp, D., Deutscher, N. M., Eldering, A., Fisher, M. L., Griffith, D. W., Gunson, M., Heikkinen, P., Keppel-Aleks, G., Kyro, E., Lindemaier, R., Macatangay, R., Mendonca, J., Messerschmidt, J., Miller, C. E., Morino, I., Notholt, J., Oyafuso, F. A., Rettinger, M., Robinson, J., Roehl, C. M., Salawitch, R. J., Sherlock, V., Strong, K., Sussmann, R., Tanaka, T., Thompson, D. R., Uchino, O., Warneke, T. & Wofsy, S. C. (2011). A method for evaluating bias in global measurements of CO2 total columns from space. Atmospheric Chemistry and Physics, 11 (23), 12317-12337.

Abstract

We describe a method of evaluating systematic errors in measurements of total column dry-air mole fractions of CO2 (XCO2) from space, and we illustrate the method by applying it to the v2.8 Atmospheric CO2 Observations from Space retrievals of the Greenhouse Gases Observing Satellite (ACOS-GOSAT) measurements over land. The approach exploits the lack of large gradients in XCO2 south of 25S to identify large-scale offsets and other biases in the ACOS-GOSAT data with several retrieval parameters and errors in instrument calibration. We demonstrate the effectiveness of the method by comparing the ACOS-GOSAT data in the Northern Hemisphere with ground truth provided by the Total Carbon Column Observing Network (TCCON).We use the observed correlation between free-tropospheric potential temperature and XCO2 in the Northern Hemisphere to define a dynamically informed coincidence criterion between the ground-based TCCON measurements and the ACOSGOSAT measurements. We illustrate that this approach provides larger sample sizes, hence giving a more robust comparison than one that simply uses time, latitude and longitude criteria. Our results show that the agreement with the TCCON data improves after accounting for the systematic errors, but that extrapolation to conditions found outside the region south of 25S may be problematic (e.g., high airmasses, large surface pressure biases, M-gain, measurements made over ocean). A preliminary evaluation of the improved v2.9 ACOS-GOSAT data is also discussed.

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Link to publisher version (DOI)

http://dx.doi.org/10.5194/acp-11-12317-2011