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Bias Correction of the Ratio of Total Column CH₄ to CO₂ Retrieved from GOSAT Spectra

Oshio, Haruki and Yoshida, Yukio and Matsunaga, Tsuneo and Deutscher, Nicholas M. and Dubey, Manvendra and Griffith, David W. T. and Hase, Frank and Iraci, Laura T. and Kivi, Rigel and Liu, Cheng and Morino, Isamu and Notholt, Justus and Oh, Young-Suk and Ohyama, Hirofumi and Petri, Christof and Pollard, David F. and Roehl, Coleen and Shiomi, Kei and Sussmann, Ralf and Té, Yao and Velazco, Voltaire A. and Warneke, Thorsten and Wunch, Debra (2020) Bias Correction of the Ratio of Total Column CH₄ to CO₂ Retrieved from GOSAT Spectra. Remote Sensing, 12 (19). Art. No. 3155. ISSN 2072-4292. https://resolver.caltech.edu/CaltechAUTHORS:20200928-075434934

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Abstract

The proxy method, using the ratio of total column CH₄ to CO₂ to reduce the effects of common biases, has been used to retrieve column-averaged dry-air mole fraction of CH₄ from satellite data. The present study characterizes the remaining scattering effects in the CH₄/CO₄ ratio component of the Greenhouse gases Observing SATellite (GOSAT) retrieval and uses them for bias correction. The variation of bias between the GOSAT and Total Carbon Column Observing Network (TCCON) ratio component with GOSAT data-derived variables was investigated. Then, it was revealed that the variability of the bias could be reduced by using four variables for the bias correction—namely, airmass, 2 μm band radiance normalized with its noise level, the ratio between the partial column-averaged dry-air mole fraction of CH₄ for the lower atmosphere and that for the upper atmosphere, and the difference in surface albedo between the CH₄ and CO₄ bands. The ratio of partial column CH₄ reduced the dependence of bias on the cloud fraction and the difference between hemispheres. In addition to the reduction of bias (from 0.43% to 0%), the precision (standard deviation of the difference between GOSAT and TCCON) was reduced from 0.61% to 0.55% by the correction. The bias and its temporal variation were reduced for each site: the mean and standard deviation of the mean bias for individual seasons were within 0.2% for most of the sites.


Item Type:Article
Related URLs:
URLURL TypeDescription
https://doi.org/10.3390/rs12193155DOIArticle
ORCID:
AuthorORCID
Oshio, Haruki0000-0003-1896-3932
Yoshida, Yukio0000-0002-3515-1488
Matsunaga, Tsuneo0000-0002-3380-5230
Deutscher, Nicholas M.0000-0002-2906-2577
Griffith, David W. T.0000-0002-7986-1924
Kivi, Rigel0000-0001-8828-2759
Morino, Isamu0000-0003-2720-1569
Oh, Young-Suk0000-0001-8010-1597
Ohyama, Hirofumi0000-0003-2109-9874
Pollard, David F.0000-0001-9923-2984
Roehl, Coleen0000-0001-5383-8462
Té, Yao0000-0001-6405-8074
Velazco, Voltaire A.0000-0002-1376-438X
Wunch, Debra0000-0002-4924-0377
Additional Information:© 2020 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (http://creativecommons.org/licenses/by/4.0/). Received: 21 August 2020; Accepted: 23 September 2020; Published: 25 September 2020. GOSAT clear-sky retrieval in the present study was conducted at the GOSAT-2 Research Computation Facility. The Garmisch TCCON station has been supported by the European Space Agency (ESA) under grant 4000120088/17/I-EF and by the German Bundesministerium für Wirtschaft und Energie (BMWi) via the Deutsche Zentrum für Luft- und Raumfahrt (DLR) under grant 50EE1711D. TCCON stations at Tsukuba, Rikubetsu and Burgos are supported in part by the GOSAT series project. Burgos is also partially supported by the Energy Development Corp, Philippines. Darwin and Wollongong TCCON sites and NMD are supported by Australian Research Council funding via FT180100327, DP160101598, DP140101552, DP110103118, DP0879468 and LE0668470 and NASA grants NAG5-12247 and NNG05-GD07G and the University of Wollongong. The Paris TCCON site has received funding from Sorbonne Université, the French research center CNRS, the French space agency CNES, and Région Île-de-France. Author Contributions: Conceptualization, Y.Y.; methodology, H.O. (Haruki Oshio) and Y.Y.; software, H.O. (Haruki Oshio) and Y.Y.; validation, H.O. (Haruki Oshio); formal analysis, H.O. (Haruki Oshio) and Y.Y.; investigation, H.O. (Haruki Oshio); resources, T.M., N.M.D., M.D., D.W.T.G., F.H., L.T.I., R.K., C.L., I.M., J.N., Y.-S.O., H.O. (Hirofumi Ohyama), C.P., D.F.P., C.R., K.S., R.S., Y.T., V.A.V., T.W., and D.W.; data curation, Y.Y. and T.M.; writing—original draft preparation, H.O. (Haruki Oshio); writing—review and editing, all; visualization, H.O. (Haruki Oshio); supervision, Y.Y.; project administration, T.M.; funding acquisition, T.M. All authors have read and agreed to the published version of the manuscript. The authors declare no conflict of interest.
Funders:
Funding AgencyGrant Number
European Space Agency (ESA)4000120088/17/I-EF
Bundesministerium für Wirtschaft und Energie (BMWi)UNSPECIFIED
Deutsches Zentrum für Luft- und Raumfahrt (DLR)50EE1711D
Greenhouse Gases Observing Satellite (GOSAT)UNSPECIFIED
Energy Development Corp.UNSPECIFIED
Australian Research CouncilFT180100327
Australian Research CouncilDP160101598
Australian Research CouncilDP140101552
Australian Research CouncilDP110103118
Australian Research CouncilDP0879468
Australian Research CouncilLE0668470
NASANAG5-12247
NASANNG05-GD07G
University of WollongongUNSPECIFIED
Sorbonne UniversitéUNSPECIFIED
Centre National de la Recherche Scientifique (CNRS)UNSPECIFIED
Centre National d'Études Spatiales (CNES)UNSPECIFIED
Région Île-de-FranceUNSPECIFIED
Subject Keywords:methane; proxy method; GOSAT; TCCON
Issue or Number:19
Record Number:CaltechAUTHORS:20200928-075434934
Persistent URL:https://resolver.caltech.edu/CaltechAUTHORS:20200928-075434934
Official Citation:Oshio, H.; Yoshida, Y.; Matsunaga, T.; Deutscher, N.M.; Dubey, M.; Griffith, D.W.T.; Hase, F.; Iraci, L.T.; Kivi, R.; Liu, C.; Morino, I.; Notholt, J.; Oh, Y.-S.; Ohyama, H.; Petri, C.; Pollard, D.F.; Roehl, C.; Shiomi, K.; Sussmann, R.; Té, Y.; Velazco, V.A.; Warneke, T.; Wunch, D. Bias Correction of the Ratio of Total Column CH4 to CO2 Retrieved from GOSAT Spectra. Remote Sens. 2020, 12, 3155
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:105577
Collection:CaltechAUTHORS
Deposited By: Tony Diaz
Deposited On:28 Sep 2020 15:50
Last Modified:28 Sep 2020 15:50

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