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Improved Constraints on Northern Extratropical CO₂ Fluxes Obtained by Combining Surface-Based and Space-Based Atmospheric CO₂ Measurements

Byrne, B. and Liu, J. and Lee, M. and Baker, I. and Bowman, K. W. and Deutscher, N. M. and Feist, D. G. and Griffith, D. W. T. and Iraci, L. T. and Kiel, M. and Kimball, J. S. and Miller, C. E. and Morino, I. and Parazoo, N. C. and Petri, C. and Roehl, C. M. and Sha, M. K. and Strong, K. and Velazco, V. A. and Wennberg, P. O. and Wunch, D. (2020) Improved Constraints on Northern Extratropical CO₂ Fluxes Obtained by Combining Surface-Based and Space-Based Atmospheric CO₂ Measurements. Journal of Geophysical Research. Atmospheres, 125 (15). Art. No. e2019JD032029. ISSN 2169-897X.

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Top‐down estimates of CO₂ fluxes are typically constrained by either surface‐based or space‐based CO₂ observations. Both of these measurement types have spatial and temporal gaps in observational coverage that can lead to differences in inferred fluxes. Assimilating both surface‐based and space‐based measurements concurrently in a flux inversion framework improves observational coverage and reduces sampling related artifacts. This study examines the consistency of flux constraints provided by these different observations and the potential to combine them by performing a series of 6‐year (2010–2015) CO₂ flux inversions. Flux inversions are performed assimilating surface‐based measurements from the in situ and flask network, measurements from the Total Carbon Column Observing Network (TCCON), and space‐based measurements from the Greenhouse Gases Observing Satellite (GOSAT), or all three data sets combined. Combining the data sets results in more precise flux estimates for subcontinental regions relative to any of the data sets alone. Combining the data sets also improves the accuracy of the posterior fluxes, based on reduced root‐mean‐square differences between posterior flux‐simulated CO₂ and aircraft‐based CO₂ over midlatitude regions (0.33–0.56 ppm) in comparison to GOSAT (0.37–0.61 ppm), TCCON (0.50–0.68 ppm), or in situ and flask measurements (0.46–0.56 ppm) alone. These results suggest that surface‐based and GOSAT measurements give complementary constraints on CO₂ fluxes in the northern extratropics and can be combined in flux inversions to improve constraints on regional fluxes. This stands in contrast with many earlier attempts to combine these data sets and suggests that improvements in the NASA Atmospheric CO₂ Observations from Space (ACOS) retrieval algorithm have significantly improved the consistency of space‐based and surface‐based flux constraints.

Item Type:Article
Related URLs:
URLURL TypeDescription
http://tccondata.orgRelated ItemCCON data archive
https://www.bgc-jena.mpg.deRelated ItemFLUXCOM products ItemMERRA‐2 products
https://cds.climate.copernicus.euRelated ItemGOSAT OCFP v7.1 ItemGLOBALVIEW plus package
https://www.esa-soilmoisture-cci.orgRelated ItemESA CCI soil moisture data
https://co2.jpl.nasa.govRelated ItemGOSAT and OCO‐2 ACOS retrievals
https://data.nas.nasa.govRelated ItemPrior and posterior NEE and ocean fluxes
https://cmsflux.jpl.nasa.govRelated ItemPrior and posterior NEE and ocean fluxes ItemJR‐STATION data set Paper
Byrne, B.0000-0003-0619-3045
Liu, J.0000-0002-7184-6594
Lee, M.0000-0002-8797-8209
Baker, I.0000-0001-5162-1956
Bowman, K. W.0000-0002-8659-1117
Deutscher, N. M.0000-0002-2906-2577
Feist, D. G.0000-0002-5890-6687
Griffith, D. W. T.0000-0002-7986-1924
Iraci, L. T.0000-0002-2859-5259
Kiel, M.0000-0002-9784-962X
Kimball, J. S.0000-0002-5493-5878
Miller, C. E.0000-0002-9380-4838
Morino, I.0000-0003-2720-1569
Parazoo, N. C.0000-0002-4424-7780
Petri, C.0000-0002-7010-5532
Roehl, C. M.0000-0001-5383-8462
Sha, M. K.0000-0003-1440-1529
Strong, K.0000-0001-9947-1053
Velazco, V. A.0000-0002-1376-438X
Wennberg, P. O.0000-0002-6126-3854
Wunch, D.0000-0002-4924-0377
Additional Information:© 2020 The Authors. This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited. Issue Online: 26 July 2020; Version of Record online: 26 July 2020; Accepted manuscript online: 24 June 2020; Manuscript accepted: 13 June 2020; Manuscript revised: 05 May 2020; Manuscript received: 08 November 2019. BB was supported by an appointment to the NASA Postdoctoral Program at the Jet Propulsion Laboratory, administered by Universities Space Research Association under contract with NASA. JL was supported by the NASA OCO2/3 science team program NNH17ZDA001N‐OCO2. KWB was supported by the NASA Carbon Monitoring System (CMS) project (NNH16ZDA001N‐CMS). The research carried out at the Jet Propulsion Laboratory, California Institute of Technology, was under a contract with the National Aeronautics and Space Administration. Resources supporting this work were provided by the NASA High‐End Computing (HEC) Program through the NASA Advanced Supercomputing (NAS) Division at Ames Research Center. Odiac project is supported by Greenhouse Gas Observing SATellite (GOSAT) project, National Institute for Environmental Studies (NIES), Japan. We thank S. Basu for providing downscaled ODIAC emissions. We thank T. Machida, H. Matsueda, Y. Sawa, and Y. Niwa for providing CONTRAIL measurements. The TCCON site at Reunion Island is operated by the Royal Belgian Institute for Space Aeronomy with financial support in 2014, 2015, 2016, 2017, 2018, and 2019 under the EU project ICOS‐Inwire and the ministerial decree for ICOS (FR/35/IC2) and local activities supported by LACy/UMR8105 Universit de La Reunion. The TCCON project for Rikubetsu site is supported in part by the GOSAT series project. The Ascension Island TCCON station has been supported by the European Space Agency (ESA) under grant 4000120088/17/I‐EF and by the German Bundesministerium fur Wirtschaft und Energie (BMWi) under grants 50EE1711C and 50EE1711E. We thank the ESA Ariane Tracking Station at North East Bay, Ascension Island, for hosting and local support. Data Availability Statement: TCCON data were obtained from the TCCON Data Archive, hosted by CaltechDATA ( FLUXCOM products were obtained from the Data Portal of the Max Planck Institute for Biochemistry []. MERRA‐2 products were downloaded from MDISC (, managed by the NASA Goddard Earth Sciences (GES) Data and Information Services Center (DISC). GOSAT OCFP v7.1 urn:x-wiley:jgrd:media:jgrd56355:jgrd56355-math-0041 retrievals were downloaded from the Copernicus Climate Change Service website ( Version 4.1 of the GLOBALVIEW plus package was downloaded from ESA CCI soil moisture data was downloaded from Odiac emissions data set was provided by T. Oda of Colorado State University, Fort Collins CO, USA/Global Monitoring Division, NOAA Earth System Research Laboratory, Boulder CO, USA. GOSAT and OCO‐2 ACOS retrievals were downloaded from the CO2 virtual science data environment: Prior and posterior NEE and Ocean fluxes presented in this study will be available for download from and The JR‐STATION data set is available from the Global Environmental Database, hosted by Center for Global Environmental Research (CGER), National Institute for Environmental Studies (NIES) ( OceanicMonitoring).
Funding AgencyGrant Number
NASA Postdoctoral ProgramUNSPECIFIED
National Institute for Environmental Studies (Japan)UNSPECIFIED
Royal Belgian Institute for Space AeronomyUNSPECIFIED
European UnionFR/35/IC2
Université de La RéunionLACy/UMR8105
European Space Agency (ESA)4000120088/17/I‐EF
Bundesministerium für Wirtschaft und Energie (BMWi)50EE1711C
Bundesministerium für Wirtschaft und Energie (BMWi)50EE1711E
Subject Keywords:carbon cycle; CO2 flux; data assimilation; GOSAT; TCCON; OCO‐2
Issue or Number:15
Record Number:CaltechAUTHORS:20200819-102214184
Persistent URL:
Official Citation:Byrne, B., Liu, J., Lee, M., Baker, I., Bowman, K. W., Deutscher, N. M., et al. (2020). Improved constraints on northern extratropical CO2 fluxes obtained by combining surface‐based and space‐based atmospheric CO2 measurements. Journal of Geophysical Research: Atmospheres, 125, e2019JD032029.
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:105025
Deposited By: Tony Diaz
Deposited On:19 Aug 2020 17:53
Last Modified:03 Mar 2021 20:16

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