Improved winter data coverage of the Southern Ocean CO2 sink from extrapolation of summertime observations

Mackay, Neill, Watson, Andrew J., Suntharalingam, Parvada, Chen, Zhaohui and Landschützer, Peter (2022) Improved winter data coverage of the Southern Ocean CO2 sink from extrapolation of summertime observations. Communications Earth & Environment, 3. ISSN 2662-4435

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Abstract

The Southern Ocean is an important sink of anthropogenic CO2, but it is among the least well-observed ocean basins, and consequentially substantial uncertainties in the CO2 flux reconstruction exist. A recent attempt to address historically sparse wintertime sampling produced ‘pseudo’ wintertime observations of surface pCO2 using subsurface summertime observations south of the Antarctic Polar Front. Here, we present an estimate of the Southern Ocean CO2 sink that combines a machine learning-based mapping method with an updated set of pseudo observations that increases regional wintertime data coverage by 68% compared with the historical dataset. Our results confirm the suggestion that improved winter coverage has a modest impact on the reconstruction, slightly strengthening the uptake trend in the 2000s. After also adjusting for surface boundary layer temperature effects, we find a 2004-2018 mean sink of −0.16 ± 0.07 PgC yr−1 south of the Polar Front and −1.27 ± 0.23 PgC yr−1 south of 35°S, consistent with independent estimates from atmospheric data.

Item Type: Article
Additional Information: Funding Information: The authors acknowledge funding from the U.K. Natural Environment Research Council under the SONATA grant (NE/P021298/1) and the UNICORNS grant (NE/W001543/1). Computational resources for the SOSE were provided by NSF XSEDE resource grant OCE130007. This study has been conducted using E.U. Copernicus Marine Service Information. SOCCOM float data were collected and made freely available by the Southern Ocean Carbon and Climate Observations and Modeling (SOCCOM) Project funded by the National Science Foundation, Division of Polar Programs (NSF PLR −1425989, extension NSF OPP-1936222), supplemented by NASA, and by the International Argo Program and the NOAA programs that contribute to it (http://www.argo.ucsd.edu , http://argo.jcommops.org). Argo data were collected and made freely available by the International Argo Program and the national programs that contribute to it (http://www.argo.ucsd.edu , http://argo.jcommops.org). The Argo Program is part of the Global Ocean Observing System. Argo float data and metadata from Global Data Assembly Centre (Argo GDAC) SEANOE https://doi.org/10.17882/42182 . CCMP Version-2.0 vector wind analyses are produced by Remote Sensing Systems. Data are available at www.remss.com . We would also like to thank the reviewers for their thoughtful comments and suggestions that have helped significantly improve the paper.
Uncontrolled Keywords: environmental science(all),earth and planetary sciences(all) ,/dk/atira/pure/subjectarea/asjc/2300
Faculty \ School: Faculty of Science
Faculty of Science > School of Environmental Sciences
Related URLs:
Depositing User: LivePure Connector
Date Deposited: 15 Dec 2022 03:51
Last Modified: 15 Dec 2022 03:51
URI: https://ueaeprints.uea.ac.uk/id/eprint/90074
DOI: 10.1038/s43247-022-00592-6

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