Strong Southern Ocean carbon uptake evident in airborne observations

Matthew C Long; Britton B Stephens; Kathryn McKain; Colm Sweeney; Ralph F Keeling; Eric A Kort; Eric J Morgan; Jonathan D Bent; Naveen Chandra; Frederic Chevallier; Róisín Commane; Bruce C Daube; Paul B Krummel; Zoë Loh; Ingrid T Luijkx; David Munro; Prabir Patra; Wouter Peters; Michel Ramonet; Christian Rödenbeck; Ann Stavert; Pieter Tans; Steven C Wofsy

doi:10.1126/science.abi4355

Strong Southern Ocean carbon uptake evident in airborne observations

Science. 2021 Dec 3;374(6572):1275-1280. doi: 10.1126/science.abi4355. Epub 2021 Dec 2.

Authors

Matthew C Long¹, Britton B Stephens¹, Kathryn McKain^{2

3}, Colm Sweeney³, Ralph F Keeling⁴, Eric A Kort⁵, Eric J Morgan⁴, Jonathan D Bent^{1

4}, Naveen Chandra⁶, Frederic Chevallier⁷, Róisín Commane⁸, Bruce C Daube⁹, Paul B Krummel¹⁰, Zoë Loh¹⁰, Ingrid T Luijkx¹¹, David Munro^{2

3}, Prabir Patra¹², Wouter Peters^{11

13}, Michel Ramonet⁷, Christian Rödenbeck¹⁴, Ann Stavert¹⁰, Pieter Tans³, Steven C Wofsy^{9

15}

Affiliations

¹ National Center for Atmospheric Research, Boulder, CO, USA.
² Cooperative Institute for Research in Environmental Sciences, University of Colorado, Boulder, CO, USA.
³ Global Monitoring Laboratory, National Oceanic and Atmospheric Administration, Boulder, CO, USA.
⁴ Scripps Institution of Oceanography, University of California, San Diego, La Jolla, CA, USA.
⁵ Department of Climate and Space Sciences and Engineering, University of Michigan, Ann Arbor, MI, USA.
⁶ National Institute of Environmental Studies, Tsukuba, Japan.
⁷ Laboratoire des Sciences du Climat et de l'Environnement, IPSL-LSCE, CEA-CNRS-UVSQ, UMR8212 91191, France.
⁸ Department of Earth and Environmental Sciences, Lamont-Doherty Earth Observatory of Columbia University, Palisades, NY, USA.
⁹ Department of Earth and Planetary Sciences, Harvard University, Cambridge, MA, USA.
¹⁰ Climate Science Centre, CSIRO Oceans and Atmosphere, Aspendale, Victoria, Australia.
¹¹ Department of Meteorology and Air Quality, Environmental Sciences Group, Wageningen University, Netherlands.
¹² Research Institute for Global Change, Japan Agency for Marine-Earth Science and Technology (JAMSTEC), Yokohama, Japan.
¹³ Centre for Isotope Research, University of Groningen, Groningen, Netherlands.
¹⁴ Max Planck Institute for Biogeochemistry, Jena, Germany.
¹⁵ Harvard John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, MA, USA.

PMID: 34855495
DOI: 10.1126/science.abi4355

Abstract

The Southern Ocean plays an important role in determining atmospheric carbon dioxide (CO₂), yet estimates of air-sea CO₂ flux for the region diverge widely. In this study, we constrained Southern Ocean air-sea CO₂ exchange by relating fluxes to horizontal and vertical CO₂ gradients in atmospheric transport models and applying atmospheric observations of these gradients to estimate fluxes. Aircraft-based measurements of the vertical atmospheric CO₂ gradient provide robust flux constraints. We found an annual mean flux of –0.53 ± 0.23 petagrams of carbon per year (net uptake) south of 45°S during the period 2009–2018. This is consistent with the mean of atmospheric inversion estimates and surface-ocean partial pressure of CO₂ (Pco₂)–based products, but our data indicate stronger annual mean uptake than suggested by recent interpretations of profiling float observations.

Publication types

Research Support, Non-U.S. Gov't