Journal cover Journal topic
Biogeosciences An interactive open-access journal of the European Geosciences Union
Biogeosciences, 10, 607-627, 2013
© Author(s) 2013. This work is distributed under
the Creative Commons Attribution 3.0 License.
Research article
29 Jan 2013
An assessment of the Atlantic and Arctic sea–air CO2 fluxes, 1990–2009
U. Schuster1, G. A. McKinley2, N. Bates3, F. Chevallier4, S. C. Doney5, A. R. Fay2, M. González-Dávila6, N. Gruber7, S. Jones1, J. Krijnen1, P. Landschützer1, N. Lefèvre8, M. Manizza9, J. Mathis10, N. Metzl11, A. Olsen12, A. F. Rios13, C. Rödenbeck14, J. M. Santana-Casiano6, T. Takahashi15, R. Wanninkhof16, and A. J. Watson1 1University of East Anglia, Norwich, UK
2University of Wisconsin, Madison, WI, USA
3Bermuda Institute of Ocean Science, Bermuda
4LSCE-IPSL, Paris, France
5Woods Hole Oceanographic Institution, Woods Hole, MA, USA
6Universidad de Las Palmas de Gran Canaria, Las Palmas, Gran Canaria, Spain
7ETH-Zürich, Zürich, Switzerland
8LOCEAN, Université Pierre et Marie Curie, Paris, France
9Scripps Institution of Oceanography, La Jolla, CA, USA
10NOAA Pacific Marine Environmental Laboratory, Seattle, WA, USA
11LOCEAN-IPSL, CNRS, UPMC, Paris, France
12Uni Research, Bergen, Norway
13Instituto de Investigaciones Marinas, IIM-CSIC, Vigo, Spain
14Max-Planck-Institut für Biogeochemie, Jena, Germany
15Lamont Doherty Earth Observatory of Columbia University, Palisades, NY, USA
16NOAA/Atlantic Oceanographic and Meteorological Laboratory, Miami, FL, USA
Abstract. The Atlantic and Arctic Oceans are critical components of the global carbon cycle. Here we quantify the net sea–air CO2 flux, for the first time, across different methodologies for consistent time and space scales for the Atlantic and Arctic basins. We present the long-term mean, seasonal cycle, interannual variability and trends in sea–air CO2 flux for the period 1990 to 2009, and assign an uncertainty to each. We use regional cuts from global observations and modeling products, specifically a pCO2-based CO2 flux climatology, flux estimates from the inversion of oceanic and atmospheric data, and results from six ocean biogeochemical models. Additionally, we use basin-wide flux estimates from surface ocean pCO2 observations based on two distinct methodologies. Our estimate of the contemporary sea–air flux of CO2 (sum of anthropogenic and natural components) by the Atlantic between 40° S and 79° N is −0.49 ± 0.05 Pg C yr−1, and by the Arctic it is −0.12 ± 0.06 Pg C yr−1, leading to a combined sea–air flux of −0.61 ± 0.06 Pg C yr−1 for the two decades (negative reflects ocean uptake). We do find broad agreement amongst methodologies with respect to the seasonal cycle in the subtropics of both hemispheres, but not elsewhere. Agreement with respect to detailed signals of interannual variability is poor, and correlations to the North Atlantic Oscillation are weaker in the North Atlantic and Arctic than in the equatorial region and southern subtropics. Linear trends for 1995 to 2009 indicate increased uptake and generally correspond between methodologies in the North Atlantic, but there is disagreement amongst methodologies in the equatorial region and southern subtropics.

Citation: Schuster, U., McKinley, G. A., Bates, N., Chevallier, F., Doney, S. C., Fay, A. R., González-Dávila, M., Gruber, N., Jones, S., Krijnen, J., Landschützer, P., Lefèvre, N., Manizza, M., Mathis, J., Metzl, N., Olsen, A., Rios, A. F., Rödenbeck, C., Santana-Casiano, J. M., Takahashi, T., Wanninkhof, R., and Watson, A. J.: An assessment of the Atlantic and Arctic sea–air CO2 fluxes, 1990–2009, Biogeosciences, 10, 607-627,, 2013.
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