[en] We determine the distribution of oceanic CO2 partial pressure (pCO(2)) with respect to remotely sensed parameters (sea surface temperature (SST) and chlorophyll (Chl)) in order to gain an understanding of the small-scale (10-100 km) pCO(2) variability and to estimate the net air-sea CO2 flux in the region (125 degrees E-205 degrees E; 45 degrees S-60 degrees S), which represents 22% of the Southern Ocean area between 45 degrees S and 60 degrees S. We split the study area into several biogeochemical provinces. In chlorophyll-poor regions, pCO(2) is negatively correlated with SST, indicating that pCO(2) is mostly controlled by mixing processes. For Chl > 0.37 mg m(-3), pCO(2) is negatively correlated with Chl, indicating that pCO(2) variability is mostly controlled by carbon fixation by biological activity. We deduce fields of pCO(2) and of air-sea CO2 fluxes from satellite parameters using pCO(2)-SST, pCO(2)-chlorophyll relationships and air-sea gas exchange coefficient, K, from satellite wind speed. We estimate an oceanic CO2 sink from December 1997 to December 1998 of -0.08 GtC yr(-1) with an error of 0.03 GtC yr(-1). This sink is approximately 38% smaller than that computed from the Takahashi et al. (2002) climatological distribution of Delta pCO(2) for the 1995 year but with the same K (-0.13 GtC yr(-1)). When we correct ocean pCO(2) for the interannual variability between 1995 and 1998, the difference is even larger, and we cannot reconcile both estimates in February-March and from June to November. This strengthens the need of new in situ measurements for validating extrapolation methods and for improving knowledge of interannual pCO(2) variability.
Disciplines :
Earth sciences & physical geography
Author, co-author :
Rangama, Y.
Boutin, J.
Etcheto, J.
Merlivat, L.
Takahashi, T.
Delille, Bruno ; Université de Liège - ULiège > Département d'astrophys., géophysique et océanographie (AGO) > Océanographie chimique
Frankignoulle, Michel
Bakker, D. C. E.
Language :
English
Title :
Variability of the net air-sea CO2 flux inferred from shipboard and satellite measurements in the Southern Ocean south of Tasmania and New Zealand
Publication date :
08 September 2005
Journal title :
Journal of Geophysical Research. Oceans
ISSN :
2169-9275
eISSN :
2169-9291
Publisher :
American Geophysical Union (AGU), Washington, United States - Washington
Volume :
110
Issue :
C9
Peer reviewed :
Peer Reviewed verified by ORBi
Funders :
CNRS - Centre National de la Recherche Scientifique [FR] CNES - Centre National d'Études Spatiales [FR]
Commentary :
An edited version of this paper was published by AGU. Copyright 2005 American Geophysical Union
Bakker, D. C. E., A. J. Watson, and C. S. Law (2001), Southern Ocean iron enrichment promotes inorganic carbon drawdown, Deep Sea Res., Part II, 48, 2483-2507.
Belkin, I. M., and A. L. Gordon (1996), Southern Ocean fronts from the Greenwich meridian to Tasmania, J. Geophys. Res., 101, 3675-3694.
Boutin, J., Y. Rangama, J. Etcheto, L. Merlivat, T. Takahashi, B. Delille, and M. Frankignoulle (2001), Variability of the air-sea CO2 fluxes inferred from in situ and remotely sensed parameters in the Southern Ocean, paper presented at the Sixth International Carbon Dioxide Conference, World Meteorol. Org., Sendai, Jpn.
Boutin, J., J. Etcheto, L. Merlivat, and Y. Rangama (2002), Influence of gas exchange coefficient parameterisation on seasonal and regional variability of CO2 air-sea fluxes, Geophys. Res. Lett., 29(8), 1182, doi:10.1029/2001GL013872.
Frankignoulle, M., A. Borges, and R. Biondo (2001), A new design of equilibrator to monitor carbon dioxide in highly dynamic and turbid environments, Water Resour. Res., 35(5), 1344-1347.
Frew, N. M., E. J. Bock, U. Schimpf, T. Hara H. Haussecker, J. B. Edson, W. R. McGillis, R. K. Nelson, S. P. McKenna, M. B. M. Uz, and B. Jahne (2004), Air-sea gas transfer: Its dependence on wind stress, small-scale roughness and surface films, J. Geophys. Res., 109, C08S17, doi:10.1029/ 2003JC002131.
GlobalView-CO2 (2003), Cooperative Atmospheric Data Integration Project-Carbon Dioxide [CD-ROM], Climate Monit. and Diagn. Lab., Natl. Oceanic and Atmos. Admin., Boulder, Colo.
Gloor, M., N. Gruber, J. Sarmiento, C. L. Sabine, R. A. Feely, and C. Rödenbeck (2003), A first estimate of present and preindustrial air-sea CO2 flux patterns based on ocean interior carbon measurements and models, Geophys. Res. Lett., 30(1), 1010, doi:10.1029/ 2002GL015594.
Gurney, K. R., et al. (2004), Transcom 3 inversion intercomparison: Model mean results for estimation of seasonal carbon sources and sinks, Global Biogeochem. Cycles, 18, GB1010, doi:10.1029/2003GB002111.
Liss, P. S., and L. Merlivat (1986), Air-sea gas exchange rates: Introduction and synthesis, in The Role of Air-Sea Exchange in Geochemical Cycling, edited by P. Buat-Ménart, pp. 113-127, Springer, New York.
Metzl, N., B. Tilbrook, and A. Poisson (1999), The annual fCO2 cycle and the air-sea CO2 flux in the sub-Antarctic ocean, Tellus, Ser. B, 51, 849-861.
Moore, J. K., and M. R. Abbott (2000), Phytoplankton chlorophyll distributions and primary production in the Southern Ocean, J. Geophys. Res., 105, 28,709-28,722.
Morrison, J. M., S. Gaurin, L. A. Codispoti, T. Takahashi, F. J. Millero, W. D. Gardner, and M. J. Richardson (2001), Seasonal evolution of hydrographic properties in the Antarctic Circumpolar Current at 170°W during 1997-1998, Deep Sea Res., Part II, 48, 3943-3972.
Nightingale, P. D., G. Malin, C. S. Law, A. J. Watson, P. S. Liss, M. I. Liddicoat, J. Boutin, and R. C. Upstill-Goddard (2000), In-situ evaluation of air-sea gas exchange parameterisations using novel conservative and volatile tracers, Global Biogeochem. Cycles, 14, 373-387.
Orsi, A. H., T. Whitworth III, and W. D. Nowlin Jr. (1995), On the meridional extent and fronts of the Antarctic Circumpolar Current, Deep Sea Res., Part I, 42, 641-673.
Peacock, S. (2004), Debate over the ocean bomb radiocarbon sink: Closing the gap, Global Biogeochem. Cycles, 18, GB2022, doi:10.1029/2003GB002211.
Reynolds, R. W., and T. M. Smith (1994), Improved global sea surface temperature analyses using interpolation, J. Clim., 7, 929-948.
Rubin, S. I. (2003), Carbon and nutrient cycling in the upper water column across the Polar Frontal Zone and Antarctic Circumpolar Current along 170°W, Global Biogeochem. Cycles, 17(3), 1087, doi:10.1029/ 2002GB001900.
Sweeney, C., E. M. Gloor, J. A. Jackobson, R. M. Key, G. McKinley, and J. L. Sarmiento (2004), Estimating air-sea gas exchange using bomb 14C: Revisited, paper presented at SOLAS Science 2004, Surface Ocean-Lower Atmos. Study, Halifax, Nova Scotia, Canada.
Takahashi, T., C. Sweeney, S. C. Sutherland, D. W. Chipman, J. Goddard, and S. I. Rubin (2000), Method of underway pCO2 measurements in surface waters and the atmosphere during the AESOPS Expeditions, 1996-1998 in the Pacific sector of the Southern Ocean and the Ross Sea, U.S. JGOFS Data Cent., Woods Hole Oceanogr. Inst., Woods Hole, Mass.
Takahashi, T., et al. (2002), Global sea-air CO2 fluxes based on climatological surface ocean pCO2 and seasonal biological and temperature effects, Deep Sea Res., Part II, 1601-1622.
Wanninkhof, R. (1992), Relationship between wind speed and gas exchange over the ocean, J. Geophys. Res., 97, 7373-7382.
Wanninkhof, R., and W. R. McGillis (1999), A cubic relationship between air-sea CO2 exchange coefficient and wind speed, Geophys. Res. Lett., 26, 1889-1892.
Wanninkhof, R., K. F. Sullivan, and Z. Top (2004), Air-sea gas transfer in the Southern Ocean, J. Geophys. Res., 109, C08S19, doi:10.1029/ 2003JC001767.
Watson, A. J., D. C. E. Bakker, P. W. Boyd, A. J. Ridgwell, and C. S. Law (2000), Effect of iron supply on Southern Ocean CO2 uptake and implications for glacial atmospheric CO2, Nature, 407, 730-733.
Weiss, R. F., and B. A. Price (1980), Nitrous oxide solubility in water and seawater, Mar. Chem., 8, 347-359.