Air-sea CO2 flux in the Pacific Ocean for the period 1990-2009
| Type | Article | ||||||||
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| Date | 2014 | ||||||||
| Language | English | ||||||||
| Author(s) | Ishii M.1, 2, Feely R. A.3, Rodgers K. B.4, Park G. -H.5, 6, Wanninkhof R.5, Sasano D.1, 2, Sugimoto H.2, Cosca C. E.3, Nakaoka S.7, Telszewski M.7, Nojiri Y.7, Fletcher S. E. Mikaloff8, Niwa Y.1, Patra P. K.9, Valsala V.7, Nakano H.1, Lima I.10, Doney S. C.10, Buitenhuis E. T.11, Aumont Olivier12, Dunne J. P.13, Lenton A.14, Takahashi T.15 | ||||||||
| Affiliation(s) | 1 : Japan Meteorol Agcy, Meteorol Res Inst, Oceanog & Geochem Res Dept, Tsukuba, Ibaraki 3050052, Japan. 2 : Japan Meteorol Agcy, Global Environm & Marine Dept, Tokyo 1008122, Japan. 3 : NOAA, Pacific Marine Environm Lab, Ocean Climate Res Div, Seattle, WA 98115 USA. 4 : Princeton Univ, Program Atmospher & Ocean Sci, Princeton, NJ 08544 USA. 5 : NOAA, Atlant Oceanog & Meteorol Lab, Ocean Chem Div, Miami, FL 33149 USA. 6 : Univ Miami, Cooperat Inst Marine & Atmospher Studies, Miami, FL 33149 USA. 7 : Natl Inst Environm Studies, Ctr Global Environm Res, Tsukuba, Ibaraki 3058506, Japan. 8 : Natl Inst Water & Atmospher Res, Wellington 6021, New Zealand. 9 : Japan Agcy Marine Sci & Technol, Res Inst Global Change, Yokohama, Kanagawa 2360001, Japan. 10 : Woods Hole Oceanog Inst, Dept Marine Chem & Geochem, Woods Hole, MA 02543 USA. 11 : Univ E Anglia, Sch Environm Sci, Norwich NR4 7TJ, Norfolk, England. 12 : Ctr IRD Bretagne, Lab Phys Oceans, F-29280 Plouzane, France. 13 : NOAA, Geophys Fluid Dynam Lab, Princeton, NJ 08540 USA. 14 : CSIRO Marine & Atmospher Res, Ctr Australian Weather & Climate Res, Hobart, Tas 7000, Australia. 15 : Columbia Univ, Lamont Doherty Earth Observ, Palisades, NY 10964 USA. |
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| Source | Biogeosciences (1726-4170) (Copernicus Gesellschaft Mbh), 2014 , Vol. 11 , N. 3 , P. 709-734 | ||||||||
| DOI | 10.5194/bg-11-709-2014 | ||||||||
| WOS© Times Cited | 67 | ||||||||
| Abstract | Air-sea CO2 fluxes over the Pacific Ocean are known to be characterized by coherent large-scale structures that reflect not only ocean subduction and upwelling patterns, but also the combined effects of wind-driven gas exchange and biology. On the largest scales, a large net CO2 influx into the extratropics is associated with a robust seasonal cycle, and a large net CO2 efflux from the tropics is associated with substantial interannual variability. In this work, we have synthesized estimates of the net air-sea CO2 flux from a variety of products, drawing upon a variety of approaches in three sub-basins of the Pacific Ocean, i. e., the North Pacific extratropics (18-66 degrees N), the tropical Pacific (18 degrees S-18 degrees N), and the South Pacific extratropics (44.5-18 degrees S). These approaches include those based on the measurements of CO2 partial pressure in surface seawater (pCO(2)sw), inversions of ocean-interior CO2 data, forward ocean biogeochemistry models embedded in the ocean general circulation models (OBGCMs), a model with assimilation of pCO(2)sw data, and inversions of atmospheric CO2 measurements. Long-term means, interannual variations and mean seasonal variations of the regionally integrated fluxes were compared in each of the sub-basins over the last two decades, spanning the period from 1990 through 2009. A simple average of the long-term mean fluxes obtained with surface water pCO(2) diagnostics and those obtained with ocean-interior CO2 inversions are -0.47 +/- 0.13 Pg Cyr(-1) in the North Pacific extratropics, +/- 0.44 +/- 0.14 Pg Cyr(-1) in the tropical Pacific, and -0.37 +/- 0.08 Pg C yr(-1) in the South Pacific extratropics, where positive fluxes are into the atmosphere. This suggests that approximately half of the CO2 taken up over the North and South Pacific extratropics is released back to the atmosphere from the tropical Pacific. These estimates of the regional fluxes are also supported by the estimates from OBGCMs after adding the riverine CO2 flux, i.e., -0.49 +/- 0.02 Pg Cyr(-1) in the North Pacific extratropics, +0.41 +/- 0.05 Pg Cyr(-1) in the tropical Pacific, and -0.39 +/- 0.11 Pg Cyr(-1) in the South Pacific extratropics. The estimates from the atmospheric CO2 inversions show large variations amongst different inversion systems, but their median fluxes are consistent with the estimates from climatological pCO(2)sw data and pCO(2)sw diagnostics. In the South Pacific extratropics, where CO2 variations in the surface and ocean interior are severely undersampled, the difference in the air-sea CO2 flux estimates between the diagnostic models and ocean-interior CO2 inversions is larger (0.18 Pg Cyr(-1)). The range of estimates from forward OBGCMs is also large (-0.19 to -0.72 Pg Cyr(-1)). Regarding interannual variability of air-sea CO2 fluxes, positive and negative anomalies are evident in the tropical Pacific during the cold and warm events of the El Nino-Southern Oscillation in the estimates from pCO(2)sw diagnostic models and from OBGCMs. They are consistent in phase with the Southern Oscillation Index, but the peak-to-peak amplitudes tend to be higher in OBGCMs (0.40 +/- 0.09 Pg Cyr(-1)) than in the diagnostic models (0.27 +/- 0.07 Pg Cyr(-1)). | ||||||||
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