• Bunker, A., 1976: Computations of surface-energy flux and annual air–sea interaction cycles of the North Atlantic Ocean. Mon. Wea. Rev., 104 , 11221140.

    • Search Google Scholar
    • Export Citation
  • Dai, A., and K. Trenberth, 2002: Estimates of freshwater discharge from continents: Latitudinal and seasonal variations. J. Hydrometeor., 3 , 660687.

    • Search Google Scholar
    • Export Citation
  • Doney, S., W. Large, and F. Bryan, 1998: Surface ocean fluxes and water-mass transformation rates in the coupled NCAR Climate System Model. J. Climate, 11 , 14201441.

    • Search Google Scholar
    • Export Citation
  • Doos, K., and A. Coward, 1997: The Southern Ocean as the major upwelling zone of North Atlantic Deep Water. International WOCE Newsletter, No. 27, WOCE International Project Office, Southampton, United Kingdom, 3–4.

    • Search Google Scholar
    • Export Citation
  • Dorman, C., and R. Bourke, 1981: Precipitation over the Atlantic Ocean, 30°S to 70°N. Mon. Wea. Rev., 109 , 554563.

  • Fekete, B., C. Vorosmarty, and W. Grabs, 2002: High-resolution fields of global runoff combining observed river discharge and simulated water balances. Global Biogeochem. Cycles, 16 , 10421057.

    • Search Google Scholar
    • Export Citation
  • Ganachaud, A., and C. Wunsch, 2003: Large-scale ocean heat and freshwater transports during the World Ocean Circulation Experiment. J. Climate, 16 , 696705.

    • Search Google Scholar
    • Export Citation
  • Gent, P., and J. McWilliams, 1990: Isopycnal mixing in ocean circulation models. J. Phys. Oceanogr., 20 , 150155.

  • Gnanadesikan, A., 1999: A simple predictive model for the structure of the oceanic pycnocline. Science, 283 , 20772079.

  • Gordon, C., and Coauthors, 2000: The simulation of SST, sea ice extents and ocean heat transports in a version of the Hadley Centre coupled model without flux adjustments. Climate Dyn., 16 , 147168.

    • Search Google Scholar
    • Export Citation
  • Grist, J., and S. Josey, 2003: Inverse analysis adjustment of the SOC air–sea flux climatology using ocean heat transport constraints. J. Climate, 16 , 32743295.

    • Search Google Scholar
    • Export Citation
  • Jacobs, S., H. Helmer, C. Doake, A. Jenkins, and R. Frolich, 1992: Melting of ice shelves and the mass balance of Antarctica. J. Glaciol., 38 , 375387.

    • Search Google Scholar
    • Export Citation
  • Josey, S., E. Kent, and P. Taylor, 1998: The Southampton Oceanography Centre (SOC) ocean–atmosphere heat, momentum and freshwater flux atlas. Southampton Oceanography Centre Rep. 6, University of Southampton, Southampton, United Kingdom, 30 pp. + figures.

    • Search Google Scholar
    • Export Citation
  • Large, W., and A. Nurser, 2001: Ocean surface water mass transformation. Ocean Circulation and Climate: Observing and Modelling the Global Ocean, G. Siedler, J. Church, and J. Gould, Eds., Academic Press, 317–336.

    • Search Google Scholar
    • Export Citation
  • Lumpkin, R., and K. Speer, 2007: Global ocean meridional overturning. J. Phys. Oceanogr., 37 , 25502562.

  • Marshall, J., and T. Radko, 2003: Residual-mean solutions for the Antarctic Circumpolar Current and its associated overturning circulation. J. Phys. Oceanogr., 33 , 23412354.

    • Search Google Scholar
    • Export Citation
  • Nurser, A., R. Marsh, and R. Williams, 1999: Diagnosing water mass formation from air–sea fluxes and surface mixing. J. Phys. Oceanogr., 29 , 14681487.

    • Search Google Scholar
    • Export Citation
  • Pardaens, A., H. Banks, J. Gregory, and P. Rowntree, 2003: Freshwater transports in HadCM3. Climate Dyn., 21 , 177195.

  • Rintoul, S., C. Hughes, and D. Olbers, 2001: The Antarctic Circumpolar current system. Ocean Circulation and Climate: Observing and Modelling the Global Ocean, G. Siedler, J. Church, and J. Gould, Eds., Academic Press, 271–300.

    • Search Google Scholar
    • Export Citation
  • Sallee, J., R. Morrow, and K. Speer, 2008: Eddy heat diffusion and subantarctic mode water formation. Geophys. Res. Lett., 35 , L05607. doi:10.1029/2007GL032827.

    • Search Google Scholar
    • Export Citation
  • Schmitt, R., P. Bogden, and C. Dorman, 1989: Evaporation minus precipitation and density fluxes for the North Atlantic. J. Phys. Oceanogr., 19 , 12081221.

    • Search Google Scholar
    • Export Citation
  • Speer, K., 1997: A note on average cross-isopycnal mixing in the North Atlantic Ocean. Deep-Sea Res. I, 44 , 19811990.

  • Speer, K., and E. Tziperman, 1992: Rates of water mass formation in the North Atlantic Ocean. J. Phys. Oceanogr., 22 , 93104.

  • Speer, K., H. Isemer, and A. Biastoch, 1995: Water mass formation from revised COADS data. J. Phys. Oceanogr., 25 , 24442457.

  • Speer, K., S. Rintoul, and B. Sloyan, 1997: Subantarctic mode water formation by air–sea fluxes. International WOCE Newsletter, No. 27, WOCE International Project Office, Southampton, United Kingdom, 29–31.

    • Search Google Scholar
    • Export Citation
  • Speer, K., E. Guilyardi, and G. Madec, 2000a: Southern Ocean transformation in a coupled model with and without eddy mass fluxes. Tellus, 52A , 554565.

    • Search Google Scholar
    • Export Citation
  • Speer, K., S. Rintoul, and B. Sloyan, 2000b: The diabatic Deacon cell. J. Phys. Oceanogr., 30 , 32123222.

  • Toggweiler, J., and B. Samuels, 1995: Effect of Drake Passage on the global thermohaline circulation. Deep-Sea Res. I, 42 , 477500.

  • Tziperman, E., 1986: On the role of interior mixing and air–sea fluxes in determining the stratification and circulation of the oceans. J. Phys. Oceanogr., 16 , 680693.

    • Search Google Scholar
    • Export Citation
  • Tziperman, E., and K. Speer, 1994: A study of water mass transformation in the Mediterranean Sea—Analysis of climatological data and a simple 3-box model. Dyn. Atmos. Oceans, 21 , 5382.

    • Search Google Scholar
    • Export Citation
  • Visbeck, M., J. Marshall, T. Haine, and M. Spall, 1997: Specification of eddy transfer coefficients in coarse-resolution ocean circulation models. J. Phys. Oceanogr., 27 , 381402.

    • Search Google Scholar
    • Export Citation
  • Walin, G., 1982: On the relation between sea-surface heat-flow and thermal circulation in the ocean. Tellus, 34 , 187195.

  • Xie, P., and P. Arkin, 1996: Analyses of global monthly precipitation using gauge observations, satellite estimates, and numerical model predictions. J. Climate, 9 , 840858.

    • Search Google Scholar
    • Export Citation
All Time Past Year Past 30 Days
Abstract Views 0 0 0
Full Text Views 0 0 0
PDF Downloads 0 0 0

A New Climatology of Air–Sea Density Fluxes and Surface Water Mass Transformation Rates Constrained by WOCE

View More View Less
  • 1 Department of Physics, Imperial College, London, United Kingdom
Restricted access

Abstract

Global air–sea heat and freshwater flux data, constrained by World Ocean Circulation Experiment (WOCE) hydrographic section transports, is used to construct a new global density flux climatology. Global transformations calculated using this density flux dataset show two regimes: surface waters with density less than ∼1023.3 kg m−3 are transformed to lighter density classes with a maximum rate of 130 Sv (1 Sv ≡ 106 m3 s−1) at σ ∼ 1021.6 kg m−3, and surface waters with density greater than 1023.3 kg m−3 are transformed to denser density classes with a maximum rate of 100 Sv at σ = 1025.4 kg m−3. At higher density (σ = 1027 kg m−3) the net transformation rates vanish, reflecting heat loss in the Northern Hemisphere balanced by Southern Hemisphere freshening. This results in a kink in the global transformation rate, which is attributed to the presence of Drake Passage. Further analysis of the control run of the third Hadley Centre global climate model, HadCM3, suggests this feature to be robust and to reflect the “channel” geometry of the Southern Ocean and the “basin” geometry of the Northern Hemisphere.

Corresponding author address: N. Howe, Imperial College, Prince Consort Rd., Huxley Bldg., London SW7 2AZ, United Kingdom. Email: n.howe06@imperial.ac.uk

Abstract

Global air–sea heat and freshwater flux data, constrained by World Ocean Circulation Experiment (WOCE) hydrographic section transports, is used to construct a new global density flux climatology. Global transformations calculated using this density flux dataset show two regimes: surface waters with density less than ∼1023.3 kg m−3 are transformed to lighter density classes with a maximum rate of 130 Sv (1 Sv ≡ 106 m3 s−1) at σ ∼ 1021.6 kg m−3, and surface waters with density greater than 1023.3 kg m−3 are transformed to denser density classes with a maximum rate of 100 Sv at σ = 1025.4 kg m−3. At higher density (σ = 1027 kg m−3) the net transformation rates vanish, reflecting heat loss in the Northern Hemisphere balanced by Southern Hemisphere freshening. This results in a kink in the global transformation rate, which is attributed to the presence of Drake Passage. Further analysis of the control run of the third Hadley Centre global climate model, HadCM3, suggests this feature to be robust and to reflect the “channel” geometry of the Southern Ocean and the “basin” geometry of the Northern Hemisphere.

Corresponding author address: N. Howe, Imperial College, Prince Consort Rd., Huxley Bldg., London SW7 2AZ, United Kingdom. Email: n.howe06@imperial.ac.uk

Save