• Banks, H., , and R. Wood, 2002: Where to look for anthropogenic change in the ocean. J. Climate, 15 , 879891.

  • Beal, L. M., , and H. L. Bryden, 1999: The velocity and vorticity structure of the Agulhas Current at 32°S. J. Geophys. Res, 104 , 51515176.

    • Search Google Scholar
    • Export Citation
  • Bindoff, N. L., , and J. A. Church, 1992: Warming of the water column in the southwest Pacific Ocean. Nature, 357 , 5962.

  • Bindoff, N. L., , and T. J. McDougall, 1994: Diagnosing climate change and ocean ventilation using hydrographic data. J. Phys. Oceanogr, 24 , 11371152.

    • Search Google Scholar
    • Export Citation
  • Broecker, W. S., , S. Sutherland, , and T-H. Peng, 1999: A possible 20th-century slowdown of Southern Ocean deep water formation. Science, 286 , 11321135.

    • Search Google Scholar
    • Export Citation
  • Bryan, K., 1969: A numerical method for the study of the circulation of the World Ocean. J. Comput. Phys, 3 , 347376.

  • Bryan, K., , and L. J. Lewis, 1979: A water mass model of the World Ocean. J. Geophys. Res, 84 , 25032517.

  • Burroughs, W. J., 1992: Weather Cycles: Real or Imaginary? Cambridge University Press, Cambridge, 99 pp.

  • Cai, W., , P. H. Whetton, , and D. J. Karoly, 2003: The response of the Antarctic Oscillation to increasing and stabilized atmospheric CO2. J. Climate, 16 , 15251538.

    • Search Google Scholar
    • Export Citation
  • Carleton, A. M., 2003: Atmospheric teleconnections involving the Southern Ocean. J. Geophys. Res.,108, 8080, doi:10.1029/ 2000JC000379.

  • Chelton, D. B., , M. G. Schlax, , D. L. Witter, , and J. G. Richman, 1990: Geostat altimeter observations of sea surface circulation of the southern ocean. J. Geophys. Res, 95 , 1787717903.

    • Search Google Scholar
    • Export Citation
  • Clarke, R. A., 1984: Transport through the Cape Farewell–Flemish Cap section. Rapp. V. P. Reun. Cons. Int. Explor, 185 , 120130.

  • Cox, M. D., 1984: A primitive equation, three-dimensional model of the ocean. GFDL Ocean Group Tech. Rep. 1, 143 pp.

  • Danabasoglu, G., , and J. C. McWilliams, 1995: Sensitivity of the global ocean circulation to parameterizations of mesoscale tracer transports. J. Climate, 8 , 29672987.

    • Search Google Scholar
    • Export Citation
  • Danabasoglu, G., , J. C. McWilliams, , and P. R. Gent, 1994: The role of mesoscale tracer transports in the global ocean circulation. Science, 264 , 11231126.

    • Search Google Scholar
    • Export Citation
  • Das, S. C., 1956: Statistical analysis of Australian pressure data. Aust. J. Phys, 9 , 394399.

  • England, M. H., 1992: On the formation of Antarctic Intermediate and Bottom Water in ocean general circulation models. J. Phys. Oceanogr, 22 , 918926.

    • Search Google Scholar
    • Export Citation
  • England, M. H., 1993: Representing the global-scale water masses in ocean general circulation models. J. Phys. Oceanogr, 23 , 15231552.

    • Search Google Scholar
    • Export Citation
  • England, M. H., 1995: The age of water and ventilation timescales in a global ocean model. J. Phys. Oceanogr, 25 , 27562777.

  • England, M. H., , and V. C. Garcon, 1994: South Atlantic circulation in a world ocean model. Ann. Geophys, 12 , 812825.

  • England, M. H., , and A. C. Hirst, 1997: Chlorofluorocarbon uptake in a World Ocean model, 2. Sensitivity to surface thermohaline forcing and subsurface mixing parameterization. J. Geophys. Res, 102 , 1570915731.

    • Search Google Scholar
    • Export Citation
  • England, M. H., , J. S. Godfrey, , A. C. Hirst, , and M. Tomczak, 1993: The mechanism for Antarctic Intermediate Water renewal in a World Ocean model. J. Phys. Oceanogr, 23 , 15531560.

    • Search Google Scholar
    • Export Citation
  • Fieux, M., , R. Molcard, , and A. G. Ilahude, 1996: Geostrophic transport of the Pacific–Indian Oceans throughflow. J. Geophys. Res, 101 , 1242112432.

    • Search Google Scholar
    • Export Citation
  • Fyfe, J. C., 2003: Separating extratropical zonal wind variability and mean change. J. Climate, 16 , 863874.

  • Fyfe, J. C., , G. J. Boer, , and G. M. Flato, 1999: The Arctic and Antarctic Oscillations and their projected changes under global warming. Geophys. Res. Lett, 26 , 16011604.

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

  • Gent, P. R., , J. Willebrand, , T. J. McDougall, , and J. C. McWilliams, 1995: Parameterizing eddy-induced tracer transports in ocean circulation models. J. Phys. Oceanogr, 25 , 463474.

    • Search Google Scholar
    • Export Citation
  • Gille, S. T., 2002: Warming of the Southern Ocean since the 1950s. Science, 295 , 12751277.

  • Gnanadesikan, A., , and R. W. Hallberg, 2000: On the relationship of the Circumpolar Current to Southern Hemisphere winds in coarse-resolution ocean models. J. Phys. Oceanogr, 30 , 20132034.

    • Search Google Scholar
    • Export Citation
  • Hall, A., , and M. Visbeck, 2002: Synchronous variability in the Southern Hemisphere atmosphere, sea ice, and ocean resulting from the Annular Mode. J. Climate, 15 , 30433057.

    • Search Google Scholar
    • Export Citation
  • Harris, G. P., , P. Davies, , M. Nunez, , and G. Meyers, 1988: Interannual variability in climate and fisheries in Tasmania, Australia. Nature, 333 , 754757.

    • Search Google Scholar
    • Export Citation
  • Hartmann, D. L., , and F. Lo, 1998: Wave-driven zonal flow vacillation in the Southern Hemisphere. J. Atmos. Sci, 55 , 13031315.

  • Hartmann, D. L., , J. M. Wallace, , V. Limpasuvan, , D. W. J. Thompson, , and J. R. Holton, 2000: Can ozone depletion and greenhouse warming interact to produce rapid climate change? Proc. Natl. Acad. Sci. USA, 97 , 14121417.

    • Search Google Scholar
    • Export Citation
  • Hellerman, S., , and M. Rosenstein, 1983: Normal monthly wind stress over the world ocean with error estimates. J. Phys. Oceanogr, 13 , 10931104.

    • Search Google Scholar
    • Export Citation
  • Hirst, A. C., , and T. J. McDougall, 1996: Deep water properties and surface flux as simulated by a Cartesian model including eddy- induced advection. J. Phys. Oceanogr, 26 , 13201343.

    • Search Google Scholar
    • Export Citation
  • Jones, J. M., , and M. Widmann, 2003: Instrument- and tree-ring-based estimates of the Antarctic Oscillation. J. Climate, 16 , 35113524.

    • Search Google Scholar
    • Export Citation
  • Kalnay, E., and Coauthors, 1996: The NCEP/NCAR 40-Year Reanalysis Project. Bull. Amer. Meteor. Soc, 77 , 437471.

  • Kushner, P. J., , I. M. Held, , and T. L. Delworth, 2001: Southern Hemisphere atmospheric circulation response to global warming. J. Climate, 14 , 22382249.

    • Search Google Scholar
    • Export Citation
  • Levitus, S., 1982: Climatological Atlas of the World. NOAA Prof. Paper 13, 173 pp. and 17microfiche.

  • Levitus, S., , J. I. Antonov, , T. P. Boyer, , and C. Stephens, 2000: Warming of the world oceans. Science, 287 , 22252229.

  • Limpasuvan, V., , and D. L. Hartmann, 1999: Eddies and the annular modes of climate variability. Geophys. Res. Lett, 26 , 31333136.

  • Maamaatuaiahutapu, K., , V. Garcon, , C. Provost, , and H. Mercier, 1998: Transports of the Brazil and Malvinas Currents at their confluence. J. Mar. Res, 56 , 417438.

    • Search Google Scholar
    • Export Citation
  • Mata, M. M., , M. Tomczak, , S. Wijffels, , and J. Church, 2000: East Australian current volume transports at 30°S: Estimates from the WOCE hydrographic section PR11/P6 and PCM3 current meter array. J. Geophys. Res, 105 , 2850928526.

    • Search Google Scholar
    • Export Citation
  • McCartney, M. S., 1977: Subantarctic Mode Water. A Voyage of Discovery, George Deacon 70th Anniversary Volume, M. Angel, Ed., Pergamon Press, 103–119.

    • Search Google Scholar
    • Export Citation
  • McDermott, D., 1996: The regulation of Northern Hemisphere overturning by Southern Hemisphere winds. J. Phys. Oceanogr, 26 , 12341255.

    • Search Google Scholar
    • Export Citation
  • McDougall, T. J., , and J. A. Church, 1986: Pitfalls with the numerical representation of isopycnal and diapycnal mixing. J. Phys. Oceanogr, 16 , 196199.

    • Search Google Scholar
    • Export Citation
  • Meadows, A. J., 1975: A hundred years of controversy over sunspots and weather. Nature, 256 , 9597.

  • Nof, D., 2000: Does the wind control the import and export of the South Atlantic? J. Phys. Oceanogr, 30 , 26502667.

  • 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, 42 , 641673.

    • Search Google Scholar
    • Export Citation
  • Orsi, A. H., , G. C. Johnson, , and J. L. Bullister, 1999: Circulation, mixing and production of Antarctic Bottom Water. Progress in Oceanography, Vol. 43, Pergamon, 55–109.

    • Search Google Scholar
    • Export Citation
  • Pacanowski, R. C., 1995: MOM2 documentation user's guide and reference manual. GFDL Ocean Group Tech. Rep. 3, 232 pp.

  • Rahmstorf, S., , and M. H. England, 1997: Influence of Southern Hemisphere winds on North Atlantic Deep Water flow. J. Phys. Oceanogr, 27 , 20402054.

    • Search Google Scholar
    • Export Citation
  • Redi, M. H., 1982: Oceanic isopycnal mixing by coordinate rotation. J. Phys. Oceanogr, 12 , 11541158.

  • Ribbe, J., 1999: On wind-driven mid-latitude convection in ocean general circulation models. Tellus, 51A , 517525.

  • Rintoul, S. R., , and M. H. England, 2002: Ekman transport dominates local air–sea fluxes in driving variability of subantarctic mode water. J. Phys. Oceanogr, 32 , 13081321.

    • Search Google Scholar
    • Export Citation
  • Robitaille, D. Y., , and A. J. Weaver, 1995: Validation of sub-grid scale mixing schemes using CFCs in a global ocean model. Geophys. Res. Lett, 22 , 29172920.

    • Search Google Scholar
    • Export Citation
  • Rogers, J. R., , and H. van Loon, 1982: Spatial variability of SLP and 500 mb height anomalies over the Southern Hemisphere. Mon. Wea. Rev, 110 , 13751392.

    • Search Google Scholar
    • Export Citation
  • Smethie, W. M., , and R. A. Fine, 2001: Rates of North Atlantic Deep Water formation from chlorofluorocarbon inventories. Deep-Sea Res, 48 , 189215.

    • Search Google Scholar
    • Export Citation
  • Smith, S. R., , and C. R. Stearns, 1993: Antarctic climate anomalies surrounding the minimum in the Southern Oscillation Index. Antarctic Meteorology and Climatology: Studies Based on Automatic Weather Stations, D. H. Bromwich and C. R. Stearns, Eds., Antarctic Research Series, Vol. 61, Amer. Geophys. Union, 149–174.

    • Search Google Scholar
    • Export Citation
  • Smith, W. H. F., , and D. T. Sandwell, 1997: Global seafloor topography from satellite altimetry and ship depth soundings. Science, 277 , 19571962.

    • Search Google Scholar
    • Export Citation
  • Stommel, H., 1957: A survey of ocean current theory. Deep-Sea Res, 4 , 149184.

  • Stommel, H., 1979: Determination of water-mass properties of water pumped down from the Ekman layers to the geostrophic flow below. Proc. Natl. Acad. Sci. USA, 76 , 30513055.

    • Search Google Scholar
    • Export Citation
  • Thompson, D. W. J., , and S. Solomon, 2002: Interpretation of recent Southern Hemisphere climate change. Science, 296 , 895899.

  • Thompson, D. W. J., , J. M. Wallace, , and G. C. Hegerl, 2000: Annular modes in the extratropical circulation. Part II: Trends. J. Climate, 13 , 10181036.

    • Search Google Scholar
    • Export Citation
  • Thresher, R. E., 2002: Solar correlates of Southern Hemisphere mid- latitude climate variability. Int. J. Climate, 22 , 901915.

  • Toggweiler, J. R., , and B. Samuels, 1993: Is the magnitude of the deep outflow from the Atlantic Ocean actually governed by Southern Hemisphere winds? The Global Carbon Cycle, M. Heimann, Ed., Springer, 303–331.

    • Search Google Scholar
    • Export Citation
  • Toggweiler, J. R., , and B. Samuels, 1995: Effect of Drake Passage on the global thermohaline circulation. Deep-Sea Res, 42 , 477500.

  • van Loon, H., , and K. Labitzke, 1998: The global range of the stratospheric decadal wave. Part I: Its association with the sunspot cycle in summer and in the annual mean, and with the troposphere. J. Climate, 11 , 15291537.

    • Search Google Scholar
    • Export Citation
  • Watterson, I. G., 2000: Southern midlatitude zonal wind vacillation and its interaction with the ocean in GCM simulations. J. Climate, 13 , 562578.

    • Search Google Scholar
    • Export Citation
  • Whetton, P., , M. H. England, , S. P. O'Farell, , I. G. Watterson, , and A. B. Pittock, 1996: Global comparison of the regional rainfall results of enhanced greenhouse coupled and mixed layer ocean experiments: Implications for climate change scenario development. Climatic Change, 33 , 497519.

    • Search Google Scholar
    • Export Citation
  • White, W. B., , and R. G. Peterson, 1996: An Antarctic circumpolar wave in surface pressure, temperature and sea-ice extent. Nature, 380 , 699702.

    • Search Google Scholar
    • Export Citation
  • Whitworth III, T., 1983: Monitoring the transport of the Antarctic Circumpolar Current at the Drake Passage. J. Phys. Oceanogr, 13 , 20452057.

    • Search Google Scholar
    • Export Citation
  • Whitworth III, T., , W. D. Nowlin, , and S. J. Worley, 1982: The net transport of the Antarctic Circumpolar Current through the Drake Passage. J. Phys. Oceanogr, 12 , 960971.

    • Search Google Scholar
    • Export Citation
  • Wong, A. P. S., , N. L. Bindoff, , and J. A. Church, 1999: Large-scale freshening of intermediate waters in the Pacific and Indian Oceans. Nature, 400 , 440443.

    • Search Google Scholar
    • Export Citation
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Oceanic Response to Changes in the Latitude of the Southern Hemisphere Subpolar Westerly Winds

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  • 1 Centre for Environmental Modelling and Prediction, School of Mathematics, University of New South Wales, Sydney, Australia
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Abstract

The oceanic response to imposed changes in the latitude of the subpolar westerly winds (SWWs) over the Southern Ocean is assessed in a global ocean model. The latitude changes are achieved by applying a zonally uniform zonal wind stress anomaly that is quasi-sinusoidal in latitude, with a positive (negative) band to the south (north) of about 50°S. This form of anomaly is chosen because it projects onto the Antarctic Oscillation, also known as the Southern Hemisphere annular mode, that is known to have a long-term trend. The response to both long-term trend and quasi-decadal periodic changes is examined in the latitude of the SWWs. In the long-term trend case, a 5.4° poleward shift of the SWWs over a 100-yr simulation is found to cause the poleward heat transport to increase by an average of 25% between 50°S and the equator. This change is primarily due to greater northward Ekman transport of cold water and its associated cooling of Subantarctic Mode Water (SAMW) by up to 0.5°C in the central-south Pacific. The authors also find that the rate of formation of Antarctic Intermediate Water increases as the SWWs shift poleward, resulting in cooling and freshening at intermediate depths. In the periodic experiment, where the SWWs axis has a range of 5.4° latitude, the poleward heat transport, North Atlantic Deep Water outflow and the overturning of Antarctic Bottom Water are all modulated by 20%–30%. Significant cooling is found at intermediate and upper-level water depths in the trend experiment and temperature fluctuations with a range of up to 0.4°C in the periodic experiment. These changes are of the same magnitude and form as that recently observed at intermediate depths in the Southern Ocean. The authors conclude that latitudinal shifts of the SWWs may play a significant role in generating observed temperature fluctuations at intermediate water depths.

Current affiliation: CSIRO Marine Research, Hobart, Tasmania, Australia

Corresponding author address: Dr. Peter R. Oke, CSIRO Marine Research, GPO Box 1538, Castray Esplanade, Hobart TAS 7001 Australia. Email: peter.oke@csiro.au

Abstract

The oceanic response to imposed changes in the latitude of the subpolar westerly winds (SWWs) over the Southern Ocean is assessed in a global ocean model. The latitude changes are achieved by applying a zonally uniform zonal wind stress anomaly that is quasi-sinusoidal in latitude, with a positive (negative) band to the south (north) of about 50°S. This form of anomaly is chosen because it projects onto the Antarctic Oscillation, also known as the Southern Hemisphere annular mode, that is known to have a long-term trend. The response to both long-term trend and quasi-decadal periodic changes is examined in the latitude of the SWWs. In the long-term trend case, a 5.4° poleward shift of the SWWs over a 100-yr simulation is found to cause the poleward heat transport to increase by an average of 25% between 50°S and the equator. This change is primarily due to greater northward Ekman transport of cold water and its associated cooling of Subantarctic Mode Water (SAMW) by up to 0.5°C in the central-south Pacific. The authors also find that the rate of formation of Antarctic Intermediate Water increases as the SWWs shift poleward, resulting in cooling and freshening at intermediate depths. In the periodic experiment, where the SWWs axis has a range of 5.4° latitude, the poleward heat transport, North Atlantic Deep Water outflow and the overturning of Antarctic Bottom Water are all modulated by 20%–30%. Significant cooling is found at intermediate and upper-level water depths in the trend experiment and temperature fluctuations with a range of up to 0.4°C in the periodic experiment. These changes are of the same magnitude and form as that recently observed at intermediate depths in the Southern Ocean. The authors conclude that latitudinal shifts of the SWWs may play a significant role in generating observed temperature fluctuations at intermediate water depths.

Current affiliation: CSIRO Marine Research, Hobart, Tasmania, Australia

Corresponding author address: Dr. Peter R. Oke, CSIRO Marine Research, GPO Box 1538, Castray Esplanade, Hobart TAS 7001 Australia. Email: peter.oke@csiro.au

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