• Baker, D. J., 1982: A note on Sverdrup balance in the Southern Ocean. J. Mar. Res.,40 (Suppl), 21–26.

  • Bryan, F., 1987: Parameter sensitivity of a primitive equation ocean general circulation model. J. Phys. Oceanogr.,17, 970–985.

  • Bryan, K., and L. J. Lewis, 1979: A water mass model of the world ocean. J. Geophys. Res.,84, 2503–2517.

  • Charney, J. G., and J. G. DeVore, 1979: Multiple flow equilibria in the atmosphere and blocking. J. Atmos. Sci.,36, 1205–1216.

  • Danabasoglu, G., and J. McWilliams, 1995: Sensitivity of the global ocean circulation to parameterizations of mesoscale tracer transports. J. Climate,8, 2967–2987.

  • Gent, P. R., W. G. Large, and F. O. Bryan, 2000: What sets the mean transport through Drake Passage? J. Geophys. Res., in press.

  • Gill, A. E., and K. Bryan, 1971: Effects of geometry on the circulation of a three-dimensional Southern Hemisphere ocean model. Deep-Sea Res.,18, 685–721.

  • Gille, S. T., 1997: The Southern Ocean momentum balance: Evidence for topographic effects from numerical model output and altimeter data. J. Phys. Oceanogr.,27, 2219–2232.

  • ——, and K. A. Kelly, 1996: Scales of spatial and temporal variability in the Southern Ocean. J. Geophys. Res.,101, 8759–8773.

  • Gnanadesikan, A., 1999: A simple predictive model for the structure of the oceanic pycnocline. Science,283, 2077–2079.

  • Hallberg, R., 1995: Some aspects of the circulation in ocean basins with isopycnal intersecting the sloping boundaries. Ph.D. dissertation, University of Washington, 244 pp.

  • ——, 1997: Localized coupling between surface and bottom-intensified flows over topography. J. Phys. Oceanogr.,27, 977–998.

  • Hellerman, S., and M. Rosenstein, 1983: Normal monthly wind stress over the world ocean with error estimates. J. Phys. Oceanogr.,13, 1093–1104.

  • Hughes, C. W., 1997: Comments on “On the obscurantist physics of form drag in theorizing about the Circumpolar Current.” J. Phys. Oceanogr.,27, 209–210.

  • Hughes, T. M. C., and A. J. Weaver, 1994: Multiple equilibria of an asymmetric two-basin model. J. Phys. Oceanogr.,24, 619–637.

  • Johnson, G. C., and H. Bryden 1989: On the strength of the Circumpolar Current. Deep-Sea Res.,36, 39–53.

  • Kalnay, E., and Coauthors, 1996: The NCEP/NCAR 40-Year Reanalysis Project. Bull. Amer. Meteor. Soc.,77, 437–471.

  • Kawase, M., 1987: Establishment of deep ocean circulation driven by deep-water production. J. Phys. Oceanogr.,17, 2294–2317.

  • Killworth, P. D., and M. M. Nanneh, 1994: Isopycnal momentum budget of the Antarctic Circumpolar Current in the Fine Resolution Antarctic Model. J. Phys. Oceanogr.,24, 1203–1224.

  • Krupitsky, A., and M. A. Cane, 1994: On topographic pressure drag in a zonal channel. J. Mar. Res.,52, 1–22.

  • ——, V. M. Kamenkovich, N. Naik, and M. A. Cane, 1996: A linear equivalent barotropic model of the Antarctic Circumpolar Current with realistic coastlines and bottom topography. J. Phys. Oceanogr.,26, 1803–1824.

  • Marshall, J., D. Olbers, H. Ross, and D. Wolf-Gladrow, 1993: Potential vorticity constraints on the dynamics and hydrography of the Southern Ocean. J. Phys. Oceanogr.,23, 465–487.

  • McDermott, D., 1996: The regulation of Northern Hemisphere overturning by Southern Hemisphere winds. J. Phys. Oceanogr.,26, 1234–1255.

  • Mestaz-Nunez, A. M., D. B. Chelton, and R. A. DeSzoeke, 1992: Evidence of time-dependent Sverdrup circulation in the South Pacific from the Seasat scatterometer and altimeter. J. Phys. Oceanogr.,22, 934–943.

  • Munk, W., and A. Palmen, 1951: Note on the dynamics of the Antarctic Circumpolar Current. Tellus,3, 53–55.

  • Olbers, D., 1998: Comments on “On the obscurantist physics of ‘form drag’ in theorizing about the Circumpolar Current.” J. Phys. Oceanogr.,28, 1647–1654.

  • ——, and C. Völker, 1996: Steady states and variability in oceanic zonal flows. Decadal Climate Variability, D. L. T. Anderson and J. Willebrand, Eds., NATO ASI Ser. I, Vol. 44, Springer-Verlag, 407–433.

  • Orsi, A. H., T. Whitworth III, and W. D. Nowlin, 1995: On the meridional extent and fronts of the Antarctic Circumpolar Current. Deep-Sea Res. I,42, 641–673.

  • Pacanowski, R. C., 1996: MOM 2 documentation, user’s guide and reference manual. GFDL Ocean Tech. Rep. 3.1, Geophysical Fluid Dynamics Laboratory, NOAA, 329 pp. [Available from GFDL, P.O. Box 308, Princeton, NJ 08542.].

  • Park, Y. G., and K. Bryan, 2000: Comparison of thermally driven circulations from a depth-coordinate model and an isopycnal layer model. Part I: A scaling-law sensitivity to vertical diffusivity. J. Phys. Oceanogr.,30, 590–605.

  • Saunders, P., and S. R. Thompson, 1993: Transport, heat and freshwater fluxes within a diagnostic numerical model (FRAM). J. Phys. Oceanogr.,23, 452–464.

  • Stevens, D. P., and V. O. Ivchenko, 1997: The zonal momentum balance in an eddy-resolving general circulation model of the Southern Ocean. Quart. J. Roy. Meteor. Soc.,123, 929–951.

  • Stommel, H., 1957: A survey of ocean current theory. Deep-Sea Res.,4, 149–184.

  • ——, 1961: Thermohaline convection with two stable regimes of flow. Tellus,13, 224–230.

  • Straub, D., 1993: On the transport and angular momentum balance of channel models of the Antarctic Circumpolar Current. J. Phys. Oceanogr.,23, 776–782.

  • Sverdrup, H. U., M. W. Johnson, and R. H. Fleming, 1942: The Oceans: Their Physics, Chemistry and Biology. Prentice-Hall, 620 pp.

  • Thompson, S. R., 1993: Estimation of the transport of heat in the Southern Ocean using a fine-resolution numerical model. J. Phys. Oceanogr.,23, 2493–2497.

  • Toggweiler, J. R., and B. Samuels, 1993: New radiocarbon constraints on the upwelling of abyssal water to the ocean’s surface. The Global Carbon Cycle, M. Heimann, Ed., Springer-Verlag, 333–365.

  • ——, and ——, 1995: Effect of Drake Passage on the global thermohaline circulation. Deep-Sea Res.,42, 477–500.

  • ——, and ——, 1998: On the ocean’s large-scale circulation near the limit of no vertical mixing. J Phys. Oceanogr.,28, 1832–1852.

  • Völker, C., 1999: Momentum balance in zonal flows and resonance of baroclinic Rossby waves. J. Phys. Oceanogr.,29, 1666–1681.

  • Wang, L., 1994: A linear homogeneous channel model for topographic control of the Antarctic Circumpolar Current. J. Mar. Res.,52, 649–685.

  • ——, and R. X. Huang, 1995: A linear homogeneous model of wind-driven circulation in a β-plane channel. J. Phys. Oceanogr.,25, 587–603.

  • Warren, B., 1990: Suppression of deep oxygen concentrations by Drake Passage. Deep-Sea Res.,37, 1899–1907.

  • ——, J. LaCasce, and P. A. Robbins, 1996: On the obscurantist physics of “form drag” in theorizing about the Circumpolar Current. J. Phys. Oceanogr.,26, 2297–2301.

  • Wells, N. C, and B. A. DeCuevas, 1995: Depth-integrated vorticity budget of the Southern Ocean from a general circulation model. J. Phys. Oceanogr.,25, 2569–2582.

  • Whitworth, T., III, 1983: Monitoring the transport of the Antarctic Circumpolar Current at Drake Passage. J. Phys. Oceanogr.,13, 2045–2057.

  • ——, W. D. Nowlin, and S. J. Worley, 1982: The net transport of the Antarctic Circumpolar Current through Drake Passage. J. Phys. Oceanogr.,12, 960–971.

  • Wright, D. G., T. F. Stocker, and D. Mercer, 1998: Closures used in zonally averaged ocean models. J. Phys. Oceanogr.,28, 791–804.

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On the Relationship of the Circumpolar Current to Southern Hemisphere Winds in Coarse-Resolution Ocean Models

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  • 1 Atmospheric and Oceanic Sciences Program, Princeton University, Princeton, New Jersey
  • | 2 NOAA/Geophysical Fluid Dynamics Laboratory, Princeton, New Jersey
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Abstract

The response of the Circumpolar Current to changing winds has been the subject of much debate. To date most theories of the current have tried to predict the transport using various forms of momentum balance. This paper argues that it is also important to consider thermodynamic as well as dynamic balances. Within large-scale general circulation models, increasing eastward winds within the Southern Ocean drive a northward Ekman flux of light water, which in turn produces a deeper pycnocline and warmer deep water to the north of the Southern Ocean. This in turn results in much larger thermal wind shear across the Circumpolar Current, which, given relatively small near-bottom velocities, results in an increase in Antarctic Circumpolar Current (ACC) transport. The Ekman flux near the surface is closed by a deep return flow below the depths of the ridges. A simple model that illustrates this picture is presented in which the ACC depends most strongly on the winds at the northern and southern edges of the channel. The sensitivity of this result to the formulation of buoyancy forcing is illustrated using a second simple model. A number of global general circulation model runs are then presented with different wind stress patterns in the Southern Ocean. Within these runs, neither the mean wind stress in the latitudes of Drake Passage nor the wind stress curl at the northern edge of Drake Passage produces a prediction for the transport of the ACC. However, increasing the wind stress within the Southern Ocean does increase the ACC transport.

Corresponding author address: Dr. Anand Gnanadesikan, NOAA/GFDL and AOS Program, Princeton University, 302 Sayre Hall, Post Office Box CN710, Princeton, NJ 08544-0710.

Email: gnana@princeton.edu

Abstract

The response of the Circumpolar Current to changing winds has been the subject of much debate. To date most theories of the current have tried to predict the transport using various forms of momentum balance. This paper argues that it is also important to consider thermodynamic as well as dynamic balances. Within large-scale general circulation models, increasing eastward winds within the Southern Ocean drive a northward Ekman flux of light water, which in turn produces a deeper pycnocline and warmer deep water to the north of the Southern Ocean. This in turn results in much larger thermal wind shear across the Circumpolar Current, which, given relatively small near-bottom velocities, results in an increase in Antarctic Circumpolar Current (ACC) transport. The Ekman flux near the surface is closed by a deep return flow below the depths of the ridges. A simple model that illustrates this picture is presented in which the ACC depends most strongly on the winds at the northern and southern edges of the channel. The sensitivity of this result to the formulation of buoyancy forcing is illustrated using a second simple model. A number of global general circulation model runs are then presented with different wind stress patterns in the Southern Ocean. Within these runs, neither the mean wind stress in the latitudes of Drake Passage nor the wind stress curl at the northern edge of Drake Passage produces a prediction for the transport of the ACC. However, increasing the wind stress within the Southern Ocean does increase the ACC transport.

Corresponding author address: Dr. Anand Gnanadesikan, NOAA/GFDL and AOS Program, Princeton University, 302 Sayre Hall, Post Office Box CN710, Princeton, NJ 08544-0710.

Email: gnana@princeton.edu

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