• Bitz, C. M., M. M. Holland, A. J. Weaver, and M. Eby, 2001: Simulating the ice-thickness distribution in a coupled climate model. J. Geophys. Res., 106 , 24412464.

    • Search Google Scholar
    • Export Citation
  • Bryan, K., and L. Lewis, 1979: A water mass model of the World Ocean. J. Geophys. Res., 84 , 311337.

  • Duffy, P., M. Eby, and A. Weaver, 2001: Climate model simulations of effects of increased atmospheric CO2 and loss of sea ice on ocean salinity and tracer uptake. J. Climate, 14 , 520532.

    • Search Google Scholar
    • Export Citation
  • England, M. H., and S. Rahmstorf, 1999: Sensitivity of ventilation rates and radiocarbon uptake to subgrid scale mixing in ocean models. J. Phys. Oceanogr., 29 , 28022827.

    • 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
  • Gent, P. R., and J. C. McWilliams, 1990: Isopycnal mixing in ocean general circulation models. J. Phys. Oceanogr., 20 , 150155.

  • Kalnay, E., M. Kanamitsu, and R. Kistler, and Coauthors. 1996: The NCEP/NCAR 40-Year Reanalysis Project. Bull. Amer. Meteor. Soc., 77 , 437471.

    • Search Google Scholar
    • Export Citation
  • Keith, D. W., 1995: Meridional energy transport: Uncertainty in zonal means. Tellus, 47A , 3044.

  • Levitus, S., and T. P. Boyer, 1994: Salinity,. Vol. 3, World Ocean Atlas 1994. NOAA Atlas NESDIS 3, 99 pp.

  • McCartney, M. S., 1977: Subantarctic Mode Water. A Voyage of Discovery, M. V. Angel, Ed., Pergamon, 103–119.

  • 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., 1996: MOM 2 Documentation, User's Guide, and Reference Manual. The GFDL Ocean Group Tech. Rep. 3.2, GFDL, 329 pp.

  • Pollard, R. T., J. F. Read, J. T. Allen, G. Griffiths, and A. I. Morrison, 1995: On physical structure of a front in the Bellingshausen Sea. Deep-Sea Res., 42B , 955982.

    • Search Google Scholar
    • Export Citation
  • Read, J. F., R. T. Pollard, A. I. Morrison, and C. Symon, 1995: On the southerly extent of the Antarctic Circumpolar Current in the southeast Pacific. Deep-Sea Res., 42B , 933954.

    • Search Google Scholar
    • Export Citation
  • Saenko, O. A., and A. J. Weaver, 2001: Importance of wind-driven sea ice motion for the formation of Antarctic Intermediate Water. Geophys. Res. Lett., 28 , 41474150.

    • Search Google Scholar
    • Export Citation
  • Saenko, O. A., A. Schmittner, and A. J. Weaver, 2002: On the role of wind-driven sea ice motion on ocean ventilation. J. Phys. Oceanogr., 32 , 33763395.

    • Search Google Scholar
    • Export Citation
  • Sorensen, J. V. T., J. Ribbe, and G. Shaffer, 2001: Antarctic Intermediate Water mass formation in ocean general circulation models. J. Phys. Oceanogr., 31 , 32953311.

    • Search Google Scholar
    • Export Citation
  • Sverdrup, H. U., M. W. Johnson, and R. H. Fleming, 1942: The Oceans: Their Physics, Chemistry and General Biology. Prentice Hall, 1087 pp.

    • Search Google Scholar
    • Export Citation
  • Talley, L. D., 1996: Antarctic Intermediate Water in the South Atlantic. The South Atlantic, G. Wefer et al., Eds., Springer-Verlag, 219–238.

    • Search Google Scholar
    • Export Citation
  • Weaver, A. J., M. Eby, and E. C. Wiebe, and Coauthors. 2001: The UVic Earth System Climate Model: Model description, climatology and application to past, present and future climates. Atmos.–Ocean, 39 , 361428.

    • 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 1 1 1

A Region of Enhanced Northward Antarctic Intermediate Water Transport in a Coupled Climate Model

View More View Less
  • 1 School of Earth and Ocean Sciences, University of Victoria, Victoria, British Columbia, Canada
  • | 2 Centre for Environmental Modelling and Prediction, University of New South Wales, Sydney, New South Wales, Australia
Restricted access

Abstract

A global coupled model is used to examine pathways of freshwater transport in the Southern Ocean. On the background of a strong zonal freshwater transport along the pathway of the Antarctic Circumpolar Current (ACC), there are meridional freshwater flows distributed nonuniformly around the globe, including in the upper ocean. The analysis does not support a simple two-dimensional scheme of Antarctic Intermediate Water (AAIW) formation, according to which the fresh AAIW forms uniformly around the circumpolar ocean. Rather, a more complex three-dimensional picture of the freshwater transport in the Southern Ocean is revealed, with enhanced AAIW formation in the southeast Pacific Ocean both north and south of the Drake Passage latitudes. Freshened by intense precipitation and surface waters from around Antarctica, the ACC transports freshwater from the northwest to the southeast toward Drake Passage. There, a fraction of this freshwater is transported southward across 60°S with the subsurface ACC and the eddy-induced flow. West of the Antarctic Peninsula, the freshwater subducts to intermediate depths and turns northward, following the ACC and contributing to the formation of AAIW. This analysis supports previous results of enhanced subduction localized to the southern tip of South America.

Corresponding author address: Dr. Oleg A. Saenko, School of Earth and Ocean Sciences, University of Victoria, P.O. Box 3055, Victoria, BC V8W 3P6, Canada. Email: oleg@ocean.seos.uvic.ca

Abstract

A global coupled model is used to examine pathways of freshwater transport in the Southern Ocean. On the background of a strong zonal freshwater transport along the pathway of the Antarctic Circumpolar Current (ACC), there are meridional freshwater flows distributed nonuniformly around the globe, including in the upper ocean. The analysis does not support a simple two-dimensional scheme of Antarctic Intermediate Water (AAIW) formation, according to which the fresh AAIW forms uniformly around the circumpolar ocean. Rather, a more complex three-dimensional picture of the freshwater transport in the Southern Ocean is revealed, with enhanced AAIW formation in the southeast Pacific Ocean both north and south of the Drake Passage latitudes. Freshened by intense precipitation and surface waters from around Antarctica, the ACC transports freshwater from the northwest to the southeast toward Drake Passage. There, a fraction of this freshwater is transported southward across 60°S with the subsurface ACC and the eddy-induced flow. West of the Antarctic Peninsula, the freshwater subducts to intermediate depths and turns northward, following the ACC and contributing to the formation of AAIW. This analysis supports previous results of enhanced subduction localized to the southern tip of South America.

Corresponding author address: Dr. Oleg A. Saenko, School of Earth and Ocean Sciences, University of Victoria, P.O. Box 3055, Victoria, BC V8W 3P6, Canada. Email: oleg@ocean.seos.uvic.ca

Save