• Allison, L. C., 2009: Spin-up and adjustment of the Antarctic Circumpolar Current and global pycnocline. Ph.D. thesis, University of Reading, 207 pp.

  • Biastoch, A., and C. W. Böning, 2013: Anthropogenic impact on Agulhas leakage. Geophys. Res. Lett., 40, 11381143, https://doi.org/10.1002/grl.50243.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Biastoch, A., C. W. Böning, F. U. Schwarzkopf, and J. Lutjeharms, 2009: Increase in Agulhas leakage due to poleward shift of Southern Hemisphere westerlies. Nature, 462, 495498, https://doi.org/10.1038/nature08519.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Boccaletti, G., R. Ferrari, A. Adcroft, D. Ferreira, and J. Marshall, 2005: The vertical structure of ocean heat transport. Geophys. Res. Lett., 32, L10603, https://doi.org/10.1029/2005GL022474.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Cessi, P., and C. S. Jones, 2017: Warm-route versus cold-route interbasin exchange in the meridional overturning circulation. J. Phys. Oceanogr., 47, 19811997, https://doi.org/10.1175/JPO-D-16-0249.1.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Childress, S., and A. D. Gilbert, 2008: Magnetic structure in steady integrable flows. Stretch, Twist, Fold: The Fast Dynamo, Springer Science & Business Media, 124–127.

  • Danabasoglu, G., and J. C. McWilliams, 1995: Sensitivity of the global ocean circulation to parameterizations of mesoscale tracer transports. J. Climate, 8, 29672987, https://doi.org/10.1175/1520-0442(1995)008<2967:SOTGOC>2.0.CO;2.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Ferrari, R., S. M. Griffies, A. J. G. Nurser, and G. K. Vallis, 2010: A boundary-value problem for the parameterized mesoscale eddy transport. Ocean Modell., 32, 143156, https://doi.org/10.1016/j.ocemod.2010.01.004.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Garzoli, S. L., M. O. Baringer, S. Dong, R. C. Perez, and Q. Yao, 2013: South Atlantic meridional fluxes. Deep-Sea Res. I, 71, 2132, https://doi.org/10.1016/j.dsr.2012.09.003.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Gent, P. R., and J. C. McWilliams, 1990: Isopycnal mixing in ocean circulation models. J. Phys. Oceanogr., 20, 150155, https://doi.org/10.1175/1520-0485(1990)020<0150:IMIOCM>2.0.CO;2.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Gordon, A. L., 1985: Indian-Atlantic transfer of thermocline water at the Agulhas retroflection. Science, 227, 10301034, https://doi.org/10.1126/science.227.4690.1030.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Gordon, A. L., 1986: Interocean exchange of thermocline water. J. Geophys. Res., 91, 50375046, https://doi.org/10.1029/JC091iC04p05037.

  • Jones, C. S., and P. Cessi, 2016: Interbasin transport of the meridional overturning circulation. J. Phys. Oceanogr., 46, 11571169, https://doi.org/10.1175/JPO-D-15-0197.1.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Jones, C. S., and P. Cessi, 2017: Size matters: Another reason why the Atlantic is saltier than the Pacific. J. Phys. Oceanogr., 47, 28432859, https://doi.org/10.1175/JPO-D-17-0075.1.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Lumpkin, R., and K. Speer, 2007: Global ocean meridional overturning. J. Phys. Oceanogr., 37, 25502562, https://doi.org/10.1175/JPO3130.1.

  • Marshall, J., A. Adcroft, C. Hill, L. Perelman, and C. Heisey, 1997a: A finite-volume, incompressible Navier Stokes model for studies of the ocean on parallel computers. J. Geophys. Res., 102, 57535766, https://doi.org/10.1029/96JC02775.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Marshall, J., C. Hill, L. Perelman, and A. Adcroft, 1997b: Hydrostatic, quasi-hydrostatic, and nonhydrostatic ocean modeling. J. Geophys. Res., 102, 57335752, https://doi.org/10.1029/96JC02776.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Nilsson, J., P. L. Langen, D. Ferreira, and J. Marshall, 2013: Ocean basin geometry and the salinification of the Atlantic Ocean. J. Climate, 26, 61636184, https://doi.org/10.1175/JCLI-D-12-00358.1.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Rahmstorf, S., 1996: On the freshwater forcing and transport of the Atlantic thermohaline circulation. Climate Dyn., 12, 799811, https://doi.org/10.1007/s003820050144.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Redi, M. H., 1982: Oceanic isopycnal mixing by coordinate rotation. J. Phys. Oceanogr., 12, 11541158, https://doi.org/10.1175/1520-0485(1982)012<1154:OIMBCR>2.0.CO;2.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Reid, J. L., 1961: On the temperature, salinity, and density differences between the Atlantic and Pacific Oceans in the upper kilometre. Deep-Sea Res., 7, 265275, https://doi.org/10.1016/0146-6313(61)90044-2.

    • Search Google Scholar
    • Export Citation
  • Ridgway, K. R., and J. R. Dunn, 2007: Observational evidence for a Southern Hemisphere oceanic supergyre. Geophys. Res. Lett., 34, L13612, https://doi.org/10.1029/2007GL030392.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Rintoul, S. R., 1991: South Atlantic interbasin exchange. J. Geophys. Res. Oceans, 96, 26752692, https://doi.org/10.1029/90JC02422.

  • Speich, S., B. Blanke, and G. Madec, 2001: Warm and cold water routes of an O.G.C.M. thermohaline conveyor belt. Geophys. Res. Lett., 28, 311314, https://doi.org/10.1029/2000GL011748.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Speich, S., B. Blanke, P. de Vries, S. Drijfhout, K. Döös, A. Ganachaud, and R. Marsh, 2002: Tasman leakage: A new route in the global ocean conveyor belt. Geophys. Res. Lett., 29, 1416, https://doi.org/10.1029/2001GL014586.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • van Sebille, E., A. Biastoch, P. J. van Leeuwen, and W. P. M. de Ruijter, 2009: A weaker Agulhas Current leads to more Agulhas leakage. Geophys. Res. Lett., 36, L03601, https://doi.org/10.1029/2008GL036614.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Wolfe, C. L., and P. Cessi, 2015: Multiple regimes and low-frequency variability in the quasi-adiabatic overturning circulation. J. Phys. Oceanogr., 45, 16901708, https://doi.org/10.1175/JPO-D-14-0095.1.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Young, W. R., 2012: An exact thickness-weighted average formulation of the Boussinesq equations. J. Phys. Oceanogr., 42, 692707, https://doi.org/10.1175/JPO-D-11-0102.1.

    • Crossref
    • Search Google Scholar
    • Export Citation
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Components of Upper-Ocean Salt Transport by the Gyres and the Meridional Overturning Circulation

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  • 1 Lamont Doherty Earth Observatory, Columbia University, Palisades, New York
  • | 2 Scripps Institution of Oceanography, University of California, San Diego, San Diego, California
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Abstract

The salt transport by the wind-driven gyres and the meridional overturning circulation (MOC) is studied in an idealized-geometry primitive equation ocean model. Two narrow continents, running along meridians, divide the model domain into two basins of different widths connected by a re-entrant channel south of 52.5°S. One of the continents, representing the Americas, is longer than the other, representing Europe/Africa. Two different configurations of the model are used: the “standard” one, in which the short continent is west of the wide basin, and the “exchanged” one, in which the short continent is west of the narrow basin. In both cases, deep water is formed in the basin to the west of the short continent. Most residual transport of the MOC’s upper branch enters this basin by flowing along open streamlines that pass westward south of the short continent before proceeding northward. The meridional salt transport in the upper ocean of the sinking basin is decomposed into two portions: transport along open streamlines and transport by closed streamlines (gyres). In the Northern Hemisphere of the basin in which deep water is formed, the total northward salt transport per unit width along open streamlines is larger in the standard configuration than in the exchanged configuration. This larger salt transport is caused by two factors: a larger northward advection of salt by the interbasin transport and a larger cross-streamline salt transport out of the subpolar gyre. It is concluded that increasing interbasin flow south of Africa would likely bring more salt into the Atlantic Ocean.

© 2018 American Meteorological Society. For information regarding reuse of this content and general copyright information, consult the AMS Copyright Policy (www.ametsoc.org/PUBSReuseLicenses).

Corresponding author: C. S. Jones, spencerj@ldeo.columbia.edu

Abstract

The salt transport by the wind-driven gyres and the meridional overturning circulation (MOC) is studied in an idealized-geometry primitive equation ocean model. Two narrow continents, running along meridians, divide the model domain into two basins of different widths connected by a re-entrant channel south of 52.5°S. One of the continents, representing the Americas, is longer than the other, representing Europe/Africa. Two different configurations of the model are used: the “standard” one, in which the short continent is west of the wide basin, and the “exchanged” one, in which the short continent is west of the narrow basin. In both cases, deep water is formed in the basin to the west of the short continent. Most residual transport of the MOC’s upper branch enters this basin by flowing along open streamlines that pass westward south of the short continent before proceeding northward. The meridional salt transport in the upper ocean of the sinking basin is decomposed into two portions: transport along open streamlines and transport by closed streamlines (gyres). In the Northern Hemisphere of the basin in which deep water is formed, the total northward salt transport per unit width along open streamlines is larger in the standard configuration than in the exchanged configuration. This larger salt transport is caused by two factors: a larger northward advection of salt by the interbasin transport and a larger cross-streamline salt transport out of the subpolar gyre. It is concluded that increasing interbasin flow south of Africa would likely bring more salt into the Atlantic Ocean.

© 2018 American Meteorological Society. For information regarding reuse of this content and general copyright information, consult the AMS Copyright Policy (www.ametsoc.org/PUBSReuseLicenses).

Corresponding author: C. S. Jones, spencerj@ldeo.columbia.edu
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