• Arakawa, A., and V. Lamb, 1977: Computational design of the basic dynamical processes of the UCLA general circulation model. Meth. Comput. Phys.17, 174–267.

  • Armi, L., 1978: Some evidence for boundary mixing in the deep ocean. J. Geophys. Res.,83, 1971–1979.

  • Böning, C. W., W. R. Holland, F. O. Bryan, G. Danabasoglu, and J. C. McWilliams, 1995: An overlooked problem in model simulations of the thermohaline circulation and heat transport in the Atlantic Ocean. J. Climate,8, 515–523.

  • Bryan, F., 1986: High-latitude salinity effects and interhemispheric thermohaline circulation. Nature,323, 301–304.

  • ——, 1987: Parameter sensitivity of primitive equation ocean general circulation models. J. Phys. Oceanogr.,17, 970–985.

  • Bryan, K., 1984: Accelerating the convergence to equilibrium of ocean-climate models. J. Phys. Oceanogr.,14, 666–673.

  • ——, and M. D. Cox, 1967: A numerical investigation of the oceanic general circulation. Tellus,19, 54–80.

  • Capotondi, A., and R. Saravanan, 1996: Sensitivity of the thermohaline circulation to surface buoyancy forcing in a two-dimensional ocean model. J. Phys. Oceanogr.,26, 1039–1058.

  • Cessi, P., and W. Young, 1992: Multiple equilibria in two-dimensional thermohaline circulation. J. Fluid Mech.,241, 291–309.

  • Colin de Verdiere, A., 1988: Buoyancy driven planetary flows. J. Mar. Res.,46, 215–265.

  • Cox, M. D., 1984: A primitive equation, 3-dimensional model of the ocean. GFDL Ocean Group Tech. Rep. 1, Geophysical Fluid Dynamics Laboratory/NOAA, 40 pp. [Available from GFDL/NOAA, Princeton University, P.O. Box 308, Princeton, NJ 08542.].

  • ——, 1989: An idealized model of the World Ocean. Part I: The global-scale water masses. J. Phys. Oceanogr.,19, 1730–1752.

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

  • ——, ——, and P. R. Gent, 1994: The role of mesoscale tracer transports in the global ocean circulation. Science,264, 1123–1126.

  • Dijkstra, H. A., and M. J. Molemaker, 1997: Symmetry breaking and overturning oscillations in thermohaline-driven flows. J. Fluid Mech.,331, 169–198.

  • Drazin, P. G., 1992: Nonlinear Systems. Cambridge University Press, 317 pp.

  • England, M. H., 1993: Representing the global-scale water masses in ocean general circulation models. J. Phys. Oceanogr.,23, 1523–1552.

  • Gargett, A. E., and G. Holloway, 1992: Sensitivity of the GFDL ocean model to different diffusivities for heat and salt. J. Phys. Oceanogr.,22, 1158–1177.

  • Gent, P. R., and J. C. McWilliams, 1990: Isopycnal mixing in ocean circulation models. J. Phys. Oceanogr.,20, 150–155.

  • ——, J. Willebrand, T. J. McDougall, and J. C. McWilliams, 1995: Parameterizing eddy-induced tracer transports in ocean circulation models. J. Phys. Oceanogr.,25, 463–474.

  • Gordon, A. L., 1986: Interocean exchange of thermocline water. J. Geophys. Res.,91, 5037–5046.

  • Huang, R. X., 1994: Thermohaline circulation: Energetics and variability in a single-hemisphere basin model. J. Geophys. Res.,99, 12 471–12 485.

  • ——, and R. L. Chou, 1994: Parameter sensitivity study of the saline circulation. Climate Dyn.,9, 391–409.

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

  • Ledwell, J. R., and A. Bratkovich, 1995: A tracer study of mixing in the Santa Cruz Basin. J. Geophys. Res.,100, 20 681–20 704.

  • Lenderink, G., and R. J. Haarsma, 1994: Variability and multiple equilibria of the thermohaline circulation associated with deep-water formation. J. Phys. Oceanogr.,24, 1480–1493.

  • Levitus, S., and T. P. Boyer, 1994: World Ocean Atlas 1994, Vol. 4:Temperature. NOAA Atlas NESDIS 4, NOAA, NESDIS, Washington, DC, 117 pp.

  • Macdonald, A. M., 1993: Property fluxes at 30° S and their implications for the Pacific–Indian Throughflow and the global heat budget. J. Geophys. Res.,98, 6851–6868.

  • ——, and C. Wunsch, 1996: An estimate of global ocean circulation and heat fluxes. Nature,382, 436–439.

  • Marotzke, J., 1990: Instabilities and multiple equilibria of the thermohaline circulation. Ph.D. thesis, Berichte Institut für Meereskunde, Kiel, Germany, 126 pp. [Available from J. Marotzke, Center for Global Change Science, MIT, Rm. 54-1514, Cambridge, MA 02139.].

  • ——, 1996: Analysis of thermohaline feedbacks. Decadal Climate Variability: Dynamics and Predictability. D. L. T. Anderson and J. Willebrand, Eds., NATO ASI Series, 333–378.

  • ——, 1997: Boundary mixing and the dynamics of three-dimensional thermohaline circulations. J. Phys. Oceanogr.,27, 1713–1728.

  • ——, and J. Willebrand, 1991: Multiple equilibria of the global thermohaline circulation. J. Phys. Oceanogr.,21, 1372–1385.

  • ——, and D. W. Pierce, 1997: On spatial scales and lifetimes of SST anomalies beneath a diffusive atmosphere. J. Phys. Oceanogr.,27, 133–139.

  • ——, P. Welander, and J. Willebrand, 1988: Instability and multiple steady states in a meridional-plane model of the thermohaline circulation. Tellus,40A, 162–172.

  • Mikolajewicz, U., and E. Maier-Reimer, 1994: Mixed boundary conditions in ocean general circulation models and their influence of the stability of the model’s conveyor belt. J. Geophys. Res.,99, 22 633–22 644.

  • Munk, W., 1966: Abyssal recipes. Deep-Sea Res.,13, 707–730.

  • Nakamura, M., P. H. Stone, and J. Marotzke, 1994: Destabilization of the thermohaline circulation by atmospheric eddy transports. J. Climate,7, 1870–1882.

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

  • Peixoto, J. P., and A. H. Oort, 1992: Physics of Climate. Amer. Inst. Phys., 520 pp.

  • Peterson, W. H., 1979: A steady thermohaline convection model (driven by turbulent buoyant plumes from multiple isolated sources in a large non-turbulent finite region, with applications to the oceanic thermocline circulation). Ph.D. thesis, University of Miami, 160 pp.

  • Quon, C., and M. Ghil, 1992: Multiple equilibria in thermosolutal convection due to salt-flux boundary conditions. J. Fluid Mech.,245, 449–483.

  • ——, and ——, 1995: Multiple equilibria and stable oscillations in the thermosolutal convection at small aspect ratio. J. Fluid Mech.,291, 33–56.

  • Rahmstorf, S., 1996: On the freshwater forcing and transport of the Atlantic thermohaline circulation. Climate Dyn.,12, 799–811.

  • ——, and J. Willebrand, 1995: The role of temperature feedback in stabilising the thermohaline circulation. J. Phys. Oceanogr.,25, 787–805.

  • Rintoul, S. R., 1991: South Atlantic interbasin exchange. J. Geophys. Res.,96, 2675–2692.

  • Rooth, C., 1982: Hydrology and ocean circulation. Progress in Oceanography, Vol. 11, Pergamon, 131–149.

  • Saravanan, R., and J. C. McWilliams, 1995: Multiple equilibria, natural variability, and climate transitions in an idealized ocean–atmosphere model. J. Climate,8, 2296–2323.

  • Schmidt, G. A., and L. A. Mysak, 1996: The stability of a zonally averaged thermohaline circulation model. Tellus,48, 158–178.

  • Schmitt, R. W., P. S. Bogden, and C. E. Dorman, 1989: Evaporation minus precipitation and density fluxes for the North Atlantic. J. Phys. Oceanogr.,19, 1208–1221.

  • Scott, J. R., J. Marotzke, and P. H. Stone, 1999: Interhemispheric thermohaline circulation in a coupled box model. J. Phys. Oceanogr.,29, 351–365.

  • Speer, K. G., and M. S. McCartney, 1991: Tracing lower North Atlantic Deep Water across the equator. J. Geophys. Res.,96, 20 443–20 448.

  • Stocker, T. F., and D. G. Wright, 1991: A zonally averaged ocean model for the thermohaline circulation. Part II: Interocean circulation in the Pacific–Atlantic basin system. J. Phys. Oceanogr.,21, 1725–1739.

  • ——, D. G. Wright, and L. A. Mysak, 1992: A zonally averaged, coupled ocean–atmosphere model for paleoclimate studies. J. Climate,5, 773–797.

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

  • ——, and A. B. Arons, 1960: On the abyssal circulation of the World Ocean. Part I: Stationary planetary flow patterns on a sphere. Deep-Sea Res.,6, 140–154.

  • ——, ——, and A. J. Faller, 1958: Some examples of stationary planetary flow patterns in bounded basins. Tellus,10, 179–187.

  • Thual, O., and J. C. McWilliams, 1992: The catastrophe structure of thermohaline convection in a two-dimensional fluid model and a comparison with low-order box models. Geophys. Astrophys. Fluid Dyn.,64, 67–95.

  • Toole, J. M., R. W. Schmitt, K. L. Polzin, and E. Kunze, 1997: Near-boundary mixing above the flanks of a midlatitude seamount. J. Geophys. Res.,102, 947–959.

  • Tziperman, E., 1997: Inherently unstable climate behavior due to weak thermohaline ocean circulation. Nature,386, 592–595.

  • Vellinga, M., 1996: Instability of two-dimensional thermohaline circulation. J. Phys. Oceanogr.,26, 305–319.

  • Veronis, G., 1975: The role of models in tracer studies. Numerical Models of the Ocean Circlation, U.S. Natl. Acad. Sci., 133–145.

  • Wang, X., P. H. Stone, and J. Marotzke, 1999a: Global thermohaline circulation. Part I: Sensitivity to Atmospheric Moisture Transport. J. Climate,12, 71–82.

  • ——, ——, and ——, 1999b: Global thermohaline circulation. Part II: Sensitivity with interactive atmospheric transports. J. Climate,12, 83–91.

  • Warren, B. A., 1981: Deep circulation of the World Ocean. Evolution of Physical Oceanography, B. A. Warren and C. Wunsch, Eds., MIT Press, 6–42.

  • ——, 1983: Why is no deep water formed in the North Pacific? J. Mar. Res.,41, 327–347.

  • Weaver, A. J., and E. S. Sarachik, 1990: On the importance of vertical resolution in certain ocean general circulation models. J. Phys. Oceanogr.,20, 600–609.

  • ——, and ——, 1991: The role of mixed boundary conditions in numerical models of the ocean’s climate. J. Phys. Oceanogr.,21, 1470–1493.

  • ——, and M. Eby, 1997: On the numerical implementation of advection schemes for use in conjunction with various mixing parameterizations in the GFDL ocean model. J. Phys. Oceanogr.,27, 369–377.

  • ——, E. S. Sarachik, and J. Marotzke, 1991: Freshwater flux forcing of decadal and interdecadal oceanic variability. Nature,353, 836–838.

  • ——, J. Marotzke, P. F. Cummins, and E. S. Sarachik, 1993: Stability and variability of the thermohaline circulation. J. Phys. Oceanogr.,23, 39–60.

  • Weber, S. L., 1998: Parameter sensitivity of a coupled atmosphere–ocean model. Climate Dyn.,14, 201–212.

  • Welander, P., 1986: Thermohaline effects in the ocean circulation and related simple models. Large-Scale Transport Processes in Oceans and Atmospheres, J. Willebrand and D. L. T. Anderson, Eds., NATO ASI Series, D. Reidel, 163–200.

  • Wijffels, S. E., R. W. Schmitt, H. L. Bryden, and A. Stigebrandt, 1992: Transport of freshwater by the oceans. J. Phys. Oceanogr.,22, 155–162.

  • Winton, M., 1996: The role of horizontal boundaries in parameter sensitivity and decadal-scale variability of coarse-resolution ocean general circulation models. J. Phys. Oceanogr.,26, 289–304.

  • ——, and E. S. Sarachik, 1993: Thermohaline oscillations induced by strong steady salinity forcing of ocean general circulation models. J. Phys. Oceanogr.,23, 1389–1410.

  • Wunsch, C., 1970: On oceanic boundary mixing. Deep-Sea Res.,17, 293–301.

  • Zhang, J., R. W. Schmitt, and R. X. Huang, 1998: Sensitivity of GFDL Modular Ocean Model to the parameterization of double-diffusive processes. J. Phys. Oceanogr.,28, 589–605.

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Behavior of Double-Hemisphere Thermohaline Flows in a Single Basin

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  • 1 Oceanographic Center, Nova Southeastern University, Dania Beach, Florida
  • | 2 Center for Global Change Science, Massachusetts Institute of Technology, Cambridge, Massachusetts
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Abstract

A coarse resolution, three-dimensional numerical model is used to study how external parameters control the existence and strength of equatorially asymmetric thermohaline overturning in a large-scale, rotating ocean basin. Initially, the meridional surface density gradient is directly set to be larger in a “dominant” hemisphere than in a “subordinate” hemisphere. The two-hemisphere system has a broader thermocline and weaker upwelling than the same model with the dominant hemisphere only. This behavior is in accord with classical scaling arguments, providing that the continuity equation is employed, rather than the linear vorticity equation.

The dominant overturning cell, analogous to North Atlantic Deep Water formation, is primarily controlled by the surface density contrast in the dominant hemisphere, which in turn is largely set by temperature. Consequently, in experiments with mixed boundary conditions, the dominant cell strength is relatively insensitive to the magnitude QS of the salinity forcing. However, QS strongly influences subordinate hemisphere properties, including the volume transport of a shallow overturning cell and the meridional extent of a tongue of low-salinity intermediate water reminiscent of Antarctic Intermediate Water.

The minimum QS is identified for which the steady, asymmetric flow is stable; below this value, a steady, equatorially symmetric, temperature-dominated overturning occurs. For high salt flux, the asymmetric circulation becomes oscillatory and eventually gives way to an unsteady, symmetric, salt-dominated overturning. For given boundary conditions, it is possible to have at least three different asymmetric states, with significantly different large-scale properties. An expression for the meridional salt transport allows one to roughly predict the surface salinity and density profile and stability of the asymmetric state as a function of QS and other external parameters.

Corresponding author address: Dr. Barry A. Klinger, Oceanographic Center, Nova Southeastern University, 8000 North Ocean Drive, Dania Beach, FL 33004.

Email: klinger@ocean.nova.edu

Abstract

A coarse resolution, three-dimensional numerical model is used to study how external parameters control the existence and strength of equatorially asymmetric thermohaline overturning in a large-scale, rotating ocean basin. Initially, the meridional surface density gradient is directly set to be larger in a “dominant” hemisphere than in a “subordinate” hemisphere. The two-hemisphere system has a broader thermocline and weaker upwelling than the same model with the dominant hemisphere only. This behavior is in accord with classical scaling arguments, providing that the continuity equation is employed, rather than the linear vorticity equation.

The dominant overturning cell, analogous to North Atlantic Deep Water formation, is primarily controlled by the surface density contrast in the dominant hemisphere, which in turn is largely set by temperature. Consequently, in experiments with mixed boundary conditions, the dominant cell strength is relatively insensitive to the magnitude QS of the salinity forcing. However, QS strongly influences subordinate hemisphere properties, including the volume transport of a shallow overturning cell and the meridional extent of a tongue of low-salinity intermediate water reminiscent of Antarctic Intermediate Water.

The minimum QS is identified for which the steady, asymmetric flow is stable; below this value, a steady, equatorially symmetric, temperature-dominated overturning occurs. For high salt flux, the asymmetric circulation becomes oscillatory and eventually gives way to an unsteady, symmetric, salt-dominated overturning. For given boundary conditions, it is possible to have at least three different asymmetric states, with significantly different large-scale properties. An expression for the meridional salt transport allows one to roughly predict the surface salinity and density profile and stability of the asymmetric state as a function of QS and other external parameters.

Corresponding author address: Dr. Barry A. Klinger, Oceanographic Center, Nova Southeastern University, 8000 North Ocean Drive, Dania Beach, FL 33004.

Email: klinger@ocean.nova.edu

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