• Bryan, F., 1987: Parameter sensitivity of primitive equation ocean general circulation models. J. Phys. Oceanogr, 17 , 970985.

  • Bryan, K., 1984: Accelerating the convergence to equilibrium of ocean-climate models. J. Phys. Oceanogr, 14 , 666673.

  • Chen, F., and M. Ghil, 1995: Interdecadal variability of the thermohaline circulation and high-latitude surface fluxes. J. Phys. Oceanogr, 25 , 25472568.

    • Search Google Scholar
    • Export Citation
  • Colin de Verdière, A., and T. Huck, 1999: Baroclinic instability: An oceanic wavemaker for interdecadal variability. J. Phys. Oceanogr, 29 , 893910.

    • Search Google Scholar
    • Export Citation
  • Delworth, T. L., and R. J. Greatbatch, 2000: Multidecadal thermohaline circulation variability driven by atmospheric surface flux forcing. J. Climate, 13 , 14811495.

    • Search Google Scholar
    • Export Citation
  • Delworth, T. L., and M. E. Mann, 2000: Observed and simulated multidecadal variability in the Northern Hemisphere. Climate Dyn, 16 , 661676.

    • Search Google Scholar
    • Export Citation
  • Delworth, T. L., S. Manabe, and R. J. Stouffer, 1993: Interdecadal variations of the thermohaline circulation in a coupled ocean–atmosphere model. J. Climate, 6 , 19932011.

    • Search Google Scholar
    • Export Citation
  • Greatbatch, R. J., and S. Zhang, 1995: An interdecadal oscillation in an idealized ocean basin forced by constant heat flux. J. Climate, 8 , 8291.

    • Search Google Scholar
    • Export Citation
  • Greatbatch, R. J., and K. A. Peterson, 1996: Interdecadal variability and oceanic thermohaline adjustment. J. Geophys. Res, 101 , 2046720482.

    • Search Google Scholar
    • Export Citation
  • Griffies, S. M., and E. Tziperman, 1995: A linear thermohaline oscillator driven by stochastic atmospheric forcing. J. Climate, 8 , 24402453.

    • Search Google Scholar
    • Export Citation
  • Huck, T., and G. K. Vallis, 2001: Linear stability analysis of the three-dimensional thermally-driven ocean circulation: Application to interdecadal oscillations. Tellus, 53A , 526545.

    • Search Google Scholar
    • Export Citation
  • Huck, T., A. Colin de Verdière, and A. J. Weaver, 1999: Interdecadal variability of the thermohaline circulation in box-ocean models forced by fixed surface fluxes. J. Phys. Oceanogr, 29 , 865892.

    • Search Google Scholar
    • Export Citation
  • Huck, T., G. K. Vallis, and A. Colin de Verdière, 2001: On the robustness of interdecadal modes of the thermohaline circulation. J. Climate, 14 , 940963.

    • Search Google Scholar
    • Export Citation
  • Jin, F-F., 1997: A theory of interdecadal climate variability of the North Pacific ocean–atmosphere system. J. Climate, 10 , 18211835.

    • Search Google Scholar
    • Export Citation
  • Kantz, H., and T. Schreiber, 1997: Nonlinear Time Series Analysis. Cambridge University Press, 304 pp.

  • Kushnir, Y., 1994: Interdecadal variations in North Atlantic sea surface temperature and associated atmospheric conditions. J. Climate, 7 , 141157.

    • Search Google Scholar
    • Export Citation
  • Mann, M. E., R. S. Bradley, and M. K. Hughes, 1998: Global-scale temperature patterns and climate forcing over the the past six centuries. Nature, 392 , 779787.

    • Search Google Scholar
    • Export Citation
  • Moron, V., R. Vautard, and M. Ghil, 1998: Trends, interdecadal and interannual oscillations in global sea-surface temperature. Climate Dyn, 14 , 545569.

    • Search Google Scholar
    • Export Citation
  • National Research Council, 1995: Natural Climate Variability on Decade-to-Century Time Scales. National Academy Press, 644 pp.

  • Oberhuber, J. M., 1988: The budget of heat, buoyancy and turbulent kinetic energy at the surface of the global ocean. Max Planck Institut für Meteorologie Hamburg Rep. 15, 148 pp.

    • Search Google Scholar
    • Export Citation
  • Pacanowski, R. C., and S. M. Griffies, 1998: Mom 3.0 manual. [Available online at http://www.gfdl.gov/∼smg/MOM/web/guide_parent/guide_parent.html.].

    • Search Google Scholar
    • Export Citation
  • Plaut, G., and R. Vautard, 1994: Spells of low-frequency oscillations and weather regimes in the Northern Hemisphere. J. Atmos. Sci, 51 , 210236.

    • Search Google Scholar
    • Export Citation
  • Rivin, I., and E. Tziperman, 1997: Linear versus self-sustained interdecadal thermohaline variability in a coupled box model. J. Phys. Oceanogr, 27 , 12161232.

    • Search Google Scholar
    • Export Citation
  • te Raa, L. A., and H. A. Dijkstra, 2002: Instability of the thermohaline ocean circulation on interdecadal time scales. J. Phys. Oceanogr, 32 , 138160.

    • Search Google Scholar
    • Export Citation
  • te Raa, L. A., and H. A. Dijkstra, 2003: Modes of internal thermohaline variability in a single-hemispheric ocean basin. J. Mar. Res, 61 , 491516.

    • Search Google Scholar
    • Export Citation
  • Weaver, A. J., J. Marotzke, P. F. Cummings, and E. S. Sarachik, 1993: Stability and variability of the thermohaline circulation. J. Phys. Oceanogr, 23 , 3960.

    • Search Google Scholar
    • Export Citation
  • Weaver, A. J., S. Aura, and P. G. Myers, 1994: Interdecadal variability in an idealized model of the North Atlantic. J. Geophys. Res, 99 , 1242312441.

    • Search Google Scholar
    • Export Citation
  • 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 , 289304.

    • Search Google Scholar
    • Export Citation
  • Yin, F. L., and E. S. Sarachik, 1995: On interdecadal thermohaline oscillations in a sector ocean general circulation model. J. Phys. Oceanogr, 25 , 24652484.

    • Search Google Scholar
    • Export Citation
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Identification of the Mechanism of Interdecadal Variability in the North Atlantic Ocean

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  • 1 Institute for Marine and Atmospheric Research Utrecht, Department of Physics and Astronomy, Utrecht University, Utrecht, Netherlands
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Abstract

The aim of this paper is to identify the physical mechanism of interdecadal variability in simulations of the North Atlantic Ocean circulation with the Modular Ocean Model of the Geophysical Fluid Dynamics Laboratory. To that end, a hierarchy of increasingly complex model configurations is used. The variability in the simplest case, that of viscous, purely thermally driven flows in a flat-bottom ocean basin with a box-shaped geometry, is shown to be caused by an internal interdecadal mode. The westward propagation of temperature anomalies and the phase difference between the anomalous zonal and meridional overturning that characterize the interdecadal mode are used as “fingerprints” of the physical mechanism of the variability. In this way, the variability can be followed toward a less viscous regime in which the effects of continental geometry and bottom topography are also included. It is shown that, although quantitative aspects of the variability like period and spatial pattern are changing, the physical mechanism of the interdecadal variability in the more complex simulations can be attributed to the same processes as in the simplest model configuration.

Current affiliation: College of Oceanic and Atmospheric Sciences, Oregon State University, Corvallis, Oregon

Current affiliation: Department of Atmospheric Science, Colorado State University, Fort Collins, Colorado

Corresponding author address: Lianke te Raa, Institute for Marine and Atmospheric Research Utrecht, Department of Physics and Astronomy, Utrecht University, Princetonplein 5, 3584 CC Utrecht, Netherlands. Email: l.a.teraa@phys.uu.nl

Abstract

The aim of this paper is to identify the physical mechanism of interdecadal variability in simulations of the North Atlantic Ocean circulation with the Modular Ocean Model of the Geophysical Fluid Dynamics Laboratory. To that end, a hierarchy of increasingly complex model configurations is used. The variability in the simplest case, that of viscous, purely thermally driven flows in a flat-bottom ocean basin with a box-shaped geometry, is shown to be caused by an internal interdecadal mode. The westward propagation of temperature anomalies and the phase difference between the anomalous zonal and meridional overturning that characterize the interdecadal mode are used as “fingerprints” of the physical mechanism of the variability. In this way, the variability can be followed toward a less viscous regime in which the effects of continental geometry and bottom topography are also included. It is shown that, although quantitative aspects of the variability like period and spatial pattern are changing, the physical mechanism of the interdecadal variability in the more complex simulations can be attributed to the same processes as in the simplest model configuration.

Current affiliation: College of Oceanic and Atmospheric Sciences, Oregon State University, Corvallis, Oregon

Current affiliation: Department of Atmospheric Science, Colorado State University, Fort Collins, Colorado

Corresponding author address: Lianke te Raa, Institute for Marine and Atmospheric Research Utrecht, Department of Physics and Astronomy, Utrecht University, Princetonplein 5, 3584 CC Utrecht, Netherlands. Email: l.a.teraa@phys.uu.nl

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