• Adcroft, A., C. Hill, and J. Marshall, 1997: Representation of topography by shaved cells in a height coordinate ocean model. Mon. Wea. Rev., 125, 22932315, doi:10.1175/1520-0493(1997)125<2293:ROTBSC>2.0.CO;2.

    • Search Google Scholar
    • Export Citation
  • Amante, C., and B. Eakins, 2009: ETOPO1 1 Arc-Minute Global Relief Model: Procedures, data sources and analysis. NOAA Tech. Memo. NESDIS NGDC-24, NOAA/National Geophysical Data Center, accessed 3 December 2015, doi:10.7289/V5C8276M.

  • Barnier, B., L. Siefried, and P. Marchesiello, 1995: Thermal forcing for a global ocean circulation model using a three-year climatology of ECMWF analyses. J. Mar. Syst., 6, 363380, doi:10.1016/0924-7963(94)00034-9.

    • Search Google Scholar
    • Export Citation
  • Bryan, F. O., M. Hecht, and R. Smith, 2007: Resolution convergence and sensitivity studies with North Atlantic circulation models. Part I: The western boundary current system. Ocean Modell., 16, 141159, doi:10.1016/j.ocemod.2006.08.005.

    • Search Google Scholar
    • Export Citation
  • Carton, J., and B. Giese, 2008: A reanalysis of ocean climate using Simple Ocean Data Assimilation (SODA). Mon. Wea. Rev., 136, 29993017, doi:10.1175/2007MWR1978.1.

    • Search Google Scholar
    • Export Citation
  • Chassignet, E., and D. Marshall, 2008: Gulf stream separation in numerical ocean models. Ocean Modeling in an Eddying Regime, Geophys. Monogr., Vol. 177, Amer. Geophys. Union, 3961.

  • Conkright, M., R. Locarnini, H. Garcia, T. O’Brien, T. Boyer, C. Stephens, and J. Antonov, 2002: World Ocean Atlas 2001: Objective analyses, data statistics and figures. CD-ROM documentation, National Oceanographic Data Center, 17 pp. [Available online at http://odv.awi.de/fileadmin/user_upload/odv/data/WOA01/README.PDF.]

  • Danabasoglu, G., W. Large, J. Tribbia, P. Gent, B. Briegleb, and J. McWilliams, 2006: Diurnal coupling in the tropical oceans of CCSM3. J. Climate, 19, 23472365, doi:10.1175/JCLI3739.1.

    • Search Google Scholar
    • Export Citation
  • da Silva, A., C. Young, and S. Levitus, 1994: Algorithms and Procedures, Vol. 1, Atlas of Surface Marine Data 1994, NOAA Atlas NESDIS 6, 74 pp.

  • Deremble, B., N. Wienders, and W. Dewar, 2013: CheapAML: A simple, atmospheric boundary layer model for use in ocean-only model calculations. Mon. Wea. Rev., 141, 809821, doi:10.1175/MWR-D-11-00254.1.

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

    • Search Google Scholar
    • Export Citation
  • Gent, P., and Coauthors, 2011: The Community Climate System Model version 4. J. Climate, 24, 49734991, doi:10.1175/2011JCLI4083.1.

  • Gula, J., J. Molemaker, and J. McWilliams, 2015: Gulf Stream dynamics along the southeastern U.S. seaboard. J. Phys. Oceanogr., 45, 690715, doi:10.1175/JPO-D-14-0154.1.

    • Search Google Scholar
    • Export Citation
  • Haidvogel, D., J. McWilliams, and P. Gent, 1992: Boundary current separation in a quasigeostrophic, eddy-resolving ocean circulation model. J. Phys. Oceanogr., 22, 882902, doi:10.1175/1520-0485(1992)022<0882:BCSIAQ>2.0.CO;2.

    • Search Google Scholar
    • Export Citation
  • Holland, W., 1973: Baroclinic and topographic influences on the transport in western boundary currents. Geophys. Fluid Dyn., 4, 336354, doi:10.1080/03091927208236095.

    • Search Google Scholar
    • Export Citation
  • Hughes, C., 2000: A theoretical reason to expect inviscid western boundary currents in realistic oceans. Ocean Modell., 2, 7383, doi:10.1016/S1463-5003(00)00011-1.

    • Search Google Scholar
    • Export Citation
  • Hughes, C., and B. DeCuevas, 2001: Why western boundary currents in realistic oceans are inviscid: A link between form stress and bottom pressure torques. J. Phys. Oceanogr., 31, 28712885, doi:10.1175/1520-0485(2001)031<2871:WWBCIR>2.0.CO;2.

    • Search Google Scholar
    • Export Citation
  • Hughes, R., 1986: On the role of criticality in coastal flows over irregular bottom topography. Dyn. Atmos. Oceans, 10, 129147, doi:10.1016/0377-0265(86)90003-5.

    • Search Google Scholar
    • Export Citation
  • Jackson, L., C. Hughes, and R. Williams, 2006: Topographic control of basin and channel flows: The role of bottom pressure torques and friction. J. Phys. Oceanogr., 36, 17861805, doi:10.1175/JPO2936.1.

    • Search Google Scholar
    • Export Citation
  • Jochum, M., G. Danabasoglu, M. Holland, Y. Kwon, and W. Large, 2008: Ocean viscosity and climate. J. Geophys. Res., 113, C06017, doi:10.1029/2007JC004515.

  • Large, W., and S. Yeager, 2009: The global climatology of an inter-annually varying air-sea flux data set. Climate Dyn., 33, 341364, doi:10.1007/s00382-008-0441-3.

    • Search Google Scholar
    • Export Citation
  • Large, W., J. McWilliams, and S. Doney, 1994: Oceanic vertical mixing: A review and a model with a nonlocal boundary layer parameterization. Rev. Geophys., 32, 363403, doi:10.1029/94RG01872.

    • Search Google Scholar
    • Export Citation
  • Large, W., G. Danabasoglu, J. McWilliams, P. Gent, and F. Bryan, 2001: Equatorial circulation in a global ocean climate model with anisotropic horizontal viscosity. J. Phys. Oceanogr., 31, 518536, doi:10.1175/1520-0485(2001)031<0518:ECOAGO>2.0.CO;2.

    • Search Google Scholar
    • Export Citation
  • Lemarié, F., J. Kurian, A. Shchepetkin, M. Molemaker, F. Colas, and J. McWilliams, 2012: Are there inescapable issues prohibiting the use of terrain-following coordinates in climate models? Ocean Modell., 42, 5779, doi:10.1016/j.ocemod.2011.11.007.

    • Search Google Scholar
    • Export Citation
  • Maltrud, M., R. Smith, A. Semtner, and R. Malone, 1998: Global eddy resolving ocean simulations driven by 1985-1995 atmospheric fields. J. Geophys. Res., 103, 30 82530 853, doi:10.1029/1998JC900013.

    • Search Google Scholar
    • Export Citation
  • Marshall, J., C. Hill, L. Perelman, and A. Adcroft, 1997: Hydrostatic, quasi-hydrostatic, and non-hydrostatic ocean modelling. J. Geophys. Res., 102, 57335753, doi:10.1029/96JC02776.

    • Search Google Scholar
    • Export Citation
  • Munk, W., 1950: On the wind-driven ocean circulation. J. Meteor., 7, 7993, doi:10.1175/1520-0469(1950)007<0080:OTWDOC>2.0.CO;2.

  • Penven, P., L. Debreu, P. Marchesiello, and J. McWilliams, 2006: Application of ROMS embedding procedure for the central California upwelling system. Ocean Modell., 12, 157187, doi:10.1016/j.ocemod.2005.05.002.

    • Search Google Scholar
    • Export Citation
  • Risien, C., and D. Chelton, 2008: A global climatology of surface wind and wind stress fields from eight years of QuikSCAT scatterometer data. J. Phys. Oceanogr., 38, 23792413, doi:10.1175/2008JPO3881.1.

    • Search Google Scholar
    • Export Citation
  • Shchepetkin, A., and J. McWilliams, 2005: The Regional Ocean Modeling System (ROMS): A split-explicit, free-surface, topography-following-coordinate ocean model. Ocean Modell., 9, 347404, doi:10.1016/j.ocemod.2004.08.002.

    • Search Google Scholar
    • Export Citation
  • Smith, R. D., and J. McWilliams, 2003: Anisotropic horizontal viscosity for ocean models. Ocean Modell., 5, 129156, doi:10.1016/S1463-5003(02)00016-1.

    • Search Google Scholar
    • Export Citation
  • Smith, R. D., and Coauthors, 2010: The Parallel Ocean Program (POP) reference manual: Ocean component of the Community Climate System Model (CCSM) and Community Earth System Model (CESM). LANL Doc., 140 pp [Available online at http://www.cesm.ucar.edu/models/cesm1.0/pop2/doc/sci/POPRefManual.pdf.]

  • Smith, W. H. F., and D. T. Sandwell, 1997: Global sea floor topography from satellite altimetry and ship depth soundings. Science, 277, 19561962, doi:10.1126/science.277.5334.1956.

    • Search Google Scholar
    • Export Citation
  • Stern, M., 1998: Separation of a density current from the bottom of a continental shelf. J. Phys. Oceanogr., 28, 20402049, doi:10.1175/1520-0485(1998)028<2040:SOADCF>2.0.CO;2.

    • Search Google Scholar
    • Export Citation
  • Stommel, H., 1948: The westward intensification of wind-driven ocean currents. Eos, Trans. Amer. Geophys. Union, 29, 202206, doi:10.1029/TR029i002p00202.

    • Search Google Scholar
    • Export Citation
  • Talandier, C., and Coauthors, 2014: Improvements of simulated western North Atlantic current system and impacts on the AMOC. Ocean Modell., 76, 119, doi:10.1016/j.ocemod.2013.12.007.

    • Search Google Scholar
    • Export Citation
All Time Past Year Past 30 Days
Abstract Views 0 0 0
Full Text Views 12 12 12
PDF Downloads 13 13 13

North Atlantic Barotropic Vorticity Balances in Numerical Models

View More View Less
  • 1 Geophysical Fluid Dynamics Institute, Florida State University, Tallahassee, Florida
  • | 2 Department of Earth, Ocean and Atmospheric Sciences, Florida State University, Tallahassee, Florida
  • | 3 Department of Atmospheric and Oceanic Sciences, University of California, Los Angeles, Los Angeles, California
  • | 4 National Center for Atmospheric Research, Boulder, Colorado
Restricted access

Abstract

Numerical simulations are conducted across model platforms and resolutions with a focus on the North Atlantic. Barotropic vorticity diagnostics confirm that the subtropical gyre is characterized by an inviscid balance primarily between the applied wind stress curl and bottom pressure torque. In an area-integrated budget over the Gulf Stream, the northward return flow is balanced by bottom pressure torque. These integrated budgets are shown to be consistent across model platforms and resolution, suggesting that these balances are robust. Two of the simulations, at 100- and 10-km resolutions, produce a more northerly separating Gulf Stream but obtain the correct integrated vorticity balances. In these simulations, viscous torque is nonnegligible on smaller scales, indicating that the separation is linked to the details of the local dynamics. These results are shown to be consistent with a scale analysis argument that suggests that the biharmonic viscous torque in particular is upsetting the inviscid balance in simulations with a more northerly separation. In addition to providing evidence for locally controlled inviscid separation, these results provide motivation to revisit the formulation of subgrid-scale parameterizations in general circulation models.

Geophysical Fluid Dynamics Institute Contribution Number 474.

The National Center for Atmospheric Research is sponsored by the National Science Foundation.

Corresponding author address: Joseph Schoonover, Geophysical Fluid Dynamics Institute, Florida State University, 77 Chieftan Way, Tallahassee, FL 32306. E-mail: js08s@my.fsu.edu

Abstract

Numerical simulations are conducted across model platforms and resolutions with a focus on the North Atlantic. Barotropic vorticity diagnostics confirm that the subtropical gyre is characterized by an inviscid balance primarily between the applied wind stress curl and bottom pressure torque. In an area-integrated budget over the Gulf Stream, the northward return flow is balanced by bottom pressure torque. These integrated budgets are shown to be consistent across model platforms and resolution, suggesting that these balances are robust. Two of the simulations, at 100- and 10-km resolutions, produce a more northerly separating Gulf Stream but obtain the correct integrated vorticity balances. In these simulations, viscous torque is nonnegligible on smaller scales, indicating that the separation is linked to the details of the local dynamics. These results are shown to be consistent with a scale analysis argument that suggests that the biharmonic viscous torque in particular is upsetting the inviscid balance in simulations with a more northerly separation. In addition to providing evidence for locally controlled inviscid separation, these results provide motivation to revisit the formulation of subgrid-scale parameterizations in general circulation models.

Geophysical Fluid Dynamics Institute Contribution Number 474.

The National Center for Atmospheric Research is sponsored by the National Science Foundation.

Corresponding author address: Joseph Schoonover, Geophysical Fluid Dynamics Institute, Florida State University, 77 Chieftan Way, Tallahassee, FL 32306. E-mail: js08s@my.fsu.edu
Save