Mesoscale Eddy Buoyancy Flux and Eddy-Induced Circulation in Eastern Boundary Currents

François Colas Institute of Geophysics and Planetary Physics, University of California, Los Angeles, Los Angeles, California

Search for other papers by François Colas in
Current site
Google Scholar
PubMed
Close
,
Xavier Capet Laboratoire de Physique des Oceans, Ifremer, Plouzane, France

Search for other papers by Xavier Capet in
Current site
Google Scholar
PubMed
Close
,
James C. McWilliams Institute of Geophysics and Planetary Physics, University of California, Los Angeles, Los Angeles, California

Search for other papers by James C. McWilliams in
Current site
Google Scholar
PubMed
Close
, and
Zhijin Li Jet Propulsion Laboratory/California Institute of Technology, Pasadena, California

Search for other papers by Zhijin Li in
Current site
Google Scholar
PubMed
Close
Restricted access

We are aware of a technical issue preventing figures and tables from showing in some newly published articles in the full-text HTML view.
While we are resolving the problem, please use the online PDF version of these articles to view figures and tables.

Abstract

A dynamical interpretation is made of the mesoscale eddy buoyancy fluxes in the Eastern Boundary Currents off California and Peru–Chile, based on regional equilibrium simulations. The eddy fluxes are primarily shoreward and upward across a swath several hundred kilometers wide in the upper ocean; as such they serve to balance mean offshore air–sea heating and coastal upwelling. In the stratified interior the eddy fluxes are consistent with the adiabatic hypothesis associated with a mean eddy-induced velocity advecting mean buoyancy and tracers. Furthermore, with a suitable gauge choice, the horizontal fluxes are almost entirely aligned with the mean horizontal buoyancy gradient, consistent with the advective parameterization scheme of Gent and McWilliams. The associated diffusivity κ is surface intensified, matching the vertical stratification profile. The fluxes span the across-shore band of high eddy energy, but their alongshore structure is unresolved because of sampling limitations. In the surface layer the eddy flux is significantly diabatic with a shallow eddy-induced circulation cell and downgradient lateral diapycnal flux. The dominant eddy generation process is baroclinic instability, but there are significant regional differences between the upwelling systems in the flux and κ that are not consistent with simple instability theory.

Corresponding author address: Francois Colas, Institute of Geophysics and Planetary Physics, UCLA, Los Angeles, CA 90095. E-mail: francois@atmos.ucla.edu

Abstract

A dynamical interpretation is made of the mesoscale eddy buoyancy fluxes in the Eastern Boundary Currents off California and Peru–Chile, based on regional equilibrium simulations. The eddy fluxes are primarily shoreward and upward across a swath several hundred kilometers wide in the upper ocean; as such they serve to balance mean offshore air–sea heating and coastal upwelling. In the stratified interior the eddy fluxes are consistent with the adiabatic hypothesis associated with a mean eddy-induced velocity advecting mean buoyancy and tracers. Furthermore, with a suitable gauge choice, the horizontal fluxes are almost entirely aligned with the mean horizontal buoyancy gradient, consistent with the advective parameterization scheme of Gent and McWilliams. The associated diffusivity κ is surface intensified, matching the vertical stratification profile. The fluxes span the across-shore band of high eddy energy, but their alongshore structure is unresolved because of sampling limitations. In the surface layer the eddy flux is significantly diabatic with a shallow eddy-induced circulation cell and downgradient lateral diapycnal flux. The dominant eddy generation process is baroclinic instability, but there are significant regional differences between the upwelling systems in the flux and κ that are not consistent with simple instability theory.

Corresponding author address: Francois Colas, Institute of Geophysics and Planetary Physics, UCLA, Los Angeles, CA 90095. E-mail: francois@atmos.ucla.edu
Save
  • 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.

    • Search Google Scholar
    • Export Citation
  • Bryan, K., J. Dukowicz, and R. Smith, 1999: On the mixing coefficient in the parameterization of bolus velocity. J. Phys. Oceanogr., 29, 24422456.

    • Search Google Scholar
    • Export Citation
  • Bryden, H., and R. Heath, 1985: Energetic eddies at the northern edge of the Antarctic Circumpolar Current in the southwest pacific. Prog. Oceanogr., 14, 6587.

    • Search Google Scholar
    • Export Citation
  • Capet, X., P. Marchesiello, and J. C. McWilliams, 2004: Upwelling response to coastal wind profiles. Geophys. Res. Lett., 31, L13311, doi:10.1029/2004GL020123.

    • Search Google Scholar
    • Export Citation
  • Capet, X., E. J. Campos, and A. M. Paiva, 2008a: Submesoscale activity over the Argentinian Shelf. Geophys. Res. Lett., 35, L15605, doi:10.1029/2008GL034736.

    • Search Google Scholar
    • Export Citation
  • Capet, X., F. Colas, P. Penven, P. Marchesiello, and J. C. McWilliams, 2008b: Eddies in eastern-boundary subtropical upwelling systems. Ocean Modeling in an Eddying Regime, Geophys. Monogr., Vol. 177, Amer. Geophys. Union, 131–147, doi:10.1029/177GM10.

  • Capet, X., J. C. McWilliams, M. J. Molemaker, and A. Shchepetkin, 2008c: Mesoscale to submesoscale transition in the California Current System. Part I: Flow structure and eddy flux. J. Phys. Oceanogr., 38, 2943.

    • 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.

    • Search Google Scholar
    • Export Citation
  • Casey, K. S., and P. Cornillon, 1999: A comparison of satellite and in situ based sea surface temperature climatologies. J. Climate, 12, 18481863.

    • Search Google Scholar
    • Export Citation
  • Centurioni, L. R., J. C. Ohlman, and P. P. Niiler, 2008: Permanent meanders in the California Current System. J. Phys. Oceanogr., 38, 16901710.

    • Search Google Scholar
    • Export Citation
  • Cerovecki, I., R. A. Plumb, and W. Heres, 2009: Eddy transport and mixing in a wind- and buoyancy-driven jet on a sphere. J. Phys. Oceanogr., 39, 11331149.

    • Search Google Scholar
    • Export Citation
  • Cessi, P., and C. Wolfe, 2009: Eddy-driven buoyancy gradients on eastern boundaries. J. Phys. Oceanogr., 39, 15951614.

  • Chaigneau, A., and O. Pizarro, 2005: Mean surface circulation and mesoscale turbulent flow characteristics in the eastern South Pacific from satellite tracked drifters. J. Geophys. Res., 110, C05014, doi:10.1029/2004JC002628.

    • Search Google Scholar
    • Export Citation
  • Chaigneau, A., M. LeTexier, G. Eldin, C. Grados, and O. Pizarro, 2011: Vertical structure of mesoscale eddies in the eastern South Pacific Ocean: A composite analysis from altimetry and Argo profiling floats. J. Geophys. Res., 116, C07002, doi:10.1029/2011JC007134.

    • Search Google Scholar
    • Export Citation
  • Charney, J. G., 1971: Geostrophic turbulence. J. Atmos. Sci., 28, 10871095.

  • Colas, F., X. Capet, J. C. McWilliams, and A. Shchepetkin, 2008: 1997-98 El Nino off Peru: A numerical study. Prog. Oceanogr., 79, 138155.

    • Search Google Scholar
    • Export Citation
  • Colas, F., J. C. McWilliams, X. Capet, and J. Kurian, 2012: Heat balance and eddies in the Peru–Chile Current system. Climate Dyn., 39, 509529, doi:10.1007/s00382-011-1170-6.

    • Search Google Scholar
    • Export Citation
  • Colbo, K., and R. Weller, 2007: The variability and heat budget of the upper ocean under the Chile-Peru stratus. J. Mar. Res., 65, 607637.

    • Search Google Scholar
    • Export Citation
  • 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. National Oceanographic Center Internal Tech. Rep. 17, CD-ROM.

  • Da Silva, A. M., C. C. Young, and S. Levitus, 1994: Algorithms and Procedures. Vol. 1, Atlas of Surface Marine Data 1994, NOAA Atlas NESDIS 6, 74 pp.

  • de Szoeke, S. P., C. W. Fairall, D. E. Wolfe, L. Bariteau, and P. Zuidema, 2010: Surface flux observations on the southeastern tropical Pacific Ocean and attribution of SST errors in coupled ocean-atmosphere models. J. Climate, 23, 41524174.

    • Search Google Scholar
    • Export Citation
  • Dewitte, B., S. Illig, L. Renault, K. Goubanova, K. Takahashi, D. Gushchina, K. Mosquera, and S. Purca, 2011: Modes of covariability between sea surface temperature and wind stress intraseasonal anomalies along the coast of Peru from satellite observations (2000–08). J. Geophys. Res., 116, C04028, doi:10.1029/2010JC006495.

    • Search Google Scholar
    • Export Citation
  • Ducet, N., P. Y. Le Traon, and G. Reverdin, 2000: Global high-resolution mapping of ocean circulation from TOPEX/Poseidon and ERS-1 and -2. J. Geophys. Res., 105, 19 47719 498.

    • Search Google Scholar
    • Export Citation
  • Eden, C., R. J. Greatbach, and J. Willebrand, 2007: A diagnosis of thickness fluxes in an eddy-resolving model. J. Phys. Oceanogr., 37, 727742.

    • 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.

    • Search Google Scholar
    • Export Citation
  • Ferreira, D., J. Marshall, and P. Heimbach, 2005: Estimating eddy stresses by fitting dynamics to observations using a residual-mean. J. Phys. Oceanogr., 35, 18911910.

    • Search Google Scholar
    • Export Citation
  • Flierl, G., and J. McWilliams, 1977: On the sampling requirements for measuring moments of eddy variability. J. Mar. Res., 35, 797820.

    • Search Google Scholar
    • Export Citation
  • Fox-Kemper, B., R. Ferrari, and J. Pedlosky, 2003: On the indeterminacy of rotational and divergent eddy fluxes. J. Phys. Oceanogr., 33, 478483.

    • Search Google Scholar
    • Export Citation
  • Fox-Kemper, B., R. Ferrari, and R. Hallberg, 2008: Parameterization of mixed layer eddies. I: Theory and diagnosis. J. Phys. Oceanogr., 38, 11451165.

    • Search Google Scholar
    • Export Citation
  • Fox-Kemper, B., and Coauthors, 2011: Parameterization of mixed layer eddies. III: Implementation and impact in global ocean climate simulations. Ocean Modell., 39, 6178.

    • Search Google Scholar
    • Export Citation
  • Gent, P. R., and J. C. McWilliams, 1990: Isopycnal mixing in ocean circulation models. J. Phys. Oceanogr., 20, 150155.

  • Gent, P. R., J. Willebrand, T. J. McDougall, and J. C. McWilliams, 1995: Parameterizing eddy-induced tracer transports in ocean circulation models. J. Phys. Oceanogr., 25, 463474.

    • Search Google Scholar
    • Export Citation
  • Gruber, N., Z. Lachkar, H. Frenzel, P. Marchesiello, M. Munnich, J. McWilliams, T. Nagai, and G. Plattner, 2011: Eddy-induced reduction of biological production in eastern boundary upwelling systems. Nat. Geophys., 4, 787792.

    • Search Google Scholar
    • Export Citation
  • Haine, T. W. N., and J. Marshall, 1998: Gravitational, symmetric, and baroclinic instability of the ocean mixed layer. J. Phys. Oceanogr., 28, 634658.

    • Search Google Scholar
    • Export Citation
  • Haney, R., R. Hale, and D. Dietrich, 2001: Offshore propagation of eddy kinetic energy in the California Current. J. Geophys. Res., 106, 11 70911 717.

    • Search Google Scholar
    • Export Citation
  • Held, I. M., and T. Schneider, 1999: The surface branch of the zonally averaged mass transport circulation in the troposphere. J. Atmos. Sci., 56, 16881697.

    • Search Google Scholar
    • Export Citation
  • Herbette, S., Y. Morel, and M. Arhan, 2003: Erosion of a surface vortex by a seamount. J. Phys. Oceanogr., 33, 16641679.

  • Herbette, S., Y. Morel, and M. Arhan, 2004: Subduction of a surface vortex under an outcropping front. J. Phys. Oceanogr., 34, 16101627.

    • Search Google Scholar
    • Export Citation
  • Hoskins, B., 1982: The mathematical theory of frontogenesis. Annu. Rev. Fluid Mech., 14, 131151.

  • 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.

    • Search Google Scholar
    • Export Citation
  • Lee, W.-J., and M. Mak, 1996: The role of orography in the dynamics of storm tracks. J. Atmos. Sci., 53, 17371750.

  • Lemarié, F., L. Debreu, A. F. Shchepetkin, and J. C. McWilliams, 2012a: On the stability and accuracy of the harmonic and biharmonic adiabatic mixing operators in ocean models. Ocean Modell., 52-53, 935.

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

    • Search Google Scholar
    • Export Citation
  • Li, Z., Y. Chao, and J. C. McWilliams, 2006: Computation of the streamfunction and velocity potential for limited and irregular domains. Mon. Wea. Rev., 134, 33843394.

    • Search Google Scholar
    • Export Citation
  • Mahadevan, A., A. Tandon, and R. Ferrari, 2010: Rapid changes in mixed layer stratification driven by submesoscale instabilities and winds. J. Geophys. Res., 115, C03017, doi:10.1029/2008JC005203.

    • Search Google Scholar
    • Export Citation
  • Marchesiello, P., J. C. McWilliams, and A. Shchepetkin, 2001: Open boundary conditions for long-term integration of regional oceanic models. Ocean Modell., 3, 120.

    • Search Google Scholar
    • Export Citation
  • Marchesiello, P., J. C. McWilliams, and A. Shchepetkin, 2003: Equilibrium structure and dynamics of the California Current System. J. Phys. Oceanogr., 33, 753783.

    • Search Google Scholar
    • Export Citation
  • Marchesiello, P., L. Debreu, and X. Couvelard, 2009: Spurious diapycnal mixing in terrain-following coordinate models: The problem and a solution. Ocean Modell., 26, 156169.

    • Search Google Scholar
    • Export Citation
  • Marchesiello, P., X. Capet, and C. Menkes, 2011: Submesoscale turbulence in tropical instability waves. Ocean Modell., 39, 3146.

  • Marshall, J., and G. Shutts, 1981: A note on rotational and divergent eddy fluxes. J. Phys. Oceanogr., 11, 16771680.

  • Mason, E., M. J. Molemaker, A. F. Shchepetkin, F. Colas, J. C. McWilliams, and P. Sangra, 2010: Procedures for offline grid nesting in regional ocean models. Ocean Modell., 35, 115.

    • Search Google Scholar
    • Export Citation
  • McDougall, T. J., and P. C. McIntosh, 1996: The temporal-residual-mean velocity. Part I: Derivation and the scalar conservation equations. J. Phys. Oceanogr., 26, 26532665.

    • Search Google Scholar
    • Export Citation
  • Mechoso, C. M., and R. Wood, 2010: An abbreviated history of VOCALS. CLIVAR Exchanges, No. 53, International Clivar Project Office, Southampton, United Kingdom, 3–5.

  • Penven, P., V. Echevin, J. Pasapera, F. Colas, and J. Tam, 2005: Average circulation, seasonal cycle, and mesoscale dynamics of the Peru Current System: a modeling approach. J. Geophys. Res., 110, C10021, doi:10.1029/2005JC002945.

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

    • Search Google Scholar
    • Export Citation
  • Scharffenber, M., and D. Stammer, 2010: Seasonal variations of the large-scale geostrophic flow field and eddy kinetic energy inferred from the TOPEX/Poseidon and Jason-1 tandem mission data. J. Geophys. Res., 115, C02008, doi:10.1029/2008JC005242.

    • Search Google Scholar
    • Export Citation
  • Shchepetkin, A., and J. C. McWilliams, 2005: The Regional Oceanic Modeling System: A split-explicit, free-surface, topography-following-coordinate ocean model. Ocean Modell., 9, 347404.

    • Search Google Scholar
    • Export Citation
  • Shchepetkin, A., and J. C. McWilliams, 2008: Computational kernel algorithms for fine-scale, multi-process, long-time oceanic simulations. Handb. Numer. Anal., 14, 121183, doi:10.1016/S1570-8659(08)01202-0.

    • Search Google Scholar
    • Export Citation
  • Shchepetkin, A., and J. C. McWilliams, 2011: Accurate Boussinesq modeling with a practical, “stiffened” equation of state. Ocean Modell., 34, 4170.

    • Search Google Scholar
    • Export Citation
  • Smith, K. S., and G. K. Vallis, 2002: The scales and equilibration of midocean eddies: Forced-dissipative flow. J. Phys. Oceanogr., 32, 16991720.

    • Search Google Scholar
    • Export Citation
  • Song, T., and D. Haidvogel, 1994: A semi-implicit ocean circulation model using a generalized topography-following coordinate system. J. Comput. Phys., 115, 228244.

    • Search Google Scholar
    • Export Citation
  • Thompson, S., 1993: Estimation of the transport of heat in the Southern Ocean using a fine-resolution numerical model. J. Phys. Oceanogr., 23, 24932497.

    • Search Google Scholar
    • Export Citation
  • Veitch, J., P. Penven, and F. Shillington, 2010: Modelling equilibrium dynamics of the Benguela Current system. J. Phys. Oceanogr., 40, 19421964.

    • Search Google Scholar
    • Export Citation
  • Visbeck, M., J. Marshall, and T. Haine, 1997: Specification of eddy transfer coefficients in coarse-resolution ocean circulation models. J. Phys. Oceanogr., 27, 381402.

    • Search Google Scholar
    • Export Citation
  • Wood, R., C. R. Mechoso, C. Bretherton, B. Huebert, and R. Weller, 2007: The VAMOS Ocean-Cloud-Atmosphere-Land Study (VOCALS). CLIVAR Variations Newsletter, No. 5, International Clivar Project Office, Southampton, United Kingdom, 1–5.

All Time Past Year Past 30 Days
Abstract Views 0 0 0
Full Text Views 1563 882 245
PDF Downloads 576 123 8