Eddy Subduction and the Vertical Transport Streamfunction

Mei-Man Lee National Oceanography Centre, Southampton, United Kingdom

Search for other papers by Mei-Man Lee in
Current site
Google Scholar
PubMed
Close
and
A. J. George Nurser National Oceanography Centre, Southampton, United Kingdom

Search for other papers by A. J. George Nurser in
Current site
Google Scholar
PubMed
Close
Restricted access

Abstract

Subduction—the transport of fluid across the base of mixed layer—exchanges water masses and tracers between the ocean surface and interior. Eddies can affect subduction in a variety of ways. First, eddies shoal the mixed layer by restratifying water columns through baroclinic instabilities. Second, eddies induce an isopycnic transport that leads to the entrainment of warm waters and subduction of cold waters, which effectively counters the wind-driven overturning circulation. In this study, the authors use an idealized model to examine these two mechanisms by which eddies influence subduction and to discuss how eddy subduction may be better approximated using the concept of vertical transport streamfunction than the conventional meridional transport streamfunction.

Corresponding author address: Dr. A. J. George Nurser, Marine Systems Modelling Group, National Oceanography Centre, Southampton SO14 3ZH, United Kingdom. E-mail: agn@noc.ac.uk

Abstract

Subduction—the transport of fluid across the base of mixed layer—exchanges water masses and tracers between the ocean surface and interior. Eddies can affect subduction in a variety of ways. First, eddies shoal the mixed layer by restratifying water columns through baroclinic instabilities. Second, eddies induce an isopycnic transport that leads to the entrainment of warm waters and subduction of cold waters, which effectively counters the wind-driven overturning circulation. In this study, the authors use an idealized model to examine these two mechanisms by which eddies influence subduction and to discuss how eddy subduction may be better approximated using the concept of vertical transport streamfunction than the conventional meridional transport streamfunction.

Corresponding author address: Dr. A. J. George Nurser, Marine Systems Modelling Group, National Oceanography Centre, Southampton SO14 3ZH, United Kingdom. E-mail: agn@noc.ac.uk
Save
  • Blanke, B., and P. Delecluse, 1993: Variability of the tropical Atlantic Ocean simulated by a general circulation model with two different mixed-layer physics. J. Phys. Oceanogr., 23, 13631388.

    • Search Google Scholar
    • Export Citation
  • Cerovečki, I., and J. Marshall, 2008: Eddy modulation of air–sea interaction and convection. J. Phys. Oceanogr., 38, 6583.

  • Cushman-Roisin, B., 1987: Subduction. Dynamics of the Ocean Surface Mixed Layer, P. Muller and D. Henderson, Eds., Hawaii Institute of Geophysical Special Publications, 181–196.

  • Gaspar, P., Y. Grgoris, and J.-M. Lefevre, 1990: A simple eddy kinetic energy model for simulations of the oceanic vertical mixing: Tests at station Papa and long-term upper ocean study site. J. Geophys. Res., 95 (C9), 16 17916 193.

    • 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
  • Lee, M.-M., G. Nurser, A. Coward, and B. A. de Cuevas, 2007: Eddy advective and diffusive transports of heat and salt in the Southern Ocean. J. Phys. Oceanogr., 37, 13761393.

    • Search Google Scholar
    • Export Citation
  • Lee, M.-M., A. J. G. Nurser, I. Stevens, and J.-B. Sallée, 2011: Subduction over the southern Indian Ocean in a high-resolution atmosphere–ocean coupled model. J. Climate, 24, 38303849.

    • Search Google Scholar
    • Export Citation
  • Levy, M., A. Estublier, and G. Madec, 2001: Choice of an advection scheme for biogeochemical models. Geophys. Res. Lett., 28, 37253728.

    • Search Google Scholar
    • Export Citation
  • Madec, G., 2008: NEMO ocean engine. Institut Pierre-Simon Laplace Note du Pôle de Modélisation 27, 217 pp.

  • Madec, G., P. Delecluse, M. Imbard, and C. Levy, 1998: OPA 8 ocean general circulation model—Reference manual. LODYC/IPSL Tech. Note 11, 91 pp.

  • Marshall, D., 1997: Subduction of water masses in an eddying ocean. J. Mar. Res., 55, 201222.

  • Marshall, J., and T. Radko, 2003: Residual-mean solutions for the Antarctic Circumpolar Current and its associated overturning circulation. J. Phys. Oceanogr., 33, 23412354.

    • Search Google Scholar
    • Export Citation
  • Marshall, J., D. Jamous, and J. Nilsson, 1999: Reconciling thermodynamic and dynamic methods of computation of water-mass transformation rates. Deep-Sea Res. I, 46, 545572.

    • Search Google Scholar
    • Export Citation
  • McCarthy, M. C., and L. D. Talley, 1999: Three-dimensional isoneutral potential vorticity structure in the Indian Ocean. J. Geophys. Res., 104, 13 25113 267.

    • Search Google Scholar
    • Export Citation
  • McDougall, T. J., and P. C. McIntosh, 2001: The temporal-residual-mean velocity. Part II: Isopycnal interpretation and the tracer and momentum equations. J. Phys. Oceanogr., 31, 12221246.

    • Search Google Scholar
    • Export Citation
  • McIntosh, P. C., and T. J. McDougall, 1996: Isopycnal averaging and the residual mean circulation. J. Phys. Oceanogr., 26, 16551660.

  • Nurser, A. J. G., and J. C. Marshall, 1991: On the relationship between subduction rates and diabatic forcing of the mixed layer. J. Phys. Oceanogr., 21, 17931802.

    • Search Google Scholar
    • Export Citation
  • Nurser, A. J. G., and J. W. Zhang, 2000: Eddy-induced mixed layer shallowing and mixed layer/thermocline exchange. J. Geophys. Res., 105 (C9), 21 85121 868.

    • Search Google Scholar
    • Export Citation
  • Nurser, A. J. G., and M.-M. Lee, 2004a: Isopycnal averaging at constant height. Part I: The exact formulation and a case study. J. Phys. Oceanogr., 34, 27212739.

    • Search Google Scholar
    • Export Citation
  • Nurser, A. J. G., and M.-M. Lee, 2004b: Isopycnal averaging at constant height. Part II: Relating to residual streamfunction. J. Phys. Oceanogr., 34, 27402755.

    • Search Google Scholar
    • Export Citation
  • Oschlies, A., 2002: Improved representation of upper-ocean dynamics and mixed layer depths in a model of the North Atlantic on switching from eddy-permitting to eddy-resolving grid resolution. J. Phys. Oceanogr., 32, 22772298.

    • Search Google Scholar
    • Export Citation
  • Sabine, C. L., and Coauthors, 2004: The oceanic sink for anthropogenic CO2. Science, 305, 367371.

  • Sallée, J.-B., K. Speer, S. R. Rintoul, and S. Wijffels, 2010: Southern Ocean thermocline ventilation. J. Phys. Oceanogr., 40, 509529.

    • Search Google Scholar
    • Export Citation
  • Walin, G., 1982: On the relation between sea-surface heat flow and thermal circulation in the ocean. Tellus, 34, 187195.

  • Zalesak, S., 1979: Fully multidimensional flux-corrected transport algorithms for fluids. J. Comput. Phys., 31, 335362.

All Time Past Year Past 30 Days
Abstract Views 0 0 0
Full Text Views 217 74 6
PDF Downloads 160 39 4