• Arhan, M., 1987: On the large scale dynamics of the Mediterranean Outflow. Deep-Sea Res.,34, 1187–1208.

  • ——, A. Colin de Verdière, and L. Mèmery, 1994: The eastern boundary of the subtropical North Atlantic. J. Phys. Oceanogr.,24, 1295–1316.

  • Armi, L., and D. Haidvogel, 1982: Effects of variable and anisotropic diffusivities in a steady state diffusion model. J. Phys. Oceanogr.,12, 785–794.

  • ——, and H. Stommel, 1983: Four views of a portion of the North Atlantic subtropical gyre. J. Phys. Oceanogr.,13, 828–857.

  • ——, D. Herbert, N. Oakey, and J. Price, 1989: Two years in the life of a Mediterranean salt lens. J. Phys. Oceanogr.,19, 354–370.

  • Baringer, M. O., and J. F. Price, 1997a: Mixing and spreading of the Mediterranean outflow. J. Phys. Oceanogr.,27, 1654–1677.

  • ——, and ——, 1997b: Momentum and energy balance of the Mediterranean outflow. J. Phys. Oceanogr.,27, 1678–1692.

  • Bower, A. S., L. Armi, and I. Ambar, 1995: Direct evidence of meddy formation off the southwestern coast of Portugal. Deep-Sea Res.,42, 1621–1630.

  • ——, ——, and ——, 1997: Lagrangian observations of Meddy formation during a Mediterranean Undercurrent seeding experiment. J. Phys. Oceanogr.,27, 2545–2575.

  • Chérubin, L., A. Serpette, X. Carton, and J. Paillet, 1997: Descriptive analysis of the hydrology and currents on the Iberian shelf from Gibraltar to Cape Finisterre: Preliminary results from the SEMANE and INTERAFOS experiments. Ann. Hydrograph.,21 (768), 5–69.

  • Curry, R. G., 1996: Hydrobase: A database of hydrographic stations and tools for climatologic analysis. Woods Hole Oceanographic Institution Tech Rep. 96-01, 50 pp. [Available from Woods Hole Oceanographic Institution, Woods Hole, MA 02543.].

  • Daniault, N., J. P. Maze, and M. Arhan, 1994: Circulation and mixing of Mediterranean Water west of the Iberian Peninsula. Deep-Sea Res.,41, 1685–1714.

  • D’Asaro, E. A., 1988: Generation of submesoscale vortices: A new mechanism. J. Geophys. Res.,93, 6685–6693.

  • DaSilva, A., A. C. Young, and S. Levitus, 1994: NOAA SMD94. Tech. Rep. 6, NOAA/NESDIS, Washington, DC, 83 pp.

  • 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 transports in ocean circulation models. J. Phys. Oceanogr.,25, 463–474.

  • Green, J. S., 1970: Transfer properties of the large-scale eddies and the general circulation of the atmosphere. Quart. J. Roy. Meteor. Soc.,96, 157–185.

  • Howe, M. R., 1984: Current and hydrographical measurements in the Mediterranean Undercurrent near Cape St. Vincent. Oceanol. Acta,7, 163–168.

  • Kase, R. H., and W. Zenk, 1996: The structure of the Mediterranean water and meddy characteristics in the northeastern Atlantic. The Warmwatersphere of the North Atlantic, Gebruder Borntraeger.

  • Lacombe, H., 1971: Le detroit de Gibraltar oceanographie physique. Extrait de: Memoire explicatif de la Carte geotechnique de Tanger au 1/25 000. Notes M. Serv. Geol. Maroc,222, 111–146.

  • Lee, M., D. P. Marshall, and R. G. Williams, 1997: On the eddy transfer of tracers: Advective or diffusive? J. Mar. Res.,55, 483–505.

  • Lozier, M. S., W. B. Owens, and R. G. Curry, 1995: The climatology of the North Atlantic. Progress in Oceanography, Vol. 36, Academic Press, 1–44.

  • Luyten, J. R., J. Pedlosky, and H. Stommel, 1983: The ventilated thermocline. J. Phys. Oceanogr.,13, 292–309.

  • Maze, J. P., M. Arhan, and H. Mercier, 1997: Volume budget of the eastern boundary layer off the Iberian Peninsula. Deep-Sea Res.,44, 1543–1574.

  • McDowell, S. E., and H. T. Rossby, 1978: Mediterranean Water: An intense mesoscale eddy off the Bahamas. Science,202, 1085–1087.

  • Müller, T. J., and G. Siedler, 1992: Multiyear current time-series in the eastern North Atlantic Ocean. J. Mar. Res.,50, 63–98.

  • Needler, G. T., and R. A. Heath, 1975: Diffusion coefficients calculated from the Mediterranean salinity anomaly in the North Atlantic Ocean. J. Phys. Oceanogr.,5, 173–182.

  • Paillet, J., and H. Mercier, 1997: An inverse model of the eastern North Atlantic general circulation and thermocline ventilation. Deep-Sea Res.,44, 1293–1328.

  • Pedlosky, J., 1996: Ocean Circulation Theory. Springer-Verlag, 453 pp.

  • Press, W. H., S. A. Teukolsky, W. T. Vetterling, and B. P. Flannery, 1992: Numerical Recipes in FORTRAN. The Art of Scientific Computing. Cambridge University Press, 989 pp.

  • Reid, J. L., 1979: On the contribution of the Mediterranean Sea outflow to the Norwegian–Greenland Sea. Deep-Sea Res.,26A, 1199–1223.

  • Rhines, P. B., and W. R. Young, 1982a: Homogenization of potential vorticity in planetary gyres. J. Fluid Mech.,122, 347–368.

  • ——, and ——, 1982b: A theory of the wind-driven circulation. Part 1: Mid-ocean gyres. J. Mar. Res.,40, 559–596.

  • Richardson, P. L., and K. Mooney, 1975: The Mediterranean Outflow—A simple advection–diffusion model. J. Phys. Oceanogr.,5, 476–482.

  • ——, and A. Tychensky, 1998: Semaphore meddy trajectories. J. Geophys. Res.,103, 25 029–25 045.

  • ——, D. Walsh, and L. Armi, 1989: Tracking three meddies with SOFAR floats. J. Phys. Oceanogr.,19, 371–383.

  • ——, M. S. McCartney, and C. Maillard, 1991: A search for meddies in historical data. Dyn. Atmos. Oceans,15, 241–265.

  • Saunders, P. M., 1982: Circulation in the eastern North Atlantic. J. Mar. Res.,40 (Suppl), 641–651.

  • Schopp, R., and M. Arhan, 1986: A ventilated mid-depth circulation model for the eastern North Atlantic. J. Phys. Oceanogr.,16, 344–357.

  • Shapiro, G. I., S. L. Meschanov, and M. V. Emelianov, 1995: Mediterranean lens “Irving” after its collision with seamounts. Oceanol. Acta.,18, 309–318.

  • Spall, M. A., 1994: Mechanism for low-frequency variability and salt-flux in the Mediterranean salt tongue. J. Geophys. Res.,99, 10 121–10 129.

  • ——, 1999: A simple model of the large scale circulation of Mediterranean Water and Labrador Sea Water. Deep Sea Res.,46, 181–204.

  • ——, P. L. Richardson, and J. Price, 1993: Advection and eddy mixing in the Mediterranean salt tongue. J. Mar. Res.,51, 797–818.

  • Stommel, H., 1948: The westward intensification of wind-driven ocean currents. Trans. Amer. Geophys. Union,29, 202–206.

  • Stone, P., 1972: A simplified radiative–dynamical model for the static stability of rotating atmospheres. J. Atmos. Sci.,29, 405–418.

  • Talley, L. D., and M. S. McCartney, 1982: Distribution and circulation of Labrador Sea Water. J. Phys. Oceanogr.,12, 1189–1205.

  • Tziperman, E., 1987: The Mediterranean Outflow as an example of deep buoyancy-driven flow. J. Geophys. Res.,92 (C13), 14 510–14 520.

  • Visbeck, M., J. Marshall, T. Haine, and M. Spall, 1997: Specification of eddy transfer coefficients in coarse-resolution ocean circulation models. J. Phys. Oceanogr.,27, 381–402.

  • Zenk, W., and T. J. Müller, 1988: Seven-year current meter record in the eastern North Atlantic. Deep-Sea Res.,35, 1259–1268.

  • ——, and L., Armi, 1990: The complex spreading of Mediterranean Water off the Portuguese continental slope. Deep-Sea Res.,37, 1805–1823.

All Time Past Year Past 30 Days
Abstract Views 0 0 0
Full Text Views 220 67 11
PDF Downloads 81 47 10

Dynamics of the Mediterranean Salinity Tongue

View More View Less
  • 1 Department of Meteorology, University of Reading, Reading, United Kingdom
Restricted access

Abstract

A reduced-gravity planetary-geostrophic model of the North Atlantic consisting of two active layers overlying a motionless abyss is developed to investigate the effect of the wind field in shaping the dynamics of the Mediterranean salinity tongue. The model is driven by climatological winds and eastern boundary ventilation in a basin of realistic geometry and includes a parameterization of meddies.

The upper-layer depth from the model shows a clear similarity to observations, both in terms of the location and intensity of the subtropical gyre and also the position of the outcropping line in the northern basin. Potential vorticity in layer two reproduces the sweep of potential-vorticity contours southwestward from the eastern boundary and extending westward into the interior, and provides the pathways along which Mediterranean Water spreads into the model interior.

The authors solve for the steady salinity field in the second layer, including sources of Upper Labrador Sea Water and Antarctic Intermediate Water on the isopycnal surface. The shape and spreading latitude of the model salinity tongues bear a striking resemblance to observations. Both the wind forcing and the occurrence of a mean transport of Mediterranean Water away from the eastern boundary are crucial in obtaining a realistic salinity tongue. The salinity tongues are remarkably stable to variations in the Peclet number.

A simple parameterization of meddies in the model is also included. Where meddies are dissipated locally by collisions with topographic seamounts, for example, they may generate large recirculations extending across to the western boundary. The net effect of these recirculations is to shift the salinity tongue equatorward.

Corresponding author address: James C. Stephens, Department of Meteorology, University of Reading, P.O. Box 243, Reading RG6 6BB, United Kingdom.

Email: swrsteph@met.reading.ac.uk

Abstract

A reduced-gravity planetary-geostrophic model of the North Atlantic consisting of two active layers overlying a motionless abyss is developed to investigate the effect of the wind field in shaping the dynamics of the Mediterranean salinity tongue. The model is driven by climatological winds and eastern boundary ventilation in a basin of realistic geometry and includes a parameterization of meddies.

The upper-layer depth from the model shows a clear similarity to observations, both in terms of the location and intensity of the subtropical gyre and also the position of the outcropping line in the northern basin. Potential vorticity in layer two reproduces the sweep of potential-vorticity contours southwestward from the eastern boundary and extending westward into the interior, and provides the pathways along which Mediterranean Water spreads into the model interior.

The authors solve for the steady salinity field in the second layer, including sources of Upper Labrador Sea Water and Antarctic Intermediate Water on the isopycnal surface. The shape and spreading latitude of the model salinity tongues bear a striking resemblance to observations. Both the wind forcing and the occurrence of a mean transport of Mediterranean Water away from the eastern boundary are crucial in obtaining a realistic salinity tongue. The salinity tongues are remarkably stable to variations in the Peclet number.

A simple parameterization of meddies in the model is also included. Where meddies are dissipated locally by collisions with topographic seamounts, for example, they may generate large recirculations extending across to the western boundary. The net effect of these recirculations is to shift the salinity tongue equatorward.

Corresponding author address: James C. Stephens, Department of Meteorology, University of Reading, P.O. Box 243, Reading RG6 6BB, United Kingdom.

Email: swrsteph@met.reading.ac.uk

Save