• Adcroft, A., C. Hill, and J. Marshall, 1997: The representation of topography by shaved cells in a height coordinate model. Mon. Wea. Rev., 125 , 22932315.

    • Search Google Scholar
    • Export Citation
  • Ambar, I., L. Armi, A. Bower, and T. Ferreira, 1999: Some aspects of time variability of the Mediterranean Water off south Portugal. Deep-Sea Res., 46 , 11091136.

    • Search Google Scholar
    • Export Citation
  • Antoniou, A., 1993: Digital Filters: Analysis, Design, and Applications. 2d ed. McGraw-Hill, 689 pp.

  • Astraldi, M., and Coauthors, 1999: The role of straits and channels in understanding the characteristics of Mediterranean circulation. Progress in Oceanography, 44 , Pergamon,. 65108.

    • Search Google Scholar
    • Export Citation
  • Bormans, M., and C. Garrett, 1989: The effects of nonrectangulal cross section, friction, and barotropic fluctuations on the exchange through the Strait of Gibraltar. J. Phys. Oceanogr., 19 , 15431557.

    • Search Google Scholar
    • Export Citation
  • Brandt, P., A. Rubino, D. V. Sein, B. Baschek, A. Izquierdo, and J. O. Backhaus, 2004: Sea level variations in the Western Mediterranean studied by a numerical tidal model of the Strait of Gibraltar. J. Phys. Oceanogr., 34 , 433443.

    • Search Google Scholar
    • Export Citation
  • Candela, J., C. D. Winant, and H. L. Bryden, 1989: Meteorologically forced subinertial flows through the Strait of Gibraltar. J. Geophys. Res., 94 , 1266712679.

    • Search Google Scholar
    • Export Citation
  • Cazenave, A., P. Bonnefond, F. Mercier, K. Dominh, and V. Toumazou, 2002: Sea level variations in the Mediterranean Sea and Black Sea from satellite altimetry and tide gauges. Global Planet. Change, 34 , 5986.

    • Search Google Scholar
    • Export Citation
  • Csanady, G. T., 1974: Barotropic currents over the continental shelf. J. Phys. Oceanogr., 4 , 357371.

  • Csanady, G. T., 1982: Circulation in the Coastal Ocean. Reidel, 279 pp.

  • Dorman, C. E., R. C. Beardsley, and R. Limeburner, 1995: Winds in the strait of Gibraltar. Quart. J. Roy. Meteor. Soc., 121 , 19031921.

    • Search Google Scholar
    • Export Citation
  • Feddersen, F., E. L. Gallagher, R. T. Guza, and S. Elgar, 2003: The drag coefficient, bottom roughness, and wave-breaking in the nearshore. Coastal Eng., 48 , 189195.

    • Search Google Scholar
    • Export Citation
  • Fieguth, P. W., D. Menemenlis, T. Ho, A. S. Willsky, and C. Wunsch, 1998: Mapping Mediterranean altimeter data with a multiresolution optimal interpolation algorithm. J. Atmos. Oceanic Technol., 15 , 535546.

    • Search Google Scholar
    • Export Citation
  • Fukumori, I., D. Menemenlis, and T. Lee, 2007: A near-uniform basin-wide sea level fluctuation of the Mediterranean Sea. J. Phys. Oceanogr., 37 , 338358.

    • Search Google Scholar
    • Export Citation
  • García-Lafuente, J., J. Delgado, and F. Criado, 2002a: Inflow interruption by meteorological forcing in the Strait of Gibraltar. Geophys. Res. Lett., 29 .1914, doi:10.1029/2002GL015446.

    • Search Google Scholar
    • Export Citation
  • García-Lafuente, J., E. A. Fanjul, J. M. Vargas, and A. W. Ratsimandresy, 2002b: Subinertial variability in the flow through the Strait of Gibraltar. J. Geophys. Res., 107 .3168, doi:10.1029/2001JC001104.

    • Search Google Scholar
    • Export Citation
  • García-Lafuente, J., J. D. Río, E. A. Fanjul, D. Gomis, and J. Delgado, 2004: Some aspects of the seasonal sea level variations around Spain. J. Geophys. Res., 109 .C09008, doi:10.1029/2003JC002070.

    • Search Google Scholar
    • Export Citation
  • Garrett, C., 1983: Variable sea level and strait flows in the Mediterranean: A theoretical study of the response to meteorological forcing. Oceanol. Acta, 6 , 7987.

    • Search Google Scholar
    • Export Citation
  • Garrett, C., 2004: Frictional processes in straits. Deep-Sea Res., 51 , 393410.

  • Garrett, C., and F. Majaess, 1984: Nonisostatic response of sea level to atmospheric pressure in the Eastern Mediterranean. J. Phys. Oceanogr., 14 , 656665.

    • Search Google Scholar
    • Export Citation
  • Garrett, C., J. Akerley, and K. Thompson, 1989: Low-frequency fluctuations in the Strait of Gibraltar from MEDALPEX sea level data. J. Phys. Oceanogr., 19 , 16821696.

    • Search Google Scholar
    • Export Citation
  • Gill, A. E., 1982: Atmosphere–Ocean Dynamics. International Geophysics Series, Vol. 30, Academic Press, 662 pp.

  • Gravili, D., E. Napolitano, and S. Pierini, 2001: Barotropic aspects of the dynamics of the Gulf of Naples (Tyrrhenian Sea). Contin. Shelf Res., 21 , 455471.

    • Search Google Scholar
    • Export Citation
  • Kara, A. B., P. A. Rochford, and H. E. Hurlburt, 2000: Efficient and accurate bulk parameterizations of air–sea fluxes for use in general circulation models. J. Atmos. Oceanic Technol., 17 , 14211438.

    • Search Google Scholar
    • Export Citation
  • Kistler, R., and Coauthors, 2001: The NCEP–NCAR 50-year reanalysis: Monthly means CD-ROM and documentation. Bull. Amer. Meteor. Soc., 82 , 247268.

    • Search Google Scholar
    • Export Citation
  • Larnicol, G., P-Y. Le Traon, N. Ayoub, and P. D. Mey, 1995: Mean sea level and surface circulation variability of the Mediterranean Sea from two years of TOPEX/POSEIDON altimetry. J. Geophys. Res., 100 , 2516325177.

    • Search Google Scholar
    • Export Citation
  • Leith, C. E., 1996: Stochastic models of chaotic systems. Physica D, 98 , 481491.

  • Le Traon, P-Y., and P. Gauzelin, 1997: Response of the Mediterranean mean sea level to atmospheric pressure forcing. J. Geophys. Res., 102 , 973984.

    • Search Google Scholar
    • Export Citation
  • Marshall, J., A. Adcroft, C. Hill, L. Perelman, and C. Heisey, 1997a: A finite-volume, incompressible Navier–Stokes model for studies of the ocean on parallel computers. J. Geophys. Res., 102 , 57535766.

    • Search Google Scholar
    • Export Citation
  • Marshall, J., C. Hill, L. Perelman, and A. Adcroft, 1997b: Hydrostatic, quasi-hydrostatic and non-hydrostatic ocean modeling. J. Geophys. Res., 102 , 57335752.

    • Search Google Scholar
    • Export Citation
  • Ponte, R. M., D. A. Salstein, and R. D. Rosen, 1991: Sea level response to pressure forcing in a barotropic numerical model. J. Phys. Oceanogr., 21 , 10431057.

    • Search Google Scholar
    • Export Citation
  • Press, W. H., S. A. Teukolsky, W. T. Vetterling, and B. P. Flannery, 1992: Numerical Recipes in FORTRAN: The Art of Scientific Computing. 2d ed. Cambridge University Press, 963 pp.

    • Search Google Scholar
    • Export Citation
  • Ross, T., and C. Garrett, 2000: Western Mediterranean sea-level rise: Changing exchange flow through the Strait of Gibraltar. Geophys. Res. Lett., 27 , 29492952.

    • Search Google Scholar
    • Export Citation
  • Sandstrom, H., 1980: On the wind-induced sea level changes on the Scotian Shelf. J. Geophys. Res., 85 , 461468.

  • Sannino, G., A. Bargagli, and V. Artale, 2004: Numerical modeling of the semidiurnal tidal exchange through the Strait of Gibraltar. J. Geophys. Res., 109 .C05011, doi:10.1029/2003JC002057.

    • Search Google Scholar
    • Export Citation
  • Smith, W. H. F., and D. T. Sandwell, 1997: Global sea floor topography from satellite altimetry and ship depth soundings. Science, 277 , 19561962.

    • Search Google Scholar
    • Export Citation
  • Stanichny, S., V. Tigny, R. Stanichnaya, and S. Djenidi, 2005: Wind driven upwelling along the African coast of the Strait of Gibraltar. Geophys. Res. Lett., 32 .L04604, doi:10.1029/2004GL021760.

    • Search Google Scholar
    • Export Citation
  • Tsimplis, M. N., and T. F. Baker, 2000: Sea level drop in the Mediterranean Sea: An indicator of deep water salinity and temperature changes? Geophys. Res. Lett., 27 , 17311734.

    • Search Google Scholar
    • Export Citation
  • Tsimplis, M. N., and S. A. Josey, 2001: Forcing of the Mediterranean Sea by atmospheric oscillations over the North Atlantic. Geophys. Res. Lett., 28 , 803806.

    • Search Google Scholar
    • Export Citation
  • Wunsch, C., 1996: The Ocean Circulation Inverse Problem. Cambridge University Press, 442 pp.

All Time Past Year Past 30 Days
Abstract Views 0 0 0
Full Text Views 18 18 18
PDF Downloads 9 9 9

Atlantic to Mediterranean Sea Level Difference Driven by Winds near Gibraltar Strait

View More View Less
  • 1 Jet Propulsion Laboratory, California Institute of Technology, Pasadena, California
Restricted access

Abstract

Observations and numerical simulations show that winds near Gibraltar Strait cause an Atlantic Ocean to Mediterranean Sea sea level difference of 20 cm peak to peak with a 3-cm standard deviation for periods of days to years. Theoretical arguments and numerical experiments establish that this wind-driven sea level difference is caused in part by storm surges due to alongshore winds near the North African coastline on the Atlantic side of Gibraltar. The fraction of the Moroccan coastal current offshore of the 284-m isobath is deflected across Gibraltar Strait, west of Camarinal Sill, resulting in a geostrophic surface pressure gradient that contributes to a sea level difference at the stationary limit. The sea level difference is also caused in part by the along-strait wind setup, with a contribution proportional to the along-strait wind stress and to the length of Gibraltar Strait and adjoining regions and inversely proportional to its depth. In the 20–360-day band, average transfer coefficients between the Atlantic–Alboran sea level difference and surface wind stress at 36°N, 6.5°W, estimated from barometrically corrected Ocean Topography Experiment (TOPEX)/Poseidon data and NCEP–NCAR reanalysis data, are 0.10 ± 0.04 m Pa−1 with 1 ± 5-day lag and 0.19 ± 0.08 m Pa−1 with 5 ± 4-day lag for the zonal and meridional wind stresses, respectively. This transfer function is consistent with equivalent estimates derived from a 1992–2003 high-resolution barotropic simulation forced by the NCEP–NCAR wind stress. The barotropic simulation explains 29% of the observed Atlantic–Alboran sea level difference in the 20–360-day band. In turn, the Alboran and Mediterranean mean sea level time series are highly correlated, ρ = 0.7 in the observations and ρ = 0.8 in the barotropic simulation, hence providing a pathway for winds near Gibraltar Strait to affect the mean sea level of the entire Mediterranean.

Corresponding author address: Dimitris Menemenlis, Jet Propulsion Laboratory, California Institute of Technology, Mail Stop 300–323, 4800 Oak Grove Dr., Pasadena, CA 91109. Email: menemenlis@jpl.nasa.gov

This article included in the In Honor of Carl Wunsch special collection.

Abstract

Observations and numerical simulations show that winds near Gibraltar Strait cause an Atlantic Ocean to Mediterranean Sea sea level difference of 20 cm peak to peak with a 3-cm standard deviation for periods of days to years. Theoretical arguments and numerical experiments establish that this wind-driven sea level difference is caused in part by storm surges due to alongshore winds near the North African coastline on the Atlantic side of Gibraltar. The fraction of the Moroccan coastal current offshore of the 284-m isobath is deflected across Gibraltar Strait, west of Camarinal Sill, resulting in a geostrophic surface pressure gradient that contributes to a sea level difference at the stationary limit. The sea level difference is also caused in part by the along-strait wind setup, with a contribution proportional to the along-strait wind stress and to the length of Gibraltar Strait and adjoining regions and inversely proportional to its depth. In the 20–360-day band, average transfer coefficients between the Atlantic–Alboran sea level difference and surface wind stress at 36°N, 6.5°W, estimated from barometrically corrected Ocean Topography Experiment (TOPEX)/Poseidon data and NCEP–NCAR reanalysis data, are 0.10 ± 0.04 m Pa−1 with 1 ± 5-day lag and 0.19 ± 0.08 m Pa−1 with 5 ± 4-day lag for the zonal and meridional wind stresses, respectively. This transfer function is consistent with equivalent estimates derived from a 1992–2003 high-resolution barotropic simulation forced by the NCEP–NCAR wind stress. The barotropic simulation explains 29% of the observed Atlantic–Alboran sea level difference in the 20–360-day band. In turn, the Alboran and Mediterranean mean sea level time series are highly correlated, ρ = 0.7 in the observations and ρ = 0.8 in the barotropic simulation, hence providing a pathway for winds near Gibraltar Strait to affect the mean sea level of the entire Mediterranean.

Corresponding author address: Dimitris Menemenlis, Jet Propulsion Laboratory, California Institute of Technology, Mail Stop 300–323, 4800 Oak Grove Dr., Pasadena, CA 91109. Email: menemenlis@jpl.nasa.gov

This article included in the In Honor of Carl Wunsch special collection.

Save