Generation and Kinematics of the Internal Tide in the Strait of Gibraltar
Observations from moorings and hydrographic surveys during the Gibraltar Experiment are used to describe the structure in space and time of the internal tide in the strait. By internal tide is meant those fluctuations of the interface (separating inflowing Atlantic from outflowing Mediterranean waters) that have a persistent and demonstrable phase relationship to the barotropic tide. Two modes of fluctuation dominate the variance at semi-diurnal frequency: rising and falling of the interface throughout the strait, which explains about half of the total variance, and fluctuations in the cross-strait slope of the interface, which explains about 25% of the variance. The largest amplitude fluctuations are found at the Camarinal sill. The interface rises and falls approximately in quadrature with the barotropic current, and a kinematic argument for why that should occur is presented. The cross-strait slope of the interface changes approximately in phase with the barotropic tidal currents, corresponding to changes in the vertical shear, in what may be an incomplete geostrophic adjustment in the cross-strait direction.
KeywordsSurface Elevation Empirical Orthogonal Function Tidal Current Internal Tide Empirical Orthogonal Function Mode
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- Bray, N. A. (1986) Gibraltar experiment CTD data report, March-April 1986, USNS Lynch, SIO Ref. 86–21, 212 pp., Scripps Inst, of Oceanogr., La Jolla, Calif., USA.Google Scholar
- Bray, N. A., and H. Lacombe (1989) Tidal modulation of water mass exchange in the Strait of Gibraltar. In preparation.Google Scholar
- Candela, J., C. D. Winant, and H. L. Bryden (1989) Meteorologically forced subinertial flows through the Strait of Gibraltar, accepted by J. Geophys. Res.Google Scholar
- Candela, J., C. D. Winant, and A. Ruiz (submitted 1989) Tides in the Strait of Gibraltar, J. Geophys. Res.Google Scholar
- Kinder, T. H., D. A. Burns, and R. D. Broome (1986) Hydrographic measurements in the Strait of Gibraltar, November 1985, Naval Ocean Research and Development Activity Report 141, 332 pp.Google Scholar
- Kinder, T. H., D. A. Burns, and M. R. Wilcox (1987) Hydrographic measurements in the Strait of Gibraltar, June 1986, NORDA Tech. Note 378-1 (Appendix), 355 pp.Google Scholar
- Shull, S., and N. A. Bray (1989) Gibraltar Experiment CTD data report: September-October 1986, USNS Lynch. In preparation.Google Scholar