INTERNAL TIDES

Energy flux of the internal tides as estimated from a parameterization of internal wave drag in a forward model for the barotropic tides. Globally, deep ocean internal tides extract roughly 1 Terrawatt of energy from the surface tide (Jayne and St. Laurent 2001 ).

Internal waves are an ubiquitous class of oceanic phenomena, where wave motion transfers energy and momentum in the deep interior of the sea. Internal tides are generated at regions where the barotropic tidal current encounters variations in bottom topography. The resulting waves arise at the dominant tidal bands. The principle lunar semidiurnal (M2) and the lunar-solar diurnal (K1) are generally the most significant constituents in many locations. Since the diurnal and Coriolis frequencies are equal at roughly 30°, freely radiating diurnal internal tides are possible only equatorward of this latitude. This accounts for roughly half the ocean area, and semidiurnal internal tides are freely radiating over nearly all of the oceans, to 75° latitude.

The internal wave energy spectrum is generally "red," with most energy tied to low baroclinic modes of the internal tide with horizontal wavelengths between 10 and 100 km. At these scales, waves are very stable. A considerable succession of physical processes must be implicated to cascade low-mode energy to the scales where instability can act to produce turbulence.

Reviewed Publications

St. Laurent, L. and J. Nash, 2004. An examination of the radiative and dissipative properties of the internal tides. Deep-Sea Research II, 51, 3029—3042, doi:10.1016/j.dsr2.2004.09.008.

Simmons, H. L., S. R. Jayne, L. St. Laurent, and A. Weaver, 2004. Tidally driven mixing in a numerical model of the ocean general circulation. Ocean Modelling, 6, 245--263, doi:10.1016/S1463-5003(03)00011-8.

St. Laurent, L., S. Stringer, C. Garrett, and D. Perrault-Joncas, 2003. The generation of internal tides at abrupt topography. Deep-Sea Research I, 50, 987--1003, doi:10.1016/S0967-0637(03)00096-7.

St. Laurent, L., H. L. Simmons, S. R. Jayne, 2002. Estimating tidally driven mixing in the deep ocean. Geophysical Research Letters, 29, 2106-2110, doi:10.1029/2002GL015633.

St. Laurent, L., and C. Garrett, 2002. The Role of Internal Tides in Mixing the Deep Ocean. Journal of Physical Oceanography, 32, 2882-2899.

Garrett, C., and L. St. Laurent, 2002. Aspects of Deep Ocean Mixing. Journal of the Oceanographic Society of Japan, 58, 11-24.

St. Laurent, L., J. M. Toole, and R. W. Schmitt, 2001. Buoyancy forcing by turbulence above rough topography in the abyssal Brazil Basin. Journal of Physical Oceanography, 31, 347-3495.

Jayne, S. R., and L. St. Laurent, 2001. Parameterizing Tidal Dissipation Over Rough Topography. Geophysical Research Letters, 28, 811-814.

Additional Publications

Jayne, S. R., L. C. St. Laurent, and S. T. Gille, 2004. Connections between ocean bottom topography and Earth's climate. Oceanography, 17, 65--74.

St. Laurent, L., and J. Nash, 2003. On the fraction of internal tide energy dissipated near topography. In Proceedings of the 'Aha Huliko'a Hawaiian Winter Workshop, 45--58.

St. Laurent, L., and C. Garrett, 2002. Energy dissipation by internal ocean tides. Bulletin of the American Meteorological Society, 83, 1457--1458.

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This page was last updated on 12/12/25