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Detailed Reference Information |
Guizien, K., Barthélemy, E. and Inall, M.E. (1999). Internal tide generation at a shelf break by an oblique barotropic tide: Observations and analytical modeling. Journal of Geophysical Research 104: doi: 10.1029/1999JC900089. issn: 0148-0227. |
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An analytical model has been developed to describe the generation of a linear interfacial wave over a steep ocean margin by a barotropic tide propagating toward the shelf break with a variable angle of incidence. The stratification is reduced to a two-layer system, and the model uses step-like shelf geometry. In both shallow and deep regions an open boundary is assumed (this implies particularly that there is no reflection at the coast). The model is forced with the amplitude and direction of an incident barotropic Poincar¿ wave propagating toward the shelf break. With this forcing, the model gives the amplitude, direction of propagation, and wavenumber of both barotropic and baroclinic Poincar¿ waves transmitted onto the shelf and reflected into the deep region in the vicinity of the shelf break. After comparison with Baines' <1973> model, our model is compared with internal tide observations made in July 1996 on the Malin Shelf within the U.K. Land Ocean Interaction Study-Shelf Edge Study program. The observations are from moored thermistor chains and acoustic Doppler current profilers sited at two locations, one near the shelf break and the other 47.5 km onto the shelf. Observations at this latter mooring are not described by the generation model because of nonlinear changes and damping as the internal wave propagates through shallow water. Baroclinic displacements of the thermocline of 8 m amplitude were observed close to the shelf break, and total baroclinic energy was estimated at 2.4 J/m3 during neap tide and 3 J/m3 during spring tide. Both amplitude and energy of the shoreward propagating internal tide waves are compared with the model. Using a barotropic forcing taken from bibliographical data, good agreement with observations is found during neap tide (when the density structure is close to being two-layer) for an incident barotropic tide of 1 m amplitude and propagation direction on a bearing of 23 ¿T (T means from True North in a clockwise sense). ¿ 1999 American Geophysical Union |
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Abstract |
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Keywords
Oceanography, General, Remote sensing and electromagnetic processes, Oceanography, Physical, Internal and inertial waves |
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Publisher
American Geophysical Union 2000 Florida Avenue N.W. Washington, D.C. 20009-1277 USA 1-202-462-6900 1-202-328-0566 service@agu.org |
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