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Theses
Ajustement géostrophique nonlinéaire en présence de guides d'ondes équatorial, côtier, topographique et frontal.
Ajustement géostrophique nonlinéaire en présence de guides d'ondes équatorial, côtier, topographique et frontal.
Abstract : Geostrophic adjustment, the process of relaxation of a perturbation toward a state of geostrophic equilibrium, well-known in an infinite fluid, is modified in the presence of waveguides. Waveguides are ubiquitous in the ocean and in the atmosphere: varying topography (marine / mountains), coasts and density fronts. We studied the modification of the scenario of geostrophic adjustment in the presence of four different waveguides: the coastal waveguide, the topographic waveguide, the midlatitude frontal waveguide and the equatorial frontal waveguide. We used the rotating shallow water model and finite volume numerical methods adapted to treat the topography and the incropping/outcropping of fronts. In all cases, generation of trapped waves takes place and the nonlinear evolution of the trapped waves depend on the dispersive properties of the trapped waves. Non-dispersive waves like the coastal Kelvin wave, during their nonlinear evolution, break and so contribute to the small scale mixing. Dispersive waves like the topographic Rossby waves, or the waves propagating along the frontal waveguide, reconnect streamlines, altering the transport properties of the flow. We show that the dynamical splitting between slow/balanced and fast/unbalanced motions, known in free flow, is always effective in the presence of the waveguides.
https://tel.archives-ouvertes.fr/tel-00357654
Contributor : Emilie Scherer <>
Submitted on : Saturday, January 31, 2009 - 12:36:02 AM
Last modification on : Thursday, December 10, 2020 - 12:37:16 PM
Long-term archiving on: : Tuesday, June 8, 2010 - 9:45:31 PM
Contributor : Emilie Scherer <>
Submitted on : Saturday, January 31, 2009 - 12:36:02 AM
Last modification on : Thursday, December 10, 2020 - 12:37:16 PM
Long-term archiving on: : Tuesday, June 8, 2010 - 9:45:31 PM