Internal Tide Generation by Tall Ocean Ridges
WOODS HOLE OCEANOGRAPHIC INSTITUTION MA
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Internal tides are internal waves of tidal period generated by tidal currents owing over submarine topography. Tall ridges that are nominally two-dimensional 2-D are sites of particularly strong generation. The subsequent dissipation of internal tides contributes to ocean mixing, thereby playing an important role in the circulation of the ocean. Strong internal tides can also evolve into internal wave solitons, which aect acoustic communication, oshore structures and submarine navigation. This thesis addresses the generation of internal tides by tall submarine ridges using a combined analytical and experimental approach. The rst part of the thesis is an experimental investigation of a pre-existing Green function formulation for internal tide generation by a tall symmetric ridge in a uniform density stratication. A modal decomposition technique was developed to characterize the structure of the experimental wave elds generated by 2D model topographies in a specially congured wave tank. The theory accurately predicts the low mode structure of internal tides, and reasonably predicts the conversion rate of internal tides in nite tidal excursion regimes, for which the emergence of non-linearities was notable in the laboratory.
- Hydrology, Limnology and Potamology