"Ocean Acoustic Tomography Applied to the Estimation of
Internal Tides in the Continental Platform"
PhD thesis by Orlando C. Rodríguez
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Abstract: this thesis discusses the application of the methods of Ocean Acoustic Tomography to monitorize and invert the variations of internal tides in coastal environments. The material of this thesis starts with the detailed theoretical description of the propagation of internal tides, in the linear and non-linear cases. This discussion allows one to introduce the concept of Hydrostatic Normal Modes (HNMs). It is shown, in particular, that the HNMs constitute a complete orthogonal basis to represent the fields of pressure, current, temperature, sound speed and salinity. Furthermore, ray-tracing simulations are used to predict the effects of variations on waveguide geometry, and sound speed, on the temporal arrivals of the acoustic signal. The simulations allow one to develop a robust strategy of tomographic inversion, which is first tested with simulated data, and then on real acoustic data from the INTIMATE'96 experiment. Finally, it is shown that the methods of Ocean Acoustic Tomography can be efficiently applied to monitorize and invert the propagation of the internal tide, allowing one to achieve a high degree of tomographic precision.