OCEAN SOUND FIELD CHARACTERIZATION USING PROCESSING TECHNIQUES BASED ON NOISE SPATIAL COHERENCE

The spatial coherence of ambient noise can be used for noise-based inversion studies using appropriate coherence models. The main findings of this thesis are presented in four chapters. In chapter 2, using a two-component noise coherence model (wind and shipping), an inversion scheme is developed to determine the relative and absolute contribution of frequency-dependent ship noise to the total sound field. A simple model of vertical coherence for a broadband acoustic source is developed in chapter 3 to understand the characteristics of the sound field produced by ships. In the fourth chapter, a map of vertical noise coherence is generated to study the environmental dependence of vertical coherence at the mesoscale. Finally, in chapter 5, a three-component (wind, close-range shipping, and distant wind and shipping) depth-dependent noise coherence model is developed to identify and partition the noise field in deep water.