Time-angle ocean acoustic tomography using sensitivity kernels: The forward problem

Session 3pAO: Ocean Acoustical Tomography 3pAO3. Time-angle ocean acoustic tomography using sensitivity kernels: Numerical and experimental inversion results

In shallow water acoustic tomography, broadband mid-frequency acoustic waves (1 to 5 kHz) follow multiple ray-like paths to travel through the ocean. Travel-time (TT) variations associated to these raypaths are classically used to estimate sound speed perturbations of the water column using the ray theory. In this shallow water environment, source and receiver arrays, combined with adapted arra...

Time-angle sensitivity kernels for sound-speed perturbations in a shallow ocean.

Acoustic waves traveling in a shallow-water waveguide produce a set of multiple paths that can be characterized as a geometric approximation by their travel time (TT), direction of arrival (DOA), and direction of departure (DOD). This study introduces the use of the DOA and DOD as additional observables that can be combined to the classical TT to track sound-speed perturbations in an oceanic wa...

Ocean Acoustic Tomography

The idea of using the sound to monitor the changes in the marine environment motivated the oceanographers to develop the concept of ocean acoustic tomography. Starting from the early 80’s when the pioneers started to pave the way leading to the acoustical monitoring of the ocean change and coming to the beginning of the new millennium, several achievements in the field can be reported vindicati...

Ocean acoustic tomography structured covariance estimation

Classic Ocean Acoustic Tomography by Wiener inversion needs good estimates of the noises power affecting the errors between the in situ measurements of the travel times and their estimates obtained by reliable simulations. We investigate the maximum likelihood estimation of a structured covariance matrix, whose subspaces of interest are known, but whose associated powers are unknown. Using the ...

An autonomous system for ocean acoustic tomography