Tomography of the surface elevation in shallow water between two source-receiver ultrasonic arrays: A small scale experiment demonstration.

Abstract

Based on single-scattering effects, the diffraction-based sensitivity kernels which make the link between the acoustic perturbations and the medium fluctuations have been extensively studied. We propose a similar study for perturbations at the air-water interface in an ultrasonic waveguide that scales down with a 1-km-long, 50-m-deep ocean acoustic channel in the kilohertz regime. Using array processing between two source-receiver arrays, the sensitivity kernel for both time and amplitude has been experimentally inferred for each acoustic echo reverberated in the waveguide to a small surface elevation. We demonstrate a good agreement between experimental and theoretical sensitivity kernels. Finally, using theoretical sensivity kernels for both amplitude and time ultrasonic fluctuations, we give a real-time estimation of the surface elevation at any point between the source and receiver arrays.