Geo-acoustic inversion with vector sensors in shallow water.

Abstract

Vector sensors have attracted much attention in recent years. However, relative few papers have been published on the geo-acoustic inversion with vector sensors. The data recorded with vector sensors in several shallow water acoustic experiments have been studied in this paper. The experimental data and theoretical analyses indicate that (1) the intensity of the vertical particle velocity decreases faster than that of the horizontal particle velocity; (2) the same normal modes of the horizontal particle velocity and the vertical particle velocity have similar transmission losses, but different amplitudes and phases; (3) the difference of the mode amplitudes between the horizontal particle velocity and the vertical particle velocity is dependent on the eigen-value and receiver depth. With those properties, two geo-acoustic inversion schemes employing vector sensors have been developed. The first inversion scheme uses a combination of matched field processing and the difference of transmission losses between pressure and particle velocity. The second estimates the bottom sound speed and attenuation from the amplitudes of normal modes of particle velocities. Experimental results show that the developed geo-acoustic inversion methods with vector sensors can decrease the uncertainty of inversion in comparison with that by hydrophones.