Two-Step Inversion of Geoacoustic Parameters with Bottom Reverberation and Transmission Loss in the Deep Ocean

Abstract

The parameters of deep ocean sediments are relevant for accurately predicting the sound field; however, it is difficult to measure the parameters in situ. Most inversion methods used in shallow water are inapplicable in the deep ocean because of the considerable differences in propagation characteristics. At present, no method for simultaneously obtaining sound speed, density, and attenuation that considers the sensitivity of sediment parameters is yet available. This study proposes a two-step inversion of geoacoustic parameters in the deep ocean. On the basis of the half-space model, the decline tendency of bottom reverberation level with travel time is used for the inversion of sound speed and density, whereas transmission loss is used for inversion of attenuation. Inversion results can be practical for acoustic applications when this method is used. Experimental data from the South China Sea in the summer of 2014 are processed during the inversion process. The sediment parameters obtained from the inversion process are close to the laboratory-measured sampling values and may be used to predict the sound field in various applications, such as in transmission loss in the deep ocean.