Geoacoustic inversion based on near-field frequency-range interference pattern in deep water

A method by matching the measured sound intensity periodical structure is proposed to solve the problem of non-uniqueness and low efficiency to separate the thickness and sound speed of sediment in geoacoustic inversion. This method is able to estimate the thickness and sound speed of sediment with the source near the sea surface and the receiver near the sea bottom. This periodicity structure is caused by the interference between the direct arrival wave and the reflected wave from the sediment, and the interference cycle is closely related to the thickness and sound speed of sediment. As a result, the thickness and sound speed of sediment can be estimated by matching the interference cycle from experimental measurement and theoretical prediction. A sea trial was carried out. By matching the measured sound intensity interference stripes caused by near-range shipping noise, the difference between the inversion result of sound speed and the core data is less than 20 m/s. Results in simulation and experiment show that the proposed method is able to estimate the thickness and sound speed of sediment in deep water.