深海近距离声场频率-距离干涉结构反演海底声学参数

地声反演一般存在多解性的问题,不易有效分离沉积层声速与厚度,本文提出了一种当声源与接收水听器分别位于海面与海底附近时匹配声场干涉周期反演深海沉积层声速与厚度的方法。该声场周期结构由直达波与海底沉积层反射回波干涉形成,其干涉周期受沉积层声速和厚度影响,通过匹配实测与理论计算的声场干涉周期可有效反演沉积层声速和厚度。开展了深海实验验证,利用水听器接收到的近距离船舶噪声的声场干涉条纹,反演得到的实验海域海底沉积层声速与该海域海底表层采样平均值差小于20 m/s。数值仿真与实验结果表明该方法可以有效反演沉积层的声速与厚度。

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.