浅海空气声入水传播特性分析

Analysis of sound transmission through the sea surface in shallow water

结合射线和波数谱积分方法,对空气声入水传播途径进行了分析,利用海上试验数据进行了比较检验。结果表明,在浅海环境中,对水下声场有主要贡献的空气声入水传播途径,主要是透射穿过海面边界的折射直达声以及后续的海底反射声途径,其中折射直达声途径的贡献主要集中在声源正下方附近区域,当距离较远时,由于声线扩展损失效应以及直达声影区两方面的限制,折射直达声传播损失显著增加,对接收声场起主要贡献的是可以到达更远水平距离上的海底反射声,包括海底海面多次反射声。

Different paths of sound waves penetrating through air into water are examined by use of both ray theory and wavenmnber spectral integration method. Some comparisons with the experimental data are also given. It follows from the results that the main contribution paths to the underwater acoustic field in shallow water are the direction path and the successive bottom reflection path. The contribution of the direct path concentrates mainly around the area just below the air-borne source. With the range increasing, the propagation loss of the direct path increases remarkably because of the spread loss and shadow zone effect. The main contribution to the long-distance underwater acoustic field comes from the bottom reflection path, including the multiple reflection paths of the bottom and sea surface.