大陆坡海域二维声传播研究

针对在西北太平洋大陆坡外海进行的一次实验中观测到的接收信号能量在声道轴深度附近较为集中的现象,分析了存在向下斜坡时声源置于海面附近和斜坡表面两种情况下斜坡分别对声传播的影响。通过数值模拟,得到了不同声源深度下的传播损失和脉冲的时域波形,数值结果表明,当声源置于海面附近时,声波在水平不变深海环境中随距离衰减很快,而大陆坡的存在可实现能量的远距离传播;当声源置于斜坡表面时,大陆坡会改变水体中声波能量的分布,使其在声道轴深度附近比较集中,这种传播条件下小掠射角声线产生的时间展宽很小, 

Two-dimensional sound propagation over a continental slope

A phenomenon was observed during an experiment conducted in the Northwestern Pacific, which showed that the energy of the received signal around the sound channel axis was significantly stronger than that at other depths. To analyze the effect of a slope on sound propagation, we consider two scenarios: the source near the sea surface and the source near the bottom. As illustrated by numerical simulations, the sound wave decays fast in a range-independent environment when the source is located near the sea surface. However, the presence of a continental slope enables the acoustic signal to propagate to a very long range, which is also true for the case where the source is located near the bottom. Moreover, as the source is located near the bottom, the continental slope changes the distribution of the sound energy, making it converged around the channel axis. In this case, the multipath time spread corresponding to small grazing angles is very small.