声速剖面主导的浅海声传播最佳深度规律研究

Study on the influence of sound speed profiles on the optimum depth of shallow water acoustic propagation

[目的]为提高实际海洋环境中不同季节时的水声通信和声呐探测能力,对浅海声传播的最佳深度现象进行研究。[方法]运用简正波方法,针对不同季节的典型声速剖面,计算典型声速剖面下不同频率和不同接收点深度的非相干声传播损失随距离和深度变化的伪彩图,研究不同声速剖面对声传播最佳深度的影响。[结果]结果显示:低频时,最佳深度不随声速剖面和声源深度的变化而变化,始终位于海水层中层附近;高频时,当声源位于等梯度海水层或负跃层下较深海水的等温层时,最佳深度位于声源深度和声源在等声速层内的对称深度,正梯度和负梯度下的最佳深度位于声源深度处。[结论]研究结果可为水声通信的接收点深度和被动声呐位置的选取提供参考。

[Objectives]To improve underwater acoustic communication and sonar detection ability in different seasons in an actual coastal environment,this study focuses on the optimum depth of shallow water acoustic propagation.[Methods]Using normal mode methods,incoherent transmission loss versus depth and range is calculated with different source locations and frequencies under typical sound speed profiles,and the effects of different sound speed profiles on the optimum depth are studied.[Results]Optimum depth at low frequencies does not change with sound speed profiles and source locations;it is always located near the middle of the water layer.At high frequencies,when the source is located at the isothermal layer of thermocline shallow water or a water layer with a constant gradient,the optimum depth is equal to the source depth and its conjugate depth within the iso-velocity layer.The optimum depth of positive and negative gradient shallow water is the same as the source depth.[Conclusions]The results of this study can provide useful references for the selection of receiver depth and passive sonar.