深远海线性内波条件下声场时间相关性的空间分布

深海声场特定的干涉结构导致其时间相关性的空间起伏,研究这种空间特性可以为水声信号的探测与处理提供重要参考。利用抛物方程声场仿真模型,联合Monte-Carlo数值方法计算分析了深远海线性内波条件下声场时间相关性的空间分布特性。与现有的研究相比,给出了时间相关性的距离和深度起伏特征。结果表明,当接收达到一定距离,声场时间相关性的空间分布具有与声场干涉条纹类似的结构,声场干涉越强,时间相关性越好。此外,声源频率和声速标准差的变化会引起时间相关性空间分布规律的改变,且会聚区传播模式下的改变强于深海声道传播模式。 

Spatial structure of temporal coherence for long range sound propagation in deep ocean with linear internal waves

The specific interference structure of sound field in deep ocean causes spatial fluctuations of temporal coherence whose study is of great significance for acoustic signals detection and processing. Here, the spatial characteristic of temporal coherence for long range sound propagation in deep ocean with linear internal waves is calculated and analyzed by Monte-Carlo simulations based on the parabolic equation method. Compared with previous study, the range and depth fluctuated characteristic of temporal coherence is demonstrated. The results show that spatial structures of temporal coherence are analogous to the interference patterns of sound field except at close receiving range, and the temporal coherence is much better for stronger interference field. Moreover, the spatial structure can be changed by frequency and sound speed standard deviation variations, where the changes for sound propagation along convergence zones with a shallow source are much more distinct than that along a deep sound channel.