随机浅海声传播简正波起伏(英文)

Normal mode fluctuation of sound propagating in random shallow water

随机浅海环境中声传播起伏的研究,对于随机海洋环境声场预报及海洋环境参数反演和遥测都有十分重要的意义。文中对随机浅海中声传播的简正波起伏进行了研究,利用L.B.Dozier统计耦合模式方程,通过MonteCarlo数值模拟分析声速场随机变化所产生的声场起伏规律。随机声速场模型由海上温度链测量数据统计规律分析得到。结果表明,声速场随机起伏所导致的简正波幅度起伏远高于声压的起伏;当声源处在某一阶简正波的敏感深度位置时,该阶简正波的闪烁系数会比简正波幅度起伏方差高2～3个量级;在所分析随机声速场模型下,声压起伏方差、简正波幅度起伏方差及简正波闪烁系数随距离的增加基本上是线性增大。

Research of fluctuation of sound propagation in a random shallow water environment is of great interest in predicting sound field and environmental parameters for random ocean investigation and monitoring. This paper studies the normal mode fluctuation of sound propagation in random shallow water. Monte Carlo simulation is used to analyze the sound field fluctuation induced by sound speeds random fluctuation with Dozier＇s statistical coupled mode equations in a random ocean. The random sound speed model is derived based on the statistic analysis of a temperature chain data in shallow sea. The results show that the amplitude fluctuation of normal mode induced by sound speed random fluctuation is larger than the amplitude fluctuation of sound pressure. If the source position is close to the sensitive depth of a normal mode, the scintillation index of this normal mode would be 2～3 order of magnitude larger than the variance of normal mode amplitude fluctuation. As such, the scintillation index of normal mode is an important parameter for detecting sound propagating fluctuation. This article reveals that variance of the sound pressure fluctuation is linear against distance, variance of normal mode amplitude fluctuation, and modal scintillation index.