深海海底斜坡环境对声传播规律的影响

发布时间：2018-02-25 22:18

本文关键词： 深海海底斜坡声传播本征声线　出处：《中国科学:物理学力学天文学》2016年09期 　论文类型：期刊论文

【摘要】：海底地形变化对声传播具有重要影响.针对在南海深海区域海底斜坡环境下进行的一次声传播实验中观测到的一些不同于平坦海底的声传播现象,利用射线声学方法分析并解释了海底地形变化引起声传播差异的原因.结果表明,当声源深度位于131 m处时,在第一影区内,海底斜坡前较小幅度的海底山丘(凸起高度小于1/10海深),对第一次与海底作用而入射到该小海底山丘处的小掠射角(绝对值在10° 20°范围内)声波有反射遮挡作用,导致在其反射区特定传播距离上出现影响深度可达海面以下1300 m的倒三角声影区,比平坦海底环境下相同影区位置处的传播损失增大约8 dB.在第一会聚区内,海底斜坡对声波的反射阻挡作用使得从海面反射及水体向下折射的小掠射角(绝对值小于10°)声波所形成的会聚区结构消失,只保留从水体向上折射的会聚结构.因此,准确的海底地形对深海声传播预报及目标探测等应用非常重要.
[Abstract]:The variation of submarine topography has an important influence on sound propagation. In the case of an infrasound sound propagation experiment carried out in the deep sea slope environment of the South China Sea, some sound propagation phenomena different from those observed in the flat seabed are observed. The difference of sound propagation caused by the variation of submarine topography is analyzed and explained by means of ray acoustics. The results show that when the depth of sound source is at 131 m, it is in the first shadow region. The smaller amplitude of the submarine hill in front of the submarine slope (the elevation of which is less than 1/10 sea depth) has the effect of shielding the acoustic waves from the small grazing angle (in the range of 10 掳to 20 掳in absolute value) which is incident to the small submarine hill for the first time when it is interacting with the sea floor, The inverted triangular acoustics area with an effect depth of 1300 m below the sea level on the specific propagation distance of the reflection zone increases by about 8 dB compared with the propagation loss at the same position of the shadow area in the flat seafloor environment. The reflection and blocking effect of submarine slope on sound wave causes the confluence area structure formed by the small grazing angle (absolute value < 10 掳) refraction from the sea surface and the water body to disappear, and only the confluence structure refraction from the water body is retained. Accurate submarine topography is very important for deep sea acoustic propagation prediction and target detection.
【作者单位】：中国科学院声学研究所声场声信息国家重点实验室;中国科学院大学;中国科学院声学研究所南海研究站;
【基金】：国家自然科学基金资助项目(编号:11434012,41561144006,11174312,11404366)
【分类号】：P733.2

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