利用海洋环境噪声直接提取海底反射系数
Directly extracting seabed reflection coefficient using ocean ambient noise
-
摘要: 提出了一种利用海洋环境噪声直接(非迭代)提取海底反射系数的方法,基于海洋环境噪声垂直相关函数与方向密度函数的相似性,结合海洋环境噪声射线理论,由两个垂直排列的水听器实现海底反射系数的被动获取。方法适应性的仿真分析说明较高海况下且近场无航船干扰的海洋环境噪声数据有利于方法的实现;对于两层海底,海洋环境噪声垂直相干函数经高通滤波后,由海洋环境噪声垂直相关函数对时间的导数可准确提取垂直方向沉积层反射系数;将方法用于较高风速下的实测海洋环境噪声数据处理,结果表明直接提取方法可准确获取大于临界角部分的海底反射系数。Abstract: A method was proposed for the direct(non iterative) extraction of the seabed reflection coefficient using only two hydrophones arranged vertically.Based on the similarity between the vertical cross correlation function and the directional density function of the ocean ambient noise,and combined with the ray theory of ocean ambient noise,the passive acquisition of seabed reflection coefficient is realized by two vertically arranged hydrophones.Simulation analysis of method adaptability shows that the ocean ambient noise data collected in high sea condition and without near-field ship interference is beneficial to the realization of the method.For two layers seabed,the sediment reflection coefficient of in vertical direction can be accurately extracted from the derivative of the cross correlation function of ocean ambient noise to time after applying high-pass filter to the vertical coherence function of ambient noise.The method is applied to process the measured ocean ambient noise under high wind speed.The results show that the direct extraction method can accurately obtain the seabed reflection coefficient in the part greater than the critical angle.