利用海洋环境噪声估计海流流速

Estimation of current speed from ocean ambient noise

为了观测海流在短时间尺度上的变化,基于被动声层析原理,提出了一种利用浅海海洋环境噪声估计海流流速的方法。通过波束形成增加噪声互相关函数的能量积累,从环境噪声互相关函数提取出两个水平阵列间的经验格林函数,利用经验格林函数的时间到达结构反演阵列间的浅海海流流速。海上实验数据处理结果表明,该方法提取了2 h时间平均的经验格林函数和海流流速,可观测到海流流速的变化。通过仿真,论证了方法在该实验环境下的可行性,并分析了海水深度和传播距离失配带来的流速反演误差,其影响较小,可忽略。

For the observation of short-time ocean current,a method for estimating the velocity of ocean current using ambient noise is proposed in shallow water based on the passive acoustic tomography.The energy accumulation of noise cross-correlation functions can be increased by beamforming.The empirical Green’s functions between two horizontal arrays are extracted from the noise cross-correlation functions,and the time arrival structures of the empirical Green’s functions are used to invert the current velocity between arrays.By processing the experimental data,the empirical Green’s functions and current velocities are extracted for 2 hours,and the velocity variation of ocean current can be observed.The simulation demonstrates the feasibility of the method in this experimental environment,and the mismatch of depth and range is analyzed.Its effect is negligible.