南海北部海水声速剖面声学反演

Inversion for sound speed profiles in the northern of South China Sea

2009年6月在南海北部进行了一次海洋环境和声学同步观测实验.实验观测到内波活动导致水体声速剖面随时间和空间起伏.从温度链长期观测数据提取出声速剖面经验正交函数(EOF).数值仿真研究了水平变化海洋环境下平均声速剖面的声学反演,结果表明,反演结果与传播路径上的平均声速剖面具有很好的一致性.在此基础上,利用实验中垂直接收阵记录的宽带爆炸声源信号反演海水声速剖面,并与实验测量声速剖面进行比较,验证了匹配场声学反演海水声速剖面的有效性和稳定性.

This paper represents the water column sound speed profiles （SSPs） by the empirical orthogonal functions （EOFs） and inverts them by the matched field method using the acoustic and oceanographic data simultaneously collected in the northern of South China Sea during a shallow water experiment in June 2009. The water column data show evident spatial and temporal variations caused by the internal waves. The EOFs are extracted from the long time water temperature data continuously measured by a temperature sensor array. Using a two-dimensional advective frozen-ocean model, the simulation of the inversions for the range-dependent shallow-water environment is performed and the results show that the inverted sound speed profile is consistent with the mean one along the acoustic signal propagation path. Eventually, the wide-band source （WBS） signals recorded by a vertical line array during the experiment are used to invert the average sound speed profiles, and the results agree well with the experimental measurements, demonstrating that the matched field method is valid and stable.