利用简正波频散特征映射方法进行海洋环境参数反演

浅海波导中传播的脉冲信号可以通过频散特征映射方法(warping变换)进行简正波的有效分离,这使得频散曲线的获取更加容易和准确.利用简正波频散特征映射方法分析2010年南海声层析实验中单个阵元接收的声学信号,有效分离出各号简正波,并进一步通过Wigner-Ville分布处理提取出波导中各号简正波的频散曲线.将提取的频散曲线与理论计算到达时差进行匹配,实现了利用单水听器信号的海洋环境参数反演.实验结果表明:将简正波分离与Wigner-Ville分布相结合可有效消除Wigner-Ville分布在估计多分量信号时的交叉干扰,提取的频散特征可很好地用于同时反演海水和海底声速剖面。为评价反演结果的有效性,对反演结果进行了后验概率分析,并将一小时内的海水声速剖面反演结果与温度链实测值作对比,二者符合较好. 

Inversion for the environmental parameters in shallow water using warping transforms

The normal modes of the impulsive signals propagating in shallow water waveguide can be separated using warping transforms. It facilitates the extraction of the dispersion curves of normal modes. The warping transform is applied to the signals received by a single hydrophone collected in the South China Sea during the tomography experiment in 2010. The dispersion curves are extracted using Wigner-Ville Distribution. It demonstrates that the isolation of normal modes can eliminate the intercross interference of Wigner-Ville Distribution effectively. By matching the arrival time differences of normal modes with the numerical results, both the sound speed profile of water and the acoustic parameters of sediment are well inverted. The validity of inversion was evaluated by the posteriori probability. The inverted sound speed profiles of sea water are consistent with the experimental measurements. It is shown that the inversion scheme can provide a valid and stable environmental estimation.