由简正波群延时及幅度反演海底参数

Inversion for the sea bottom acoustic parameters by using the group time delays and amplitude of normal mode

摘要: 由简正波过滤技术得到1号与2号简正波群延时及幅度。通过匹配简正波群延时差来反演海底的声速、密度等参数,衰减系数由简正波的幅度反演得到。遗传算法用来在参数域内搜索待反演的参数。在200~500 Hz频率范围内海底衰减系数随频率的变化关系为α=0.29f^1.9dB/m(f的单位为kHz)。最后给出由反演出的参数计算得到的传播损失与实验的声传播损失数据的比较,结果符合的较好。

Abstract: The group time delays and amplitudes of the normal mode are derived using the normal mode filter. The sea bottom sound speed, density and attenuation are inversely deduced by matching the group time delays and the amplitude of the normal mode. A genetic algorithm (GA) is used for optimization search in the parameter space. The inverted attenuation has the nonlinear frequency relationship α=0.29f^1.9dB/m(the unit of frequency is kHz) in the frequency range 200 - 500 Hz. The theoretical transmission loss calculated using the deduced parameters matches the experiment data very well.