南海北部负跃层环境下海底参数声学反演

利用2015年南海北部声学实验的实验数据,对海底声学参数进行反演。在综合分析声速起伏及海底模型对海底反演影响的基础上,通过选择等效的海水声速剖面和海底模型,改进了多参量联合地声反演方法,使得其不仅能解决反演中的多值性问题,还能适用于负跃层起伏环境下的声学反演。即当用匹配场反演海底声速和用传播损失反演海底衰减时,如果温跃层内有内波等随机起伏,可使用传播路径上平均声速剖面和单层等效海底进行声场计算。反演得到的海底声速和密度结果与海底采样测量符合较好,拟合给出了海底衰减系数随频率的非线性经验关系式。反演结果可为南海北部声传播规律研究与应用提供海底参数。

Geoacoustic inversion for bottom parameters in a thermocline environment in the northern area of the South China Sea

The acoustic parameters of the seabed in the northern South China Sea were inversed using the experiment data from an acoustic experiment in 2015. Based on the comprehensive analysis of the influence of the sound speed fluctuation and the submarine model on seabed inversion, the multi-parameter hybrid acoustic inversion scheme is improved by selecting the equivalent sound speed profile and the submarine model to apply in the thermocline environment with fluctuation. In other words, mean sound speed profile and half infinite bottom model are used in forward sound field calculation to save the inversion dimensions. The inverted seafloor velocity and density are in good agreement with the core sampling measurements. The nonlinear empirical relationship of the attenuation coefficient with frequency is given out. The inversion results are meaningful to the sound propagation research and application in the northern area of the South China Sea.