利用传播损失反演海底单参数

根据地声反演复杂性随着待反演参数的个数减少不断降低的原理,提出一种利用传播损失反演海底单个参数的方法。通过对海底声阻抗的推导,利用声速、密度和衰减系数拟合出海底反射损失对掠射角的斜率F。基于简正波理论推导了用F描述声场的公式,并据此设计出对传播损失数据进行最小二乘法处理的反演方法。得益于将待反演参数减少至一个,该方法只需单个水听器,避免了复杂测量及多维寻优。对东海实验数据进行了实际反演,并介绍了利用反演结果F进行传播损失预报和海底性质估计的步骤。所获结果与多参数混合反演方法及实测真值进行比较,其一致性验证了方法的有效性。 

Single parameter inversion using transmission loss in shallow water

According to the fact that inversion complexity decreased with the number of parameters,a single parameter inversion scheme which conveniently obtains seabed property from range-intensity relation was proposed.Considering bottom impedance,the slope of bottom loss versus grazing angle F was established by fitting sound speed,density and attenuation.The acoustic field expression,described by F,was deduced based on the normal mode approach. Accordingly,an inversion scheme using a least-squares fitting to transmission loss was designed.Due to reducing the number of parameters to one,this method only requires single hydrophone and avoids complex measurement and optimization algorithm.Experimental data in East China Sea were inverted.The applications of F for transmission loss prediction and seabed property estimation were described.Both results were compared with the results from multiparameter hybrid inversion and measurement,and the agreement evaluated the validity of inversion.