摘要
大多数基于浅海简正波模态频散数据的地声参数反演方法无法对深层底质声学参数进行可靠估计,究其原因是仅利用了简正波水波频散特征,忽略了与深层底质声学参数密切相关的底波频散特征,因此,本文在分析了包含水波和底波的浅海宽带数据的基础上,结合底波频散特征对深层底质声学参数变化更加敏感的物理特性,实现了基于完整简正波频散特性的贝叶斯地声参数反演,并针对简正波宽带声场模型计算复杂度较高的现实问题,利用变分贝叶斯蒙特卡罗方法的推断优势,完成了未知参数的可靠估计和快速后验分析.仿真和海上实验结果表明:联合简正波水波和底波频散特征数据的贝叶斯地声参数反演,不仅可以有效估计深层底质声学参数,而且降低了其他相关环境参数的估计不确定性.
Most of shallow water geo acoustic inversions based on modal dispersion cannot reliably estimate the deep geoacoustic parameters.Because these studies focused on the dispersions of water waves but ignored the dispersions of ground waves.Therefore,in this paper a Bayesian geoacoustic inversion is studied based on wideband modal dispersions of water waves and ground waves.Firstly,the modal dispersion curves with Airy phase components are discussed.Secondly,the Bayesian inversion theory and a novel sample-efficient inference algorithm,namely Variational Bayesian Monte Carlo,are introduced briefly.In the Bayesian inversion,the posterior probability densities of unknown parameters are inferred,which can provide the prediction closest to the observation data and the uncertainty of the prediction.Considering that the forward acoustic model is computationally intensive,the posterior analysis is carried out by using the Variational Bayesian Monte Carlo method.It is performed by finding the variational distribution closest to the target distribution and requires less computation time than the Markov chain Monto Carlo method.In the simulation study,a range-independent two-layer seabed,including the sediment layer and basement layer,is modeled,on the assumption that the water column is homogeneous.The function of shear wave in waveguide is ignored.The compressional sound speed of the sediment layer varies linearly from c1Uto c1Lbetween 0 and h1,while other geoacoustic parameters are constant.By comparing the inversion results with and without the information of ground waves for different signal-to-noise ratios,it can be concluded that the deep geoacoustic parameters are more sensitive to the dispersions of ground waves.And then,a shallow-water experimental study is carried out in the Bohai Sea of China.The average water depth is about 20 m.The wideband pulse signals are recorded by a hydrophone with a sensitivity of-170 dB re 1 V/μPa.The received signals include well-defined Airy phase components,and the modal dispersion cu
作者
郝望
段睿
杨坤德
Hao Wang;Duan Rui;Yang Kun-De(School of Marine Science and Technology,Northwestern Polytechnical University,Xi’an 710072,China;Ocean Institute of Northwestern Polytechnical University,Taicang 215400,China;Key Laboratory of Ocean Acoustics and Sensing,Ministry of Industry and Information Technology,Northwestern Polytechnical University,Xi’an 710072,China)
出处
《物理学报》
SCIE
EI
CAS
CSCD
北大核心
2023年第5期203-215,共13页
Acta Physica Sinica
基金
国家自然科学基金(批准号:12074315,42076198)
中船726研究所重点实验室基金(批准号:JCKY2021207CH02)资助的课题。
关键词
模态频散
地声参数反演
水波
底波
modal dispersion
geoacoustic inversion
water wave
ground wave
