基于多层水平变化浅海海底模型的低频反演方法  

Low frequency inversion method based on multi-layer holizontal variation shallow seafloor model

作　　者：康娟 彭朝晖[1] 何利[1] 李晟昊 于小涛 Kang Juan;Peng Zhao-Hui;He Li;Li Sheng-Hao;Yu Xiao-Tao(State Key Laboratory of Acoustics,Institute of Acoustics,Chinese Academy of Sciences,Beijing 100190,China;School of Physical Sciences,University of Chinese Academy of Sciences,Beijing 101407,China)

机构地区：[1]中国科学院声学研究所,声场声信息国家重点实验室,北京100190 [2]中国科学院大学物理学院,北京101407

出　　处：《物理学报》2024年第5期167-177,共11页Acta Physica Sinica

基　　金：国家重点研发计划(批准号:2021YFF0501200);国家自然科学基金(批准号:12204507)资助的课题.

摘　　要：准确获取海底声学参数对声场分析、声纳应用等具有重要意义.反演是获取海底声学参数的重要手段之一.为了避免反演中的多值问题,地声反演往往尽量减少待反演参数,多采用单层或双层水平不变地声模型,反演后的声学参数仅能在有限频段应用,难以同时应用于较宽频段.本文以实验中浅地层剖面仪测量的海底沉积层分层结构为基础建立地声模型,采用多物理量分步联合手段反演各沉积层声学参数,并通过匹配场定位、后验概率分析、采样等手段对反演结果进行验证.将反演结果与单层等效地声模型反演结果进行对比分析,结果说明,本文建立的多层水平变化海底声学参数更接近真实情况,可以应用在较宽频段范围,解释不同声学现象,且精度更高.Sound propagation in shallow water is significantly influenced by geoacoustic properties.Estimating these geoacoustic parameters is essential for sound field analysis and sonar performance assessment.As a common practice,the seafloor is often treated as a single-layer or two-layer range-independent geoacoustic model to reduce the number of involved parameters.However,acoustic parameters inverted through these two geoacoustic models are typically limited in their applicability to a specific frequency range,thus posing challenges when applied across a broader frequency range.A range-dependent multi-layer geoacoustic model based on experimental measurements obtained with a sub-bottom profiler is proposed in this study.The inversion scheme combines three inversion methods to estimate geoacoustic parameters,considering the different sensitivities of geoacoustic parameters to different physical parameters within the acoustic field.Firstly,modal dispersion is used to invert the geoacoustic parameters of each layer,with the dispersion curve obtained through warping transform and the Wigner-Ville distribution.After that,both the localization using matched field processing and the dispersion curve fitting demonstrate the effectiveness of the inversion results for each layer,although the peak of the probability distribution of sound speed in the first layer is broader than in others.Secondly,matched field processing is employed to invert the geoacoustic parameters of the first layer.This method is based on the theory that as frequency increases,the depth of sound rays penetrating the seabed decreases,revealing changes in the first layer's sound speed with the seabed depth.Lastly,bottom attenuation coefficients at different frequencies are inverted by the transmission loss(TL),and a fitting relationship between the attenuation coefficient and the frequency is derived.The inversion results obtained by using the rangedependent multi-layer geoacoustic model are compared with results estimated by the single-layer geoacoustic mod

关 键 词：宽带地声反演 多层水平变化海底 简正波频散 传播损失 

分 类 号：P733.2[天文地球—物理海洋学]