中国近海主要表层沉积物类型的原位声学特性

In-situ acoustic properties of the main types of sedimentin the offshore areas of China

海底表层沉积物的声学特性对于海洋声传播和声探测有重要影响。不同类型的海底沉积物表现出不同的声学特性。针对海洋声学研究对海底声学特性参数快速获取的需求,本文利用近年来获得的100个站位的声学特性原位测量和沉积物样品测试数据,统计了中国近海8种典型沉积类型的声速、声衰减系数等声学特性和平均粒径、密度等物理性质。通过与已有测量数据和统计结果的对比显示,其与多种原位测量系统获得的数据有很好的一致性,但Hamilton统计的声速比、声衰减因子等参数则显著偏高。基于VGS理论的频散模型计算结果表明:Hamilton统计结果的偏高并非完全由其较高的测量频率引起。对于缺少直接测量数据的海域,本文的统计结果提供了一种基于沉积物类型进行海底声学特性初步估计的方案。

The acoustic properties of the surficial sediment at the seafloor are essential influential factors in underwater sound propagation and acoustic detection;different sediment types show distinct acoustic properties.Aiming at the demand of marine acoustic research for quickly obtaining the acoustic property parameters at the seafloor,based on the in-situ survey data of the acoustic properties and the testing data on the sediment samples at 100 stations obtained in recent years,this paper conducts statistics on the acoustic properties such as the sound speed and attenuation coefficient and the physical properties such as the mean grain size and density of eight typical sediment types in the offshore areas of China.By comparing the survey data and the statistical results of the predecessors,it is shown that they have excellent consistency with the data obtained in multiple in-situ survey systems;however,parameters such as the sound speed ratio and attenuation factor obtained by Hamilton are substantially high.The calculation results obtained using the frequency dispersion model based on the VGS theory show that the overhigh Hamilton statistical results are not completely caused by the higher survey frequency.For the marine areas lacking direct survey data,the statistical results in the paper provide a scheme for estimating preliminarily the acoustic properties at the seafloor based on the sediment type.