基于原位声学特性及其影响机制的南海深远海地声模型研究

The research of geoacoustic model of deep and pelagic sea sediment has important demands on military defense, marine economy, scientific research and others. The acoustic characteristics of deep and pelagic sea sediments is systematically studied, by integrating methods of in-situ acoustic measurement, samples acoustic measurement, controlled experimental measurement and mechanism analysis. It will be revealed that the influencing mechanism of sediment grain, the in-situ deposition pressure and temperature changes on the velocity of the spatial distribution of seafloor sediments. And the geoacoustic model in different scales will be constructed. The innovation lies in: based on the differences of in-situ measurement and sampling measurement, the qualitative and quantitative analysis of acoustic characteristics will provide new scientific evidences of in-situ datasets for the universal application of the sampling method for measuring sample acoustic characteristics; based on the exploration of the influence of pressure and temperature on the velocity ratio, a novel quantitative correction method is provided for different researchers to analyze the acoustic sound speed properties of sediments with different measurement methods and in different measurement environment; considering the in-situ acoustic characteristics and its influence mechanism of seafloor sediments, a new calculation, analysis and prediction method is provide for the construction of geoacoustic model of the deep and pelagic sea of the South China Sea to realize the construction of geoacoustic model in deep layer. The research solves the urgent demands of acoustic detection in the South China Sea, and promotes the development of ocean acoustics from shallow sea to deep and pelagic sea.

深远海海底沉积物地声模型研究具有重要的军事海防、海洋经济、科研探索等需求。本课题集成原位声学测量、采样声学测量、可控实验测量和机理分析等方法，系统性地研究深远海表层沉积物的声学特性，揭示沉积物颗粒、海底原位沉积压力和温度变化对海底声速空间分布的影响机理，构建南海深远海不同尺度地声模型。创新在于：基于原位与采样声学特性差异的定性和定量分析，为普遍应用的采样方法测量样品声学特性，提供科学的深远海沉积物原位声学特性新依据；探索压力和温度对海底沉积物与海水声速比影响规律，为不同研究者采用不同测量方法和基于不同测量环境状态分析海底沉积物声速特性，提供一种新颖的定量校正方法；考虑海底原位声学特性及其影响机制，为构建南海深远海底地声模型提供一种新式的计算、分析和预测方法，实现深层地声模型的建立。解决南海海洋声学探测实际需求问题，推动海洋声学研究由浅海向深远海发展。

海底沉积物以“黑箱”形式存在于水下声场，水声学家们迫切希望能够依据建立海底地声模型来精确地研究海洋声场传播特性。深远海海底沉积物地声模型研究是浅海地声模型研究的延续和拓展，具有重要的军事海防、海洋经济、科研探索等需求。本课题集成原位声学测量、采样声学测量、可控实验测量和机理分析等方法，系统性研究浅海和深远海表层海底沉积物的声学特性，揭示沉积物粗细颗粒、海底原位沉积压力和温度变化对海底声学特性影响机理，构建南海浅海和深远海不同尺度地声模型。主要开展研究内容有：探索深远海与浅海的细粒与粗粒类型海底沉积物声波传播影响机制差异；海底沉积物声学特性的深远海原位环境温度和压力状态影响机制；基于表层原位声学特性和沉积物声波传播机制的南海深远海地声模型的建立。获得重要进展有：提出一种分析和预报海底沉积物声速特性的通用GMSS模型；揭示出表层海底沉积物的声学特性的环境影响因素机制；提出一种基于修正声速比的海底沉积物环境影响因素的声速校正模型；提出海底沉积物地声四种基本结构和组合构建地声模型的方法；开发基于实验室模拟手段研究海底沉积物声学特性的技术和方法；得出表层基本地声模型和深远海典型地声模型。通过课题研究，基于原位与采样声学特性差异的定性和定量分析，为普遍应用的采样方法测量样品声学特性应用提供浅海和深远海沉积物原位声学特性依据；探索压力和温度对海底沉积物与海水声速比影响规律，为不同研究者采用不同测量方法和基于不同测量环境状态分析海底沉积物声速特性，提供一种有科学依据的定量校正方法；考虑海底原位声学特性及其影响机制，为构建南海深远海底地声模型提供一种结合四种基本地声结构和GMSS模型的计算、分析和预测方法，实现不同海域、不同深度海底、100米以内埋深地声模型建立。解决南海海洋声学探测实际需求问题，推动海洋声学研究由浅海向深远海发展。