Ocean Acoustic Inversion

海洋对电磁波是不透明的，但对声音是透明的;因此，声学被用于许多水下应用，例如海底属性/过程或声源位置的遥感（例如，潜水艇、海洋哺乳动物），具有地质、岩土工程、环境和声纳/防御应用。然而，声学遥感 * 需要非线性反演，定量模型选择和不确定性估计需要有意义的解释。拟议的研究建立在我们的长期计划贝叶斯（概率）反演海洋声学遥感六个项目。(1)海底声散射参数和过程的反演。我们的初步工作表明，反向散射数据的反演可以解决海底粗糙度和沉积物的非均匀性谱。我们建议开发定量模型选择方法，以确定各种物理散射机制的相对重要性，并估计不同海底类型的相关散射参数，以更好地了解海底散射的物理特性。* （2）海军数据库或岩土工程 * 应用（如电缆铺设）的横向变化海底散射参数估计。这是基于新的声学数据集的顺序贝叶斯反演，使用移动的系统，包括一个声源和接收器阵列拖在附近的 * 海床的自主水下航行器收集。* （3）通过包括剪切波、散射和倾斜层的影响，扩展我们现有的海底地声参数的高分辨率反射率反演，并应用于解决海洋沉积物中的色散（声速和衰减频率依赖性）。* （4）利用固定 * 接收器阵列记录的全场声学数据对海底地声特性进行层析成像（2D）反演。2D定量非线性反演的一个主要组成部分涉及开发新的自适应稀疏/不规则网格，以与数据的分辨率一致的方式参数化环境，以允许严格的不确定性估计。* （5）声源定位和不确定性估计，包括海洋环境特性不确定性的影响。我们最初的工作是在海军（被动声纳）的应用，但我们正在与加拿大领先的海洋技术公司JASCO研究有限公司合作，进入海洋哺乳动物 * 研究。建议 * 的方法包括一种新的方法，匹配场定位与非同步阵列系统/子系统，* 和源测距通过模式分散（时频分析）在一个单一的接收器。* （6）利用长期声学监测数据追踪数目不详的发声海洋哺乳动物，以提供概率解决办法，从中可提取关于 * 种群和行为的信息。**

Oceans are opaque to electromagnetic waves but transparent to sound; hence, acoustics is used for many underwater applications such as the remote sensing of seabed*properties/processes or the locations of sound sources (e.g., submarines, marine mammals), with geological, geotechnical, environmental and sonar/defence applications. However, acoustic remote sensing*requires nonlinear inversion, with quantitative model selection and uncertainty estimation required for meaningful interpretations. The proposed research builds on our long-term program in Bayesian (probabilistic) inversion for ocean acoustic remote sensing with six projects.***(1) Inversion for seabed acoustic scattering parameters and processes. Our initial work shows that inversion of backscatter data can resolve seafloor roughness and sediment heterogeneity spectra. We propose to develop quantitative model-selection*approaches to determine the relative importance of various physical scattering mechanisms and to estimate relevant*scattering parameters for different seabed types, to better understand the physics of seabed*scattering. ***(2) Estimation of laterally-variant seabed scattering parameters for naval databases or geotechnical*applications such as cable laying. This  is based on sequential Bayesian inversion of novel acoustic data sets collected using a mobile system comprising an acoustic source and receiver array towed near the*seabed by an autonomous underwater vehicle. ***(3) Extending our existing high-resolution reflectivity inversions for seabed geoacoustic parameters by including effects of shear waves, scattering, and dipping layers, with application to resolving dispersion (sound speed and attenuation frequency dependence) in marine sediments. ***(4) Tomographic (2D) inversion for seabed geoacoustic properties using full-field acoustic data recorded at a fixed*receiver array. A major component of quantitative nonlinear inversion in 2D involves developing new self-adaptive*sparse/irregular grids to parameterize the environment in a manner consistent with the resolving power of*the data to allow rigorous uncertainty estimation. ***(5) Acoustic source localization and uncertainty estimation, including the effects of uncertainty in ocean*environmental properties. Our initial work was in naval (passive sonar) applications, but we are moving into marine mammal*studies in collaboration with JASCO Research Ltd, a leading Canadian marine-technology company. Proposed*methods include a novel approach to matched-field localization with non-synchronized array systems/sub-systems,*and source ranging via modal dispersion (time-frequency analysis) at a single receiver. ***(6) Tracking an unknown number of vocalizing marine mammals using long-term acoustic monitoring data to provide a probabilistic solution from which information on*population and behaviour can be extracted. **