| Popis: |
Any oceanic environment with spatial gradients in sound speed and density can result in acoustic scattering hot spots. These acoustic hotspots can be rapidly evolving and vary in their spatial heterogeneity. Here, we present data collected with a variety of split-beam and multi-beam echosounders illustrating the broad array of environments and spatial scales associated with scattering from physical microstructure, including shear instabilities in estuarine environments, non-linear internal waves on the continental shelf, strong interface scattering due to double-diffusion, scattering from strong gradients, or interfaces, and turbulent microstructure at the new England Shelf Break Front. The theoretical acoustic scattering formulations for different types of physical microstructure are applied to these different environments, and recommendations are made for optimal frequency bands to sample the different types of physical microstructure and the optimal measurements for inference of parameters that describe the physical microstructure. The impact of other scattering sources, such as suspended sediments, bubbles, and biological targets, on successful acoustic sampling of physical microstructure is also discussed. [This work was supported by the ONR.] |
