Scattering effects of internal waves in the shallow-water ocean environment

The effects on acoustic energy caused by variations in the ocean environment have long been of interest to the ocean acoustics community. The shallow-water environment can be highly variable on both temporal and spatial scales. An example of shallow water environmental variability is the phenomena of internal waves. Under certain constraints, such as the spatial extent of the internal wave and the acoustic frequency, internal waves can produce very significant effects (on the order of 20 dB) on the propagation of acoustic energy. Depending on the geometry of the source and the target, the presence of an internal wave can either enhance or degrade the strength of a signal. In this work we (1) demonstrate the redistribution of acoustic energy that can be caused by the presence of shallow water internal waves, (2) show that this loss in propagated energy involves mode conversion coupled with a lossy shallow water bottom, and (3) illustrate that this phenomena can occur at a variety of frequencies that are dependent on the soliton's varying size and physical configuration. A significant implication is that solitons could be a possible explanation for the anomalous shallow-water propagation loss observed at a number of different frequencies.