Acoustic anomalies in the boundary layers of the ocean

Boundary layers - the near-surface and bottom layers - play an important role in the structure of the ocean. The involvement of bubbles in the sea water column in surface waves leads to the appearance of bubble clouds, which can reach significant depths in strong winds. Bubbles may also be contained in the bottom layers in the areas of the outlet of underwater gas flares. They are often compared with the presence of gas hydrate deposits, or with the release of gases through cracks in the earth's crust near active volcanoes. The paper discusses methods and experimental results on the acoustics of boundary layers in the ocean containing a two-phase liquid with gas bubbles, as well as methods for their diagnosis. The possibilities of acoustic sounding for visualization of complex structure, dynamics and diagnostics of anomalies of physical properties of boundary layers are shown. Typical experimental results obtained in the Far Eastern seas are presented and discussed.