Thirty years of scintillating acoustic data in diverse ocean environments, thanks to David Farmer

The acoustic scintillation method was first applied in a coastal tidal channel in the early 1980s by David Farmer and this laid the foundation for studies of estuarine channel flows, bottom boundary layer dynamics, deep-sea hydrothermal plumes, and now more recently hydrocarbon seeps. Over short distances, using high frequencies and high transmission rates, amplitude and phase fluctuations measured over transmitter and receiver arrays have been used to infer horizontal (or vertical) flows and turbulent motions, all averaged along the acoustic path over the range separating transmitters and receivers. Autonomous and cabled instrumentation have provided measurements of temporally and spatially averaged quantities, continuously in time. This ability to make long-term continuous measurements has shown major advances in our understanding of acoustic forward scatter from velocity and temperature fluctuations in moving random media and for identifying strong turbulence levels in a variety of ocean settings. Much...