Remote sensing of ocean flows by spatial filtering of acoustic scintillations: Observations

Abstract

The concept of spatial aperture filtering is tested with a linear array of four sources and four hydrophones on opposite sides of a tidal channel. The system is used to develop time series of the spatially filtered signal at different locations in the channel, from which flow speed may be derived. Results are in reasonable accord with independent current measurements, and reproduce the observed time-dependent horizontal shear of the flow. A concept of synthetic spatial aperture filtering is introduced whereby additional transmitter-receiver paths are synthesized through appropriate time delays so as to derive new information on the flow field.