Space-time analysis of acoustic scintillations in ocean current sensing

We present a new approach for measuring ocean flows by observing scintillation drift. In propagating through a turbulent bcean an acoustic wave encounters refractive-index fluctuations that perturb the phase and amplitude of the wave. From the slope of the time-lagged amplitude or phase covariance function of two detectors at zero lag, we can determine the path-averaged component of the current perpendicular to the line-of-sight between the transmitter and receiver array. We tested the concept at Cordova Channel near Sidney B.C. The results showed close agreement between in situ current meters and the acoustic-scintillation-derived currents. This paper also describes an elaboration of the scintillation technique, using multiple transmitters and receivers, that would provide profiles of the transverse current.