Line-averaged measurement of velocity fine structure in the ocean using acoustical reciprocal transmission

Abstract

Reciprocal acoustical travel time measurements over paths of several hundred metres can be used to probe the statistical behaviour of turbulent velocity fine structure in the ocean. For homogeneous isotropic flows, and for long measuring baselines, an analytic expression relating line-averaged and point measurements of velocity is derived. Anisotropic and inhomogeneous flows are also considered. Correction formulas for the spatial and temporal variability of advection velocity along the measuring baseline are obtained. Practical limitations are established and experimental data from the arctic boundary layer beneath ice is compared with the theory