Separation of turbulence velocity and temperature sound‐speed variability with reciprocal transmission

Acoustical scintillation results from the combined contribution of scalar (i.e., temperature and salinity) and vector (velocity) fluctuations. Reciprocal transmission allows us to separate these components. In a turbulent flow, in which the measured scales lie within the vertical subrange, the velocity fluctuations can be used to derive the rate of turbulent kinetic energy dissipation. Reciprocal transmission measurements at 67 kHz were recently acquired as part of the U.S. Office of Naval Research ‘‘Moderate to High Frequency’’ research program. The results are interpreted in terms of the effective refractive index structure parameter and compared both with the independent shear probe measurements of Lueck (personal communication) and the recent theoretical analysis of Ostachev [Waves Random Media 4, 403–428 (1994)].