Sensing stratified turbulence and shear instability using an acoustic high frequency broadband backscatter array

Abstract

High-frequency broadband acoustical backscattering measurements with an array of transducers have allowed the temporal and spatial evolution of shear instabilities in a strongly stratified estuarine environment to be investigated. Development of accurate remote sensing techniques for estimating mixing are of significant interest to the geophysical fluid dynamics community. An array of six high-frequency (120–600 kHz) broadband and narrow beam width (1 to 6 degrees half-beamwidth, depending on the frequency) transducers spaced 1.2 m apart were deployed in the Connecticut River estuary both in the along stream and across stream direction to observe high Reynolds number stratified shear instabilities. In this presentation, results of these high-resolution temporal and spatial sampling measurements of shear instabilities are shown. These measurements demonstrate the utility of these techniques for improving our understanding of the evolution of shear instabilities.