Spatial Processing of Range-Bin ADCP Data to Resolve Small-Scale Frontal Features

Abstract

A new approach is proposed for the processing of acoustic Doppler current profiler (ADCP) data that has the potential to better resolve the structure of small-scale dynamical features such as strongly convergent current fronts. The essence of this approach is to assign each range bin of radial velocity and backscatter data an x, y, and z position, and then to spatially average the bin data relative to the feature of interest. The approach is illustrated by an analysis of surface-towed ADCP data collected across the Connecticut River plume front. Results using an across-front averaging length of 5 m show that the frontal morphology and circulation (gravity-current head structure, shallow inflow layer, strong sinking motion) are consistently resolved, while 1-m averaging appears additionally to resolve flow instabilities occurring along the frontal interface. Other possible applications are briefly discussed.