Sediment Laden Ice Detection using Broadband Acoustic Backscattering Measurements from Calibration Targets in Ice

Abstract

In the winter, the tidal flats in the Bay of Fundy are littered with large muddy icebergs that are dense enough to sink. This sediment-laden ice to poses a risk to tidal power infrastructure. I attempted to identify echoes from the interior of the ice using a broadband echosounder system. Acoustic backscattering measurements from calibration targets encased in bubble-free ice were used to potentially locate strong targets in ice. Scattering from a planar surface of bubble-free ice overwhelmed echoes from encased targets, hence I was unable to conclusively detect solid and hollow spheres in ice. The total echoes from ice with inclusions could not be differentiated from ice without inclusions. My results imply that echoes from sediment laden ice blocks cannot be interpreted by modelling separate scattering mechanisms within the ice, and that future modelling should focus on echoes from sediment-laden ice surfaces.