Broadband backscattering signatures of a submerged tidewater glacier

Observations of tidewater glaciers in polar regions are few, owing to the challenging environmental conditions and calving dangers associated with the glacial terminus. Remote measurements made by active acoustic systems have the potential to fill observational gaps in these critical high-latitude regions. Here, we discuss the broadband (170–250 kHz) backscattering from a submerged tidewater glacier terminus over a range of grazing angles. Scientific echosounder observations were collected at Hans glacier in Svalbard, and the submerged ice face position and local slope were derived using split-aperture processing methods. Spectral backscattering trends from the ice face showed a weak frequency dependence across grazing angles. The processing procedure and results will be discussed, including consideration of potential scattering mechanisms associated with the ice–ocean interface (e.g., surface roughness, gas bubbles, thermohaline structure), along with the need for the collection of in situ measurements of submerged termini properties.