Acoustic propagation and ambient sound on the Chukchi shelf

Abstract

This paper presents a yearlong record of acoustic propagation and ambient sound collected on the Chukchi Shelf collected as part of a set of experiments known as the Canada Basin acoustic propagation experiment (CANAPE) and shallow-water CANAPE which took place from 2016 to 2017. Over the course of the yearlong experiment, the surface conditions transitioned from completely open water to fully ice-covered. The propagation conditions in the deep basin were dominated by a subsurface duct; however, over the slope and shelf, the duct was seen to significantly weaken during the winter and spring. The combination of these surface and subsurface conditions led to changes in the received level of the deep-water tomography sources that exceeded 60 dB. The ambient sound data were analyzed using k-means clustering to quantify the occurrence of six spectral shapes over the yearlong experiment. Each cluster type was associated with a different sound generation process based on the correlations with environmental observations. The cluster observed most frequently was associated with wind-generated sound, and the cluster with the smallest number of observations was attributed to wind effects on frazil ice forming in open leads during the ice-covered season. [Work sponsored by ONR.]