Arctic ambient noise measurement comparisons in the Beaufort Sea

Abstract

During ICEX 2016, an MIT autonomous underwater vehicle (AUV) was deployed in the Beaufort Sea region of the Arctic Ocean with the technical objectives of demonstrating the deployment, operation and recovery of an AUV with a towed array under extreme under-ice Arctic conditions, and the scientific objective of characterizing the acoustic environment. Part of this effort included suspending the AUV from a hydro-hole with the acoustic array hanging in a vertical configuration. This new data set created a choice opportunity to reprocess similar vertical array data from the same region of the Beaufort Sea collected by MIT during SIMI 1994. In the intervening twenty-two years between these two ice camps, significant changes have occurred in the Arctic, including rapidly reducing extent and thickness of the summer ice cover. Furthermore, a persistent inflow of a shallow “tongue” of warm Pacific water has recently been discovered in the Beaufort Sea, creating a strong acoustic duct between approximately 100 and 200 m depth. This paper presents noise properties measured more than two decades apart in a region of rapid and significant change. [Work supported by ONR and DARPA.]