Temporal and spatial dependence of a yearlong record of sound propagation from the Canada Basin to the Chukchi Shelf

Abstract

During the Canada Basin Acoustic Propagation Experiment (CANAPE), low-frequency signals from five tomographic sources located in the Canada Basin were recorded by an array of hydrophones located on the Chukchi Shelf. The propagation distances ranged from 240 km to 520 km, and the propagation conditions changed from persistently ducted in the basin to seasonally upward refracting on the continental shelf. An analysis of the received level from the tomography sources revealed a spatial dependence in the onset of the seasonal increase in transmission loss, which was correlated with the locations of the sources in the basin. This observation led to the hypothesis that the water advected from Barrow Canyon westward over the continental slope by the Chukchi slope current contributes to the temporal and spatial dependence observed in the acoustic record. The water column properties and ice draft were measured by oceanographic sensors on the basin tomography moorings and by six arrays of oceanographic moorings on the continental shelf to characterize the temporal and spatial variability of the environment. This talk examines the range-dependent measurements and explains the observed variability in the received signals through propagation modeling. [Work sponsored by ONR.]

An Embedded Tactical Decision Aid Framework for Environmentally Adaptive Autonomous Underwater Vehicle Communication and Navigation

“…The Beaufort Lens is as a warm water intrusion in an intensely stratified water mass, creating a local temperature (and sound speed) maximum around 50-60 m. From the surface down, there is less saline surface water via ice melt; warm, saline Pacific Summer Water (forming the lens); cold Pacific Winter Water; warm, saline Atlantic water; and then Arctic Deep This work is licensed under a Creative Commons Attribution 4.0 License. For more information, see https://creativecommons.org/licenses/by/4.0/ Water [18], [19]. This stratification creates a unique double ducted environment that has drastic consequences for acoustic communication, sensing, and navigation compared to historical conditions of a monotonically increasing sound speed [20].…”