Spatial and temporal correlations of mid-frequency acoustic signals on the Chukchi Sea Shelf

Abstract

The spatial and temporal correlations of 1.5–4 kHz LFM signals were measured using a 64-element billboard array and a mid-frequency acoustic source, deployed on the Chuckchi Sea Shelf during October 2016 to March 2017. The billboard array was deployed at 150 m water depth and the acoustic source was deployed at 320 m water depth near the shelf break to measure the acoustic signals propagating along a 20 km cross-shelf path. Both receiver depth (100 m) and source depth (200 m) were chosen to provide an effective transmission in a sound channel bounded by Pacific Summer Water at 40–100 m and warm Atlantic Water at 140-320 m below the surface. It was observed that signal amplitude variations and correlations were strongly affected by a combination of highly dynamic oceanography and Arctic sea ice. The effects of measured ocean and sea-ice variabilities were also simulated using a PE acoustic propagation model. The agreement between numerical predictions and measured data provides a framework for a robust mid-frequency sonar performance prediction capability in the Arctic. [Work supported by the ONR.]