Azimuthal, spatial, and temporal variability of acoustic intensity in along-the-shelf direction of Chukchi shelf from June to August 2017

Abstract

Spatial, temporal, and azimuthal variability of sound propagation with simultaneously measured oceanography on the Chukchi shelf is reported. Broadband acoustic signals (0.7 to 1.1 kHz) were transmitted from a single sound source placed near the sound channel axis in 150 m water depth and received by two arrays about 32 km away at different angles forming two acoustic tracks. One was along the 120–150 m isobath and the other crossing 120 to 220 m isobath. The angle between the two acoustic paths was 30 deg. Sound emitted from the common source shows different behavior along each acoustic track. Concurrently detailed water column environmental parameters (i.e., salinity and temperature) were measured in the region in both “along” and “cross-shelf” directions. Emergence of a warm water masses during from late June to July caused a variable channel where transmissions showed markedly large intensity variations (∼20 dB). This presentation quantifies data analysis using correlation between acoustics and environmental signals. [Work supported by ONR 322OA.]Spatial, temporal, and azimuthal variability of sound propagation with simultaneously measured oceanography on the Chukchi shelf is reported. Broadband acoustic signals (0.7 to 1.1 kHz) were transmitted from a single sound source placed near the sound channel axis in 150 m water depth and received by two arrays about 32 km away at different angles forming two acoustic tracks. One was along the 120–150 m isobath and the other crossing 120 to 220 m isobath. The angle between the two acoustic paths was 30 deg. Sound emitted from the common source shows different behavior along each acoustic track. Concurrently detailed water column environmental parameters (i.e., salinity and temperature) were measured in the region in both “along” and “cross-shelf” directions. Emergence of a warm water masses during from late June to July caused a variable channel where transmissions showed markedly large intensity variations (∼20 dB). This presentation quantifies data analysis using correlation between acoustics and enviro...