Arctic Ocean Background Noise Caused by Ridging of Sea Ice.

• Main Author: Pritchard,R S
• Other Authors: FLOW INDUSTRIES INC KENT WA
• Format: Text
• Language: English
• Published: 1983
• Subjects: Snow; Ice and Permafrost; Acoustics; *BACKGROUND NOISE; *SEA ICE; SIMULATION; SOURCES; WINTER; UNDERWATER ACOUSTICS; ACOUSTIC DATA; RIDGES; BEAUFORT SEA; ARCTIC OCEAN; PACK ICE; UNDERICE; PE61153N; Arctic; Arctic Ocean; Beaufort Sea; Ice; permafrost; Sea ice
• Online Access: http://www.dtic.mil/docs/citations/ADA159587; http://oai.dtic.mil/oai/oai?&verb=getRecord&metadataPrefix=html&identifier=ADA159587

A new method is presented to explain how noise is generated under pack ice by ridging of the pack ice. The energy dissipated during the ridging process is assumed to be the proper measure of the noise source level. Noise source levels generated by ridging are simulated. Noise intensity at a specific site is calculated by summing signals from all these sources after accounting for propagation losses. Calculations are made to compare this simulated noise with observations for an experiment conducted during the winter of 1975-76 in the Beaufort Sea. During a 120-day period, 46% of the intensity of the noise signal is explained using this process, and over several 20-day periods, in excess of 64% is explained. In addition to explaining a significant amount of energy and ambient noise, the model is attractive on physical grounds and properly explains lack of noise when winds are high but ice is strong enough to resist ridging.