Low Frequency Attenuation in the Arctic Ocean

• Main Authors: DiNapoli, F R, Mellen, R H
• Other Authors: NAVAL UNDERWATER SYSTEMS CENTER NEW LONDON CT
• Format: Text
• Language: English
• Published: 1985
• Subjects: Physical and Dynamic Oceanography; Acoustics; *ARCTIC OCEAN; *ATTENUATION; *LOW FREQUENCY; *SOUND TRANSMISSION; ABSORPTION; ACOUSTIC CHANNELS; CANOPIES; ESTIMATES; EXPERIMENTAL DATA; FREQUENCY; ICE; INTERFACES; LONG RANGE(DISTANCE); LOSSES; MEASUREMENT; MODELS; OCEAN SURFACE; PERTURBATIONS; REFRACTION; ROUGHNESS; SCATTERING; SEA WATER; STATISTICS; SYMPOSIA; Arctic; Arctic Ocean
• Online Access: http://www.dtic.mil/docs/citations/ADA630596; http://oai.dtic.mil/oai/oai?&verb=getRecord&metadataPrefix=html&identifier=ADA630596

Long-range sound propagation in the Arctic Ocean is characterized by a refractive surface sound channel with a rough water-ice interface. Recent experimental measurements show that, for frequencies below 100 Hz, attenuation exceeds sea water absorption by two orders of magnitude. The most likely mechanism is scattering from the rough ice canopy. Theoretical estimates of the scattering loss, obtained using the method of small perturbation and statistical measures of the under ice roughness obtained from experimental data, were examined for models of the ice canopy having varying degrees of realism. All theoretical estimates for scattering loss, irrespective of the particular model for the ice canopy, were substantially lower than the measured values of scattering loss. The physics of the loss mechanism is evidently not well understood and evidently additional experimental and theoretical investigations are required. NUWC2015 The contents of this memo represent the written version of a presentation at the Ocean Seismic-Acoustic Conference held at LaSpezia, Italy June 10-14 1985.