Low-Frequency Acoustic Propagation Loss in the Arctic Ocean: Results of the Arctic Climate Observations using Underwater Sound Experiment

• Main Authors: Gavrilov, Alexander N., Mikhalevsky, Peter N.
• Other Authors: SCIENCE APPLICATIONS INTERNATIONAL CORPMCLEAN VA
• Format: Text
• Language: English
• Published: 2004
• Subjects: Snow; Ice and Permafrost; Acoustics; *ACOUSTIC DATA; *SEA ICE; *ARCTIC OCEAN; MATHEMATICAL MODELS; COUPLING(INTERACTION); PROPAGATION; THICKNESS; PARAMETERS; ARRAYS; SEASONAL VARIATIONS; MATHEMATICAL PREDICTION; VERTICAL ORIENTATION; SIGNALS; REMOTE DETECTORS; SOUND TRANSMISSION; CLIMATE; TOMOGRAPHY; ACOUSTIC VELOCITY; LOW FREQUENCY; UNDERWATER SOUND; TRANSMISSION LOSS; ARCTIC REGIONS; NOISE(SOUND); ACOUSTIC DETECTORS; FRANZ JOSEF LAND; ACOUS(ARCTIC OBSERVATIONS USING UNDERWATER SOUND); Arctic; Arctic Ocean; Franz Josef Land; Barrow; Ice; Lincoln Sea; permafrost; Point Barrow; Sea ice; Alaska
• Online Access: http://www.dtic.mil/docs/citations/ADA433378; http://oai.dtic.mil/oai/oai?&verb=getRecord&metadataPrefix=html&identifier=ADA433378

Acoustic data from the Arctic Climate Observations using Underwater Sound (ACOUS) experiment are analyzed to determine the correlation between acoustic propagation loss and the seasonal variability of sea ice thickness. The objective of this research is to provide long-term synoptic monitoring of sea ice thickness, an important global climate variable, using acoustic remote sensing. As part of the ACOUS program an autonomous acoustic source deployed northwest of Franz Josef Land transmitted tomographic signals at 20.5 Hz once every four days from October 1998 until December 1999. These signals were received on a vertical array in the Lincoln Sea 1250 km away. Two of the signals transmitted in April 1999 were received on a vertical array at ice camp APLIS in the Chukehi Sea north of Point Barrow, Alaska, at a distance of approximately 2720 kin from the source. Temporal variations of the modal propagation loss are examined. The influence of ice parameters, variations of the sound speed profile, and mode- coupling effects on the propagation losses of individual modes is studied. The experimental results are compared to the results of the earlier experiments and the theoretical prediction using numerical modeling. The original document contains color images.