Long-Range Sound Propagation Across Atlantic Ocean Seamounts: Implications for Ambient Noise.

• Main Authors: Koenigs,P D, Browning,D G, LaPlante,R F, Martin,R L
• Other Authors: NAVAL UNDERWATER SYSTEMS CENTER NEW LONDON CT NEW LONDON LAB
• Format: Text
• Language: English
• Published: 1981
• Subjects: Physical and Dynamic Oceanography; Acoustics; *SOUND TRANSMISSION; *UNDERWATER SOUND; *ACOUSTIC CHANNELS; COUPLING(INTERACTION); SHIP NOISE; EXPLOSIVE CHARGES; WINTER; LONG RANGE(DISTANCE); SLOPE; AMBIENT NOISE; NORTH ATLANTIC OCEAN; OCEAN BOTTOM TOPOGRAPHY; TRANSMISSION LOSS; OCEAN RIDGES; DEEP DEPTH; EXTREMELY LOW FREQUENCY; SEAMOUNTS; UNDERWATER SOUND GENERATORS; SUPERLOW FREQUENCY; Deep sound channels; Corner seamounts; SOFAR; Mid Atlantic Ridge; LPN-NUSC-A65005; Canada; Mid-Atlantic Ridge; North Atlantic
• Online Access: http://www.dtic.mil/docs/citations/ADA102909; http://oai.dtic.mil/oai/oai?&verb=getRecord&metadataPrefix=html&identifier=ADA102909

A low frequency (50-800 Hz) sound-propagation experiment was conducted along a 1400-km path running eastward from Bermuda toward the Mid-Atlantic Ridge. SUS charges were detonated at depths of 18, 154, 615, and 1230 m. The receiver was located at the axis of the deep sound channel (125 m) at a maximum range of 1300 km. The acoustic path crossed several seamounts of the Corner Seamount Group. The highest of these peaks rose to the sound axis. This paper presents the relative enhancement of signal level of SOFAR propagation due to these seamounts as a function of source depth and frequency. The enhancement was minimal for the 1230-m shots, while the greatest enhnacement occurred for the 18-m shots at the 50-Hz filter band. This implies these seamounts and other topographic features such as the mid-Atlantic Ridge can significantly increase the coupling of low-frequency ship-generated noise into the deep sound channel. (Author) Paper presented at the Meeting of the Acoustical Society of America (101st), Ottawa (Canada), 20 May 81.