Long-Range Acoustic Propagation in the Shallow Bering Sea.

• Main Author: Mackenzie,Kenneth V.
• Other Authors: NAVAL UNDERSEA RESEARCH AND DEVELOPMENT CENTER SAN DIEGO CALIF
• Format: Text
• Language: English
• Published: 1972
• Subjects: Physical and Dynamic Oceanography; Acoustics; (*SHALLOW WATER; UNDERWATER SOUND); (*UNDERWATER SOUND; *BERING SEA); SOUND TRANSMISSION; ATTENUATION; OCEAN BOTTOM; VELOCITY; UNDERWATER SOUND EQUIPMENT; UNDERWATER EXPLOSIONS; CORRELATION TECHNIQUES; Most Project-2; Bering Sea
• Online Access: http://www.dtic.mil/docs/citations/AD0745735; http://oai.dtic.mil/oai/oai?&verb=getRecord&metadataPrefix=html&identifier=AD0745735

Propagation measurements were obtained with explosives and CW signals of 58,350,700, and 1300 Hz in 25-fathom waters of the Bering Sea. Sound was received by an anchored string of 14 hydrophones spaced vertically at 10-ft intervals. Measurements to ranges of 80 kyd were confined to areas that had previously been surveyed acoustically to determine sediment properties and thicknesses. CW tones exhibited amplitude fluctuations of 50 dB with attendant frequency spreading. Empirical equations ar presented describing resultant half-power spectra as a function of range and frequency. Pressure levels, each based on 6000 to 10,000 data points, demonstrated a hydrophone depth dependence with minimal evidence of mode-stripping. Propagation anomalies for 700 and 1300 Hz agree with energy flux density procedures, provided a sufficiently low attenuation in the bottom is assumed. (Author)