Accession Number : AD0786728

Title :   Amplitude Fluctuations of Sound Transmitted in the Surface Duct.

Descriptive Note : Final rept.,

Corporate Author : NAVAL ORDNANCE LAB WHITE OAK MD

Personal Author(s) : Urick,R. J.

Report Date : 26 JUL 1974

Pagination or Media Count : 30

Abstract : A short field experiment was done to determine the fluctuation of sound propagating in and below the surface duct. Short pulses at an ultrasonic frequency and cw sound at 1120 Hz, were transmitted to distances between two and ten miles. The received signals were found to be Rayleigh-distributed below the duct at both frequencies. Within the duct, the Rayleigh distribution was also found at the higher frequency, but not at the lower. The results verify the view that reflection and scattering from the rough moving sea surface is the dominant cause of amplitude fluctuation in surface-ducted propagation. (Author)

Descriptors :   *Underwater sound, *Sound transmission, Intensity, Acoustic velocity, Sonobuoys, Curve fitting, Graphics

Subject Categories : Acoustic Detection and Detectors
      Acoustics

Distribution Statement : APPROVED FOR PUBLIC RELEASE