Accession Number : ADA617706


Title :   The Impact of Very High Frequency Surface Reverberation on Coherent Acoustic Propagation and Modeling


Descriptive Note : Annual rept.


Corporate Author : SCRIPPS INSTITUTION OF OCEANOGRAPHY LA JOLLA CA MARINE PHYSICAL LAB


Personal Author(s) : Deane, Grant B


Full Text : http://www.dtic.mil/get-tr-doc/pdf?AD=ADA617706


Report Date : 30 Sep 2014


Pagination or Media Count : 7


Abstract : The long-term science objective is to develop a physical model of high-frequency scattering of underwater acoustic signals from the sea surface under a range of wind-driven conditions. The model will focus on signal coherence, and second-order amplitude and Doppler statistics. The scattering of sound from the sea surface is important for the operation of underwater sonar and underwater acoustic communications systems. Studies of low to mid-frequency surface reverberation have a long history, but studies of very high frequency (300 kHz) surface scattering in the literature are rare. The physics of very high frequency (VHF) scattering is expected to be strongly dependent on wind speed, which controls surface roughness and wave breaking, which inject bubbles into the ocean. The amplitude, Doppler spread and temporal coherence of VHF scattering is important for the performance of high frequency sonars and underwater communications systems in operating scenarios where energy from the sea surface cannot be screened.


Descriptors :   *ACOUSTIC SCATTERING , *REVERBERATION , *UNDERWATER ACOUSTICS , *WIND VELOCITY , ACOUSTIC COMMUNICATIONS , ACOUSTIC SIGNALS , COHERENCE , MODELS , PROPAGATION , SONAR , SURFACE ROUGHNESS , VERY HIGH FREQUENCY , WAVES


Subject Categories : Meteorology
      Physical and Dynamic Oceanography
      Acoustics


Distribution Statement : APPROVED FOR PUBLIC RELEASE