Coherence of Sound using Navy Sonars: Deep Water Acoustics

Abstract

The long term goals are 1) to determine when methods can be used to reliably and accurately predict the temporal and spatial coherence of sound at low frequencies in the sea, 2) to develop reliable and accurate methods to make such predictions and, 3) to determine the physical mechanisms affecting coherence. The first two goals are to be achieved without tuning with data in any way whatsoever. The primary objective is to determine when the temporal and spatial scales of temporal and spatial coherence are accurately predicted by solving an approximation of the acoustic wave equation for climatological conditions in the ocean perturbed by a time-evolving field of internal gravity waves following a standard spectrum. These waves have long been thought responsible for coherence in the deep ocean at low frequencies. However despite decades of theoretical work to predict coherence, theoretical models to date are highly unreliable, often been inaccurate by several orders of magnitude. We are comparing numerical predictions for coherence with data collected with Navy sonars.

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Document Details

Document Type
Technical Report
Publication Date
Sep 30, 2010
Accession Number
ADA542058

Entities

People

  • John L. Spiesberger

Tags

DTIC Thesaurus Topics

  • Acoustic Communications
  • Acoustic Measurement
  • Acoustic Waves
  • Acoustics
  • Communication Systems
  • Deep Oceans
  • Deep Water
  • Frequency
  • Gravity Waves
  • Internal Waves
  • Measurement
  • Probability
  • Probability Distributions
  • Underwater Acoustic Communications
  • Water
  • Wave Equations
  • Waves

Fields of Study

  • Physics

Readers

  • Acoustical Oceanography.
  • Ocean-Atmosphere Mesoscale Modeling, Data Assimilation, and Flux Boundary Layers
  • Systems Analysis and Design