Vertical Structure of Shadow Zone Arrivals: Comparison of Parabolic Equation Simulations and Acoustic Data

Abstract

As part of the North Pacific Acoustic Laboratory (NPAL) program, the long-term goals of this project are to understand the physics of long-range, broadband propagation in deep water and the effect of oceanic variability on acoustic propagation. Observations made during the Acoustic Thermometry of Ocean Climate (ATOC) experiment show that acoustic energy penetrates significantly deeper in the water column below the lower turning points of the predicted acoustic ray paths than is expected from diffraction alone [1]. This energy appears anomalously deep in the water column, but the measured travel times seem to correspond well with timefronts predicted to have cusps several hundred meters above the depth of the receivers. The objective of this particular effort is to examine the vertical structure of these shadow zone arrivals and to determine the relative roles of different sources of oceanic variability such as internal waves, ocean spice, and reflections off the base of the oceanic mixed layer in contributing to the vertical scattering.

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Document Details

Document Type
Technical Report
Publication Date
Sep 30, 2007
Accession Number
ADA569225

Entities

People

  • Lora J. Van Uffelen

Organizations

  • Scripps Institution of Oceanography

Tags

DTIC Thesaurus Topics

  • Acoustic Navigation
  • Acoustic Propagation
  • Acoustic Tomography
  • Acoustics
  • Broadband
  • Deep Water
  • Deployment
  • Electrical Engineering
  • Equations
  • Internal Waves
  • Measurement
  • Physics
  • Scattering
  • Signal Processing
  • Simulations
  • Travel Time
  • Water

Readers

  • Acoustical Oceanography.