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

Abstract

Observations made on horizontal SOSUS receiving arrays during the Acoustic Thermometry of Ocean Climate (ATOC) experiment in the 1990s show that acoustic energy penetrates significantly deeper in the water column below the lower turning points of the predicted acoustic ray paths than expected from diffraction alone [1]. This energy appears anomalously deep in the water column, but the measured travel times correspond well with timefronts predicted to have cusps several hundred meters above the depth of the receivers. The primary objective of this effort was to examine the vertical structure of these "shadow-zone arrivals," and to determine the role of oceanic variability in contributing to the vertical scattering. Acoustic vertical line array (VLA) data from the Spice Experiment (SPICEX) were compared with parabolic equation simulations to determine the predictability of the extension of acoustic timefronts into the shadow zone.

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Document Details

Document Type
Technical Report
Publication Date
Jan 01, 2011
Accession Number
ADA537310

Entities

People

  • Lora J. Van Uffelen

Organizations

  • University of HawaiĘ»i System

Tags

Communities of Interest

  • Sensors

DTIC Thesaurus Topics

  • Detectors
  • Earth Sciences
  • Electrical Engineering
  • Energy Levels
  • Equations
  • Hydrophones
  • Intensity
  • Internal Waves
  • Measurement
  • North Pacific Ocean
  • Oceanography
  • Oceans
  • Pacific Ocean
  • Perturbations
  • Philippine Sea
  • Simulations
  • Temperature Gradients

Readers

  • Acoustical Oceanography.