Vertical Structure of Shadow Zone Arrivals: Comparison of Parabolic Equation Simulations and Acoustic Data
Final technical rept. 10 Nov 2006-30 Oct 2010
HAWAII UNIV HONOLULU (MANOA CAMPUS) SCHOOL OF OCEAN AND EARTH SCIENCE AND TECHNOLOGY
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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.
- Physical and Dynamic Oceanography