High Frequency Forward Acoustic Volume Scattering and Its Relation to Oceanic Fine Structure.

The long term objectives of this research are to provide a tool for observing oceanic events on a length scale smaller than those associated with internal waves and to provide improved predictive capabilities for direct path propagation fluctuations in the 20 to 70 KHz regime, where small scale even...

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Bibliographic Details
Main Authors: Holliday, D V, McCoy, J J, Beran, M J, Bratkovich, A W, Reader, W T
Other Authors: TRACOR APPLIED SCIENCES INC SAN DIEGO CA
Format: Text
Language:English
Published: 1987
Subjects:
Acoustics
*ACOUSTIC SCATTERING
*FORWARD SCATTERING
PROPAGATION
SPATIAL DISTRIBUTION
VOLUME
STOCHASTIC PROCESSES
DISSIPATION
TURBULENCE
SCALE
LENGTH
ACOUSTIC SIGNALS
OCEANS
UNDERWATER ACOUSTICS
ACOUSTIC FIELDS
INTERNAL WAVES
OPEN WATER
UNDERWATER SOUND SIGNALS
ARCTIC OCEAN
LPN-TRACOR-03-4-023
Arctic
Arctic Ocean
Online Access:http://www.dtic.mil/docs/citations/ADA178221
http://oai.dtic.mil/oai/oai?&verb=getRecord&metadataPrefix=html&identifier=ADA178221
Description
Summary:The long term objectives of this research are to provide a tool for observing oceanic events on a length scale smaller than those associated with internal waves and to provide improved predictive capabilities for direct path propagation fluctuations in the 20 to 70 KHz regime, where small scale events can dominate forward acoustic scattering. Scattering of an acoustic signal by the dynamic processes and the heterogeneous chemical and physical distribution of properties that exist in the open ocean have received considerable attention in the last decade. Our understanding of the effects of stochastic volume scatter mechanisms on a propagating acoustic field, both at the level of the second-order statistics (signal coherence measures, spread functions) and at the level of fourth-order statistics (signal intensity fluctuations and correlations) is reasonably complete. A comparably detailed description of the structure and mechanisms of physical oceanography at intermediate-to-fine scales is not yet well developed. This report represents a part of an effort to develop theory on which to base the development of new techniques to be used in developing a better understanding of the intermediate and fine scale physical processes. These are the processes that exist between the spatial scales of internal waves and the dissipative range of turbulent ocean structure.

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