The Reflection of Acoustic Waves in Sea Water from an Ice Covered Surface.

Measurements of the acoustic reflectivity of the lower surface of sea ice were made at several locations in the channels of the Canadian Arctic Archipelago from 1971 to 1973. The distance between the projector and hydrophone was typically 100 to 300 m; the grazing angle at the ice-water interface ra...

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Bibliographic Details
Main Authors: Verrall,R, Ganton,J
Other Authors: DEFENCE RESEARCH ESTABLISHMENT PACIFIC VICTORIA (BRITISH COLUMBIA)
Format: Text
Language:English
Published: 1977
Subjects:
Snow
Ice and Permafrost
Acoustics
*SOUND TRANSMISSION
*SEA ICE
*ACOUSTIC REFLECTION
ANGLES
INTERFACES
CANADA
MATHEMATICAL PREDICTION
ACOUSTIC MEASUREMENT
ACOUSTIC ATTENUATION
REFLECTIVITY
INTEGRAL EQUATIONS
SEA WATER
UNDERWATER SOUND
TRANSMISSION LOSS
ARCTIC REGIONS
GRAZING
UNDERICE
Water ice interfaces
Kirchhoff integrals
Grazing angle
Most Project-2
Arctic
Canada
Canadian Arctic Archipelago
Arctic Archipelago
Ice
permafrost
Sea ice
Online Access:http://www.dtic.mil/docs/citations/ADA047298
http://oai.dtic.mil/oai/oai?&verb=getRecord&metadataPrefix=html&identifier=ADA047298
Description
Summary:Measurements of the acoustic reflectivity of the lower surface of sea ice were made at several locations in the channels of the Canadian Arctic Archipelago from 1971 to 1973. The distance between the projector and hydrophone was typically 100 to 300 m; the grazing angle at the ice-water interface ranged up to 30 deg, and the frequency limits were 200 Hz and 20,000 Hz. The measured reflectivities show large excursions from unity. Reflectivities of -15 dB are not uncommon in spite of the uniform flatness of the ice-water interface and in spite of the shallowness of the grazing angle. However, a calculation based on Kirchhoff's Integral Theorem and involving an integration over the interface indicates that the observed undulation in the ice-water interface is sufficient to account for the observed results.

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