THE REFLECTION OF ACOUSTIC WAVES IN SEA WATER FROM AN ICE COVERED SURFACE

Authors
  1. Verrall, R.I.
  2. Ganton, J.H.
Corporate Authors
Defence Research Establishment Pacific, Victoria BC (CAN)
Abstract
Measurements of the acoustic reflectivity of the lower surface of sea ice were made at several location 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 degrees, and the frequency limits were 200 Hz and 20,000 Hz. The measured reflectivities, which are presented here, 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 Kirchoff'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.
Report Number
TM-77-8 —
Date of publication
15 Jun 1977
Number of Pages
30
DSTKIM No
77-04685
CANDIS No
101357
Format(s):
Hardcopy;Originator's fiche received by DSIS

Permanent link

Document 1 of 1

Date modified: