Depolarization of radio waves can distinguish between floating and grounded ice sheets

Polar ice is now thought to be marginally birefringent at radio echo-sounding frequencies. An experiment on the polarization behaviour of 60 MHz radio echoes from the bed of both ice shelf and land ice in Antarctica showed a marked difference in the returned polarization. It appears that differences in electrical properties or roughness of the reflecting boundary cannot explain our results. We suggest that there is a large change in the birefringence of the ice sheet at the hinge zone, caused by the effect of tidal strain on crystal orientation. This would imply a minimum value of the radio-frequency anisotropy in permittivity for the single crystal of (0.52±0.8)%. Therefore polarization changes could allow floating and grounded ice to be distinguished.

Details

Publication status:
Published
Author(s):
Authors: Woodruff, A.H.W., Doake, C.S.M.

Date:
1 January, 1979
Journal/Source:
Journal of Glaciology / 23
Page(s):
223-232
Digital Object Identifier (DOI):
https://doi.org/10.3189/S0022143000029853