Depolarization of Radio Waves can Distinguish between Floating and Grounded Ice Sheets

• Published in: Journal of Glaciology
• Main Authors: Woodruff, A. H. W., Doake, C. S. M.
• Format: Article in Journal/Newspaper
• Language: English
• Published: Cambridge University Press (CUP) 1979
• Subjects: Earth-Surface Processes; Antarc*; Antarctica; Ice Sheet; Ice Shelf; Journal of Glaciology
• Online Access: http://dx.doi.org/10.1017/s0022143000029853; https://www.cambridge.org/core/services/aop-cambridge-core/content/view/S0022143000029853

Abstract 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.