On the detection of crevasses in glacial ice with synthetic-aperture radar.

• Main Author: Brock, Billy C.
• Other Authors: United States. Department of Energy.
• Format: Report
• Language: English
• Published: Sandia National Laboratories 2010
• Subjects: Dielectric Materials; 36 Materials Science; Snow; Radar; Synthetic Aperture Radar-Image Quality; Viability Glaciers-Forecasting; Fractals; Detection; Glaciers; Scattering; Glaciers-Forecasting; Permittivity; Antarctic; Sastrugi; Antarc*
• Online Access: https://doi.org/10.2172/989382; https://digital.library.unt.edu/ark:/67531/metadc1013276/

The intent of this study is to provide an analysis of the scattering from a crevasse in Antarctic ice, utilizing a physics-based model for the scattering process. Of primary interest is a crevasse covered with a snow bridge, which makes the crevasse undetectable in visible-light images. It is demonstrated that a crevasse covered with a snow bridge can be visible in synthetic-aperture-radar (SAR) images. The model of the crevasse and snow bridge incorporates a complex dielectric permittivity model for dry snow and ice that takes into account the density profile of the glacier. The surface structure is based on a fractal model that can produce sastrugi-like features found on the surface of Antarctic glaciers. Simulated phase histories, computed with the Shooting and Bouncing Ray (SBR) method, are processed into SAR images. The viability of the SBR method for predicting scattering from a crevasse covered with a snow bridge is demonstrated. Some suggestions for improving the model are given.