Estimation of ice fabric within Whillans Ice Stream using polarimetric phase-sensitive radar sounding

Here we use polarimetric measurements from an Autonomous phase-sensitive Radio-Echo Sounder (ApRES) to investigate ice fabric within Whillans Ice Stream, West Antarctica. The survey traverse is bounded at one end by the suture zone with the Mercer Ice Stream and at the other end by a basal ‘sticky s...

Full description

Bibliographic Details
Published in:Annals of Glaciology
Main Authors: Thomas M. Jordan, Dustin M. Schroeder, Cooper W. Elsworth, Matthew R. Siegfried
Format: Article in Journal/Newspaper
Language:English
Published: Cambridge University Press 2020
Subjects:
Online Access:https://doi.org/10.1017/aog.2020.6
https://doaj.org/article/a099c7635758466585bce37be0f0d791
Description
Summary:Here we use polarimetric measurements from an Autonomous phase-sensitive Radio-Echo Sounder (ApRES) to investigate ice fabric within Whillans Ice Stream, West Antarctica. The survey traverse is bounded at one end by the suture zone with the Mercer Ice Stream and at the other end by a basal ‘sticky spot’. Our data analysis employs a phase-based polarimetric coherence method to estimate horizontal ice fabric properties: the fabric orientation and the magnitude of the horizontal fabric asymmetry. We infer an azimuthal rotation in the prevailing horizontal c-axis between the near-surface (z ≈ 10–50 m) and deeper ice (z ≈ 170–360 m), with the near-surface orientated closer to perpendicular to flow and deeper ice closer to parallel. In the near-surface, the fabric asymmetry increases toward the center of Whillans Ice Stream which is consistent with the surface compression direction. By contrast, the fabric orientation in deeper ice is not aligned with the surface compression direction but is consistent with englacial ice reacting to longitudinal compression associated with basal resistance from the nearby sticky spot.