Double reflections in novel polarized radar data reveal ice fabric in
the North East Greenland Ice Stream
Abstract
The orientation of ice crystals within large ice masses has a strong
influence on their mechanical properties, but cannot be directly
observed from the surface. The bulk birefringence of anisotropic ice
allows us to infer information about the crystal orientation fabric
(COF) from polarized radar measurements. Here, we show a new approach
for determining the orientation and strength of horizontal COF
anisotropy from the splitting of a single physical layer into two radar
reflections by anisotropic ice. We apply this method to data collected
as part of a ground-based radar survey of the North East Greenland Ice
Stream. We observe a 12-degree clockwise rotation of the fabric at the
center of the ice stream, and a tendency towards a flow-aligned COF
further southeast. This asymmetry across the ice-stream centerline adds
to growing evidence for a more variable ice stream than previously
assumed.