Polarimetric radar measurements for the characterization of ice crystal orientation fabric and anisotropic rheology within Rutford Ice Stream, 2016/2017 to 2019/2020

A ground-based radar survey consisting of 35 discrete quad-polarization measurement sites over three field seasons was undertaken on Rutford Ice Stream, West Antarctica. Sites A01 to A10 were collected on 20 January 2017, along a profile orientated perpendicular to the ice flow direction. The 10 sites are located between the central ice flowline and the ice-stream margin along a profile of length 8.5 km with the inter-site spacing decreasing toward the ice-stream margin. Sites B01 to B10 were collected on 05 December 2019, along a profile orientated parallel to the central flowline. The sites were surveyed with the first site 4 km upstream of site A01 and the inter-site distance spacing fixed at 4 km. Sites C01 to C11 were collected on 14 December 2018, and located between sites A01 and A02 at 200 m spacing. Sites D01-D04, collected on 25 January 2019, are downstream of A01 and form a diamond shape with 800 m spacing. At each site, polarimetric radar-sounding measurements were made using an autonomous phase-sensitive radio-echo sounder (ApRES), a frequency-modulated continuous-wave radar. The ApRES has a centre frequency of 300 MHz and a bandwidth of 200 MHz, which results in a range resolution of approximately 40 cm in ice. ApRES radar data were collected as part of the BEAMISH Project (NERC AFI award numbers NE/G014159/1 and NE/G013187/1).