On the Limitations of Using Polarimetric Radar Sounding to Infer the Crystal Orientation Fabric of Ice Masses

Abstract

Thus, as the crystal orientation fabric (henceforth fabric) evolves during flow in polycrystalline glacier ice or in the mineral aggregate of the upper mantle, so should the bulk directional viscosity and elasticity structure. Being able to infer fabrics in situ is central for validating largescale anisotropic ice-flow models and geodynamical models of mantle flow processes; models that might lead to a better understanding of, for example, streaming ice (Lilien et al., 2021) and the coupling between plate motions and the sublithospheric mantle (e.g., W. Wang & Becker, 2019), respectively. Furthermore, fabric anisotropy provides a unique constraint on the past and present deformation in the lithosphere and sublithospheric mantle (Fouch & Rondenay, 2006). Likewise, in the limit of weak dynamic recrystallization, ice fabrics might provide a proxy for past and present flow regimes (

Radar Characterization of Ice Crystal Orientation Fabric and Anisotropic Viscosity Within an Antarctic Ice Stream

“…Matsuoka et al, 2009) and is not considered in this study. Rathmann et al (2022) demonstrate that vertical incidence radar measurements are insensitive to a non-vertical principal axis direction and highlight the need for oblique measurements to constrain the full second-order structure tensor, requiring wide-angle radar measurements that are not available in this study.…”

Elastic wave propagation in anisotropic polycrystals: inferring physical properties of glacier ice

“…Much like our approach and in radio-glaciological methods (e.g. [86–88]), many seismic methods also rely on shear-wave splitting (travel-time anomalies) to characterize the fabric anisotropy. However, unlike laboratory experiments where the sample-of-interest can easily be rotated relative to the ultrasonic transducer (figure 2), seismic surveys are in practice constrained to walk-away seismic profiling (figure 7), limiting the range of incident angles that waves can be excited to propagate along (in analogy to limiting the range of ϕ in this study).…”

Polarimetric Analysis of Biseasonal Monostatic and Bistatic Radar Observations of a Glacier Accumulation Zone at Ku-Band

“…This is due to the relatively short but non-zero penetration depth into dry snow, which allows a large fraction of the incident radio waves to interact with the snow volume, thus providing opportunities for probing of the physical properties of the snow layer, especially when the layer thickness is insufficient for use of lower frequency bands such as the X-band [5], [6]. The snow parameters of interest include, among others, the snow water equivalent (SWE) [2], [7], [8], grain size and autocorrelation length [9], [10], snow anisotropy [11], [12], or firn depth [13]. Several spaceborne synthetic aperture radar (SAR) missions using Ku-band for snow and ice research were proposed in the past decade (CoReH2O [14], SCLP [15,Part II]) and also are under current investigation (TSMM [16]).…”