10 research outputs found
Modelled stress distributions at the Dome Summit South borehole, Law Dome, East Antarctica: a comparison of anisotropic ice flow relations
Inferring ice-flow directions from single ice-sheet surface images using the Radon transform
Meteoric and marine ice crystal orientation fabrics from the Amery Ice Shelf, East Antarctica
The tertiary creep of polycrystalline ice: experimental evidence for stress-dependent levels of strain-rate enhancement
Borehole imagery of meteoric and marine ice layers in the Amery Ice Shelf, East Antarctica
Ice flow relations for stress and strain-rate components from combined shear and compression laboratory experiments
Drivers of ASCAT C band backscatter variability in the dry snow zone of Antarctica
C band backscatter parameters contain information about the upper snowpack/firn in the dry snow zone. The wide incidence angle diversity of the Advanced Scatterometer (ASCAT) gives unprecedented characterisation of backscatter anisotropy, revealing the backscatter response to climatic forcing. The A (isotropic component) and M2 (bi-sinusoidal azimuth anisotropy) parameters are investigated here, in conjunction with data from atmospheric and snowpack models, to identify the backscatter response to surface forcing parameters (wind speed and persistence, precipitation, surface temperature, density and grain size). The long-term mean A parameter is successfully recreated with a regression using these drivers, indicating strong links between the A parameter and precipitation on long timescales. While the ASCAT time series is too short to determine which factors drive observed trends, factors influencing the seasonal and short timescale variability are revealed. On these timescales, A strongly responds to the propagation of surface temperature cycles/anomalies downward through the firn, via direct modulation of the dielectric constant. The influence of precipitation on A is small at shorter timescales. The M2 parameter is controlled by wind speed and persistence, through modification of monodirectionally-aligned surface roughness. This variability indicates that throughout much of coastal Antarctica, a microwave ‘snapshot’ is generally not representative of longer-term conditions