Refined broad-scale sub-glacial morphology of Aurora Subglacial Basin, East Antarctica derived by an ice-dynamics-based interpolation scheme

Abstract

Abstract. Ice thickness data over much of East Antarctica are sparse and irregularly distributed. This poses difficulties for reconstructing the homogeneous coverage needed to properly assess underlying sub-glacial morphology and fundamental geometric constraints on sea level rise. Here we introduce a new physically-based ice thickness interpolation scheme and apply this to existing ice thickness data in the Aurora Subglacial Basin region. The skill and robustness of the new reconstruction is demonstrated by comparison with new data from the ICECAP project. The interpolated morphology shows an extensive marine-based ice sheet, with considerably more area below sea-level than shown by prior studies. It also shows deep features connecting the coastal grounding zone with the deepest regions in the interior. This has implications for ice sheet response to a warming ocean and underscores the importance of obtaining additional high resolution data in these marginal zones for modelling ice sheet evolution.

Land-ice elevation changes from photon-counting swath altimetry: first applications over the Antarctic ice sheet

“…ICECAP used a long-range ski-equipped DC-3T modified for aerogeophysics by the University of Texas, and equipped with ice-penetrating radar, gravimeter, magnetometers and laser altimeters to investigate the geometry (Roberts and others, 2011), long-term history (Young and others, 2011), stratigraphy (Cavitte, 2011) and subglacial hydrology (Wright and others, 2012) The ICECAP geophysical system was installed on the aircraft at the McMurdo seasonal sea-ice runway at the start of each field season. Installation was followed by a calibration flight involving multiple crossovers over flat ice.…”

Simulated melt rates for the Totten and Dalton ice shelves

“…Most of the ice sheet that drains through the Totten Glacier is from the Aurora Subglacial Basin and is marine based (i.e. the ice base is grounded below sea level; Roberts et al, 2011) making the region potentially vulnerable to rapid ice sheet collapse. Weertman (1974) showed that ice grounded below sea level is inherently unstable, particularly where the bedrock slopes downwards, away from the ocean, as is the case in the Aurora Subglacial Basin .…”

Inferring ice-flow directions from single ice-sheet surface images using the Radon transform

“…Flow-orientation information can be used to refine ice-flux estimates in flux-balance simulations (Wu and Jezek, 2004), especially for Lagrangian-type flux-balance codes (e.g. Testut and others, 2003;Roberts and others, 2011). In addition, flow-direction information is frequently required in determining surface ice-sheet velocities using InSAR techniques, where the flow direction is usually assumed to correspond to the direction of steepest descent of the ice-sheet surface, derived from digital elevation models.…”