Abstract
AbstractBasal units – visibly distinct englacial structures near the ice-bed interface – warrant investigation for a number of reasons. Many are of unknown composition and origin, characteristics that could provide substantial insight into subglacial processes and ice-sheet history. Their significance, moreover, is not limited to near-bed depths; these units appear to dramatically influence the flow of surrounding ice. In order to enable improved characterization of these features, we develop and apply an algorithm that allows for the automatic detection of basal units. We use a tunable layer-optimized SAR processor to distinguish these structures from the bed, isochronous englacial layers and the ice-sheet surface, presenting a conceptual framework for the use of radio-echo character in the identification of ice-sheet features. We also outline a method by which our processor could be used to place observational constraints on basal units’ configuration, composition and provenance.
Highlights
Processes occurring at and near the base of an ice sheet can have dramatic effects on the dynamics of the ice sheet as a whole
As ice sheets are subjected to destabilizing forces from a warming land surface and ocean, it is increasingly important to understand the complex dynamics of processes near the bed
Our investigation of Antarctic basal units is twofold: first we present a novel technique for the automatic detection of these units in radargrams, we use the algorithm output to theorize about the formation and composition of a specific basal unit in Institute Ice Stream, West Antarctica (Fig. 1a)
Summary
Processes occurring at and near the base of an ice sheet can have dramatic effects on the dynamics of the ice sheet as a whole. Basal processes are intimately related to large-scale ice-sheet stability, especially among the marine sections of the West Antarctic Ice Sheet. Basal melt and its implications for ice-sheet mass balance are of particular significance in these regions (Joughin and Alley, 2011; Pollard and others, 2015; DeConto and Pollard, 2016). In West Antarctica and elsewhere, basal melt and ocean circulation are closely coupled, with important consequences for grounding line retreat and ice-sheet stability (Colleoni and others, 2018; Beckmann and others, 2019). As ice sheets are subjected to destabilizing forces from a warming land surface and ocean, it is increasingly important to understand the complex dynamics of processes near the bed
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