Automated detection and characterization of Antarctic basal units using radar sounding data: demonstration in Institute Ice Stream, West Antarctica

Abstract

Basal 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.

Five decades of radioglaciology

“…The discovery of deep internal structures that do not conform to the bed has prompted new model exploration of englacial and basal processes including interpretation of their radar scattering character, with implications for interpreting ice-sheet dynamics and the climate archive (e.g. Bell and others, 2011, 2014; Dahl-Jensen and others, 2013; Wolovick and others, 2013; Wrona and others, 2017; Kjær and others, 2018; Goldberg and others, 2020).…”

Review article: Feature tracing in radio-echo sounding products of terrestrial ice sheets and planetary bodies

“…In a number of studies radargrams were analysed to find different segments or subsurface targets (e.g. englacial boundaries, EFZ, basal units) and classes of events in each radargram (e.g., Donini et al, 2019;Goldberg et al, 2020;García et al, 2021García et al, , 2023. Even though we focus on the methods for mapping englacial ice structure and tracing IRHs and/or layer boundaries, we also take a look at studies done to detect regions and targets in radar products, since those are, in terms of methodology, in close vicinity to stratigraphy mapping endeavours.…”

“…Goldberg et al (2020) developed an algorithm to detect basal units. They introduce a SAR processing method and employed unique phase shift response functions to classify feature types such as englacial layers and potential basal units.…”