Interpretation of ice-sheet internal stratigraphy: a test-bed for automated approaches

Radar surveys across ice sheets and ice caps typically sound numerous englacial layers which can be treated as isochrones. In principle isochrone geometry has many applications for both palaeo and contemporary glaciology and climatology, for example extrapolating age-depth information beyond ice-coring sites, reconstructing palaeoaccumulation variability, and investigating past ice-sheet dynamics. However, the use of radar-sounded englacial layers for such purposes in Antarctica has been hampered by underdeveloped techniques for characterising layer continuity and geometry over large distances. Motivated by a new international effort to develop a continent-wide model of Antarctica's internal architecture, we present in this paper an assessment of potential ways forward for characterising englacial-layer geometry using automated methods of processing.

Here we present a range of test case scenarios, selected from CReSIS MCoRDS datasets over Antarctica, to test the application of automated approaches to englacial layer model building. These test cases are selected from a range of challenging environments, including broken and disturbed layering with rapid variations in dip, and ice-stream-induced deformation. Manual interpretation has been undertaken to pick internal layers, and metrics of vertical picking error statistics, lateral continuity, and dip error are presented to assess the effectiveness of a range of demonstrative, simplified algorithms. These include correlation and maximum peak tracking, image enhancement and thresholding, and local dip estimations.

These data, metrics and interpretations will be made available for the benchmarking of future approaches to automated mapping of internal layers, to assess objectively the uncertainties and potential failure points for each approach.