Extracting Dated Isochrones on Airborne Radar Data Across EastAntarctica for Input into 3-D Regional Ice Sheet Models

Modelling the past evolution of the East Antarctic Ice Sheet (EAIS) in response to climate
and ocean forcing is challenged by the scarcity of observed palaeo boundary conditions. One
of the most spatially extensive records of past ice-sheet conditions comes from radar-detected
isochrones which, if dated precisely at ice cores, can provide a highly accurate temporal and
spatial history of ice-sheet evolution over time. Previous work has highlighted the benefit of
using such isochrones for testing and benchmarking 3-D ice sheet models; however,

uncertainty remains as to which model parameters fare better and how different bed and ice-
flow conditions affect the ability of ice-sheet models to reproduce the observed isochrones.

Here, we make use of previously acquired airborne radar data over the Wilkes Subglacial
Basin (East Antarctica) to connect existing stratigraphies and extract a temporal record of
isochrones at regular time intervals spanning the Holocene to the last interglacial and beyond.
The radar flight lines were carefully selected to provide a record of isochrones crossing
boundaries of different bed and ice-flow conditions situated between the ice divide and the
ice-sheet margins to represent as diverse a set of conditions as possible. The aim of this work
is to ultimately be able to test the ability of dated isochrones to tune ice-sheet model
parameters that will reproduce isochrone elevations in different parts of the catchment and
under different bed and ice-flow conditions.