Grounding-Line-Centred Diagnostics of Ice Discharge in the Amundsen Sea Sector

The accelerating rate of global sea-level rise underscores the growing importance of
understanding how ice sheets respond to climate forcing and how this response is
represented in models. The Antarctic Ice Sheet (AIS) represents one of the largest potential
contributors to future sea-level rise, yet its projected contribution remains highly uncertain,
reflecting limitations in our understanding and representation of key dynamical processes.
Improving confidence in future projections therefore requires a clearer assessment of ice-
sheet model behaviour and of the mechanisms that control ice discharge, particularly in
dynamically active regions. To this end, we analyse ensemble simulations from ISMIP6,
which provide a unique framework to explore the diversity and consistency of ice-sheet
model responses under common climate forcings. Unlike most analyses, which evaluate
model evolution over time, here we focus on the Amundsen Sea sector and compare the
local response of models when a grid point corresponds to the grounding line. This
grounding-line-centred diagnostic allows us to assess how ice flux, thickness, and velocity
vary as the grounding line migrates, and to explore the consistency of these relationships
across models. By focusing on local dynamical behaviour rather than time-integrated
evolution, this approach aims to improve our understanding of how grounding-line
processes control ice discharge in a region that dominates Antarctic mass loss.