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

The accelerating rate of global sea-level rise underscores the growing importance ofunderstanding how ice sheets respond to climate forcing and how this response isrepresented in models. The Antarctic Ice Sheet (AIS) represents one of the largest potentialcontributors 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 indynamically active regions. To this end, we analyse ensemble simulations from ISMIP6,which provide a unique framework to explore the diversity and consistency of ice-sheetmodel responses under common climate forcings. Unlike most analyses, which evaluatemodel evolution over time, here we focus on the Amundsen Sea sector and compare thelocal response of models when a grid point corresponds to the grounding line. Thisgrounding-line-centred diagnostic allows us to assess how ice flux, thickness, and velocityvary as the grounding line migrates, and to explore the consistency of these relationshipsacross models. By focusing on local dynamical behaviour rather than time-integratedevolution, this approach aims to improve our understanding of how grounding-lineprocesses control ice discharge in a region that dominates Antarctic mass loss.