Flow Modeling of Juneau Icefield

Juneau Icefield covers 3900 km2 in the Coast Mountains on the border between Alaska and British Columbia. It has shown substantial mass loss in the last century. There have been a multitude of field campaigns on Juneau Icefield (including the well-known Juneau Icefield Research Project), so the data coverage is comparatively good. In addition there are remote-sensing studies that provide icefield-wide data on surface velocities and thickness changes. We study the future evolution of the Juneau Icefield using the Parallel Ice Sheet Model (PISM). Despite the multitude of field campaigns, the spatial distributions of ice thickness and precipitation remain poorly constrained, and obtaining a reasonable surface mass balance across the icefield proved to be challenging.We show how we calibrate the model using the mass balance, surface velocity and thickness change measurements, and investigate the remaining uncertainty in our future projections by performing sensitivity tests. The results from these tests show where additional measurements are most needed to better constrain projections of the future evolution of the icefield.