Resolution-dependent performance of grounding line motion in a shallow model compared with a full-Stokes model according to the MISMIP3d intercomparison

Published: May 1, 2014 by The PISM Authors

By using MISMIP3d simulations across a range of resolutions, this paper shows that the SIA+SSA hybrid stress balance in PISM can model grounding line motion in a perturbed ice-sheet–shelf system. The key improvements, all included in pism0.6, are: linear interpolation of the grounding line, locally-interpolated basal friction, and an improved driving-stress computation across the grounding line. The reversibility of the grounding line, after a local perturbation of basal resistance comes and goes, is captured by the model even at medium and low horizontal resolutions (> 10 km). The transient model response is qualitatively-similar to that of higher-order models, though with higher sensitivity to perturbations on very short timescales. Our findings support the application of PISM to the Antarctic ice sheet from regional up to continental scales and even at relatively-low spatial resolutions.