Parallel numerical modelling of the Antarctic Ice Sheet

Abstract

The Antarctic Ice Sheet comprises the West Antarctic Ice Sheet and the much larger East Antarctic Ice Sheet. Fast flowing ice streams and outlet glaciers are important dynamic components of the ice sheet system, and a grid resolution of at least 20 km is required to identify many of these areas. Previous fine resolution numerical models have focussed on ice flow in West Antarctica or on fine resolution modelling of subsections of the ice sheet, since the size of East Antarctica has generally precluded studies of the whole ice sheet at a resolution adequate to identify complex flow features. The equations describing ice flow are highly non-linear, making this a computationally intensive problem. We use a staggered grid for calculation of ice diffusivity to overcome numerical instability, and a sparse packing scheme to take account of the irregular boundary of Antarctica. We have developed an efficient parallel temperature-dependent ice flow model of the entire grounded portion of the Antarctic Ice Sheet at a resolution of 20 km. The model was primarily written to run on a commodity cluster of workstations, and performance results for this and other systems are presented. Ice flow patterns at steady state compare well with recently published balance velocity calculations.