A sensitivity analysis for an evolution model of the Antarctic ice sheet

The evolution of the Antarctic ice sheet for the last 200,000 years is simulated with a finite difference thermomechanical model based on the shallow ice approximation. The model depends on the surface temperature, the ice accumulation rate, the geothermal heat flux and the basal sliding coefficient, which are estimated with large uncertainty. A second-order approximation of the model in a neighborhood of the reference values for these parameters permits the computation of both local and variance-based sensitivity indices. The results show the dominant effect of the surface temperature on the model predictions.