Ice sheets are systems of such size and complexity that models of global climate do not have fine enough resolution to reproduce the processes occurring in ice sheets with sufficient accuracy. Inaccuracies in our understanding of the climate over an ice sheet mean that our confidence in predictions of future ice mass loss will be lower.

Philippe Lucas-Picher and his colleagues therefore use such global climate models as inputs for a high-resolution regional-scale model (RCM) homing in on the Greenland ice sheet; RCMs are suitable as inputs for models of the ice sheet designed to understand how it would respond to different climate change scenarios.

To ensure that the model’s calibration is correct and its outputs are accurate, the French-Danish team validate it against manned and automatic weather stations across the ice sheet. While they find that the model performs well, they encounter difficulties in validation due to the very scarce data from the ice sheet’s cold, dry interior: there are few weather stations here, and most of these have not been operational for very long. Nevertheless, improved resolution likely increases the accuracy of climate prediction. This is a crucial step towards producing more accurate predictions of how the Greenland ice sheet will change in the future, and how it will contribute to changing sea levels.

Ice2sea Work Package: WP4.2

Publication: Lucas-Picher, P., M. Wulff-Nielsen, J. H. Christensen, G. Adalgeirsdottir, R. Mottram, and S. B. Simonsen (2012), Very high resolution in regional climate model simulations for Greenland – Identifying added value, Journal of Geophysical Research, 117, 1-16.