Fingerprints of the Greenland Ice Sheet

Abstract:

The Sea-level Response to Ice Sheet Evolution (SeaRISE) effort explored the sensitivity of ice sheets to external forcings, which included the impact of warmer atmospheric and oceanic conditions, along with increased basal sliding conditions. The analysis presented here focuses on the spatial and temporal response of the Greenland ice sheet. We demonstrate that the ice thickness evolution displays a characteristic signature or “fingerprint” patterns, which propagate at different rate and to specific regions, depending on the type of sensitivity experiment. For example, warmer atmospheric conditions results in interior growth and a thinning of the ice margins, but the converse occurs with the enhanced basal sliding experiments. In addition, when two distinct forcing are used to drive the ice sheet simultaneously, the resulting complex new fingerprint is comparable to the linear combination of the two independent simpler fingerprints. We apply this technique of fingerprint analysis to develop a set of contemporary climate forcings that can be used as inputs for ice sheet models in order to reproduce recently observed ice thickness and ice margin fluctuations.