Sensitivity of Greenland ice loss to albedo change

In the past decades the Greenland Ice Sheet has been losing mass at an accelerating rate. The key drivers are increased dynamic discharge on the one hand, and changes in climatic mass balance on the other.

A common approach to calculate surface melt rates in ice sheet models are Temperature Index models, which are computationally efficient, require only temperatures as input and thus allow studying the evolution of ice sheets on very long time scales. In this study, we compare the standard positive degree day (PDD) method to an insolation temperature melt (ITM) method, which additionally takes short wave radiation and albedo changes into account. In contrast to the PDD approach, the ITM method can thus capture the ice-albedo feedback.

Here we compare the effects of the two approaches on the evolution of the Greenland Ice Sheet under idealized scenarios as simulated with the Parallel Ice Sheet Model (PISM). We further study the effect of a surface darkening, due to e.g. extreme melting or dust deposition, on the evolution of the Greenland Ice Sheet.