Temperature thresholds for degree-day modelling of Greenland ice sheet melt rates

Degree-day factors (DDFs) are calculated for the ice sheet ablation zone in southwest Greenland, using measurements of automatic weather stations and a regional atmospheric climate model. The rapid increase of DDFs for snow and ice towards higher elevations is caused by the increasing dominance of short daytime melting and nocturnal refreezing. This spatial inhomogeneity can be avoided by choosing a lower threshold for daily average 2 m air temperature (268 K instead of 273.15 K) for the degree-day calculation. Citation: van den Broeke, M., C. Bus, J. Ettema, and P. Smeets (2010), Temperature thresholds for degree-day modelling of Greenland ice sheet melt rates, Geophys. Res. Lett., 37, L18501, doi:10.1029/2010GL044123.