The Greenland Ice Sheet is very different from the "small" glaciers, in its size, its dynamics and its climatology. Covering an area of 1.71 million km², it is more than twice the size of all the small glaciers put together. In volume, the ratio is more like 15 times, and so the dynamic response of the ice sheet to climatic forcing is much slower than that of a small glacier. (Recent observations, however, cast doubt on this conventional wisdom.) Unlike nearly all small glaciers, the Greenland Ice Sheet has an extensive high-elevation dry snow zone, where the snow and ice never melt because the surface temperature never reaches the freezing point. Unlike the Antarctic Ice Sheet, however, the Greenland Ice Sheet has a distinct ablation zone, where in summer all of the winter's snowfall melts and so does some of the underlying glacier ice.

Estimating the mass balance of the Greenland Ice Sheet is a complex challenge in which dozens of glaciologists are engaged. The broad approach is to try to subdivide the problem into manageable chunks. At Trent we are studying the spatial distribution of surface accumulation (snowfall minus sublimation) on and near the ice sheet. In particular, our aim is to develop and validate formal estimates of the uncertainty of accumulation. To find out more, and to download compiled accumulation data, click Greenland Accumulation.