Clouds and their Impacts on the Greenland Ice Sheet

Clouds play a central role in the climate of the Greenland Ice Sheet, influencing the surface energy and mass budgets. Using observations from the Integrated Characterization of Energy, Clouds, Atmospheric state, and Precipitation at Summit (ICECAPS) campaign and coordinated measurements, we provide a synthesis of cloud information in central Greenland over the past six years. The observations combine a suite of ground-based active and passive remote sensors along with in situ measurements to characterize basic cloud properties, their annual variability, and the manner in which they interact with the surface energy budget. The frequent occurrence and critical role of liquid water clouds is specifically highlighted. It is shown that over the central ice sheet domain due to the high surface albedo, clouds warm the surface year round. Regional synoptic analyses are used to provide insight into the larger-scale drivers of cloudiness over central Greenland, including drivers of moisture advection. A regional coupled system model is used to examine cloud processes in more detail and to up-scale our understanding of cloud-surface interactions to cover the full ice sheet. Simulations reveal a spatially variable role of clouds that may have key implications for both enhancing and modulating melt processes over Greenland.