Towards a re-assessment of the surface mass balance of the Greenland ice sheet

At present, the mass balance and especially the surface mass balance of the Greenland Ice Sheet (GrIS) are poorly known. Current methods to determine GrIS surface mass balance as well as the inherent uncertainties are discussed. Special emphasis is placed on the increasingly important role of regional atmospheric climate models, which explicitly calculate the individual components of the surface mass balance: (solid) precipitation, melt and subsequent runoff, sublimation/deposition and refreezing in the snow. Especially the latter term is very uncertain, and poses a great challenge to modellers. Some recent advances in these fields of research are presented.