Subproject 8: Meltwater production and climatic mass balance of the 79°N glacier surface

There are many diverse and complex interactions within the earth system which control the behaviour of the large outlet glaciers of Greenland. One such interaction is between the atmosphere and the surface of the ice. The atmospheric controls on the surface melt rates have great importance for the ice dynamics: supraglacial meltwater penetrates into the interior of the glacier via water channels and contributes to mechanical and thermodynamic processes that affect the stability of the entire glacier.

This subproject, which adds the meteorological building block to GROCE and concentrates on the interaction between the atmosphere and the glacier surface, has two objectives: 1) Determine the climate mass balance of the 79°N glacier in high spatial resolution, with a specific focus on estimating the amount of supraglacial (surface) meltwater production. 2) Determine the atmospheric dynamics which are responsible for controlling the mass balance and amount of melting at a variety of spatial and temporal scales. The methodology is based on both direct meteorological observations of the near-surface atmosphere and on a multiscale modelling system that combines two different models (an atmospheric model and a surface mass balance model) in a novel way.

The determination of the spatial distribution of the supraglacial melt rates will be the main result, and will contribute to other subprojects. Similarly, the high-resolution modelling will provide adequate foundation for investigating how the mesoscale atmospheric processes impact the climatic mass balance, which will provide new insights into the atmospheric drivers of outlet glaciers in Greenland.