New study shows what triggers changes in the thick snow covering the Greenland ice sheet

Thursday 08 Nov 18
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Contact

Baptiste Robert Marcel Vandecrux
PhD student
DTU Civil Engineering

Contact

Thomas Ingeman-Nielsen
Associate Professor
DTU Civil Engineering
+45 45 25 22 51

Infrastructures in Greenland

Infrastructures in Greenland greatly depend on the massive ice sheet that covers 80% of the country: From iceberg production threatening shipping and offshore infrastructures to meltwater running off the ice sheet in the summer and creating floods such as the one that damaged a bridge in Kangerlussuaq in 2012. Worldwide, shore infrastructure design and engineering will need to account for raising sea levels to which Greenland is an important contributor. With PhD projects like this one, and the collaboration with GEUS, DTU aims at bridging the gap between the climate and glaciological sciences and the civil engineering community that need reliable estimates for future runoff and sea level contribution from the Greenland ice sheet

Using weather data and a state-of-the-art snow model, tightly constrained by in-situ firn observations, a team of researchers have revealed what controls key physical characteristics of the firn.

About 80 % of the Greenland ice sheet is covered by a thick layer of perennial snow, also called firn. It has the capacity to retain part of the surface melt in summer and thereby it reduces the contribution of the ice-sheet to sea level rise. In the vast frozen region covered with firn, few wind-beaten weather stations collect precious information about the local climate and firn conditions.

In a new open-access study, these weather data and a state-of-the-art snow model, tightly constrained by in-situ firn observations, were used to reveal what controls some of the key physical characteristics of the firn at each location. The study revealed that in some regions of the Greenland ice sheet, the firn density had increased significantly resulting in a loss of up to 18% of the meltwater retention capacity of the firn.

PhD student Baptiste Vandecrux, DTU Civil Engineering explains:
"This decreasing retention capacity indicates that, should the climate warming continue, part of the firn-covered regions of the ice sheet could start participating to sea level rise. The study also points at the sensitivity of the firn to the amount of snow that accumulates at the ice-sheet surface and highlights the necessity to get both melt and snowfall right to predict accurately the future evolution of the firn on the Greenland ice-sheet."

The study represents one of the most detailed examinations of the firn evolution in the accumulation area of the Greenland ice sheet.

The study was conducted in collaboration with researchers from the Geological Survey of Denmark and Greenland, the Danish Meteorological Institute, the University of Colorado and the Swiss Federal Institute for Forest, Snow and Landscape Research. 

 

Read scientific article
B. Vandecrux et al: "Drivers of Firn Density on the Greenland Ice Sheet Revealed by Weather Station Observations and Modeling"

Journal of Geophysical Research, Earth Surface, online September 2018

https://doi.org/10.1029/2017JF004597

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