Permanent liquid water layer discovered in the cold Arctic
A large body of liquid water layer in Greenland snow
Polar researchers from Utrecht University have contributed to the discovery and subsequent study of a liquid water layer at 5-25 m depth in the snow layer covering the Greenland ice sheet. The layer extends horizontally for hundreds of kilometers, as reported in Nature Geoscience this week.
Until now these liquid water layers, also known as aquifers, had only been observed in snowpacks and porous rocks outside of the Polar Regions. To find them in the extremely cold environment of the southern Greenland ice sheet, where annual mean temperatures range between -10 and -25 degrees centigrade, was unexpected. Using a snow model, the researchers from Utrecht University explain how liquid water can survive under these freezing conditions.
Two times the area of the Netherlands
"Our investigations show that a combination of strong melt and strong snowfall is required for aquifers to form in Greenland", says dr. Jan van Angelen of Utrecht University and one of the co-authors of the study. "The winter snow insulates the water from the cold atmosphere in winter, while strong melt replenishes the aquifer in summer. This rare combination is only found in the southeastern part of the Greenland ice sheet. We calculated that the aquifer has an extent of 70,000 square kilometers, almost two times the surface area of the Netherlands."
Further research must show whether the aquifer is a result of the recent warming in Greenland. The Greenland ice sheet is for 90% covered by a 20-100 m thick layer of compressed snow, and contains sufficient water to raise global sea levels by ~7 m. After Antarctica, the ice sheet is the largest on Earth.
The discovery of the liquid water layer in the snow layer covering the Greenland ice sheet was filmed (April 2011, thanks to Evan Burgess, Dept. of Geography, University of Utah).
‘Extensive liquid meltwater storage in firn within the Greenland ice sheet’, Nature Geoscience 2013. Jason Box, Michiel van den Broeke*, Clément Miège, Evan Burgess, Jan van Angelen*, Jan Lenaerts*, Lora Koenig, John Paden, Cameron Lewis, Sivaprasad Gogineni, C. Leuschen, Joseph McConnell. (* Utrecht University)
This research was sponsored by the Netherlands Organisation for Scientific Research (NWO).