When a Greenland aquifer was accidently discovered by glaciologists in 2011 during a snow accumulation study, little could be done to continue the study of the aquifer because their tools were not suited to work in an aquatic environment. So this past year, a team of glaciologists led another expedition to southeast Greenland in order to find out more about this liquid reservoir.

 

Southeast Greenland is a region of high snow accumulation. Researchers now believe that the thick snow cover insulates the aquifer from cold winter surface temperatures, allowing it to remain liquid throughout the year. As far as where the water comes from, researchers say the aquifer is fed by melt water that percolates from the surface during the summer.

 

Researchers used NASA's Operation Icebridge radar data to confine the limits of the water reservoir, which spreads over 27,000 square miles (69,930 square km) — an area larger than the state of West Virginia.

 

Lora Koenig, a glaciologist with NASA's Goddard Space Flight Center in Greenbelt, Md., and her team measured the top of the aquifer at around 39 feet (12 meters) under the surface. This was the depth at which the boreholes filled with water after extracting the ice cores.

 

The team estimated water volume of about 154 billion tons (140 metric gigatons). If this water was to suddenly discharge to the ocean, this would correspond to 0.016 inches (0.4 mm) of sea level rise!

 

"Our next big task is to understand how this aquifer is filling and how it's discharging," said Koenig. "The aquifer could offset some sea level rise if it's storing water for long periods of time. For example after the 2012 extreme surface melt across Greenland, it appears that the aquifer filled a little bit. The question now is how does that water leave the aquifer on its way to the ocean and whether it will leave this year or a hundred years from now."