NEW YORK: In 2008, scientists noticed the icy bottoms of lake on Greenland’s Ice Sheet occasionally crack open, releasing the water to the base of the ice sheet thousands of feet below.
New research can explain this phenomenon.
Scientist’s form Woods Hole Oceanographic Institute or WHOI and the University of Washington believe that they have identifies the mechanism that causes the ice sheet to suddenly drain over the course of mere hours.
Their theory states that the lakebeds crack because of the weight of the water itself, but this did not explain why some of them cracked while others didn’t.
Laura Stevens, a graduate student in the Massachusetts Institute of Technology-Woods Hole Oceanographic Institution (MIT/WHOI) Joint Program in Oceanography and the lead author of the study said, “Our discovery will help us predict more accurately how supraglacial lakes will affect ice sheet flow and sea level rise as the region warms in the future.”
Researchers have deployed a network of 16 GPS units around North Lake, which is a 1.5 mile long supraglacial lake in southwest Greenland. These instruments recorded ice movement surrounding the events of three major lake drainages in the summers of 2011, 2012 and 2013.
The data was analyzed by researchers and they found that in the 6 to 12 hours before the crack occurred, the ice around the lake moved upwards and horizontally. Meltwater start to drain through nearby systems of moulins that connected the surface and base of the ice sheet. This water accumulated to form bulge, causing the entire ice sheet to float and creating tension underneath the lake that eventually causes it to crack.
