Scientists at the University of Cambridge have designed a new type of drone tailored to protect against extreme Arctic conditions. They used the drones to observe for the first time the formation of cracks under the melting water lake of the Greenland ice sheet. The team says the breaks have led to catastrophic lake drainage, diverting large amounts of surface water to sensitive environments under the ice.
The new study shows how water shifts and how ice sheets react. The researchers found that the inflow of meltwater caused the lake to expand and begin to drain when the edge of the lake intersected with a crack formed a year ago. Every summer, as the ice sheet warms, thousands of lakes form on the surface of the Greenland ice sheet.
Many lakes are lost within hours, creating a cave called a mill, from which water falls to the bottom of the ice sheet. These holes usually remain open throughout the melting season, as melting water from surface streams and rivers drops below the ice. During the study, the team was able to see how the cracks moved and how they extended further 500 meters into the lake, causing the lake to drain rapidly.
The drone allowed the team to record the flow of water into the cracks and the path of the water under the ice. The reconstruction of events can show how meltwater forms new cracks and lead to the expansion of dormant cracks. Within five hours, 5 million cubic meters of water were drained through cracks to the bottom of the ice sheet, creating a new hole.
As more surface water is diverted to the riverbed, the ice flow accelerates from 2 meters per day to more than 5 meters per day. The team says the current caused the ice sheet to rise by half a meter. Using GPS and autonomous driving technology, the drone is able to stitch together hundreds of photos and perform detailed 3D reconstructions of the surface of the ice sheet.