San Diego Researcher Studies Lake Collapse On Antarctica Ice Shelf
Australian glaciologist Roland Warner was looking for far-reaching impacts of his country's recent wildfires. He posited that the particles from the fire might have drifted south to the Antarctica ice shelves.
As he reviewed images compiled by the ICE-Sat 2 satellite, he noticed something unusual in the images taken during the device’s pole-to-pole journey. There were changes in a massive ice-covered lake.
It is common for melted ice and snow to collect in low spots on the ice shelf and this lake had accumulated water over decades.
But that huge lake on the Amery ice shelf was no longer full of water.
“Right at mid-winter when you expect everything to stay just really cold. Frozen. And not much going on, especially anything involving water in liquid form,” said Helen Fricker, a glaciologist at the Scripps Institution of Oceanography in San Diego.
“And then bang,” Fricker said. “A lake drained. And we would not have known about it if it had not been for the benefit of satellite observations.”
Fricker was part of the team that tried to figure out what happened.
The lake itself was huge. Satellite images show the body of water with an ice cover of more than four square miles .
Researchers estimate there were 21 million to 26 million cubic feet of water in the lake, which is near twice the volume of water in San Diego Bay.
The team pinpointed the timing of the incident to a week in June, the middle of the Arctic winter.
“We believe the weight of water accumulated in this deep lake opened a fissure in the ice shelf beneath the lake, a process is known as hydrofracture, causing the water to drain away to the ocean below,” said study lead author Roland Warner, a glaciologist with the Australian Antarctic Program Partnership at the University of Tasmania.
Once the water escaped, the ice cover collapsed into a bowl that was about 260 feet deep. With the water load gone, the floating ice then was pushed back up, leaving a rise roughly 118 higher than the original surface of the lake.
Fricker credits the satellite for recording an event that might not ever have been discovered.
“So this capability that we’ve shown with ICE Sat-2 is going to help us learn about meltwater systems all around both ice sheets,” Fricker said.
Scientists hope understanding events like this will help scientists improve their models, which aim to predict what will happen to the ice shelf under different circumstances.
The findings are published in the journal Geophysical Research Letters.