This article has been reviewed according to Science X's editorial process and policies. Editors have highlighted the following attributes while ensuring the content's credibility: The Kronshtadskiy subglacial lake near East Antarctica's Amery Ice Shelf was hidden beneath Antarctica's ice, but its drainage left a mark visible from space as a broad depression that deepened by more than 6 meters (20 feet) at its center. By tracking that sinking surface, researchers estimate that the lake lost about 78 million cubic meters (20.6 billion gallons) of water between 2016 and 2021.
The changing shape of the depression also helped researchers Jihyun Moon and Hoonyol Lee of Kangwon National University in South Korea reconstruct how the drainage unfolded. The research is published in Scientific Reports. Beyond the main lake, nearby patches of rising and falling ice offered clues to where the water might have gone next.
As a buried lake loses water, the ice above it can sink. When the lake fills, the surface can rise. Those movements allow researchers to investigate bodies of water they cannot see directly.
Tracking that water matters because it can reduce friction between the ice and the ground, affecting how readily glaciers slide. But measurements of surface height from satellites leave gaps between their observation tracks. Radar images can map movement across a wider area.
The complication there however, is that Antarctic ice moves sideways as well as up and down, and both motions affect the signal. To separate them, the researchers compared Sentinel-1 radar images taken 24 days apart with a reference period when the lake area appeared relatively stable. Subtracting the background motion helped reveal the sinking surface, provided that the glacier's sideways flow remained sufficiently steady.
The analysis revealed a roughly circular patch of sinking ice covering about 61 square kilometers (24 square miles). This mapped the lake's effect on the surface, rather than its underground shoreline. At the center, the reconstructed surface dropped about 6.4 meters (21 feet) over five years.
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