The Antarctic Ice Sheet hides hundreds of meltwater lakes where its base meets bedrock. These lakes continuously fill and drain through a system of waterways that drain into the ocean. Using NASA’s Ice, Cloud and land Elevation Satellite 2 (ICESat-2), the most advanced Earth-observing laser instrument flown in space, scientists have improved their maps of the hidden lake systems below the West Antarctic ice sheet and discovered two more active sub glacial lakes.

The satellite measures the height of the ice surface, which rises and falls as the lakes fill and empty under the ice sheet. This knowledge provides critical insight for assessing how this system influences the speed at which ice slips into the Southern Ocean. When the ice enters the ocean, it adds freshwater that may change its circulation and ecosystems.

The study, which integrates height data from the original ICESat mission, ICESat-2’s predecessor, and from CryoSat-2, the European Space Agency's satellite dedicated to monitoring polar ice thickness, is published in the journal Geophysical Research Letters.

"The discovery of these interconnected systems of lakes at the ice-bed interface that are moving water NASA researchers on the surface of the Antarctic Ice Sheet. Source: NASA Goddard Space Flight Center/Kelly BruntNASA researchers on the surface of the Antarctic Ice Sheet. Source: NASA Goddard Space Flight Center/Kelly Bruntaround, with all these impacts on glaciology, microbiology, and oceanography — that was a big discovery from the ICESat mission," said Matthew Siegfried, assistant professor of geophysics at Colorado School of Mines and lead investigator. "ICESat-2 is like putting on your glasses after using ICESat, the data are such high precision that we can really start to map out the lake boundaries on the surface."

The research confirms that several lakes under the Mercer and Whillans ice streams in West Antarctica are experiencing a third draining period since 2003 when the original ICESat mission began measuring elevation changes on the ice sheet’s surface. This is also the region where the two newly found lakes sit. The study also found that the lake boundaries can change gradually as water enters and leaves the reservoirs.

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