In 2007, glaciologist Helen Amanda Fricker made an astonishing discovery. She found that beneath the thousands of metres thick Antarctic ice-shelves lies a whole hidden network of interconnected lakes that actively fill and drain. The presence of meltwater beneath the ice sheets was known, but such a network with an active water system was a breakthrough. Fricker had used data from NASA’s ICESat, a satellite that used laser pulses to measure elevation data for ice, clouds and land and their topography.
NASA launched a more advanced successor of ICESat, ICESat-2 in 2018. The new space satellite could gather elevation data with higher precision - up to inches. Using data from ICESat 2, Fricker, along with her fellow researcher Matthew R. Siegfried, has now discovered two new subglacial lakes - meltwater lakes under glacial ice - in Antarctica, and mapped the network of lakes with high precision.
These maps will help scientists understand the water system in Antarctica and how these glacial lakes contribute to the ocean water. Using these critical measurements, scientists can explain and predict the appearance and disappearance of Antarctic lakes. For example, an enormous lake had disappeared in just three days in the Amery Ice shelves of Antarctica.Moreover, scientists can calculate how much of this is caused by global warming and how these lakes are affecting the movement of Antarctic glaciers.
Scientists say that how slow or fast the Antarctic ice sheet moves depends upon these meltwater lakes which are lubricating it. The movement happens slowly outwards from the central region but when it approaches the Southern Ocean, the movement speeds up by a few metres. During this movement, the ice sheets suffer cracking, crevassing and other changes, which are all measured using space lasers, thanks to ICESat-2.
“These are processes that are going on under Antarctica that we wouldn’t have a clue about if we didn’t have satellite data,” said Fricker, in a statement. The study was published on July 7 in Geophysical Research Letters.
Scientists think that understanding the nature of meltwater lakes and other changes happening in ice sheets can help them understand the fate of Antarctica and guide them about how global warming is affecting the ice sheet.