Radars recorded melting glaciers in Antarctica

Radars recorded melting glaciers in Antarctica

West Antarctica records high rate of glacial retreat due to melting

Scientists at the University of Houston, together with colleagues from Germany, France and Italy have recorded an unprecedented rate of retreat of glaciers in the Amundsen Sea in West Antarctica. The floating part of these glaciers restrains the mass of ice on the shore, and its slippage could lead to a significant rise in sea level. The researchers’ findings are published in the journal Nature Geoscience.

It is known that the area of the Gulf of Amundsen, in which the glaciers of Pine Island, Toits, Pope, Smith and Kohler sink, makes a major contribution to sea level rise. It is estimated that the entire mass of ice above the shoreline is equivalent to a sea level rise of 1.2 meters. Pine Island and Touates Glaciers, considered the most dangerous, are losing record amounts of ice, but researchers have noticed that other glaciers are also retreating due to a phenomenon called sea ice sheet instability. It occurs when warm seawater erodes the grounding line, the boundary between the floating part of the glacier and the part of the glacier that lies on the bottom.

Beginning in 2014, researchers observed ground line retreat at Pope, Smith and Kohler Glaciers using synthetic aperture interferometer radar (InSAR) aboard COSMO-SkyMed satellites. These data were combined with digital models of ice surface heights created from observations from the TanDEM-X radar satellite.

It turned out that in 2017, the Pope Glacier retreated 3.5 kilometers in just 3.6 months, a rate of 11.7 kilometers per year. From 2016-2018, Smith Glacier retreated two kilometers per year and Kohler retreated 1.3 kilometers per year. Although retreat has slowed in 2018-2020, annual retreat rates are still higher than numerical models suggest and greater than the retreat rates of other glaciers in Antarctica and Greenland. Even the Toits and Pine Island glaciers are retreating at a slower rate of one kilometer per year. The authors of the paper attribute the rapid retreat to the melting of ice in the cavities that form near the grounding line, where seawater penetrates.

Although the potential contribution of the studied glaciers to sea level rise is estimated only six centimeters, the scientists emphasize that the processes that cause the retreat affects all the glaciers of West Antarctica, including the most dangerous. Future results will help more accurately determine the region’s maximum contribution to sea level rise in the coming decades.

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