Researchers led by the University of Cambridge They have used artificial intelligence techniques to monitor the sleet on the ice shelves of Antarctica and they discovered that 57% of all meltwater remains in the form of slushand the remaining amount is found in surface ponds and lakes.
Accurately monitoring Antarctic meltwater with AI
As the climate warms, more meltwater forms on the surface of ice shelves, the floating ice that surrounds Antarctica and acts as a buttress against the ice of glaciers inland. Rising meltwater may cause ice shelf instability or collapsewhich in turn leads to sea level rise.
The researchers also discovered that meltwater and accumulated meltwater cause 2.8 times more meltwater formation than predicted by standard climate modelsas it absorbs more heat from the sun than ice or snow. The results, published in the journal Nature Geoscience, could have profound implications for ice shelf stability and sea level rise.
Every summer, as the weather warms, Water accumulates on the surfaces of Antarctica’s floating ice shelvesPrevious research has shown that surface meltwater lakes can contribute to the fracturing and collapse of ice shelves, as the weight of the water can cause the ice to bend or break. However, The role of sleet in the stability of ice shelves is more difficult to determine.
“We can use satellite images to map meltwater lakes in much of Antarctica, but slush is difficult to map, because it looks like other things, such as cloud shadows, when viewed from a satellite.“said lead author Dr. Rebecca Dell of Scott Polar Research Institute (SPRI) of Cambridge. “But using machine learning techniques, we can go beyond what the human eye can see and get a clearer picture of how sleet could be affecting the ice in Antarctica.“.
Using optical data from the NASA Landsat 8 satelliteCambridge researchers, in collaboration with researchers from the University of Colorado at Boulder and Delft University of Technology, trained a machine learning model to obtain Monthly records of snowmelt and meltwater lakes on 57 Antarctic ice shelves from 2013 to 2021.
“Machine learning allows us to use more information from the satellite because it can work with more wavelengths of light than the human eye can see.“Dell said.”This allows us to determine what is and is not sleet, and we can then train the machine learning model to quickly identify it across the continent.“.
“We are interested in knowing how much sleet is present during the Antarctic summer and how it has changed over time“said co-author Professor Ian Willisalso from SPRI.
Using their machine learning model, Researchers found that at the peak of Antarctic summer in January, more than half (57%) of all meltwater on Antarctic ice shelves is in meltwater, with the remaining 43% in meltwater lakes..
“This slush has never been mapped on a large scale across all of Antarctica’s large ice shelves, so more than half of the surface meltwater has been ignored until now.“Dell said. “This is potentially significant for the hydrofracturing process, where the weight of meltwater can create or enlarge fractures in the ice.“.
Meltwater affects the stability of platforms of floating ice that line the Antarctic coast. As the climate warms and melt rates increase in Antarctica, meltwater, whether in the form of lakes or slush, can penetrate cracks in the ice, causing the cracks to become larger. This can cause ice shelf fractures and cause vulnerable ice shelves to collapse, which in turn would allow ice from inland glaciers to spill into the ocean and contribute to sea level rise.
“Since slush is more solid than meltwater, it won’t cause hydrofractures in the same way that lake water does, but it’s definitely something we need to consider when trying to predict how or if ice shelves will collapse.“Willis said.
In addition to the potential implications of slush on hydraulic fracturing, it also has a large effect on melt rates. Given the sleet and lakes are less white than snow or ice, they absorb more heat from the sun, causing more snow melt. This additional melt is not currently accounted for in climate models, which can lead to underestimates in projections of ice sheet melt and ice shelf stability.
“In the future, places in Antarctica that are currently free of water and mud are likely to begin to change.“Willis said.”As the climate continues to warm, more melting will occur, which could have implications for ice stability and sea level rise.“.
Reference
Rebecca Dell et al, Substantial contribution of slush to meltwater area across Antarctic ice shelves, Nature Geoscience (2024). DOI: 10.1038/s41561-024-01466-6
This entry was posted in News on 28 Jun 2024 by Francisco Martín León
