Antarctica contains twice as much meltwater as expected

MADRID, June 28 (EUROPA PRESS) –

melted snow (waterlogged) makes up more than half of all Antarctic ice shelf meltwater in midsummer, but the models don’t take this into account.

A team of researchers from the University of Cambridge used artificial intelligence techniques to map melting snow on Antarctic ice shelves and found that 57% of all meltwater in Antarctica is in the form of melted snow.and the rest is in surface ponds and lakes.

As the climate warms, more meltwater forms on the surface of ice shelves—the floating ice that surrounds Antarctica and acts as a bulwark against the ice of inland glaciers. Increasing the amount of melt water may cause instability or collapse of ice shelves, which in turn causes sea levels to rise.

The researchers also found that melted snow and stagnant meltwater cause the formation of 2.8 times more meltwater than predicted by standard climate models.because it absorbs more heat from the sun than ice or snow. Results published in the journal Naturecould have major implications for ice shelf stability and sea level rise.

Every summer, as the climate warms, water accumulates on the surface of Antarctica’s floating ice shelves. Previous research has shown that shallow meltwater lakes can contribute to the cracking and collapse of ice shelves because the weight of the water can cause the ice to buckle or break. However, the role of melted snow in the stability of ice shelves It’s harder to decide.

“We can use satellite imagery to map meltwater lakes across much of Antarctica, but slush is difficult to map because when viewed from satellite it looks like other objects, such as cloud shadows,” he said. this is a statement lead author Dr Rebecca Dell from the Scott Polar Research Institute (SPRI), Cambridge. “But by using machine learning techniques, we can go beyond what the human eye can see and get a clearer picture of what’s going on.” “How Soaked Snow Could Affect Ice in Antarctica.”

Using optical data from NASA’s Landsat 8 satellite, Cambridge researchers, in collaboration with researchers from the University of Colorado Boulder and Delft University of Technology, trained a machine learning model to extract monthly records of snowmelt and meltwater on 57 Antarctic ice shelves between 2013 and 2021.

“Machine learning allows us to use more information from the satellite because it can work with longer wavelengths of light than the human eye can see,” Dell said. “This allows us to identify what is melted snow and what is not, and then we can train a machine learning model to quickly identify it across the continent.”

“We’re interested to know how much of this snow falls during the Antarctic summer and how it has changed over time,” said co-author Professor Ian Willis, also of SPRI.

Using their machine learning model, the researchers found that in January, at the height of the Antarctic summer, more than half (57%) of all meltwater from Antarctic ice shelves is in the form of saturated snow, with the remaining 43% in melt lakes.

“This water-saturated snow has never been mapped at large scales across all of Antarctica’s major ice shelves, so more than half of all surface meltwater has been ignored until now,” Dell said. “This is potentially important for the fracking process. where the weight of meltwater can create or widen cracks in the ice.”

Meltwater affects the stability of the floating ice shelves that surround the Antarctic coastline. As the climate warms and the rate of ice melt in Antarctica increases, meltwater (in the form of lakes or melted snow) can penetrate ice cracks, causing them to widen. This could cause cracks in the ice shelf and lead to the collapse of vulnerable ice shelves, which in turn would allow ice from inland glaciers to spill into the ocean and contribute to sea level rise.

“Because melted snow is harder than meltwater, it won’t cause fracking in the same way that lake water will, but it’s something we definitely need to keep in mind when trying to predict how or whether ice shelves will collapse,” Willis said.

In addition to snowmelt’s potential impact on hydraulic fracturing, it also has a major impact on melt rates. Because wet snow and lakes are less white than snow or ice, they absorb more heat from the sun, causing more melting. This additional melting is not currently accounted for in climate models, which which may lead to underestimation of ice sheet melt and ice shelf stability forecasts.

NOT CONSIDERED IN CLIMATE MODELS

“I was surprised that this meltwater was so little accounted for in climate models,” Dell said. “Our job as scientists is to reduce uncertainty, so we always want to improve our models to be as accurate as possible.”

“In the future, places in Antarctica where there is currently no water and no snowmelt will likely begin to change,” Willis said. “As the climate continues to warm, there will be further melting, which could have implications for ice stability and sea level rise.”