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One of the largest ice blocks in the world is singing.
The wind blowing over the rough surface of the Ross ice floe of Antarctica brings this glacial expanse the size of France to produce a nearly continuous series of tones, according to a study published Tuesday in the journal Geophysical Research Letters.
The tones are too low to be heard by humans, but accelerated interpretations have been compared to everything from the haunting drone of a didgeridoo to the soundtrack of a 1950s movie about extraterrestrials.
The discovery of singing ice came by accident.
To find out more about the pack ice floating on the Southern Ocean next to the Antarctic continent, researchers buried dozens of seismic sensors in 2014 under the snow-covered surface of the platform. But when scientists undertook to analyze more than two years of data collected by the sensors, they discovered that the rough surface of the shelf – what scientists call the top layer – vibrated almost constantly.
Scientists also discovered that the frequency of vibration changes with changing weather conditions on the plateau – for example, when the temperature rises or falls, and when storms reshape the snow dunes on the plateau.
Douglas MacAyeal, a glaciologist at the University of Chicago, said in a written commentary that accompanied the newspaper. "It was discovered that this vibration was caused by the wind that blew on the walnut layer and interacted with the intrinsic roughness of the surface called sastrugi."
MacAyeal also proposed a more poetic description of the sound, comparing it to "the buzz produced by thousands of cicadas when they invaded the canopy and grasses in late summer".
Julien Chaput, a geophysicist and mathematician at Colorado State University in Fort Collins and head of research, said in an email to NBC News MACH that the sound sounded "a bit like yodel, except that 10 people all sing in dissonance. . "
But the singing ice is more than a sound curiosity. Chaput and his colleagues argue in their article that seismic data could be used to monitor the health of the ice packs, which have been thinning due to global warming – and causing sea level rise all over the world. the world.
Satellite data proved useful for monitoring conditions on ice shelves, but Chaput said seismic monitoring may be more nuanced.
"Our current projects are to analyze all existing Antarctic seismic stations and see if we can have a broad sense of" snow health "and deploy more stations to vulnerable ice trays in West Antarctica" , did he declare. to be the "canary in the mines" to monitor the polar regions.
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