When the wind blows, Antarctic's ice shelf 'sings'

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Courtesy/Rick Aster.Researchers lay the conduit that connects the seismometer to the solar power system (background) and recording components at a Ross Ice Shelf seismic station.

If you're still hunting for a soundtrack for your Halloween party, what about this ghostly tune by the Ross Ice Shelf?

An ice shelf is like a cork in a bottle, Aster told CNN. However, when an Antarctic ice meltdown is recorded, that means the rise of the sea levels. Ice shelves all over Antarctica have been thinning, and in some cases breaking up or retreating, due to rising ocean and air temperatures.

Mr Chaput and his team were using seismic sensors to learn more about the structure and movements of the Ross Ice Shelf, Antarctica's largest floating slab of ice, when they picked up the noises.

A thick blanket of snow covers ice sheets, which are frequently of a few meters thick, that shows considerable snow dunes, resembling sand dunes of the Sahara desert, for example.

When humans burn fossil fuels, heat-trapping gases are released into the atmosphere that contribute to the warming of the oceans and the melting of ice.

When they looked at the data, they realized the top layer of the shelf (called the firn) was nearly constantly vibrating, thanks to the winds travelling atop the snow dunes.

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Scientists heard the "song" of ice in Antarctica. The frequency of these waves vary based on changes to the loose snow in the firn, including the impacts of heavy winds or temperature shifts.

"If this vibration were audible, it would be analogous to the buzz produced by thousands of cicada bugs when they overrun the tree canopy and grasses in late summer", he wrote in a piece published in Geophysical Research Letters.

Just as musicians change pitch or note by altering how fast and through which holes air flows, strong storms and air temperatures adjust the topography.

"Either you change the velocity of the snow by heating or cooling it, or you change where you blow on the flute, by adding or destroying dunes", Chaput said.

"That's essentially the two forcing effects we can observe". Details like melt ponds or cracks forming that might indicate whether the shelf is liable to break up.

"This last point is particularly interesting", says Chaput, "because it could allow us to quantify which ice shelves have firn layers that are strongly impacted by repeated warming events, and also yield a metric of how resilient these firn layers might be". "Basically, what we have on our hands is a tool to monitor the environment, really".

The team believes that monitoring vibrations could help predict if the ice shelf is about to break.

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