Antarctic ice shelf 'sings' as winds whip across its surface

Ученые рассказали о загадочном явлении в Антарктиде

Unusual noises have come from the Antarctic before as age-old air bubbles escaped their icy prisons and large ice sheets crumbled.

So, in order to better understand how they move, the researchers buried 34 extremely sensitive seismic sensors under the ice shelf's snowy surface, allowing them to measure vibrations and study structure movements for a period of more than two years.

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.

With this newfound ability, researchers could use seismic stations to continuously monitor the conditions on ice shelves nearly in real time, allowing us to see how the ice shelf's snow jacket is responding to changing climate conditions.

Not only were whipping winds causing the ice sheet's snow to rumble, but the pitch of this seismic hum also changed depending on the slushy surface conditions.

Researchers studying the Ross Ice Shelf have discovered a new and weird acoustic phenomenon. "Basically, what we have on our hands is a tool to monitor the environment, really".

That cork, however, is slowly disintegrating: Ice shelves all over the continent are thinning, breaking up, or retreating due to rising ocean and air temperatures.

The team eventually found that these trapped firn waves were created by the constant hum of wind brushing against the snow on the surface of the shelf. What they heard however, the creeping "singing" of the ice shelf, is not at all what the anticipated they would find. The firn had been altered permanently, and the ice shelf song was changed permanently as well. This snow layer acts like a fur coat for the underlying ice, insulating the ice below from heating and even melting when temperatures rise. And ice shelves themselves are particularly important, since their melting accelerates the streaming of ice into the ocean from abutting ice sheets. For instance, changes in the hum could indicate the presence of melt ponds or cracks in the ice.

Chaput considers seismic monitoring to be a good way to keep an eye on Antarctica's ice shelves, which are considered to be among the most remote locales in the world.



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