Science & Environment

Icebergs 'have sound signature'

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Media captionUnderwater microphones captured the sound of ice calving away from a glacier in Norway in August 2013

Listening to icebergs could help to assess the extent of glacier melt, scientists report.

Researchers in Poland, the UK and US have found different types of icebergs have their own acoustic signature as they calve away from the ice.

Monitoring this could help to determine how much ice is being lost and the effect this could have on global sea level rise.

The findings are reported in the journal Geophysical Research Letters.

Oskar Glowacki, from the Institute of Geophysics at the Polish Academy of Sciences, said: "Using acoustics, we can get very accurate data and we can collect this data continuously. We just place the hydrophones - underwater microphones - in the water and listen to the sounds."

The researchers used their kit to capture every rumble, groan and snap as ice cleaved away from the Hans Glacier in Svalbard.

Combining this with time-lapse photography, they discovered that the birth of different types of icebergs creates different sounds. The team found three acoustic signatures from this tidal glacier.

This not only allows them to work out how ice is crumbling into the water, but they can use the sounds to determine the stage of the break up, even when it is taking place underwater.

Dr Glowacki said: "It was really, really difficult to study these submarine events.

"We know now that when a submarine event starts, there is a disintegration below the sea surface, there are many cracks, and cracks are propagating and we can listen to this underwater.

"After this, the ice block detaches from the ice wall and it starts to appear on the surface. And using underwater acoustics, we can identify all stages of this sound."

Currently, glaciers are mainly monitored using satellites, but while they can spot huge ice break-ups, smaller blocks of ice are harder to detect.

The researchers say that listening to the ocean could help, allowing them to more accurately monitor how much ice is being lost to the sea as global temperatures rise.

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