The deep, high-pressure zones beneath Greenland’s glaciers control how the arctic ice responds to the increasing temperatures caused by climate change, and contributes to rising sea levels.
However, studying this deep, hostile environment is extremely difficult with existing technology.
Now researchers at Cardiff University are developing a wireless sensing device, dubbed Cryoegg, to measure and characterise the liquid water beneath the ice sheets, in a bid to help scientists to predict future environmental change.
The EPSRC-funded project, led by Dr Liz Bagshaw, is developing and testing the sphere-shaped device, capable of collecting water measurements below 2.5km of ice and transmitting the data back to the surface via a radio frequency (RF) transmitter.
The environment beneath the glaciers is currently investigated using cabled sensors implanted into narrow boreholes. However, fast-flowing ice can stretch and eventually break these cables, meaning valuable data is lost, Bagshaw said.
In designing the Cryoegg, the team had to develop a device robust enough to collect measurements of water beneath the ice and be free to move around within the sub-surface meltwater.
“The Cryoegg is a sphere, about grapefruit size, and made of a very strong plastic,” Bagshaw said. “It has a waterproof seal, and enclosed within the sphere is a radio transmitter, a microprocessor and a number of sensors.”
The sensor device must also be able to operate at low temperatures and high pressures, with no external power supply for up to 12 months at a time, she said.
“We have done some trials in Greenland over the past couple of years, trying to understand the right radio frequency to use, and how to optimise the battery power underneath the ice, because we want it to operate for a long time, and we’re working at very low temperatures which isn’t great for battery performance.”
In a trial in 2017 the team tested the egg at a site 500m below the ice.
This summer, the team are planning to test the Cryoegg in a 2km-deep borehole at the East Greenland Ice Core Project (EastGRIP) site, as well as a 1.2km borehole at Store Glacier, West Greenland.
“Then if all goes well, hopefully we’ll be back to EastGRIP next year to release an egg at 2.5km,” said Bagshaw.
The project includes researchers from Aberystwyth and Copenhagen Universities, and is being supported by the EastGRIP and Responder projects, which are researching the Greenland ice sheet.
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