Jason Ford

EPSRC-funded radars track changes on ice shelf

News

A series of radars deployed on Antarctica are expected to give researchers their first ever day-by-day measurements of the health of one of the continent’s ice shelves.

The EPSRC-funded radars have been placed on the ice shelf surrounding Pine Island by University College London (UCL) and British Antarctic Survey (BAS) scientists to record changes of the Antarctic ice.

The ice shelves around Antarctica can be up to 2km thick, but preliminary trials show the new radar system can detect changes of as little as a millimetre, which EPSRC says is around the amount the Pine Island Glacier melts in 30 minutes.

In a statement, Dr Keith Nicholls of the British Antarctic Survey said: ‘Although we’ve previously taken snapshots of the ice with radar, this is the first time year-round monitoring has been possible.

‘Where changing ocean currents interact with the underside of the ice shelf, the rate of melting can change season by season, month by month, even over days or hours. The advantages of this new system cannot be overstated.’

The purpose-built radars were developed in the labs of Paul Brennan, Professor of Microwave Electronics at University College London.

‘The millimetre accuracy of the system is made possible by a phase-sensitive processing technique that we specially developed for the project,’ Prof Brennan said. ‘We have also redesigned the electronics to minimise noise, so that the units are highly sensitive at low power.’

Each radar unit runs off a single 6V battery that can last a year and can be topped up by a small wind generator or solar cells during summer. When running, the radar draws 5W of power, the same as a low-energy light bulb; standby power is 1mW.

The units also contain antenna arrays – Multiple Input Multiple Output  – that allow the researchers to construct 3D images of the ice.

‘This will be very useful because of the uneven shape of the ice-sheet’s underside,’ said Dr Nicholls. ‘We will be able to see how the shape of the surface influences the melt rate.’

Pine Island Glacier is thought to be highly sensitive to climate variability and has thinned rapidly over recent decades.

‘The main culprit is warm water in the circumpolar current, which is eating away at the underside of the ice shelf floating at the edge of Pine Island Glacier,’ said Dr Keith Nicholls of the British Antarctic Survey. ‘A continuous record of seasonal changes, which is what the new array should give us, will give us a far better understanding of how that’s happening.’