To mark the centenary of Roald Amundsen's arrival at the South Pole (to be followed a month later by Captain Scott), this series of The Essay is presented by professionals who have lived and worked in Antarctica.

David Drewry's Essay "Unveiling Antarctica" describes the extraordinary human feats undertaken to measure the depth of the Antarctic ice cap and what lies beneath it.

Working with the Americans under the newly ratified Antarctic Treaty, David pioneered the use of airborne radar to measure the fluctuating thickness of the ice sheets that cover the continent.

"What we did was to fly a radar transmitter in an aircraft, bouncing radio waves downwards through the ice. By measuring the time taken for their return we could calculate how thick the ice was. Because we sent thousands of radio pulses a second, we were able to build up a continuous profile of the ice sheet. And by flying regular tracks across the continent we began to construct a map of the land lying beneath the ice - unveiling the real geography of Antarctica".

The deeper the ice, however, the lower they had to fly to measure it. One sortie, accompanied by the infamously steely-nerved flight engineer -Bones- is graphically retold. They flew at 250 knots whilst the ice flashed by just 25 feet below.

David's work helped to reveal completely unexpected lakes of water deep under the ice. Even today it's not known what primeval creatures may lurk there.

Professor David Drewry is a glaciologist, the former director of The Scott Polar Research Institute and British Antarctic Survey and a member of the Intergovernmental Panel on Climate Change. He has a mountain and a glacier named after him.

Producer Chris Eldon Lee

A Culture Wise production for BBC Radio 3

First broadcast in December 2011. Show less