The Voice - 21 May 1996

Curtin V Norway In Race For Antarctic Prize

In a touch of deja vu Norwegians are again competing in a race against time at the South Pole. But the players and the game have changed since the Norwegian team led by Roald Amundsen beat the British expedition under Robert Scott in 1911.

This time the race is between scientists at Curtin University and at research centres in Norway. The goal is to be first to produce a highly technical instrument that accurately measures the thickness of sea ice.

The winner stands to be well rewarded via international recognition, commercial production of the equipment and by making a direct contribution to information on some major environmental issues, including global warming and the greenhouse effect.

Greg Bush and Alec Duncan with the tripod and hand-winch used to position the manual ULS under sea ice. The ice breaker RSV Aurora Australis is in the background.

Since 1992 Curtin scientists at the Centre for Marine Science and Technology have won Australian Antarctic Division contracts to design and build four acoustic sonar buoys. Officially called upward looking sonars (ULS) they provide year-round measurements of antarctic ice thickness, showing how it is affected by the changing seasons.

The ULS are positioned 150-200 metres below the sea surface ice. An echo sounder sends up a sound pulse that hits the bottom of the ice and bounces back to the ULS. Timing the pulse's journey gives the distance from the buoy to the ice bottom, and an accurate pressure sensor measures the depth of the buoy. Comparing the two measurements gives the sea ice thickness.

CMST research Greg Bush said the Curtin ULS were designed specifically for Antarctic conditions, while the Norweigans were adapting a system developed originally for the Arctic, where conditions are quite different.

Arctic sea ice is landlocked, can be 5-6 years old and up to 5 metres thick. Antarctic sea ice forms in open sea, is about 60cm thick mid-winter and melts in summer.

Last winter a team that included Greg Bush and Alec Duncan, who developed the electronics and software for the ULS, travelled to the Antarctic for on-the-spot verification of instrument performance.

"The units had collected a heap of data but no-one was ever around to say if ice was there, or how thick it was," Mr. Bush said. "Now we have information taken on sea ice and in open water and are in a strong position to verify our identification."

Within two to three months Mr. Bush hopes to publish the data which will confirm the accuracy of the units. "Once our equipment is proven, the race will be on to establish the product on the market," he said.

Working in the Antarctic is not quite like going to the office. Among other hurdles, the team found that the buoys needed to be positioned much deeper in the Antarctic because of the larger ice bergs that float around. Twice a ULS was submerged by icebergs but it returned to operating depth once the bergs passed.