Robotic submarines key to monitoring oceans




Oceanographer Ken Ridgway (right), with electronics engineer Lindsay MacDonald with the glider.

Credit: CSIRO

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Scientists have celebrated Australia's first successful deployment and retrieval of a remotely controlled, deep ocean-going robotic submarine, destined to play a central role in measuring changes in two of Australia's most influential ocean currents.

Under the joint CSIRO Wealth from Oceans National Research Flagship and Integrated Marine Observation System (IMOS) project, the underwater ocean glider was launched in February on a two-month, 1,500 kilometre voyage.

With its porpoising motion and an ability to descend to a depth of nearly 1,000 metres, the $200,000 robotic glider's sensors measure temperature and salinity, as well a range of biological parameters including oxygen and turbidity ('murkiness').

Ken Ridgway, a senior CSIRO researcher from the Wealth from Oceans Flagship, said the trial, which took place in the Tasman Sea, has generated new confidence among scientists, broadening the array of instruments available to them to better understand the East Australian Current and Leeuwin Currents.

"Ocean currents around Australia are critical to so many aspects of nature and human activity," Ridgway said.

"With the East Australian and Leeuwin Currents, we need to understand how they change from season to season and year to year, and the extent of their influence on local coastal conditions, as this affects climate, weather, fisheries, shipping and more."

Autonomous gliders are increasingly being used by marine research groups in the Northern Hemisphere, he said, with Australia just beginning to use deep-ocean gliders.

"Shallow water gliders have been deployed off Western Australia, South Australia and New South Wales in recent months...[but] the Tasman Sea deployment was the first deployment of a deep-ocean glider in the southern hemisphere.

"The appeal of these instruments is that they are out working while the scientist can be assessing what is near-real time information about ocean conditions," Ridgway said.

Together with data from research vessels, satellites and moored, drifting and expendable instruments, the glider will add a new dimension to profiling the oceans around Australia.

But there are still challenges to be overcome.

"In a lot of ways this first deployment is as much learning how to pilot the glider and guide it through and around the eddies of the East Australian Current as it is getting about the data we want," Ridgway said.