Saturday, May 7, 2011

Robotic ‘Seagliders’ Make First Plunge Into Antarctic Waters

Robots mounted with sensors could be the key to better understanding global climate change—assuming they don’t vanish into the deep ocean.
That’s what Walker O. Smith Jr., a professor of marine science at the College of William and Mary, says after serving on the first research team to send robotic submarines deep into Antarctica’s Ross Sea. In November, he and his colleagues took two sensor-packed robot submarines, known as “seagliders,” and released them from an ice shelf near the South Pole.
The researchers struggled to find a suitable spot to launch the devices, though. Mr. Smith had expected to find larger patches of open water at that time of year, but instead ice ruled, and they were forced to improvise. They set one loose in a small patch of water, after consulting with some penguin researchers in the area who convinced them that the currents there would not sweep their robot under the ice.
“It was kind of a crapshoot, and I don’t know how to play craps,” said Mr. Smith, recounting the launch. “But we won.”
The seaglider did get swept under the ice at first, but it was able to propel itself back into the open water. Both devices ended up spending weeks at sea—plunging to collect readings on sea temperature, salinity, oxygen levels, and other factors, and occasionally surfacing to beam back the data. One robot did 760 dives and the other managed 970.
Seagliders are part of a revolution in oceanography, which has long relied on ships to roam the seas to collect data. These small devices, measuring about six feet long, have an autonomous computer-control system that can decide when to dive to collect data and when to surface to beam data back to researchers. They are cheaper than ships (each of the seagliders used in Antarctica costs about $150,000) and can go deeper than most manned research vessels (the seagliders can dive more than 3,200 feet). That means scientists can now collect more data from the ocean than ever before and use it to build more-detailed models of how complex ocean systems function.
Mr. Smith hopes the data they collected will help lead to new discoveries—but they have only begun to crunch the numbers. And he expects bigger advances once the technology becomes cheaper and more widespread.
“If we had gliders in a lot of areas of the oceans,” he said, “we could get a very robust data set to see how climate change is affecting various areas.”

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