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Australian underwater robot reveals more Antarctic sea ice than previously thought

MELBOURNE, Nov. 25 — An underwater robot has shown there may be more Antarctic sea ice than previously thought after it returned the first high-resolution maps of the Antarctic depths, local media reported Tuesday.

The robot — or autonomous underwater vehicle — was sent out to east and west Antarctica four years ago and has delivered the first precise measurements of sea ice through 3D maps that provide a better snapshot of the impact of climate change.

Their underwater surveys indicated sheets of floating sea ice were "much thicker and more deformed" than previously reported with the average thickness beneath sea level being 1.4 to 5.5 meters.

Launched off a British and an Australian ship at three sites around the Antarctic Peninsula, the robot — known as SeaBED — has returned data that suggested ice thickness might have been underestimated in previous research, and that the sea ice was considerably deeper than previously thought.

The measurements covered 50 hectares and found that ice in some areas was up to 17 meters thick.

Measuring Antarctic sea ice has long been a challenge and traditional methods have often been less than ideal.

Dr. Rob Massom, senior research scientist with the Australian Antarctic Division, said to date the job had been low-tech and manual.

"We look over the side of icebreakers and we look at the way that the icebreaker overturns the sea ice and we do a visual estimate on the hour every hour," he said. "We also spend many hours drilling many holes through the ice and that's very labor-intensive."

But not any more, according to a research paper published in Nature Geoscience which details the findings of scientists from Britain, the United States and Australia — and their submersible robot.

"These (robots) provided a new view of Antarctic sea ice with three dimensional maps, it's like going from a broken pair of binoculars to a band new telescope," said Australian polar oceanographer Guy Williams of the Institute for Marine and Antarctic Studies.

"The full 3D topography of the underside of the ice provides a richness of new information about the structure of sea ice and the processes that created it. This is key to advancing our models, particularly in showing the differences between Arctic and Antarctic sea ice."

"While we have not measured all Antarctic sea ice thickness and cannot state if Antarctic sea ice is getting thicker, this study is a huge step towards the sort of expanded and more routine measurements we will need to do to truly answer these questions."

Sea ice in Antarctica expands from four millions square kilometers in summer to five times that area in colder months. Previous research was long suspected to be erroneous due to ship captains choosing to sail through thinner ice. (PNA/Xinhua)


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