Antarctic Ice Thicker Than Previously Thought

Antarctic ice is thicker than scientists previously thought, according to a new kind of robotic survey of the underside of sea ice floes.

This groundbreaking high-resolution, 3D mapping has allowed researchers to more accurately measure ice thickness in areas that were previously too difficult to access. Better understanding the changing Antarctic landscape is useful in determining how climate change is affecting the Last Continent, as well as the rest of the world.

A coalition of scientists from the United Kingdom, United States and Australia analyzed an area of ice spanning 500,000 meters squared - the size of 100 football fields - using a robot known as SeaBED.

According to the results, published in the journal Nature Geoscience, the studied Weddell, Bellinghausen and Wilkes Land sectors boast an average ice thickness between 1.4 meters and 5.5 meters, with a maximum ice thickness of 16 meters. Scientists also discovered that 76 percent of the mapped ice was "deformed" - meaning that huge slabs of ice at one point crashed into each other to create larger, denser bodies of ice.

"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," study co-author Dr. Guy Williams, from Institute of Antarctic and Marine Science, said in a statement.

Prior techniques used to measure sea ice thickness were always lacking in one way or another. While satellite observations can measure large-scale thickness from space, snow cover on the ice is a hindrance when it comes to interpreting the data. Measurements made on the sea ice by drilling holes, together with visual observations from ships, gets hairy when these vessels can't access the thicker areas, leaving gaps in the data.

But SeaBED, an autonomous underwater vehicle (AUV), can reach depths of 20 to 30 meters no problem, painting a more clearer picture of Antarctic sea ice.

"SeaBED's maneuverability and stability made it ideal for this application where we were doing detailed floe-scale mapping and deploying, as well as recovering in close-packed ice conditions," said Hanumant Singh of the Woods Hole Oceanographic Institution (WHOI), which designed the AUV.

And though this work is a big step forward, researchers hope to conduct future missions in larger areas, ultimately deploying many AUVs across Antarctica.

[Credit: AntarcticSurvey]

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