Environment & Energy

nitpicker

(7,153 posts) Wed Jul 5, 2017, 05:31 AM Jul 2017

Giant 'white wanderer' poised to break free

http://www.bbc.com/news/science-environment-40492957

Giant 'white wanderer' poised to break free

Jonathan Amos
Science correspondent

1 hour ago

From the section Science & Environment

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A rift has grown across the edge of the Larsen C Ice Shelf. A thin, 5km-long section of the floating shelf is now all that prevents a 6,600-sq-km berg from drifting away into the Weddell Sea. Think about the size for a moment. That's more than a quarter the area of Wales. Keen to gather some more statistics, scientists have used the Cryosat spacecraft to run the rule over the putative iceberg.
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Dr Gourmelen says there is an estimated 1,155 cubic km of ice in the would-be berg. This is all very useful information because it tells scientists a lot about where and how fast the Larsen object might move once it becomes free. And those are critical details if the berg were to reach shipping lanes to become a navigation hazard.
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The waters close to Antarctica are shallow and there's a good chance the berg will dig in, gouging a huge trough in the seafloor as it then turns round. Cryosat's thickness information tells researchers where the berg can and cannot go.
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The expectation, however, is that the berg will bump and grind its way northward in near-coast currents, along the Peninsula. Past history suggests it will eventually be exported on one of four major iceberg "highways" that lead beyond Antarctica. In this instance, the route is one that sends the berg into the circumpolar current and on to an eastward arc towards the South Atlantic.
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Indeed, the only reason we know this new Larsen berg is about to calve is because Europe's Sentinel-1 radar satellites take a detailed look at the shelf's behaviour every six days.
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