Friday, August 30, 2013

Discovery in the Arctic: Radar reveals huge canyon in Greenland Ice - Spiegel Online

Were it not for the many ice, the sight would be breathtaking: a ravine at least 750 miles long, up to 800 meters deep and are, ten kilometers wide. No man has ever get to see, millions of years ago they disappeared under the ice. Two miles up the glaciers of Greenland today towers above the canyon. But now scientists have made it visible -. Using radar data collected in numerous flights

As the researchers to Jonathan Bamber of the British University of Bristol in the journal “Science” write the canyon is probably older than the ice surface, the Greenland conceals since about 3.5 million years ago. They have the shape of a meandering riverbed and stretches from the center to the northern tip of the largest island in the world. Its dimensions are impressive: although it is only half as deep as the famous Grand Canyon at its deepest point. But it is at least 300 kilometers longer than the famous gorge to the U.S. state of Arizona.

But the sheer size is not the most important by far. Bamber and his colleagues suggest that the canyon plays an important role in directing the water from the melting process on the surface of the pack ice to the edge of the ice and ultimately into the Arctic Ocean. Before Greenland ice sheet is formed about 3.5 million years ago, a river must have cut the canyon from the rock.

Its function as a water manager, he apparently has not lost – only now he leads the glacial meltwater. This explains, according to the researchers about why there are no lakes in the Greenland ice pack, unlike in the Antarctic. In addition, water plays an important role in the behavior of the ice. It spreads over large areas from below, it can act as a lubricating layer between the bottom of the glacier and the rock, and so accelerate the slipping of ice into the sea.

Greenland is one of the regions most affected by climate change. The sea ice shrinks rapidly, and also the land-based ice is locally strongly decreased. The new data may help to refine models of the movements of the Greenland ice sheet, according to Bamber. However, he does not expect a fundamentally new insights into how climate change is affecting the glaciers in the far north.

expressed a similar David Vaughan of the British Antarctic Survey: The discovery of the giant canyon will probably have “no special influence” on the calculation of Eisflussraten. The canyon lies so deep under the ice that he probably still remain untouched for many decades by the effects of warming.

the canyon was discovered with the help of radar observations. Bamber and his team evaluated from large amounts of data that were collected approximately at the “IceBridge” mission of the U.S. space agency Nasa and researchers in the UK and Germany. In the electromagnetic waves of certain frequencies of the radar can penetrate and bounce off the ice cream from the underlying rock. While they were evaluating all radar data systematically, the scientists discovered the canyon and were able to reconstruct its shape.

The canyon is not the first spectacular discovery under the ice of Greenland. In 2009, researchers had discovered there a “ghost mountains” that resembles the Alps. 2012 was added in a magnificent valley, take one of the scientists that it could speed up the flow of ice into the sea. All this refutes the impression that the landscape of the earth has already been mapped and explored completely, says Bamber. “Our research shows that there is still much to discover.”


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