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Monday, August 12, 2013

Greenland's ice is melting from below by the heat of the lithosphere

The ice of Greenland is melting from below, caused by high heat flow in the lithosphere mantle, an influence varies in space and has its origin in an exceptionally thin lithosphere. Therefore, there is an increased heat flow from the mantle and a complex interaction between this geothermal heating and Greenland ice. The IceGeoHeal international research initiative led by the Centre GFZ German Research Goeciencias set to the current edition of  Nature Geoscience that this effect can not be ignored when modeling the ice as part of a climate study. The continental ice sheets play a fundamental role in climate continental ice sheets play a fundamental role in climate. The interactions and feedback processes between the ice and the temperature rise are complex and still subject of current research. The Greenland ice sheet loses about 227 gigatonnes of ice per year and contributes about 0.7 millimeters to change in the mean sea level currently observed around 3 mm per year. However, the existing model calculations are based on consideration of the ice and the effect of the lithosphere, ie the crust and upper mantle of the Earth, too simplistic and fundamentally Mechanical presses ice bark down due to its weight. GFZ scientists Alexey joined Petrunin and Irina Rogozhina ice climate model with thermomechanical another Greenland lithosphere. We carried out the model for a simulation period of three million years "We carried out the model for a simulation period of three million years and taking into account the measurements of ice cores and magnetic and seismic data independent "explains Petrunin. "Our model calculations are in good agreement with measurements. Both the thickness of the ice, and the temperature at its base are represented very accurately , "he adds. "The temperature at the base of the ice and therefore, the current dynamics of the Greenland ice cap is the result of interactions between the heat flow from the interior of the earth and the temperature changes associated with the cycles glacial, "says Irina Rogozhina. "We found areas where ice melts at the base along with other areas in which the base is very cold, "he qualifies. The current climate is influenced by processes that go much further back in the history of Earth : the lithosphere Greenland is between 2.8 to 1,700,000,000 years old and is only 70 to 80 miles thick beneath Central Greenland, so you need to explore why it is so thin. The coupling of models of ice dynamics models of the solid earth thermomechanical allows a more accurate view of the processes that are melting the ice in Greenland.

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