LARGE ICE LOSS VARIABILITY DURING THE LAST TWO DECADES AT NIOGHALVFJERDSJORDEN GLACIER, NE-GREENLAND.

Despite considerable changes of the Greenland Ice Sheet during the last decades, the northeastern part of the ice sheet was considered rather stable until some years ago. However, it became obvious that this region has the potential to discharge vast amounts of ice through the Northeast-Greenland- Ice-Stream (NEGIS) into the Greenland Sea, in the case of unstable conditions. One indicator of fundamental changes was the disintegration of the floating part of Zacharias Isbræ in the recent past. Its northern neighbor, Nioghalvfjerdsfjorden Glacier (79 North Glacier), however, showed no significant area change during the past decades. Even though recent surface elevation change measurements indicate a strong mass loss of the large floating tongue, it is not clear how the climatic change impacts the mass balance of this glacier. Here, we show for the first time the multiannual development of the ice loss from this key glacier in Northeast Greenland. We are able to prove that the nearby ocean governs the large ice thickness changes observed. Our analysis demonstrates that extreme ice thickness loss up to 10 m/yr can occur under certain oceanic conditions. [ABSTRACT FROM AUTHOR]