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Bed topography and subglacial landforms in the onset region of the Northeast Greenland Ice Stream
Annals of Glaciology ( IF 2.9 ) Pub Date : 2020-03-18 , DOI: 10.1017/aog.2020.12
Steven Franke , Daniela Jansen , Tobias Binder , Nils Dörr , Veit Helm , John Paden , Daniel Steinhage , Olaf Eisen

The Northeast Greenland Ice Stream (NEGIS) is an important dynamic component for the total mass balance of the Greenland ice sheet, as it reaches up to the central divide and drains 12% of the ice sheet. The geometric boundary conditions and in particular the nature of the subglacial bed of the NEGIS are essential to understand its ice flow dynamics. We present a record of more than 8000 km of radar survey lines of multi-channel, ultra-wideband radio echo sounding data covering an area of 24 000 km2, centered on the drill site for the East Greenland Ice-core Project (EGRIP), in the upper part of the NEGIS catchment. Our data yield a new detailed model of ice-thickness distribution and basal topography in the region. The enhanced resolution of our bed topography model shows features which we interpret to be caused by erosional activity, potentially over several glacial–interglacial cycles. Off-nadir reflections from the ice–bed interface in the center of the ice stream indicate a streamlined bed with elongated subglacial landforms. Our new bed topography model will help to improve the basal boundary conditions of NEGIS prescribed for ice flow models and thus foster an improved understanding of the ice-dynamic setting.

中文翻译:

格陵兰岛东北冰流起始区河床地形和冰下地貌

东北格陵兰冰流 (NEGIS) 是格陵兰冰盖总质量平衡的重要动态组成部分,因为它到达中央分水岭并排出 12% 的冰盖。几何边界条件,特别是 NEGIS 冰下床的性质对于了解其冰流动力学至关重要。我们提供了超过 8000 公里的多通道、超宽带无线电回波探测数据的雷达测线记录,覆盖面积为 24 000 平方公里2,以东格陵兰冰芯项目 (EGRIP) 的钻探现场为中心,位于 NEGIS 集水区的上部。我们的数据产生了该地区冰厚分布和基础地形的新详细模型。我们的床地形模型的增强分辨率显示了我们解释为由侵蚀活动引起的特征,可能在几个冰期 - 间冰期循环中。来自冰流中心冰床界面的非天底反射表明流线型床具有拉长的冰下地貌。我们的新床层地形模型将有助于改善为冰流模型规定的 NEGIS 的基础边界条件,从而促进对冰动力学设置的更好理解。
更新日期:2020-03-18
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