Bed topography and subglacial landforms in the onset region of the Northeast Greenland Ice Stream

• Published in: Annals of Glaciology
• Main Authors: Steven Franke, Daniela Jansen, Tobias Binder, Nils Dörr, Veit Helm, John Paden, Daniel Steinhage, Olaf Eisen
• Format: Article in Journal/Newspaper
• Language: English
• Published: Cambridge University Press 2020
• Subjects: Glacial geomorphology; glacier flow; ice streams; processes and landforms of glacial erosion; radio-echo sounding; Meteorology. Climatology; QC851-999; Greenland; Annals of Glaciology; East Greenland; East Greenland Ice-core Project; glacier; Greenland ice core; Greenland Ice core Project; ice core; Ice Sheet
• Online Access: https://doi.org/10.1017/aog.2020.12; https://doaj.org/article/17011c89551442029bae6505cf93c3dd

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.