First results of the AWI-Polar 6 airborne radio echo sounding survey around EGRIP drill site

• Main Authors: Franke, Steven, Jansen, Daniela, Binder, Tobias, Helm, Veit, Steinhage, Daniel, Paden, John, Weikusat, Ilka, Eisen, Olaf
• Format: Conference Object
• Language: unknown
• Published: 2018
• Subjects: East Greenland; Greenland; ice core; Ice Sheet
• Online Access: https://epic.awi.de/id/eprint/49976/; https://epic.awi.de/id/eprint/49976/1/EGRIP_Steering_Committee_2019_StevenFranke__FirstResultsOfTheAWI-Polar6AirborneRadioEchoSoundingSurveyAroundEGRIPDrillSite_compressed.pdf; https://hdl.handle.net/10013/epic.75158506-3dfc-446c-a15f-4a1cabb57d60

Fast flowing ice streams are known to contribute in a large proportion to continental ice sheet discharge and contribute therefore to sea level variability. In this study we investigate internal layering, stratigraphy and bedrock topography of an active ice stream in North East Greenland. In conjunction with data of physical properties of the EastGRIP Ice Core it enables us to expand insights from a selective data set over a broader area to gain insights into the complex mechanisms governing ice streams. We acquired airborne radar data at the North East Greenland Ice Stream in the vicinity of EastGRIP Drill Site. The data has been recorded in May 2018 in different acquisition modes with AWI’s Ultra-wideband multichannel radar installed on the AWI Polar6 Basler BT-67 aircraft. A total area of 16000 km^2 has been mapped with profiles along and perpendicular to ice flow direction. The area in direct vicinity to the drill site is has been covered with a profile spacing of 5 km, further downstream and upstream the profile distance is10 km. The survey area reaches from 150 km upstream to 150 km downstream of the drilling sites, and also includes both shear margins and parts of the slow flowing areas adjacent to the ice stream. The data have been processed and are currently evaluated for bedrock topography and 3D shape of distortion of internal layers. Our high resolution radargrams provide detailed insights into the bedrock topography, including the ~500 m step just upstream of the drill site and flow parallel bed ridges within the ice stream. Moreover, we mapped the distortion of internal reflectors within the shear margins of the ice stream in great detail, and captured the radar stratigraphy signature of a shift in the north-western shear margin. Outside of the ice stream large scale fold structures parallel to the main trunk of NEGIS were mapped.