DOI: 10.1594/pangaea.983191
title: ARK 2018: AWI airborne ultra-wideband radar data over the shear margins at the onset region of the Northeast Greenland Ice Stream (NEGIS) (EGRIP-NOR-2018 Project)

description: This dataset contains airborne radar data acquired using the AWIs multi-channel ultra-wideband radar system (AWI UWB) during the Arctic season of 2018. The radar profiles cover the onset region of the Northeast Greenland Ice Stream (NEGIS). The radar data has been acquired in May 2018 with the Alfred Wegener Institute (AWI) multichannel ultra-wideband radar mounted on the Polar6 aircraft. Radar profiles cover an area of ~24 000 km^2 and extend over the well-defined shear margins of the NEGIS. The survey area is centred at the location of the drill site of the East Greenland Ice-Core Project (EastGRIP) and several radar lines intersect at this location. The survey layout is designed to (1) map the stratigraphic signature of the shear margins with radar profiles aligned perpendicular to ice flow and (2) trace the radar stratigraphy along several flow lines. While we are able to resolve radar reflections in the deep stratigraphy, we cannot fully resolve the steeply inclined reflections at the tightly folded shear margins in the lower part of the ice column. The NEGIS is causing the most significant discrepancies between numerically modelled and observed ice surface velocities. Given the high likelihood of future climate and ocean warming, this extensive data set of new high-resolution radar data in combination with the EastGRIP ice core will be a key contribution to understanding the past and future dynamics of the NEGIS. The data are available as netCDF files (including waveforms and metadata), KML files of the profile line locations, and quicklook images of the radargrams.
description: Project: EGRIP-NOR-2018 (Characterisation of the NEGIS Onset region with Radar around EastGRIP)Region: Onset region of the Northeast Greenland Ice Stream (NEGIS), GreenlandOwner / PI: Olaf Eisen (olaf.eisen@awi.de)Email address of the provider:daniel.steinhage@awi.deveit.helm@awi.deInstrument used: AWI UWB (MCoRDS 5)Data products: CSARP_standard (SAR focussed), CSARP_qlook (unfocussed)Data product documentation: https://data.cresis.ku.edu/data/rds/rds_readme.pdfMethod of navigation : GPS data was acquired by four NovAtel DL-V3 GPS receivers operating at 20Hz--The netCDF files contain the following variables:altitude: Platform altitude (WGS84) in metersbed_elevation: Bed elevation for each trace (without applying a firn correction and permitivity of ice: 3.15) in metersbed_pick: picked Bed location for each trace, expressed as twt in seconds from time zerodata: Radar data (Values in dBm after DC conversion)data_agc: Scaled radar data using automatic gain control (AGC)distance: Along-track distance in metersice_thickness: Ice thickness for each trace (without applying a firn correction and permitivity of ice: 3.15) in meterslat: Latitude in decimal degrees (WGS84)lon: Longitude in decimal degrees (WGS84)range: Range between sensor and surface in metersspacing: Along-track trace to trace spacing in meterssurface: Surface elevation derived from radar (WGS84) in meterssurface_pick: Picked surface reflection in two-way travel time in secondstime: Seconds of daytwt: Two-way travel time (twt) in seconds--Note that the surface picks were quality-checked for the standard product. For the qlook product only an auto-tracked surface pick is available.