The establishment of a depth/age relationship dating back to 14,965 b2k from the EGRIP ice core and compression synthetic radar modelling and airborne radar around EGRIP drill site

Abstract

We have established the initial chronology for the EGRIP ice core over the Holocene and the late last glacial period. We rely on conductivity patterns and volcanic events determined by means of dielectric profiling (DEP), electrical conductivity measurements (ECM) and tephra records for the synchronization between the EGRIP, NEEM and NGRIP ice cores in Greenland. We have transferred the annual-layer-counted Greenland ice Core Chronology 2005 (GICC05) timescale from the NGRIP core to the EGRIP ice core by means of 373 match points. The second part of this study compares numerically modelled radargrams and the airborne radar measurements (radio-echo sounding) to understand the recorded physical properties of internal layers towards reflection mechanisms. Synthetic modelling of electromagnetic wave propagation has been applied to the EGRIP ice core based on the conductivity and permittivity, as measured at 250 kHz by DEP. For the comparison between synthetic and observed data, we have used radio-echo sounding data from AWI’s multichannel ultra-wideband radar around the EGRIP drill site, that were recorded during the 2018 field season