Understanding an ice stream in Greenland at the EastGRIP camp: An international-multidisciplinary effort and knowledge transfer among scientists

The East Greenland Ice-core Project (EastGRIP) aims to retrieve a 2650m long ice core by drilling through the Northeast Greenland Ice Stream (NEGIS). Scientists from a variety of physical sciences and engineers hope to gain new knowledge on ice stream dynamics and about the past climate. The project has many partners from all around the world, who contribute to the science, logistics and economics of the project. Most of the data is processed and analysed in the field. As there is limited capacity in the field camp, scientists and technical staff are encouraged to learn different working techniques to support their project partners. The community also invites scientists, who work on theoretical aspects on the ice stream to communicate the perspective on the procedures and challenges of data collection in the field. And so it happens that earth system modellers learn how to drill an ice core or non-scientific staff helps with the preparation of the ice core samples. Also, the project partners are motivated to bring together scientists at early stages in their careers to gain fieldwork experience. Once each season the field camp also welcomes high school students and teachers as a part of a joint science and education programme

A first chronology for the East Greenland Ice-core Project (EGRIP) over the Holocene and last glacial termination

This paper provides the first chronology for the deep ice core from the East Greenland Ice-core Project (EGRIP) over the Holocene and the late last glacial period. We rely mainly on volcanic events and common peak patterns recorded by dielectric profiling (DEP) and electrical conductivity measurement (ECM) for the synchronization between the EGRIP, North Greenland Eemian Ice Drilling (NEEM) and North Greenland Ice Core Project (NGRIP) ice cores in Greenland. We transfer the annual-layer-counted Greenland Ice Core Chronology 2005 (GICC05) from the NGRIP core to the EGRIP ice core by means of 381 match points, typically spaced less than 50 years apart. The NEEM ice core has previously been dated in a similar way and is only included to support the match-point identification. We name our EGRIP timescale GICC05-EGRIP-1. Over the uppermost 1383.84 m, we establish a depth–age relationship dating back to 14 967 years b2k (years before the year 2000 CE). Tephra horizons provide an independent validation of our match points. In addition, we compare the ratio of the annual layer thickness between ice cores in between the match points to assess our results in view of the different ice-flow patterns and accumulation regimes of the different periods and geographical regions. For the next years, this initial timescale will be the basis for climatic reconstructions from EGRIP high-resolution proxy data sets, e.g. stable water isotopes, chemical impurity or dust records

Hydrogen peroxide and conductivity measurements at 7 ice core drilling sites in northern Greenland

This is accumulation data is derived from the Light weight In Situ Analysis (LISA) box at the EastGRIP ice coring site in Greenland in summer 2019, H2O2 is analysed by means of continuous flow analysis, but no standards were analysed for aclinartion and is thus represented as light counts in abritary units as described in Kaufmann et al., 2008; Röthlisberger et al., 2000. Conductivity is the electrical melt water conductivity as detected using a 3082 with micro flow cell 829 from Amber Science similarly to Bigler et al. 2011

Snow pits density, accumulation, peroxide and conductivity by A portable Lightweight In Situ Analysis (LISA) box at several sites in Northern Greenland

One and two metre snow pit accumulation, density, peroxide and conductivity on a depth and age scale from summer 2019 obtained at 7 ice core drilling sites; NEEM, B16, B19, B22 as well as 3 sites in the vicinity of EastGRIP representing the years 2014 to summer 2019. The data was analysed by means of continuous flow using the Light weight In Situ Analysis (LISA) box (Kjær et al, 2021)

Accumulation of snow as determined by the summer hydrogen peroxide peak measured using the LISA box for several sites in northern Greenland

This is accumulation data is derived from the Light weight In Situ Analysis (LISA) box at the EastGRIP ice coring site in Greenland in summer 2019, by means of H2O2 summer peak identification and mean densities from 1 meter snow tubes

Acidity measured with the Electrical Conductivity Method (ECM) on the EGRIP ice core (down to 1383.84 m depth), converted to hydrogen ion concentration

ECM data of the East GReenland Ice core Project (EGRIP) core with the technique described by Hammer (1980) was recorded in the field during the 2017, 2018 and 2019 field seasons. The resolution of ECM data is 1 mm. The data is given as H+ ion concentration, but the absolute calibration must be considered tentative. For more information, see Mojtabavi et al., 2020 and Rasmussen et al., 2013

Interpolated time scale for the ice with GICC05 ages for each bag depth (0.55 m segments) of the EGRIP core in the 13.7 - 1383.8 m depth interval

A first chronology for the East GReenland Ice core Project (EGRIP) over the Holocene and last glacial termination has been derived by transferring the annual layer counted Greenland Ice Core Chronology 2005 (GICC05) from the NGRIP core to the EGRIP core using 381 matchpoints of mainly on volcanic events and common patterns (peaks and dips) recorded by electrical conductivity measurement (ECM) and dielectrical profiling (DEP) records

Permittivity measured with the dielectric profiling (DEP) technique on the NEEM ice core (down to 1493.295 m depth)

Dielectric Profiling (DEP) of the North Greenland Eemian (NEEM) core were recorded in the field during the 2008-2011field seasons with the DEP device described by Wilhelms et al. (1998). The permittivity and conductivity of DEP data are calculated by their respective densities and conductivities (Wilhelms, 2005). The resolution of DEP data is 5 mm. The DEP was not processed at a consistent temperature due to the varying temperature in the field seasons. The upper 100 m is measured on NEEM–2008–S1 core, which was the NEEM pilot core. For more information on the calibration procedure see Mojtabavi et al, 2020