Snow Profiles of stable water isotopes at the EastGRIP deep drilling site, summer seasons 2016 - 2019

Throughout the summer seasons 2016 to 2019 snow profiles were taken repeatedly. The sample positions are aligned along a 300 m wind-parallel transect at the EastGRIP ice core deep drilling site. The snow was collected at 6 positions with a 20 – 50 m spacing. Snow was sampled using carbon fiber tubes of 1-m length that were pushed gently into the snow. A maximum compaction of 1 cm was observed during extraction. The snow cores were carefully removed from the carbon fiber tubes on the cutting table. The core was then cut into slices of 1 cm thickness for the upper 10 cm and 2 cm thickness for the lower 90 cm. The samples were placed into Whirl-Pak® bags and closed airtight. The samples were shipped frozen to the Alfred-Wegener-Institut and stored at -25 °C. Prior to measurements, the samples were melted in the sample bags at room temperature. For the measurement of the isotopic composition, the instruments Picarro L2120-i, L2130-I and L2140-i were used. The measurement set-up followed the Van-Geldern protocol (Van Geldern and Barth, 2012). Each sample was injected 4 times unless otherwise noted in the comment column. As a measure of accuracy, we calculated the combined standard uncertainty (B. Magnusson, T. Näykki, H. Hovind, M. Krysell, E. Sahlin, Handbook for calculation of measurement uncertainty in environmental laboratories, Nordtest Report TR 537 (ed. 4) 2017) including the long-term reproducibility and bias of our laboratory by measuring a quality check standard in each measurement run and including the uncertainty of the certified standards. The combined uncertainty for δ18O is 0.11 ‰ and for δ2H is 0.8 ‰. Deuterium excess is calculated as both 1) d = dD - 8*d18O; (Merlivat and Jouzel, 1979) and 2) dln = ln(dD + 1) - 8.47(ln(d18O+1)) - 28.5(ln(d18O+1))2; (Uemura et al., 2012).