ALBERT

Description: Throughout the summer seasons 2017 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 instrument Picarro L2130-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 (Magnusson, et al., 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).