Snow stable water isotopes of a surface transect at the EastGRIP deep drilling site, summer season 2016, 1 cm

Snow samples were taken on a daily basis along a 1000 m wind-parallel transect at the EastGRIP ice core deep drilling site. The snow was collected at 11 to 29 positions with 10 m spacing for the first 100 m and 50 m spacing for the last 900 m in 2 depth intervals. The depth intervals are top 1 cm and top 6 cm. Each day, undisturbed snow was sampled and the exact sample location was marked to avoid sampling disturbed snow during the next sampling event. 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 was used. The measurement set-up followed the Van-Geldern protocol (Van Geldern and Barth, 2012). Each sample was injected 4 times. 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 ‰.