Snow stable water isotopes of precipitation samples at the EastGRIP deep drilling site, summer season 2019

Precipitation and rime samples were taken after precipitation events from specific boxes to collect precipitation snow. Two white plastic boxes are placed outside the camp area 1 m above the snow surface and behind a wind shield. The snow was collected using a brush, spatula and small shovel. From each box the available snow was collected into a plastic bag and sealed and labeled. In case the snow of one box was not enough for one sample, the snow of both boxes were combined as one sample. In case not all snow was sampled, the boxes were cleared out after sampling. The samples were kept frozen and shipped frozen to the Alfred-Wegener-Institute 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 a Picarro L2140-i was used. The measurement set-up followed the Van-Geldern Protocol. Each sample was injected four times and the standard deviation is computed. We calculate the average over all the standard deviations as a measure of uncertainty. We find this average to be 0.01 permil for δ18O (with stdev 0.01) and 0.12 permil for δD (stdev 0.2). The maximum standard deviation within the data set was found to be 0.07 for δ18O and 1.1 for δD. As a measure of accuracy the off-set between the defined and measured value of the quality check standard for each measurement run is provided. We calculate the average of this off-set for the whole data set and obtain a value of -0.07 permil for δ18O (stdev 0.02) and -0.73 permil for δD (stdev 0.09). The maximum off-set found within the data set was -0.1 permil for δ18O and -0.87 permil for δD