This dataset contains measurements of the water vapour isotope composition of ambient vapour obtained from a water vapour isotope analyzers manufactured by Picarro Inc, as well as discrete samples of water standards used for calibration. The analyzer was installed onboard the research aircraft MASIN of the British Antarctic Survey. Discrete sampling included standards from the on-board calibration system on the MASIN aircraft. The Picarro L2130-i analyzer is a cavity ring-down spectrometer that uses infrared absorption bands for the retrieval of the water isotope ratios for H216O, H218O, and HDO, quantified as mixing ratio of water vapour (w, ppmv), delta 18-O, and delta-D (permil) at 1 Hz time resolution. The water isotope data set for the MASIN aircraft is joined with the airborne meteorological observations data set from the MASIN aircraft at different averaging times. For further details and figures on the Picarro analyzers, and processing thereafter, please read the attached documentation.

This research is funded by the Research Council of Norway under the Sources of the Norwegian winter season snow pack constrained by stable water isotopes - SNOWPACE project (Project Nr. 262710) and the Facility for advanced isotopic research and monitoring of weather, climate and biogeochemical cycling (FARLAB) project (Project Nr. 245907).