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).

This dataset contains measurements of the water vapour isotope composition of ambient vapour obtained from a water vapour isotope analyzer manufactured by Los Gatos Research (LGR), and from discrete sampling of surface snow and precipitation and subsequent laboratory analysis. The analyzer was installed in the harbour of Húsavik, Iceland. Discrete sampling included precipitation and surface snow from two surface transects in northern Iceland and in several locations in southern Norway. The LGR LWIA analyzer is an off-axis cavity ring-down spectrometer using 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). The data set for the Húsavik station is accompanied by automatic weather station data (air temperature, relative humidity, wind speed, wind direction, sea-level pressure) from the Icelandic weather service (vedur.is) for several nearby locations. For further details and figures for the vapour measurements, and the surface sample collection during the campaign, 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).

This dataset contains measurements of the water vapour isotope composition of ambient vapour, surface snow, ocean water, and precipitation obtained from water vapour isotope analyzers manufactured by Picarro Inc., as well as from discrete sampling and subsequent laboratory analysis. The analyzer was installed onboard the NATO Research Vessel Alliance during the Iceland Greenland Seas Project. Discrete sampling included precipitation, sea water, and standards from the R/V Alliance. The Picarro L2140-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 native resolution. The data set for the R/V Alliance has been joined with the meteorological data from R/V Alliance (https://catalogue.ceda.ac.uk/uuid/b4ba8f11459c422d84d7293b9211ccf7) at 60 s averaging. For further details and figures on the Picarro analyzer, and the sample collection during the campaign, 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).