Global Water Vapor Stable Isotope Dataset

Abstract. Stable isotopes in atmospheric water vapor (reported as H and O relative to VSMOW) provide valuable constraints on moisture sources, transport, and phase-change fractionation. Yet available observations remain fragmented across platforms, regions, and time periods, and cross-study comparison is often hindered by inconsistent metadata, calibration reporting, and quality-control practices. Here we compile and harmonize a global near-surface water vapor isotope dataset from three sources: the WaterIsotopes Database (wiDB; http://wateriso.utah.edu/waterisotopes), PANGAEA (https://www.pangaea.de), and peer-reviewed literature. The dataset spans 1981–2021 and contains 87,138 records from 112 sites/platforms. We standardized coordinates to WGS84, timestamps to UTC when possible, isotope units to per mil (‰) in delta notation, and compiled measurement metadata (instrument, method, and model where explicitly reported; e.g., Picarro CRDS, LGR OA-COS, IRMS following cryogenic trapping, and satellite retrieval products). A transparent quality-control workflow was applied to identify duplicates, inconsistent metadata, and implausible or poorly documented values, while preserving traceability to original sources. The resulting product provides a consistent observational basis for model evaluation and for comparative studies of water vapor isotope variability across climates and observation strategies. The Global Water Vapor Stable Isotope Dataset is available at https://doi.org/10.6084/m9.figshare.30893984 (Zhu and Yang, 2025).