Large-scale isotopic fingerprinting of cryosphere and hydrological components in glacierized catchments

Abstract. Stable water isotopes (SWI; δ¹⁸O and δ²H) are widely used tracers for identifying water sources and reconstructing hydroclimatic processes in glacierized catchments. However, globally harmonized isotope datasets that integrate multiple cryospheric and hydrological endmembers remain limited. Here we present a global georeferenced database of stable water isotope measurements compiled across glacierized catchments worldwide. The dataset contains 12,348 individual δ¹⁸O and δ²H measurements collected from 63 publications, covering 19 countries across six continents. The temporal coverage of the isotope measurements spans from 1978 to 2023, based on data compiled from publications starting in 1981. The database integrates isotope measurements from precipitation, snowpack and snowmelt, glacier ice, firn, glacial and supraglacial meltwater, rock glaciers, ice-cored moraines, permafrost thaw waters, talus slopes, streams, lakes, and groundwater. Each record includes standardized metadata describing geographic location, elevation, sampling period, endmember classification, and analytical methods. Across the compiled dataset, δ¹⁸O values range from approximately −31 ‰ to −0.36 ‰, while δ²H values range from −247 ‰ to 0 ‰, reflecting strong variability in elevation, temperature, and moisture source conditions across glacierized environments. Cryosphere endmembers such as glacier ice and glacial meltwater typically exhibit depleted signatures (δ¹⁸O ≈ −14 ‰; δ²H ≈ −100 ‰) reflecting precipitation formed under colder climatic conditions and preserved within glacier storage, while groundwater and firn waters tend to show relatively enriched compositions due to mixing, recharge processes, and seasonal precipitation inputs. By harmonizing isotope observations across multiple cryosphere and hydrological components, this database provides a new global reference for identifying characteristic isotopic signatures of glacier-derived waters and their downstream mixing with other hydrological sources. The dataset supports comparative studies of glacier–hydrology interactions, endmember mixing analysis, and isotope-enabled hydrological modelling, contributing to improved understanding of water resources in glacier-fed catchments under changing climate conditions. The dataset is publicly available at https://doi.org/10.5281/zenodo.19062383 (Vital et al., 2026).