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

The database compiled in this study represents the first global, harmonized collection of stable water isotope (SWI) measurements across cryosphere and hydrological endmembers in glacierized catchments. It contains 12,348 individual records sourced from 63 peer‑reviewed publications, as well as unpublished datasets contributed directly by the authors. The temporal coverage spans from 1981 to 2025, ensuring both historical and contemporary representation of isotopic conditions in glacier environments. Each entry in the database is described by 44 standardized fields, grouped into four main categories: Bibliographic metadata – data owner, publication year, citation, and publication status. Geographical metadata – continent, country, catchment, glacier name, basin, and coordinates. Sampling details – sample type,sampling period, elevation, and remarks. Isotope data – δ¹⁸O, δ²H, d‑excess, analytical method, measurement error, and uncertainty.  The database integrates Cryosphere and hydrological endmembers, covering precipitation (solid and liquid), snowpack melt, glacier meltwater, glacier ice, supraglacial meltwater, talus‑slope water, rock‑glacier outflow, groundwater, lakes, firn, permafrost thaw, and ice‑cored moraine meltwater. The stable water isotopes data was generated primarily using CRDS (7,733 δ¹⁸O measurements), IRMS (2,702), OA-ICOS (418) with mean uncertainties of 0.13‰ for δ¹⁸O and 0.49‰ for δ²H. Outliers are flagged but not removed, preserving the raw data integrity.Geographically, the records span six continents and 20 countries, with strong representation in Europe (5,899 records), Asia (3,132), and North America (3,022), and smaller datasets from South America, Africa, and Oceania. Study locations predominantly include mountain regions where surface waters interact directly with glaciers, excluding most polar systems with limited terrestrial hydrology.Overall, this database provides the most comprehensive global synthesis of isotopic signatures from glacierized catchments. It supports applications such as: endmember mixing and hydrograph separation, calibration of isotope‑enabled hydrological models, assessment of moisture sources and continental climate gradients, reconstruction of past hydroclimatic processes using modern–paleoclimate linkages,  development of AI‑driven predictive models of cryosphere–hydrology interactions. Endmembers Definition References Precipitation Meteoric water, including liquid, solid and mixed precipitation, isotopic composition governed by temperature, humidity, and source, following the Global Meteoric Water Line (GMWL). Craig, 1961; Dansgaard, 1964 Stream Integrates contributions from precipitation, snow, glacier melt, and groundwater. Kendall and Coplen, 2001 Lakes Reservoir water under open-water evaporative conditions. Its isotopic composition commonly shows enrichment along an evaporation line controlled by humidity wind and temperature Gibson et al., 2002; Horita et al., 2008 Groundwater Subsurface water integrating multiple recharge events over time; well mixed, isotopic values are damped relative to precipitation, indicative of recharge conditions, pattern and timing. Clark and Fritz, 1997; Jasechko, 2017 Snowpack Seasonally accumulated snow stored on the ground prior to melt. Snowpack isotopic composition integrates mainly winter precipitation signals and may be modified by sublimation, wind redistribution, summer rain events and melt–refreeze cycles.   Clark and Fritz., 1997; Taylor et al., 2001 Snowpack melt Seasonal meltwater from snowpacks, often with lower δ18O and δ2H values compared to rainwater; key source of runoff in cold and mountain basins. Taylor et al., 2001; Penna et al., 2014 Glacier meltwater Meltwater derived from glacier ice; with lower δ18O and δ2H values compared to the stream water and precipitation due to sourcing from accumulation of cold-season precipitation and/or relict ice formed in past colder climates. Jansson et al., 2003; Immerzeel et al., 2010 Supraglacial meltwater Liquid water on the surface of a glacier, formed by the melting of snow and ice. Müller et al., 2025 Glacier ice Solid glacial mass formed from accumulated and compacted snow through firnification. Its meltwater represents a primary cryosphere endmember, typically depleted in heavy isotopes due to elevation effects, temperature-dependent fractionation, and Rayleigh distillation during snowfall. Dansgaard, 1964 Firn Partially compacted old snow, intermediate between snow and glacier ice in terms of density. Ala-aho et al., 2017 Ice cored moraines Morainic deposits that contain buried glacier ice beneath a cover of debris. Meltwater derived from ice-cored moraines typically reflects glacier ice isotopic signatures but may be altered by partial refreezing of meltwater within the moraine body.   Humlum, 2000 Rock glacier Distinct bodies of a perennially frozen debris–ice mixture covered by a seasonally thawed debris layer. Amschwand et al., 2025 Permafrost thaw Water released during the thawing of previously frozen ground (permafrost), including ice‑rich soil, ground ice, and buried glacier ice. Its isotopic composition reflects the original meteoric water preserved at the time of freezing, modified by freezing and thawing processes. Woo, 2012   Talus slopes Liquid water draining from coarse, steep debris accumulations at the base of cliffs or valley walls. Talus‑slope waters often reflect rapid infiltration of snowmelt or precipitation with limited mixing, and in cold regions may include meltwater from interstitial ice or seasonal frozen ground. Curry et al., 2023