Global patterns of stable isotope signatures across cryosphere and hydrological components of glacierized catchments

Glacierized catchments play an important role in regional and global water resources by storing, releasing, and redistributing freshwater. Stable water isotopes (SWI, δ¹⁸O and δ²H) are widely used to trace these processes, providing information on moisture sources, elevation and temperature effects, subsurface storage, and mixing between cryosphere and non-cryosphere components. They also allow quantifying the contributions of the cryosphere and hydrological component to the streamflow. Integrating SWI analysis into studies of glacierized catchments helps better quantify glacier contributions to regional water resources and assess how these contributions change under different climate conditions. 

Despite decades of isotope-based studies in glacierized environments, SWI data remain fragmented across regions and hydrological components. In this study, we introduce the first global, harmonized database of SWI signatures from cryosphere and hydrological components in glacierized catchments, enabling a global synthesis of isotope patterns. The database compiles 12,348 isotope records from peer-reviewed literature, institutional repositories, and public data platforms published between 1960 and 2025. It integrates δ¹⁸O, δ²H, and derived d-excess values for a wide range of hydrological endmembers, including precipitation, snow, stream, groundwater, lake, snowpack, snowpack melt, glacier ice, glacier meltwater, supraglacial meltwater, firn, ice-cored moraines, talus slopes, rock glacier and permafrost thaw. Each record is georeferenced and accompanied by standardized metadata describing sampling context, elevation, temporal coverage, analytical method, and uncertainty. This database covers five continents and 20 countries, with the highest data density in the Himalaya–Tibet region. The database focuses on continental glacierized catchments where glaciers interact directly with surface waters and groundwater, excluding Greenland and Antarctic ice sheets due to their specific hydrological conditions.  

The comparative analysis of isotope distributions reveals systematic contrasts among endmembers and continents. At the global scale, δ¹⁸O values (‰ VSMOW2) clearly distinguish cryosphere and hydrological endmembers. Continental-scale patterns of δ¹⁸O highlight the dominant influence of temperature, elevation, atmospheric circulation, and moisture source on isotope variability. North America shows the widest isotopic range due to strong latitude and elevational contrasts. Snow and glacier waters in the Andes are strongly depleted (−18 to −14‰) reflecting orographic effects. African data are limited but indicate warm conditions and evaporative enrichment, while Asia shows large variability driven by strong climatic and topographic gradients. European waters exhibit moderate depletion typical of mid-latitude precipitation regimes. Distributions of d-excess provide information on moisture sources and post-depositional processes. Most samples show positive d-excess values (8–15‰), indicating that the primary atmospheric signal is preserved. 

Overall, this dataset aims to support the applications of isotope tracers in water resource studies a provides benchmark constraints for isotope-enabled hydrological models (e.g., iCESM, IsoHydro, JAMS200). The interpretations presented here represent an initial exploration of this unique global compilation. By making these data openly available, we aim to support more detailed investigations into the processes governing the hydrology of glacierized catchments.