Tao Pu

Climate warming has been altering cryospheric processes in cold regions, accelerating glacier retreat, reducing snow cover, leading to increased interannual variability in runoff and more frequent extreme hydrological events, thereby exacerbating hydrological instability. Consequently, exploring reliable approaches to investigate surface water‐groundwater interactions in alpine cryospheric regions remains challenging and essential. Accordingly, we coupled the glacier‐enhanced hydrological model (SWAT‐GL) with the groundwater model (MODFLOW) to develop the integrated SWAT‐GL‐MODFLOW framework and to quantify such interactions in the cryospheric upper Shule River Basin on the northeastern Tibetan Plateau. The coupled model was calibrated and validated using observed streamflow and separated baseflow, demonstrating its capability to simulate basin‐scale runoff dynamics and groundwater processes. For runoff, SWAT‐GL‐MODFLOW achieved Nash‐Sutcliffe Efficiency values of 0.71 (calibration) and 0.65 (validation), improving by about 16.1% and 4.8% over SWAT and SWAT‐MODFLOW, respectively. For baseflow, the simulated values showed good agreement with the baseflow separation values, with a FitNRMSE of 0.82. Our results reveal that: (1) the average contribution of glacier meltwater runoff to annual river discharge was 28.8%, highlighting its key role in runoff generation; (2) groundwater storage increased at an average annual rate of 4.2 mm/a, with 6.3 mm/a during the glacier melt season from June to September; (3) annual groundwater discharge to surface water accounted for 53.4% of the total exchange, and surface water leakage to groundwater accounted for 46.6%, with contributions of 17.1% from glacier meltwater, 7.3% from snow meltwater, and 22.2% from rainfall infiltration recharge during 2005–2020. This study provides a framework for evaluating surface water‐groundwater interactions in cryospheric regions globally.

The altitude effect of stable isotopes in river water is key to paleoelevation reconstruction, yet remains poorly quantified at regional scales due to monitoring challenges. This study compiled river water isotope data across the Tibetan Plateau and used a decision‐tree‐based random forest model to simulate high‐resolution δ ¹⁸ O patterns. We produced the first systematic, spatially explicit map of the δ ¹⁸ O altitude effect over the entire plateau, revealing strong spatial heterogeneity. Results show that δ ¹⁸ O exhibits a “low in the south, high in the north” pattern driven by atmospheric circulation, while d‐excess displays a “low in the west, high in the east” trend controlled by sub‐cloud evaporation. The steepest altitudinal gradient occurs on the southern slope. This spatial heterogeneity is jointly regulated by moisture sources and sub‐cloud evaporation processes. The findings clarify the applicability and limitations of river water isotopes for paleoelevation studies on the Tibetan Plateau.

Stratosphere‐to‐troposphere transport (STT) is a key process that influences atmospheric chemical composition and radiative balance. The Tibetan Plateau (TP), the highest and most extensive plateau in the world, has been identified as a global hotspot for stratospheric intrusions. However, direct observational evidence remains limited, particularly in the southeastern TP—a region traditionally considered to have minimal STT influence. Stratospheric ³⁵ S is a powerful tracer for directly identifying STT processes. Here, we present the first measurements of ³⁵ SO ₄ ²⁻ concentrations and their seasonal variability in aerosols collected at Yaze, a remote site in the southeastern TP. The highest ³⁵ S activity (840 ± 90 atoms m ⁻³ ) occurred in spring and coincided with elevated surface ozone levels. Backward trajectory and vertical motion analyses indicate that this spring enhancement was attributable to descending stratospheric air masses originating from the Himalayan region, highlighting the prominent influence of frequent STT events during this season. A secondary ³⁵ S activity peak in November (810 ± 80 atoms m ⁻³ ) was associated with stratospheric intrusions from the northwestern TP. These findings provide direct observational evidence of pronounced seasonal variability in stratospheric intrusions over the southeastern TP and enhance our understanding of regional stratosphere–troposphere exchange processes. Furthermore, we report ³⁵ SO ₄ ²⁻ concentrations measured in spring glacier snowpits and summer precipitation from the nearby glaciers, which are associated with atmospheric ³⁵ SO ₄ ²⁻ and serve as representative end‐member values for glacier runoff, establishing essential baseline data for future assessments of glacier melt and hydrological responses in this climatically sensitive region.

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.

Chemical weathering processes has become a growing issue in research on carbon cycling, however, mineral weathering by sulfuric acid and carbonic acid and its possible impacts on carbon cycle are yet unknown over the typical glacial catchment. To investigate the mechanisms of mineral weathering processes and its influence, the spatial–temporal variations of the major ions in Mingyong River, a glacier‐originated river located on the southeastern edge of the Qinghai‐Tibetan Plateau, were investigated. The seasonal and spatial variations in river solutes were resulted from the hydrological conditions and different mineral weathering rates. The results showed that the major ion compositions of the river waters were characterized by the dominance of Ca²⁺, Mg²⁺, HCO₃⁻, with a significantly rich in SO₄²⁻. A systematic increase in ionic concentrations (apart from NH₄⁺ and NO₃⁻) was observed in the river water from non‐monsoon to monsoon season as well as from upstream to downstream. Piper diagram results showed 100% (upstream‐midstream) and 72.5% (downstream) contributions to Ca‐HCO₃ type, respectively, indicating that a dominated carbonate weathering to the river chemistry. The (Ca²⁺+Mg²⁺)/HCO₃⁻ against (SO₄²⁻/HCO₃⁻) scatter suggested that sulfuric and carbonic acid are responsible for chemical weathering. An increased contributions of sulfuric acid from upstream (43%) to downstream (87.3%) on the (Ca²⁺+Mg²⁺) and from upstream (29.6%) to downstream (88.3%) on HCO₃⁻ using the stoichiometry analysis during the monsoon season. Contrarily, H₂SO₄‐related dissolution (>65%) processes controlled the carbonate weathering during the non‐monsoon season, which indicated that sulfuric acid played a significant part in the process of rock dissolution that intensifies weathering. The effects of accelerated weathering on drinking and irrigation suitability suggested that the Mingyong River water is subject to a salinity hazard. This research demonstrates that the weathering of catchments involving sulfuric acid has the potential to alter carbon cycle and should be considered in global carbon cycle models.

This study evaluates the simulation of the seasonal cycle of water isotopic composition over Tibetan Plateau regions (TP) from six isotope‐enabled general circulation models (GCMs) participating in the second Phase of Stable Water Isotope Intercomparison Group. For both meteorological factors (precipitation rate and wind field) and isotopic composition, GCMs generally agree with reanalysis data and in‐situ observations, but there is a significant spread across models and the isotopic seasonality is systematically underestimated. In the southern TP, the precipitation isotopic composition is more depleted in summer than in winter, and the amplitude of the simulated isotopic seasonal variations is primarily driven by the amplitude of the simulated upstream precipitation. In contrast, in the northern TP, the precipitation isotopic composition is more depleted in winter than in summer, and the amplitude of the simulated seasonal variability of isotopes is mainly driven by the simulated strength of the zonal wind. We conclude that the skill of a GCM to simulate the seasonal cycle in the isotopic composition depends mainly on the skill of the GCM to simulate the Indian summer monsoon precipitation and the westerlies. The same causes contributing to the underestimated seasonality at present‐day may also contribute to the underestimated δ¹⁸O change at the mid‐Holocene.