Wei et al. (2025) Altitudinal pattern of runoff and its change during 1980–2020 in the Yarkant River, Northwest China

Identification

• Journal: Journal of Hydrology Regional Studies
• Year: 2025
• Date: 2025-12-10
• Authors: Jinyue Wei, Shiyin Liu, Yu Zhu, Xianhe Zhang, Ying Yi, Fuming Xie, Yiyuan Shen, Hua Tian, C. Chen
• DOI: 10.1016/j.ejrh.2025.103006

Research Groups

• Institute of International Rivers and Eco-security, Yunnan University, Kunming, PR China
• Yunnan Provincial Key Laboratory of International Rivers and Transboundary Eco-security, Yunnan University, Kunming, PR China
• Yunnan International Joint Laboratory of China-Laos-Bangladesh-Myanmar Natural Resources Remote Sensing Monitoring, PR China

Short Summary

This study investigated the spatial and temporal dynamics of glacier and snowmelt runoff and their contributions to total runoff in the Upper Yarkant River Basin from 1980 to 2020. It found significant declines in meltwater runoff, particularly glacier runoff in July, and revealed strong altitudinal gradients where over 80% of runoff originates from elevations above 3100 meters.

Objective

• To characterize streamflow and its components, and attribute changes in glacier and snowmelt runoff in the Yarkant River Basin from 1980 to 2020.
• To reconstruct historical runoff trends and quantify the relative contributions of glacier and snowmelt to total runoff, while identifying key climatic drivers of their variability.

Study Configuration

• Spatial Scale: Upper Yarkant Basin (UYB), located on the northwest edge of the Tibetan Plateau, specifically the upper and middle reaches of the Yarkant River Basin. The Kaqun station controls a 50,248 km² mountain basin ranging from lowlands to 8611 m. The basin was analyzed across seven elevation zones (< 1500 m, 1500–2200 m, 2200–2800 m, 2800–3100 m, 3100–3600 m, 3600–4500 m, and > 4500 m), and three broader zones (low: ≤3100 m, middle: 3100–4500 m, high: ≥4500 m).
• Temporal Scale: 1980–2020. Model calibration period: 1980–1989. Model validation period: 2001–2011. Runoff component attribution analysis: January 2001–December 2020. Glacier mass balance comparison: 2002–2020.

Methodology and Data

• Models used:
  • Coupled modeling framework "VIC-glacier" integrating:
    • Variable Infiltration Capacity (VIC) hydrological model (VIC-3L).
    • Temperature-index glacier module.
    • Volume-Area (V-A) scaling relationships for glacier area and thickness updates.
  • Conceptual Arno model for baseflow calculation within VIC.
  • Seasonal-Trend decomposition using Loess (STL) method for time series analysis.
  • Trend-Scale Factor Method and Water Balance Approach for meteorological data bias correction.
• Data sources:
  • Observational Data:
    • Daily records (1980–2016) of precipitation, maximum/minimum temperatures, and wind speed from four national meteorological stations (Tashkurgan, Pishan, Yecheng, Zepu).
    • Daily and monthly runoff data (1980–1989, 2001–2011) from Kaqun and Kuluklangan gauging stations.
  • Reanalysis Data:
    • ERA5-Land data (ECMWF): High-resolution (0.1° × 0.1°) daily precipitation, temperature extremes, and wind speed (from 1980 onward).
  • Satellite/Remote Sensing Data:
    • MODIS Daily Cloud-Free Snow Cover Extent Product (MOD10A1, MYD10A1) (China Science Data Center): 500 m spatial resolution (January 2001–December 2020).
    • MODIS evapotranspiration data (MOD16A2): 1 km resolution (since 2000).
    • University of Maryland, College Park (UMD) 1998 Global Land Cover Classification (derived from AVHRR satellite images, 1981–1994): 1 km spatial resolution.
    • Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) and Ice, Cloud and Land Elevation Satellite (ICESat) data (Hugonnet et al., 2021) for glacier mass loss acceleration dataset (2000–2019).
  • Other Geospatial Data:
    • Harmonized World Soil Database (HWSD, IIASA and FAO): 1 km spatial resolution for soil properties.
    • Shuttle Radar Topography Mission (SRTM) Digital Elevation Model (DEM): 90 m resolution for topography.
    • Randolph Glacier Inventory v7.0 (RGI V7.0, GLIMS initiative): Glacier outlines.
    • Global consensus estimates by Farinotti et al. (2019): Initial glacier thickness.

Main Results

• The coupled VIC-glacier model demonstrated high accuracy in simulating runoff, with monthly Nash-Sutcliffe Efficiency (NSE) above 0.87, correlation coefficient (R) exceeding 0.97, and relative bias (rBias) under 0.12% at Kaqun station during calibration. Snow cover and glacier mass balance simulations also showed strong agreement with observations (R=0.79-0.90 for snow cover, R=0.758 for glacier mass balance).
• Glacier melt is a critical water source, contributing 96.6% of its annual runoff between June and September, peaking in August at 62.2% of the total monthly runoff. The multi-year average contribution of glacier runoff to total runoff ranged from 12.1% (May) to 62.2% (August).
• From 1980 to 2020, both glacier and snowmelt runoff contributions to total runoff exhibited declining trends. Glacier runoff contribution reached a minimum of less than 21% in 1993, with the most pronounced monthly reductions in June and September. Snowmelt runoff contribution declined to 12% in 2011, primarily due to reductions in May and June.
• Runoff generation showed a strong altitudinal gradient: over 80% of the Yarkant River's total runoff originated from elevations above 3100 m. High (≥4500 m) and middle (3100–4500 m) elevation zones collectively contributed 91.6% of the total runoff, with high elevations alone accounting for 55.4%.
• Glacier runoff was identified as the dominant driver of total runoff variability in high-altitude regions, showing a strong correlation (Pearson R = 0.94, p < 0.001) with total runoff.
• Significant declines were observed in meltwater runoff: high-altitude glacier runoff decreased by 0.15 mm year⁻¹, and snowmelt runoff by 0.05 mm year⁻¹. The sharpest decline in glacier runoff occurred in July at high elevations, with a reduction rate of 0.32 mm year⁻¹.
• Key climatic drivers for reduced meltwater runoff were identified as a significant warming trend (0.015–0.019 ℃ year⁻¹ across middle and high altitudes), declining winter-spring snowfall (0.066–0.068 mm year⁻¹), and persistent reductions in August snow cover from the previous year (0.07–0.1% annually).

Contributions

• Developed and applied a novel coupled hydrological modeling framework ("VIC-glacier") by integrating the VIC model with a temperature-index glacier module and Volume-Area scaling relationships, enabling improved simulation of glacier area changes and melt processes in data-scarce high-altitude regions.
• Provided a detailed, elevation-specific analysis of glacier and snowmelt runoff contributions and their long-term trends (1980–2020) in the Upper Yarkant River Basin, addressing a gap in understanding altitude-dependent hydrological responses.
• Quantified the dominant role of high and middle elevation zones (above 3100 m) in total runoff generation and highlighted the strong correlation between glacier runoff and overall basin runoff variability.
• Attributed the observed declines in meltwater runoff to specific climatic drivers, including reduced winter-spring snowfall, decreased antecedent snow cover, and regional warming, offering critical insights for water resource management in arid, cryosphere-dependent regions.

Funding

• International Science and Technology Innovation Cooperation Program of the State Key Research and Development Program (2023YFE0102800)
• International Cooperation and Exchange of the National Natural Science Foundation of China (grant no. 42361144874)
• National Key Research Development Program Major Natural Disaster Prevention and Mitigation and Public Safety Project (grant no. 2024YFC3013402)
• Scientific Research and Innovation Project of Postgraduate Students in the Academic Degree of Yunnan University (Grant no. KC-24249273)

Citation

@article{Wei2025Altitudinal,
  author = {Wei, Jinyue and Liu, Shiyin and Zhu, Yu and Zhang, Xianhe and Yi, Ying and Xie, Fuming and Shen, Yiyuan and Tian, Hua and Chen, C.},
  title = {Altitudinal pattern of runoff and its change during 1980–2020 in the Yarkant River, Northwest China},
  journal = {Journal of Hydrology Regional Studies},
  year = {2025},
  doi = {10.1016/j.ejrh.2025.103006},
  url = {https://doi.org/10.1016/j.ejrh.2025.103006}
}