Yang et al. (2026) Identification of asynchronous overtopping hazard patterns of glacial lakes in the Yarlung Tsangpo Basin

Identification

• Journal: Journal of Hydrology Regional Studies
• Year: 2026
• Date: 2026-01-15
• Authors: Shengtian Yang, yulian wang, Hezhen Lou, Jiyi Gong, Tongliang Gong, Gaohu Sun, Wenlong Song, Baichi Zhou, Sailong Wu
• DOI: 10.1016/j.ejrh.2026.103131

Research Groups

• College of Water Sciences, Beijing Normal University, Beijing, China
• Xizang Agricultural and Animal Husbandry University, Tibet, China
• International Economic and Technological Cooperation and Exchange Center of the Ministry of Water Resources, Beijing, China
• Research Center on Flood and Drought Disaster Reduction of the Ministry of Water Resources, Beijing, China

Short Summary

This study analyzed glacial lake expansion and overtopping hazards in the Yarlung Tsangpo Basin from 1990 to 2023, revealing an elevation-dependent asynchronous response to climate warming where lower elevation lakes respond faster than higher elevation ones, and developed a comprehensive hazard assessment framework based on these findings.

Objective

• To analyze the expansion characteristics of 1707 glacial lakes with areas ≥0.02 km² in the Yarlung Tsangpo Basin from 1990 to 2023.
• To identify asynchronous patterns of glacial lake evolution across different elevation zones under climate forcing, revealing elevation-dependent asynchrony between climate shifts and lake responses, and their influence mechanisms on overtopping hazards.
• To develop a graded evaluation framework based on asynchronous hazard patterns to assess glacial lake overtopping hazards and propose targeted zonal management strategies.

Study Configuration

• Spatial Scale: Yarlung Tsangpo Basin, southern Tibetan Plateau, southwestern China, covering approximately 240,000 km². Elevation zones were categorized as < 4500 m, 4500–5000 m, 5000–5500 m, and ≥5500 m.
• Temporal Scale: 1990 to 2023 (34 years).

Methodology and Data

• Models used:
  • Pettitt nonparametric test (for identifying abrupt change points in temperature and glacial lake area time series).
  • One-break segmented regression (for fitting glacial lake area growth rates).
  • Weighted summation model (P = ∑ wi × pi) for comprehensive overtopping hazard assessment.
  • Natural breakpoint method (Jenks) for categorizing hazard levels.
• Data sources:
  • Satellite imagery: Landsat series (TM, ETM+, OLI, OLI-2) from Google Earth Engine (GEE) (1990–2023, 30 m spatial resolution) for glacial lake identification and Normalized Difference Water Index (NDWI) calculation.
  • Topographic data: NASA SRTM Digital Elevation Model (DEM) (2000, 30 m spatial resolution) from GEE for elevation, slope gradient, and local relief (LR).
  • Climate reanalysis data: ERA5-Land Monthly Aggregated (1990–2023, 0.1° × 0.1° spatial resolution) from GEE for average monthly temperature and monthly total precipitation.
  • Glacial lake location data: Third Pole Environment Data Center (2015) for existing glacial lake location and area accuracy calibration.
  • Glacier datasets: Third Pole Environment Data Center (2005) and National Snow and Ice Data Center (2000) for glacier distribution.
  • Academic materials: Documented glacial lake disaster cases (35 cases) for informing the weighting scheme and validating the assessment framework.

Main Results

• Glacial Lake Expansion: From 1990 to 2023, the number of glacial lakes (area ≥0.02 km²) in the Yarlung Tsangpo Basin increased by 9.68% (from 1549 to 1707), and the total lake area expanded by 24.58% (from 214.75 km² to 267.54 km²), with an average annual growth of approximately 1.55 km².
• Phased Acceleration: Glacial lake expansion rates showed significant phased acceleration, with average annual expansion areas of 0.62 km²/a (1990–2000), 1.11 km²/a (2001–2011), and 2.44 km²/a (2012–2023). Abrupt changes in expansion were identified around 2000 and 2011–2012.
• Elevation-Asynchronous Response: Glacial lake expansion exhibits distinct elevation-dependent asynchrony. Low-elevation lakes (<4500 m) reached peak expansion around 2012, mid-elevation lakes (4500–5000 m) around 2015–2017, and higher elevation zones (5000–5500 m and ≥5500 m) around 2016 and 2012, respectively.
• Lag Time (Δt): The lag time (Δt) between abrupt climatic shifts and glacial lake responses generally increases with elevation: approximately 2–4 years for low-elevation zones (<4500 m), 4–6 years for mid-elevation zones (4500–5000 m), and 6–8 years for high-elevation zones (≥5000 m).
• Overtopping Hazard Levels: The assessment classified 3.57% of glacial lakes as very high hazard, 18.86% as high hazard, 22.55% as medium hazard, 41.42% as low hazard, and 13.59% as very low hazard.
• Hazard Distribution: Very high and high-hazard glacial lakes are primarily concentrated in the Palong Tsangpo, Yigong Tsangpo, and Niyang River subbasins, mostly located at elevations between 4500 m and 5500 m, and are predominantly glacier-contact types characterized by steep slopes and high local relief.
• Hazard Governance: Glacial lake evolution and overtopping hazard are jointly governed by geomorphological potential energy and elevation-dependent climatic forcing.

Contributions

• Systematically analyzed the spatiotemporal evolution of glacial lakes and their elevation-dependent asynchronous responses to climate warming in the Yarlung Tsangpo Basin from 1990 to 2023.
• Developed a novel overtopping hazard assessment framework that integrates local topographic variability, slope gradient, expansion rate, lag time (Δt) between abrupt climate shifts and glacial lake responses, and lake recharge type.
• Provided quantitative evidence that glacial lake evolution and overtopping hazard are jointly governed by geomorphological potential energy and elevation-dependent climatic forcing.
• Offered a transferable and interpretable approach for identifying glacial lake overtopping hazards at the basin scale using remote sensing data, facilitating dynamic monitoring, hazard zoning, and adaptive management in high-mountain regions.
• Proposed a zoned response strategy (monitoring, prevention and control, early warning zones) for glacial lake hazard-informed management.

Funding

• Tibet Autonomous Region Science and Technology Program (Grant ZYYD2023000281)
• Central Government Guides Local Science and Technology Development Program (Grant XZ202301YD0002C-04)
• Xizang Autonomous Region Science and Technology Program Project, Tibet (XZ2021JD0001, XZ202401JD0001)
• Open Research Fund Project of the Key Laboratory of Digital Dual Watershed of the Ministry of Water Resources, China Institute of Water Resources and Hydropower Research ("Research on New Technology for Satellite Remote Sensing Flow Monitoring")

Citation

@article{Yang2026Identification,
  author = {Yang, Shengtian and wang, yulian and Lou, Hezhen and Gong, Jiyi and Gong, Tongliang and Sun, Gaohu and Song, Wenlong and Zhou, Baichi and Wu, Sailong},
  title = {Identification of asynchronous overtopping hazard patterns of glacial lakes in the Yarlung Tsangpo Basin},
  journal = {Journal of Hydrology Regional Studies},
  year = {2026},
  doi = {10.1016/j.ejrh.2026.103131},
  url = {https://doi.org/10.1016/j.ejrh.2026.103131}
}