Xie et al. (2025) Estimation of annual runoff using supraglacial channel geometry derived from UAV surveys of Qiyi Glacier, northern Tibetan Plateau

Identification

• Journal: ˜The œcryosphere
• Year: 2025
• Date: 2025-12-05
• Authors: Longjiang Xie, Yuwei Wu, Ninglian Wang, Anan Chen, Shiqiang Zhang, Sheng Hu
• DOI: 10.5194/tc-19-6577-2025

Research Groups

• Shaanxi Key Laboratory of Earth Surface System and Environmental Carrying Capacity, College of Urban and Environmental Science, Northwest University, Xi’an 710127, China
• Qiyi Glacier Station, College of Urban and Environmental Science, Northwest University, Xi’an 710127, China
• National Cryosphere Desert Data Center, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou 730000, China

Short Summary

This study developed a novel remote sensing method using UAV-derived supraglacial channel geometry to accurately estimate the annual meltwater discharge of Qiyi Glacier, finding that geometric parameters like lateral deviation, gradient, and width can predict annual discharge with high accuracy.

Objective

• Develop a novel remote sensing method for estimating the annual discharge of supraglacial channels on Qiyi Glacier using UAV-derived channel geometry, aiming to overcome difficulties in direct field observation and uncertainties in glacier runoff models.

Study Configuration

• Spatial Scale: Qiyi Glacier, northern Tibetan Plateau (total area approximately 2.69 km²). UAV-derived Digital Elevation Model (DEM) and orthophotos with 5 cm spatial resolution.
• Temporal Scale: Annual runoff estimation for the hydrological year from August 2022 to August 2023. UAV data acquired from 15 August to 20 August 2023.

Methodology and Data

• Models used: Stepwise regression model, Nonlinear Least Squares (NLS) regression model, Pearson's correlation, Spearman's rank correlation, partial correlation analysis.
• Data sources:
  • Unmanned Aerial Vehicle (UAV) surveys (DJI Matrice300 RTK with Zenmuse L1 lens, visible-light camera, LiDAR sensor) for high-resolution DEM and orthophotos (5 cm resolution).
  • Field observations: Ablation stakes for glacier mass balance measurements (annual intervals), rain gauge observations at glacier terminus.
  • Meteorological data: Tuole weather station (approximately 70 km from Qiyi Glacier) for precipitation reconstruction.
  • Software: Pix4D Mapper 4.5.6, CloudCompare, Lidar360, ArcGIS platform, Global Mapper.

Main Results

• The six main supraglacial channels covered 92.02 % of the total glacier area and transported 89.43 % of the annual surface meltwater yield (approximately 2.4 × 10⁶ m³ total, ranging from 0.07 × 10⁶ to 0.66 × 10⁶ m³ per channel).
• Annual discharge was significantly positively correlated with sinuosity, lateral deviation, channel width, and depth, and negatively correlated with width-to-depth ratio and gradient. Channel width showed the strongest correlation (Pearson r = 0.82, Spearman ρ = 0.86).
• A stepwise regression model incorporating lateral deviation, gradient, and width explained 78.2 % of the variance in annual discharge (RMSE = 0.097 × 10⁶ m³, MAE = 0.076 × 10⁶ m³, nRMSE = 10.60 %). After five-point moving average filtering, the explained variance increased to 81.8 %.
• A nonlinear regression model using only lateral deviation and gradient explained 66.2 % of the variance (RMSE = 0.122 × 10⁶ m³, MAE = 0.091 × 10⁶ m³, nRMSE = 12.87 %). After five-point moving average filtering, the explained variance increased to 81.4 %.
• The developed approach is well-suited for polythermal or cold-based glaciers with limited subglacial hydrological activity.

Contributions

• Developed a novel remote sensing method for estimating annual glacier meltwater runoff using UAV-derived supraglacial channel geometry, providing an alternative to traditional field observations or glacier runoff models.
• Quantified the strong statistical relationships between supraglacial channel morphological characteristics (lateral deviation, gradient, width) and annual meltwater discharge on a mountain glacier.
• Demonstrated the potential for using high-resolution satellite remote sensing data (meter-level or centimeter-level) to monitor annual glacier discharge changes, particularly with the robust nonlinear model requiring fewer input parameters.
• Provided a comprehensive supraglacial channel network and associated morphological characteristics for Qiyi Glacier, a typical subcontinental glacier on the Tibetan Plateau.

Funding

• National Natural Science Foundation of China (grant nos. 42171139 and 42130516)
• Second Tibetan Plateau Scientific Expedition and Research Program (grant no. 2019QZKK020102)
• Open Research Fund of National Cryosphere Desert Data Center (grant no. 2024NCDC001)

Citation

@article{Xie2025Estimation,
  author = {Xie, Longjiang and Wu, Yuwei and Wang, Ninglian and Chen, Anan and Zhang, Shiqiang and Hu, Sheng},
  title = {Estimation of annual runoff using supraglacial channel geometry derived from UAV surveys of Qiyi Glacier, northern Tibetan Plateau},
  journal = {˜The œcryosphere},
  year = {2025},
  doi = {10.5194/tc-19-6577-2025},
  url = {https://doi.org/10.5194/tc-19-6577-2025}
}