Zou et al. (2026) Geodetic glacier mass balance and its hydrological implications in the Upper Indus Basin: Insights into the Karakoram Anomaly

Identification

• Journal: Journal of Hydrology Regional Studies
• Year: 2026
• Date: 2026-09-18
• Authors: Xiaojuan Zou, Yinsheng Zhang, Haifeng Gao, Suhaib Bin Farhan
• DOI: 10.1016/j.ejrh.2026.103975

Research Groups

• School of Geography and Tourism, Huanggang Normal University
• Key Laboratory of Tibetan Environment Changes and Land Surface Processes, Institute of Tibetan Plateau Research, Chinese Academy of Sciences
• Satellite Application Center for Ecology and Environment, MEE
• Pakistan Space and Upper Atmosphere Research Commission

Short Summary

This study reconstructs the multi-decadal geodetic glacier mass balance (MBGeodetic) for 1973–2018 in the Upper Indus River Basin (UIB), revealing pronounced spatiotemporal heterogeneity. The Karakoram range shifted from a slight gain to a moderate deficit around 2000, indicating that the "Karakoram Anomaly" has weakened and its core has migrated westward.

Objective

• To assess the glacier imprint on streamflow trends and quantify the depletion of non-renewable meltwater in the UIB sub-basins

Study Configuration

• Spatial Scale: The study focuses on the Upper Indus River Basin (UIB), which is partitioned into eight sub-basins within three sub-regions: Hindu Kush, Karakoram, and western Himalaya.
• Temporal Scale: The study period spans 1973–2018, with a focus on pre-2000 and post-2000 glacier behavior.

Methodology and Data

• Models used: Photogrammetric-geodetic approach for estimating regional MBGeodetic over multi-decadal periods.
• Data sources: Declassified KH-9 Hexagon imagery, DEMs (KH-9, SRTM-C), dh products, ICESat-1/GLA14 laser altimetry footprints, Landsat-7 ETM + Level-1 Terrain-corrected panchromatic image, and gridded meteorological dataset derived from rain-gauge observations.

Main Results

• The UIB glaciers remained near equilibrium (−0.06 ± 0.02 m w.e. yr−1) yet exhibited pronounced spatiotemporal heterogeneity.
• Severe ice loss persisted in the Hindu Kush and western Himalaya, where negative ΔS coupled with increasing Q indicates sustained glacier overdraft and high vulnerability.
• The Karakoram range shifted from a slight gain (+0.82 ± 0.01 Gt yr−1) to a moderate deficit (−0.63 ± 0.01 Gt yr−1) around 2000, indicating that the "Karakoram Anomaly" has weakened and its core has migrated westward.

Contributions

• This study provides the first multi-decadal geodetic glacier mass balance record for the UIB sub-basins.
• The results highlight the importance of considering spatial heterogeneity in understanding glacier change and its hydrological implications.
• The study demonstrates that glaciers modulate rather than dominate runoff, with the Karakoram buffering glacial overdraft elsewhere.

Funding

• This research was funded by the National Natural Science Foundation of China (Grant No. 41771021) and the Key Research Program of Frontier Sciences, Chinese Academy of Sciences (Grant No. QYZDY-SSW-DQC012).

Citation

@article{Zou2026Geodetic,
  author = {Zou, Xiaojuan and Zhang, Yinsheng and Gao, Haifeng and Farhan, Suhaib Bin},
  title = {Geodetic glacier mass balance and its hydrological implications in the Upper Indus Basin: Insights into the Karakoram Anomaly},
  journal = {Journal of Hydrology Regional Studies},
  year = {2026},
  doi = {10.1016/j.ejrh.2026.103975},
  url = {https://doi.org/10.1016/j.ejrh.2026.103975}
}