Runoff efficiency and seasonal redistribution under warming–wetting in the Pangu River basin: A snow-state-constrained assessment
- 1Key Laboratory of Water Cycle and Related Land Surface Processes, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing, China
- 2Key Laboratory of Water Cycle and Related Land Surface Processes, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing, China; Corresponding authors.
- 3Department of Hydrogeology, Lomonosov Moscow State University, GSP-1, Leninskie Gory, Moscow, 119899, Russia
Abstract
Study region: The Pangu River basin is a data-scarce, high-latitude mountainous catchment in the northern Greater Khingan Mountains, Northeast China, where runoff is jointly shaped by seasonal snow, freeze-thaw processes, river ice, catchment storage-release, and limited direct human regulation. Study focus: We examined annual runoff and seasonal release under warming-wetting using harmonized monthly runoff observations, a cold-region process-diagnostic model (PHY), and targeted tests of total-runoff residual, parameter, and snow-structure sensitivity. Diagnostic pathway allocation was treated as secondary sensitivity analysis. New hydrological insights for the region: Within the snow-state-constrained reference model, historical runoff did not increase proportionally to wetting. Between 1961–1990 and 1995–2024, annual precipitation increased by 53.7 mm, whereas PHY annual runoff changed by only −3.0 mm and runoff efficiency declined from 0.265 to 0.228. April–June (AMJ) runoff showed a model-inferred directional decline of 4.8 mm, with a relative shift toward July–October (JASO); bootstrap intervals for AMJ runoff and seasonal-allocation contrasts included zero. In the PHY diagnostic decomposition, the snow-related spring-release index (SAI) declined from 0.312 to 0.278. Runoff directions persisted under local parameter and residual perturbations, and lower SAI persisted within the reference parameter ensemble. Removing ERA5-Land snow-state assimilation reversed the key historical directions. The efficiency contrast reflects a response conditioned by effective-forcing and numerical snow-state adjustments, not an identified fate of additional precipitation. Weaker snow-supported spring release is therefore a conditional model interpretation, not an established climatic mechanism.
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BibTeX
@article{wang2026runoff,
title = {{Runoff efficiency and seasonal redistribution under warming–wetting in the Pangu River basin: A snow-state-constrained assessment}},
author = {Tingting Wang and Ping Wang and Wenbin Liu and Hong Wang and Ziwei Li and Fubao Sun and Sergey P. Pozdniakov},
journal = {Journal of Hydrology: Regional Studies},
year = {2026},
month = oct,
doi = {10.1016/j.ejrh.2026.104124},
url = {https://doi.org/10.1016/j.ejrh.2026.104124},
note = {CC BY},
}
RIS
TY - JOUR
TI - Runoff efficiency and seasonal redistribution under warming–wetting in the Pangu River basin: A snow-state-constrained assessment
AU - Tingting Wang
AU - Ping Wang
AU - Wenbin Liu
AU - Hong Wang
AU - Ziwei Li
AU - Fubao Sun
AU - Sergey P. Pozdniakov
PY - 2026
DA - 2026/10/30
JO - Journal of Hydrology: Regional Studies
DO - 10.1016/j.ejrh.2026.104124
UR - https://doi.org/10.1016/j.ejrh.2026.104124
AB - Study region: The Pangu River basin is a data-scarce, high-latitude mountainous catchment in the northern Greater Khingan Mountains, Northeast China, where runoff is jointly shaped by seasonal snow, freeze-thaw processes, river ice, catchment storage-release, and limited direct human regulation. Study focus: We examined annual runoff and seasonal release under warming-wetting using harmonized monthly runoff observations, a cold-region process-diagnostic model (PHY), and targeted tests of total-runoff residual, parameter, and snow-structure sensitivity. Diagnostic pathway allocation was treated as secondary sensitivity analysis. New hydrological insights for the region: Within the snow-state-constrained reference model, historical runoff did not increase proportionally to wetting. Between 1961–1990 and 1995–2024, annual precipitation increased by 53.7 mm, whereas PHY annual runoff changed by only −3.0 mm and runoff efficiency declined from 0.265 to 0.228. April–June (AMJ) runoff showed a model-inferred directional decline of 4.8 mm, with a relative shift toward July–October (JASO); bootstrap intervals for AMJ runoff and seasonal-allocation contrasts included zero. In the PHY diagnostic decomposition, the snow-related spring-release index (SAI) declined from 0.312 to 0.278. Runoff directions persisted under local parameter and residual perturbations, and lower SAI persisted within the reference parameter ensemble. Removing ERA5-Land snow-state assimilation reversed the key historical directions. The efficiency contrast reflects a response conditioned by effective-forcing and numerical snow-state adjustments, not an identified fate of additional precipitation. Weaker snow-supported spring release is therefore a conditional model interpretation, not an established climatic mechanism.
SN - 2214-5818
ER -