Fu et al. (2025) Response of dry-wet abrupt alternation to precipitation variation in the Hailar River Basin, northern China

Identification

• Journal: Journal of Contaminant Hydrology
• Year: 2025
• Date: 2025-10-25
• Authors: Yanchao Fu, Baolin Xue, Yuntao Wang, A Yinglan, Jin Wu
• DOI: 10.1016/j.jconhyd.2025.104763

Research Groups

• Advanced Interdisciplinary Institute of Satellite Applications, Beijing Normal University, Beijing, China
• Autonomous Region Collaborative Innovation Center for Integrated Management of Water Resources and Water Environment in the Inner Mongolia Reaches of the Yellow River, Hohhot, China

Short Summary

This study investigates dry-wet abrupt alternation (DWAA) events in the Hailar River Basin (1980–2019) using a novel Soil Moisture Concentration Index (SMCI) and the VIC hydrological model. It reveals that DWAA driving mechanisms are spatially heterogeneous, shifting from terrestrial factors upstream to meteorological factors downstream, with an overall increasing intensity of dry-wet transitions.

Objective

• To detect dry-wet abrupt alternation (DWAA) events and evaluate the impact of precipitation pattern variations on dry-wet transitions in the Hailar River Basin using a high-resolution temporal framework and a newly developed Soil Moisture Concentration Index (SMCI).

Study Configuration

• Spatial Scale: Hailar River Basin, northern China
• Temporal Scale: 1980–2019

Methodology and Data

• Models used: Variable Infiltration Capacity (VIC) hydrological model, Random Forest model
• Data sources: Daily soil moisture (SM) data (simulated by VIC model), precipitation data (implied by analysis of precipitation variation and intensity)

Main Results

• Annual precipitation in the Hailar River Basin significantly increased by 0.47 mm y⁻¹ in the south (P < 0.05).
• Precipitation intensity showed a gradient pattern, increasing upstream (3.65 mm d⁻¹ y⁻¹) and decreasing downstream (−2.34 mm y⁻¹). The number of dry days and short-duration, high-intensity precipitation events also increased.
• Soil moisture data simulated by the VIC model effectively captured DWAA events, with significantly higher |SMCI| values downstream than upstream (P < 0.05), indicating more intense dry-wet transitions in the downstream region.
• Approximately 78 % of the study area exhibited an increasing trend in |SMCI| from 1980 to 2019, with dry-to-wet transition events occurring more frequently than wet-to-dry events (e.g., maximum coverage of 48 % in a single day in 2013).
• The random forest model revealed spatial heterogeneity in DWAA driving factors: upstream variations were dominated by water yield, while downstream variations were closely associated with precipitation intensity (R² = 0.76) and the frequency of heavy rainfall days. Permafrost degradation and land use changes further heightened hydrological sensitivity downstream.

Contributions

• Introduces a transferable methodological framework for detecting and understanding extreme hydrological events, specifically dry-wet abrupt alternation.
• Reveals the spatially heterogeneous driving mechanisms of DWAA, demonstrating a shift from terrestrial factors in headwaters to meteorological factors downstream.
• Provides significant implications for water resource management strategies in other large, heterogeneous semi-arid basins.

Funding

• Not explicitly mentioned in the provided text.

Citation

@article{Fu2025Response,
  author = {Fu, Yanchao and Xue, Baolin and Wang, Yuntao and Yinglan, A and Wu, Jin},
  title = {Response of dry-wet abrupt alternation to precipitation variation in the Hailar River Basin, northern China},
  journal = {Journal of Contaminant Hydrology},
  year = {2025},
  doi = {10.1016/j.jconhyd.2025.104763},
  url = {https://doi.org/10.1016/j.jconhyd.2025.104763}
}

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