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Journal of Desert Research ›› 2026, Vol. 46 ›› Issue (3): 97-108.DOI: 10.7522/j.issn.1000-694X.2025.00173

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The water-heat coupling transmission mechanism under extreme rainfall events and its influence on diurnal evaporation

Ruixiang Zhang1(), Jihua Chu2, Jueke Li1, Yaxian Li1, Shuixian Wang1()   

  1. 1.College of Earth and Environmental Sciences,Lanzhou University,Lanzhou 730000,China
    2.Wuwei Hydrology and Water Resources Survey Center,Wuwei 733000,Gansu,China
  • Received:2025-11-07 Revised:2025-12-24 Online:2026-05-20 Published:2026-06-11
  • Contact: Shuixian Wang

Abstract:

Rainfall is a crucial factor driving the transport of soil water and heat. Studying the transport of soil water and heat under extreme rainfall events is of great significance for the sustainable development of ecosystems in arid regions. In this study, the Jiudun Experimental Field in Wuwei was selected as the research site. Based on long-term observation data from the lysimeter and meteorological monitoring data from hydrological stations, the Hydrus-1D water-heat coupling model was used for simulation and analysis to reveal the driving mechanism of extreme rainfall on soil water and heat transport in arid regions and its impact on diurnal evaporation. The results show that the shallow soil (0-20 cm) responds intensely to sudden extreme rainfall, while the deep soil (>40 cm) is more affected by continuous extreme rainfall. The evaporation process is regulated by the migration of the zero-flux plane of soil water potential. During the day, the convergence near the surface inhibits the upward movement of liquid water, while at night, the divergence promotes the diffusion of water vapor. Below a depth of 40 cm, when the temperature gradient is less than 0.075 ℃·cm⁻¹ and the temperature fluctuation is less than 2 ℃, the thermal buffering effect significantly weakens the driving force of evaporation, forming a lagged water supply boundary. The research results can provide a scientific basis for water resource management in arid regions under extreme climate conditions.

Key words: extreme rainfall, soil moisture, water-heat coupling, diurnal evaporation, numerical simulation

CLC Number: