Simulation study on the temporal dynamics of surface soil moisture in the Kubuqi Desert based on multiple soil hydraulic parameter schemes

【Objective】The Kubuqi Desert is located in the transition zone between arid and semi-arid climates, where surface soil moisture is characterized by pulse-like recharge, rapid depletion, and pronounced seasonal variability. These dynamics play a critical role in regulating vegetation restoration, ecosystem stability, and regional hydrological processes. Land surface models provide an effective approach for obtaining spatially continuous and temporally resolved estimates of soil moisture dynamics. However, the selection of soil hydraulic models and associated parameterization schemes can substantially influence simulated soil moisture behavior.【Methods】In this study, we focused on the Kubuqi Desert and used the Noah-MP 5.0 land surface model driven by ERA5-Land meteorological forcing data from 2017 to 2024, together with SMAP surface soil moisture products, to evaluate the effects of different soil hydraulic parameterization schemes. Four simulation experiments were designed, including the Clapp–Hornberger lookup-table scheme, VGM-Rosetta3, VGM-SPINN, and VGM-SPTF. We systematically examined their impacts on the overall simulation of surface soil moisture, seasonal variations, interannual trends, and grid-scale model performance.【Results】The results indicate that soil hydraulic parameterization schemes exert a substantial influence on the simulated temporal dynamics of surface soil moisture in the Kubuqi Desert. Different schemes considerably affect the model’s ability to reproduce mean soil moisture conditions, seasonal amplitude, the timing of peak soil moisture, and interannual variability.【Conclusion】These differences further influence the simulated responses of surface soil moisture to rainfall pulses and subsequent soil water redistribution processes.