Pan et al. (2026) Evaluating saturated hydraulic conductivity schemes: impacts on soil moisture simulations and soil texture-dependent applicability

Identification

• Journal: Journal of Hydrology
• Year: 2026
• Date: 2026-02-14
• Authors: Yongjie Pan, Danyun Wang, Shihua Lyu, Xia Li, SuoSuo Li, Youqi Su
• DOI: 10.1016/j.jhydrol.2026.135129

Research Groups

• State Key Laboratory of Cryospheric Science and Frozen Soil Engineering, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou, China
• Plateau Atmosphere and Environment Key Laboratory of Sichuan Province, School of Atmospheric Sciences, Chengdu University of Information Technology, Chengdu, China
• Zibo Municipal Optimizing Doing Business Environment Service Center, Zibo Municipal Development and Reform Commission, Zibo, China

Short Summary

This study evaluated five saturated hydraulic conductivity (Ksat) schemes against laboratory measurements and then integrated them into the Community Land Model (CLM5.0) to simulate soil moisture on the Tibetan Plateau, finding that the optimal Ksat scheme for soil moisture simulation is dependent on soil texture and organic matter.

Objective

• To evaluate the performance of five typical saturated hydraulic conductivity (Ksat) estimation schemes, both against laboratory measurements and when incorporated into the Community Land Model (CLM5.0), for simulating soil moisture across the Tibetan Plateau.

Study Configuration

• Spatial Scale: Tibetan Plateau (TP), including site-scale (12 sites) and sub-regional analyses.
• Temporal Scale: Simulations over an unspecified period.

Methodology and Data

• Models used: Community Land Model (CLM5.0), XGBoost/SHAP for soil texture-dependent analysis.
• Data sources: Laboratory measurements (for Ksat scheme evaluation), soil moisture observations (for CLM5.0 evaluation at 12 sites), soil texture and organic matter data.

Main Results

• Against laboratory measurements, most Ksat schemes overestimated Ksat, except for the Campbell scheme; the CLM5.0 default scheme showed the best overall accuracy but lacked variability capture.
• At 12 site-scale locations, the Chapuis scheme exhibited the smallest root mean square error (RMSE) for soil water content simulations, while the United States Bureau of Reclamation (USBR) scheme had the highest temporal correlation.
• Across the entire study area, all simulation schemes performed similarly, with the USBR scheme being overall better, achieving an RMSE of 0.106 m³⋅m⁻³.
• Sub-regional analysis revealed that the optimal Ksat scheme for soil moisture simulation depends on soil texture and organic matter content.
• XGBoost/SHAP analysis indicated that simulated shallow soil moisture in all schemes was primarily controlled by soil organic matter (SHAP range: 0.04–0.06), with this influence diminishing with increasing depth.

Contributions

• Provided a comprehensive evaluation of Ksat estimation schemes within a land surface model (CLM5.0) context, specifically for soil moisture simulation.
• Highlighted the texture-dependent applicability of Ksat schemes, demonstrating that no single scheme is universally optimal across varying soil properties.
• Enhanced the understanding and capability of land surface models for simulating soil hydraulic processes, particularly in complex regions like the Tibetan Plateau.

Funding

• Not specified in the provided text.

Citation

@article{Pan2026Evaluating,
  author = {Pan, Yongjie and Wang, Danyun and Lyu, Shihua and Li, Xia and Li, SuoSuo and Su, Youqi},
  title = {Evaluating saturated hydraulic conductivity schemes: impacts on soil moisture simulations and soil texture-dependent applicability},
  journal = {Journal of Hydrology},
  year = {2026},
  doi = {10.1016/j.jhydrol.2026.135129},
  url = {https://doi.org/10.1016/j.jhydrol.2026.135129}
}