Development and Validation of Soil Frost Heave Scheme in the Community Land Model 5.0

Abstract

Soil frost heave from freezing–thawing (FT) affects soil structure, hydrothermal properties, and land-atmosphere interactions, affecting the reliability of permafrost engineering and increasing uncertainty in model simulations. However, most Land Surface Models (LSMs), including Community Land Model 5.0 (CLM5.0), do not simulate frost heave. To address this, a frost heave parameterization scheme, based on the porosity rate function, was developed and integrated into CLM5.0. The enhanced model (with proposed frost heave scheme) was validated at site and regional scales, focusing on its effects on soil structure, hydrothermal properties, and transfer processes on the Tibetan Plateau (TP). Results show the enhanced model accurately simulates changes in soil thickness and porosity during FT cycles, improving hydrothermal properties' simulations during thawing and representing bidirectional thawing within soil layers. At the regional scale, seasonal soil deformation along the Qinghai-Tibet Highway simulated by the enhanced model closely aligns with field experiments and InSAR data. The enhanced model predicts higher soil temperatures in southeastern TP and lower ones in the northwest compared to the original model. Additionally, the enhanced model simulates increased soil moisture especially in the Three Rivers Source region compared to the original model, which aligning better with observations. Integrating the proposed scheme in CLM5.0 advances the representation of FT processes and provides a foundation for refining land surface, regional, and global modeling frameworks.