Improvement and Application of the Parameterization Scheme for Hydrothermal Properties of Rhizosphere Soil in Alpine Grassland

<p>Plant roots&nbsp;signifificantly altered&nbsp;soil hydrothermal properties but was not typically included in land-surface process models. This omission&nbsp;affected the simulation results of&nbsp;soil water content and temperature, particularly on the Qinghai-Tibet Plateau (QTP)&nbsp;where roots in the&nbsp;shallow soil were generally high. Global grassland above-ground biomass carbon&nbsp;data and root distribution model&nbsp;were&nbsp;used to build a geographically distributed, profifiled alpine grassland roots&nbsp;density dataset for the Community Land Model (CLM). The schemes&nbsp;for&nbsp;soil hydrothermal properties were modified to accommodate soil mineral, organic matter and roots. Compared with the original schemes, the new schemes presented an increasing or decreasing trend. The new schemes&nbsp;were&nbsp;verified by single-point, regional offline simulation, and the influence of alpine grassland roots on simulation results on the QTP&nbsp;were&nbsp;explored. The new schemes&nbsp;could&nbsp;effectively block the downward migration of 0-10 cm soil water, which were&nbsp;beneficial to water conservation. The heat storage capacity of 0-10 cm soil increased obviously, and the thermal conductivity showed a certain seasonal change. Therefore, the simulated dry deviation of 0-10 cm soil water&nbsp;content in the new schemes was significantly reduced. The simulated 0-10 cm&nbsp;soil temperature&nbsp;in the new schemes during&nbsp;soil non-freezing&nbsp;was generally lower than the observed, and&nbsp;the simulated cold deviation of this layer during&nbsp;soil freezing&nbsp;was also reduced.</p>