Soils containing gravel (particle size ≥2 mm) are widely distributed over the Qinghai-Xizang Plateau (QXP).Soil mixed with gravel has different thermal and hydrological properties compared with fine soil (particle size <2 mm), and thus has marked impacts on soil water and heat transfer.However, the most commonly used land models do not consider the effects of gravel.This paper reports the development of a new scheme that simulates the thermal and hydrological processes in soil containing gravel, and its application in the QXP.The new scheme was implemented in version 4 of the Community Land Model and experiments were conducted at Nagqu (BJ).The results show that the soil hydraulic conductivity increases with the volume content of gravel in different humidity soils; on the other hand, the soil matric potential increases with gravel in dry soils and it decreases with gravel in wet soils.Considering the effects of gravel on soil thermal and hydraulic process, the new scheme performs well in simulating the soil temperature and moisture.By comparing the simulations of the old scheme with new scheme, the average root mean squared error of soil moisture reduced by 32.7%; The average root mean squared error of the soil temperature reduced by 24.6%.
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