Comparison of Soil Water and Heat Transfer Modeling Over the Tibetan Plateau Using Two Community Land Surface Model (CLM) Versions. (20th October 2020)

• Record Type: Journal Article
• Authors: Deng, Mingshan; Meng, Xianhong; Lyv, Yaqiong; Zhao, Lin; Li, Zhaoguo; Hu, Zeyong; Jing, Hui
• Is Part Of: Journal of advances in modeling earth systems. Volume 12:Number 10(2020)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2020-10-20
• Subjects: land surface model -- Tibetan Plateau -- soil moisture -- soil temperature; Geological modeling -- Periodicals; Climatology -- Periodicals; Geochemical modeling -- Periodicals; 551.5011
• DOI: 10.1029/2020MS002189
• Languages: English
• ISSNs: 1942-2466

Abstract

Abstract: Soil water and heat transfer is one of the most important parts of water and energy partition between atmosphere and land surface, and it is more complicated over the cold regions. In this study, the observed soil moisture and temperature are selected from four sites over the Tibetan Plateau (TP) to evaluate the performances two versions of Community Land Model (CLM), that is, CLM4.5 and CLM5.0. In addition, soil temperature observations from 67 sites and soil moisture observations from Maqu and Naqu monitoring network over the TP were used to evaluate the performances of regional simulations. The results indicated that the simulated soil temperature generally coincided with that of the observed, while CLM5.0 outputs are closer to the observed soil temperature in the arid and semiarid regions compared to CLM4.5. Generally, CLM5.0 tended to overestimate soil moisture at most sites at four soil depths (5, 10, 20, and 40 cm) but got some improvements at Maqu site. The overestimation of soil moisture was mainly caused by the introduction of a dry surface layer‐based (DSL) soil evaporation resistance parameterization in CLM5.0, which improves the soil evaporation simulation over the TP, especially in the semiarid region. Moreover, we tried to distinguish the factors that affect the soil water and heat transfer in the models. The results showed that soil property data play a main role in soil water and heat transfer modeling. Plain Language Summary: The CLM5.0 is the latest version of the Community Land Model (CLM). Here, we selected observed soil moisture and temperature data over the Tibetan Plateau (TP) to evaluate the performances of CLM4.5 and CLM5.0. The results showed that the simulated soil temperature generally coincided with that of the observed, while CLM5.0 outputs are closer to the observed soil temperature in the arid and semiarid regions. Moreover, the simulated soil moisture by CLM5.0 tended to reduce the bias of soil moisture at subhumid area and overestimated soil moisture at semiarid area. The overestimation of soil moisture was mainly caused by the introduction of a dry surface layer‐based (DSL) soil evaporation resistance parameterization in CLM5.0, which improves the soil evaporation and surface total water storage simulation over the TP, especially in the semiarid region. Finally, we replaced the forcing data (ITP) and soil property data by using the observed data to investigate the possibly causes in soil water and heat transfer. Single‐point simulations show that model bias was possibly influenced by the uncertainties of soil category data and atmospheric forcing data. The impact of soil property data is more important than that caused by the forcing data. Key Points: Simulation errors are evident in two CLM versions, and CLM5.0 tended to overestimated the soil moisture in semiarid and arid region Differences of soil water and heat transfer in two CLM versions mainly caused by the introduction of a DSL parameterization The sensitivity tests showed that soil property data plays a main role in soil water and heat transfer