A Simulation Study on Soil Parameterization Scheme of Seasonally Frozen Ground Regions based on CLM4.5

Abstract

In this paper， the field observation data provided by Naqu station of Plateau Climate and Environment in northern Qinghai-Xizang（Tibetan） Plateau， located in the seasonally frozen ground regions， CLM4.5 is used to analyze and evaluate the simulation ability of thermal conductivity parameterization schemes of Luo， Johansen， and Côté as well as virtual temperature parameterization scheme to calculate soil temperature and humidity， providing basis for the future work of selecting the optimal parameters and parameterization schemes to more reasonably simulate the freeze-thaw process of frozen soil on Tibet Plateau.The results suggested that： （1） The soil thermal conductivity of three parameterization schemes was significantly different， of which the Côté scheme had the highest soil thermal conductivity， while the Luo scheme had the lowest.（2） All the three-soil heat conductivity parameterization schemes can reasonably simulate the daily variation trend of soil temperature and humidity.The Johansen scheme can better simulate the annual variation trend of soil temperature， the Côté scheme has a smaller deviation from the observed value in soil temperature simulation， and Luo scheme has a better simulation on soil moisture.（3） After adding the virtual temperature equation and introducing the phase transition efficiency parameter， the negative deviation of the model for soil moisture simulation is reduced.In addition to maintaining good simulation ability of soil temperature， the Y-L scheme can further improve the simulation ability of soil moisture.

Keywords

• seasonally frozen ground regions
• clm4.5
• soil temperature and humidity
• parameterization scheme