利用中国科学院那曲高寒气候环境观测研究站冻融期(2013年3月1日至6月1日)的气象和土壤观测资料, 通过陆面模式CoLM对那曲地区土壤冻融过程进行了数值模拟.模拟结果表明, CoLM模式对土壤温度、 感热通量和潜热通量的模拟与观测较吻合, 但对土壤湿度的模拟偏差较大, 而模式冻融参数化方案的不足是造成这一较大偏差的主要原因.根据热力学平衡下土壤水势与温度之间的关系以及Clapp-Hornberger经验公式对冻融参数化方案进行了优化, 优化冻融参数化方案后, 模式能够更真实地模拟出土壤冻融过程特征, 尤其是对土壤湿度偏低的现象改进较大.
By using the observed meteorological and soil data from 1 March to 1 June 2013 at the Nagqu station of Plateau Climate and Environment over the Qinghai-Xizang Plateau as driving data, the simulation study of the freezing-thawing processes in the Nagqu area was conducted by the Common Land Model(CoLM). Comparison between the simulated and observed data show that the CoLM model can well reproduce the variation features of soil temperature, sensible heat flux and latent heat flux, but the simulated soil moisture has a huge deviation. The defect in frozen soil parameterization schemes may be the main reason for the deviation of soil moisture. According to the relationship between soil temperature and water potential under the equilibrium thermodynamics theory and Clapp-Hornberger empirical formula optimize the frozen parameterization scheme. After the frozen parameterization scheme was optimized, the results showed that the modified CoLM model can capture the characteristics of the freezing-thawing processes better, especially made a significant improvement in the soil moisture.
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