青藏高原土壤水热过程模拟研究(Ⅰ):土壤湿度

Simulative Study of Water-Heat Process in the Tibetan Plateau (I): Soil Moisture

模拟青藏高原土壤水分和热量迁移过程的连续变化对于全球变化研究具有非常重要的意义,其准确模拟是提高陆面过程模拟精度的重要条件.利用大尺度水文模型中对冻土中水分和能量平衡过程的描述,对沱沱河站点超过一年时间的土壤湿度进行了步长为1h,总时间为399d的连续模拟.与Game Tibet项目中同一时刻的土壤湿度观测资料比较的结果表明,Fuchs方程对于描述冻土中的最大未冻水含量是有效的,利用能量平衡计算获得的土壤各层的湿度与观测值相比较,其连续变化基本合理.结果表明,用该模型对高原水热过程进行长期模拟是可行的.

Water-heat process in the Tibetan Plateau is significant to global climate change, variance of soil moisture and soil temperature is the key factor of simulating water-heat process. In this paper, a water and energy balance macro-scale hydrological model is used to compare the simulated soil moisture, soil temperature and other fluxes with the observed ones on the step of 1 hour during 399 days in Tuotuohe. The results of soil moist ure are discussed. The changing tendency of the simulated soil moisture in three layers is accordant well with that of observation for more than one year. It is indicated that the Fuchs Equation can properly get the maximum unfrozen water in frozen soil in cold season, and a fairly little accumulated error exists in the simulation. The results reveal that the model is stable in yearly scale and can simulate for a long period in the Tibetan Plateau.