中文摘要：

通过1997年和1999年藏北高原沱沱河观测站土壤温、湿度变化和对应降水变化的分析，表明与高原冻融过程相联系的土壤湿度变化和高原干湿季转换及湿季降水存在联系。土壤融冻引起土壤增湿的时间比高原雨季降水开始的时间约早20天，春季高原土壤温、湿度的增加在高原地表感潜热的变化中有重要贡献。春末夏初高原土壤冻融过程引起的土壤湿度变化，在高原局地尺度的水分循环中为高原湿季开始提供了有利的水汽条件。因此，在青藏高原陆气相互作用过程中，与冻融过程相联系的土壤湿度变化在高原季节转换中是一个不可忽视的因子。

英文摘要：

The relationships between the changes of the soil-temperature and precipitation was analyzed using the data of Tuotuohe station from 1998 to 1999. The results show that the frozen-thaw process of the soil has related to the moisture variation and the precipitation in wet-seasons. The increasing of soil moisture is attribute to frozen-thaw process starting ahead the Plateau rainy season precipitation on the Tibet Plateau, and it also has played the important role in the change of the sensible heat flux in the spring. The process provides the well condition for the cycling of the water vapor in the area. Therefore, the frozen-thaw process is one of the factors that should be considered in the interaction between the atmosphere and the land-surface on the Plateau.