It hasn't yet fully understood the influence of freeze-thaw action on hydrological processes in the active layer of permafrost regions. So this article investigated one permafrost cross-section at the northern slope of Bayan Har Mountains in the Source Area of the Yellow River in Qinghai-Tibet Plateau. According to the data of field monitoring, seasonal variability of soil hydrological processes in the active layer of permafrost regions was studied and simulated by the freeze–thaw module of HYDRUS-1D software. The results show that: 1) The soil moisture and the suprapermafrost water-level are divided into four stages based on the freeze-thaw process. Rainfall infiltration is the main driving force of soil hydrological processes, and the freeze-thaw front are the main limiting factors. 2) The active layer thickness (ALT) is greater on the upslope than that on the downslope due to the influence of terrain slope. It leads to that the change variation of the soil moisture and the suprapermafrost water-level on the upslope is also more gently than that on the downslope. 3) Temperature is the key factor that affects soil hydrologic process of the active layer in permafrost regions. Soil temperature and soil moisture showed a significant exponential linear correlation at different depths. The relationship between soil temperature and suprapermafrost water level shows Boltzmann function relations. 4) Soil moisture has a downward migration trend after a freeze-thaw cycle. It will result in the formation of underground ice near the permafrost table. Driven by the temperature gradient, the unfrozen water in the active layer moves from bottom to top during the freezing stage.

尚未完全了解冻融作用对多年冻土活跃层水文过程的影响。因此，本文研究了青藏高原黄河源区巴彦Har尔山北坡的一个多年冻土断面。根据现场监测数据，利用HYDRUS-1D软件的冻融模块研究并模拟了多年冻土活动区土壤水文过程的季节变化。结果表明：1）根据冻融过程，将土壤水分和超霜冻水位分为四个阶段。降雨入渗是土壤水文过程的主要驱动力，而冻融锋是主要的限制因素。2）由于地形坡度的影响，上坡的活性层厚度（ALT）大于下坡的活性层厚度。这导致上坡的土壤水分和超霜冻水位的变化变化也比下坡的变化平缓。3）温度是影响多年冻土区活性层土壤水文过程的关键因素。在不同深度下，土壤温度和土壤水分呈显着的指数线性关系。土壤温度与超霜冻水位之间的关系显示出玻尔兹曼函数关系。4）冻融循环后，土壤水分有向下迁移的趋势。这将导致永久冻土层附近形成地下冰层。在温度梯度的驱动下，