藏北高原土壤的温湿特征

通过藏北高原两个站点(D110和安多)土壤温湿特性的分析,表明浅层土壤温度的变化幅度明显的比深层的要大,而且浅层土壤温度受地表随机天气过程的影响较大。浅层(20cm)土壤在未冻结前湿度的变化幅度不但受形成降水的地表随机天气过程的影响,而且受其下层土壤湿度状况的影响。下层土壤湿度越小,浅层(20cm)土壤湿度的变化幅度越大。土壤湿度和土壤温度之间存在着明显的相互关系,土壤的湿度状况能够影响土壤温度变化的幅度和土壤温度变化的趋势。

The Features of soil temperature and moisture on Northern Tibetan Plateau

The examination of the soil temperature and moisture features at the two sites of Amduo and D110 show that there are some similar characteristics in temperature at the two sites. The variation of soil temperature in each depth exists periodic corresponding to sine curve. The magnitude of soil temperature at shallower depth is larger than that at deeper depth and the temperature at shallower depth is affected significantly by the stochastic weather progresses. However, either at shallower depth or deeper depth, the magnitude of soil temperature at Amduo is larger than that at D110. Before the soil freezed, soil moisture at 100cm depth is smallest and at 160cm depth is largest at Amduo site. While at D110 site, the smallest soil moisture exists at 20cm depth and the largest at 100cm. The soil moistures both at 100cm and 160cm at Amduo are smaller than that at D110. However, at 20cm, the soil moisture at Amduo is larger than that at D110. The variation magnitude of soil moisture at shallower layer (20cm) is affected not only by the stochastic precipitation but also by the soil moisture condition at lower layer. The smaller the soil moisture at lower layer, the larger the variation magnitude of the soil moisture at shallower layer. There is a significant correlation between soil temperature and moisture. The soil moisture condition can affect the variation magnitude of soil temperature and its variation trend. If soil moisture is large, the variation magnitude of soil temperature will be small. And vice versa. The reason is that the heat capacity of water is much larger than that of soil. This also affects the decreasing trend of soil temperature. Thus, the soil with higher moisture content takes a pretty long time from freezing to being freezed.