摘要:在对不同植被覆盖度（95%,70%～80%,40%～50%和10%）下的土壤水分（thetaV）和土壤温度（T_s）进行日观测的基础上,研究了冻融过程中植被覆盖变化对土壤水分分布和温度的影响.土壤温度与水分关系的回归分析表明：土壤冻融过程明显受植被覆盖变化的影响,植被覆盖变化还导致土壤水分和温度的耦合变化.使用了一个土壤水分和温度的耦合模型来研究植被覆盖的影响,结果证明了这一方法的有效性.结果表明：土壤水分对土壤温度的变化范围和幅度都有影响,高盖度下的土壤比低盖度土壤持水性强.此外,在冻结过程中,由于水的热容量大于土壤的,高盖度土壤能够抑制土壤温度的降低幅度,高盖度土壤具有较好的绝热功能.对于黄河源区不同植被类型覆盖下季节冻土冻融过程中的土壤温湿空间变化研究有利于为高寒冻土地区冻土和生态环境的保护及合理利用提供科学依据.

The impact of shifTs in vegetation cover on the coupling of soil water and temperature was assessed. Soil moisture （thetav） and soil temperature（T_s） were monitored on a daily basis. MeasuremenTs were made under different vegetation coverages （95%, 70%-80%, 40%-50% and 10%） and on both thawed and frozen soils. The regression analysis of thetav vs. Ts ploTs indicated that soil freezing and thawing processes were significantly affected by changes in vegetation coverage, which also caused variations in thetav-T_s coupling. A thetav-T_s coupling model was developed in order to account for the influence of vegetation coverage. It was observed that the moisture in soil affected both the scope and trend in the soil temperature. The soil with a higher coverage held more water content than that with a lower coverage. Moreover, in the process of freezing, the trend of the reduction in the soil temperature would be blocked because the thermal capacity of water is bigger than that of soil. The soil with high vegetation coverage also functioned better for the purpose of heat-insulating. It may thus play an important role for frozen soil and environmental protection and for more effective uses of the frozen soil.