【摘要】 为定量说明黑河流域山区植被带林地与草地在不同覆盖状况下的蒸发与下渗差异,依据实际情况设计了桶式与环刀式两种小型蒸渗仪,根据测算结果评价了两类小型蒸渗仪的适用性,并剔除不合理测算数据.根据2002年雨季蒸渗仪观测试验,将黑河流域山区草地的雨季蒸发分为3个过程:雨季早期,雨季中期和雨季晚期,并对这3个过程的蒸发进行对比.根据计算结果,分析了草类和草地盖度变化对蒸散发的影响,并计算了林地与草地的平均下渗量.更多还原

【Abstract】 To quantitatively and comparatively analyze the evapotranspiration（ET）of grassland with different coverage and that of the forest floor in the mountain vegetation zone in the Hei River Basin, two types of microlysimeter are designed to measure the grassland’s and forest floor’s ET. One type is called bucket-microlysimeter in which the infiltration is taken into account, and the another type belongs to the conventional microlysimeter which does not measure the infiltration water and the soil column in it needs to be changed frequently. The results indicate that the bucket-microlysimeter only can be used in conditions that the rainfall is less than 5.0 mm and the rainfall intensity can not exceed 1.0 mm·h^-1. All the two types of the microlysimeters made with PVC have the inner-diameter 10 cm, and they are installed in the grassland and forest floor respectively. In the two underlying surfaces, the conventional microlysimeters obtain larger measurement values than those of bucket-lysimeters. The reasons for this could be attributed to the disturbance of soil column and the changes of heat and water boundary conditions. The evapotranspiration processes in the rainy season can be divided into three sub-processes, which are the less rain early period, more rain meddle period and less rain late period. Each sub-process is distinguished by the measurement of the microlysimeters. The total ET of grassland with different coverage has not distinct discrimination if the coverage is larger than 0.5. However in terms of the three periods, the grassland with larger coverage has less ET during the first period and larger ET during the second period, and it has less ET during the third period. This could be attributed to the priority of water allotment in the grass transpiration and soil evaporation. The grassland ET is about four times of forest floor evaporation, and the daily forest floor evaporation is lees than 1.0 mm and larger than 0.3 mm averagely, and the average evaporation from forest floor is 0.83 mm. The maximum infiltration water in the forest floor can reach 33.8% of rainfall, that is about two times of the grassland infiltration water.更多还原