北京山区林地凝结水特征研究

Condensed Water Characteristics of Forest Land in Beijing Mountainous Areas

[目的]研究北京山区林地凝结水的发生情况及分布特征,为该地区的水资源合理利用提供科学依据。[方法]利用首都圈森林生态定位站的大型称重式蒸渗仪对北京山区4种林地的凝结水进行2a连续观测,同时监测林地各项气象因子,分析不同林地凝结水的分布特征以及影响因子。[结果](1)北京山区非生长季凝结水出现天数和凝结水量较生长季多,非生长季月平均凝结水量约4.5mm,生长季月平均凝结水量约1.6mm;(2)4种林分年凝结水量大小关系表现为草地(38mm)>栓皮栎(36mm)>油松(30mm)>侧柏(25mm),与年凝结水出现天数大小关系相同,灌草丛是产生凝结水的主要场所,阔叶林产生的凝结水远高于针叶林;(3)空气温度和相对湿度对凝结水的产生起到决定性作用。[结论]北京山区林地凝结水在时间上分布不均,受环境因子和植被因子的综合影响。

[Objective] Studying the occurrence and distribution characteristics of condensed water of forest land in Beijing mountain areas in order and to provide a support for rational utilization of water resources.[Methods] We used four high precision weighing lysimeters at a site of China forest ecosystem research network（CFERN） during 2011-2012 to observe the distribution characteristics of woodland condensed water and meteorological factors in Beijing mountain area, and to analyze the distribution characteristics and the impact factors of condensed water in different kinds of woodlands.[Results] （1） There existed significant difference of woodland condensed water for different seasons in Beijing mountain area. The days and amounts of condensed water in the autumn and winter were far longer and higher than the corresponding values observed in spring and summer. The mean amount of monthly condensation water was about 4.5 mm in non-growing season, was 1.6 mm in growing season. （2） The order of the condensation water capacity in four forests was：grassland （38 mm） 〉 Quercus variabilis plantations（36 mm） 〉 Pinus tabulaeformispure plantations （30 mm） 〉 Platycladus orientalis plantations（25 mm）. The amount of condensed water of grassland was more than that of trees, and the broadleaf forest was more than the value of coniferous forest. （3） We can learn from the amount, the spatial and temporal characteristics of those different species that the temperature gradient, relative humidity and the leaf surface properties were the most important affecting factors on air water condensation.[Conclusion] The temporal distribution of condensed water of forest land is non-uniform in Beijing mountain areas, and the condensed water distribution was affected both by environmental and vegetation factors.