【摘要】 在人工降雨条件下,采用色斑法对黄土地区4个主要树种幼树进行林冠降雨观测。结合Auto CAD、Excel数据处理软件,在0.1 mm径级下分析不同树种的林冠降雨特性,并对比研究林外降雨和不同树种的林下降雨动能。结果表明:1)不同树种林冠降雨雨谱基本不受空旷地降雨强度影响;2)用正态分布函数和类卡方分布函数对林冠降雨雨谱描述和分析容易失真,应寻求更好的数学形式对林冠降雨雨谱进行表达;3)林冠降雨雨滴直径—体积分布密度图是双峰曲线,表明Best函数同样未能对林冠降雨大雨滴作出准确描述,而利用多项式函数直接表达累积体积效果更好;4)不同树种单位水体(1 L)的林冠降雨动能大小为侧柏(28.18 J)>油松(26.74 J)>元宝枫(25.75 J)>刺槐(20.07 J),此结论也为在充分降雨条件下判断植被冠层是否增加了降雨动能提供了可比条件。更多还原

【Abstract】 With the simulated rainfall,the rainfall characteristics under canopy of the mainly tree species in loess area was studied applying the color-spot method.Combining software,such as Auto CAD and Excel,within the stand class grade of 0.1mm,the rainfall characteristics of the trees under canopy was analyzed,and the rainfall kinetic energy in and out of forest was sludced comparably.The results showed that,1) Under varied rain intensities,the observed median diameter of canopy raindrops are kept in a range stably.The rainfall characteristics under canopy won’t be affected by the rain intensity of glade.2) It is probable to make a distortion by using gaussian distribution function and class chi-square distribution function to describe and analysis the rainfall characteristics under canopy,better math form should be found to figure it.3) The distribution chart of diameter-volume of canopy raindrop is a double-peak curve,which showed that Best function is unable to make a precise description of the large rain drops as well,while polynomial function is better than it.4) The descending order of kinetic energy of tree species per liter as the follows: Platycladus orientalis(28.18 J),Pinus tabulaeformis(26.74 J),Acer truncatum Bunge (25.75 J) and Robinia pseudoacacia Linn(20.07 J).And the results also can be used to evaluate whether vegetation canopy strengthens the rainfall energy,under the condition of abundant rainfall.更多还原