林冠对降雨截留能力的研究

林冠截留能力是指在理想条件下林冠枝叶对任意降雨量的最大吸附量,随降雨量的增加而增加。当降雨量足够大时,林冠截留能力就等于林冠截留容量。所以,林冠截留容量是林冠截留能力的最大值。借鉴水文学中蓄满产流理论,构建林冠截留降雨能力模型。此外,结合一个具体林分的实测资料,介绍了林冠截留能力的近似确定方法,并与模型的模拟结果进行了比较。结果表明,两者非常吻合,表明文章建立的林冠截留能力模型是有效的,可以用于评判和比较不同林分对降雨截留作用的大小。

Rainfall-intercepting Capability of Forest Canopy

In order to judge functions of forest canopy intercepting rainfall objectively and compare interception of forest canopy among different forests,the idea of rainfall-intercepting capability of forest canopy was posed.The interception capability is the maximum of forest canopy intercepting any rainfall under ideal conditions.The interception capability increases along with rainfall.When rainfall is enough,the interception capability is equal to the interception capacity of forest canopy.Therefore,interception capacity is also the maximum of the interception capability.Based on some assumptions,the model of interception capability was developed in terms of theory on saturated runoff-generating of hydrology and hydrologic forecast,namely If P<H,then I=αW[1-(1-P/H)^β+1] IfP≥H,then I=αW where,I is interception capability;P is rainfall;α is forest canopy density;H,W,and β are model parameters,H=W(β+1).Furthermore,by combining with observated data of a stand,approximately determination method of interception capability was introduced.Moreover,effectiveness of the model was also examined.The results show that calculation values with the model are almost same as approximate observed values and that interception capability model is effective.The model may be applied to different stands of any areas to compare and evaluate effects of forest canopy intercepting rainfall.