贡嘎山暗针叶林林冠对降雨能量再分配的影响研究

雨滴速度、雨滴动能等参量都与土壤侵蚀关系密切。充分考虑林冠结构特征与降雨特性,观测了贡嘎山不同演替阶段暗针叶林群落的林内降雨,采用经验公式和雨谱法计算出降雨雨滴的动能和势能。结果表明:雨滴终点速度与雨滴直径和雨滴动能的大小均成正比;在小雨强时,林冠可以增加降雨落地时的动能,有时甚至可以达到林外的2倍以上;林冠对降雨势能的消减量与降雨量和林冠截留量有显著相关关系,不同月份的降雨特征不同、林冠截留特征不同,致使林冠对降雨势能的削减能力也不同。

Redistribution of rainfall energy by canopy of dark coniferous forests in Gongga Mountain,southwestern China

Soil erosion is closely related to the terminal velocity and kinetic energy of raindrops. This research considerated fully the characteristics of crown structure and rainfall, and observed the throughfall at different succession stages in the dark coniferous forests of the Gongga Moutain, southwestern China. The kinetic and potential energy of raindrops were calculated by the empirical formula of Sha Yuqing and the method of raindrop size distribution. Results showed that the raindrop terminal velocity was correlated with the diameter and kinetic energy of raindrops. The terminal kinetic energy of raindrops can be increased by the canopy under low rain intensity, sometimes up to double that outside the forest. The decrease in potential raindrop energy by the canopy was correlated with rainfall and canopy interception. Rainfall and canopy interception of different months result in various levels of decrease in potential raindrop energy by the canopy.