长白山阔叶红松林的零平面位移和粗糙度

Zero-plane displacement and roughness length of the mixed forest of broad-leaved and Korean-pine in Changbai Mountain.

根据长白山阔叶红松林气象观测塔上 16个月的风速、温度、湿度及气压的连续观测资料 ,根据中性层结条件下风速随高度的对数变化规律 ,利用廓线法中的牛顿迭代法计算了该森林的零平面位移d和粗糙度z0 ,结果表明 ,d和z0 均存在着较明显的季节变化 ,在生长季d较大 ,z0 较小 ,而非生长季恰好相反 ,标准化的零平面位移d/h和粗糙度z0 /h在生长季和非生长季平均分别为 0 86 7,0 76 4和 4 4 7× 10 -2 ,3 5 9× 10 -2 。与叶面积指数对比分析发现 ,d/h和z0 /h与叶面积指数分别存在正相关和负相关的关系。敏感性分析表明 ,牛顿迭代法求d和z0对风速的精度要求较高 ,需要精度高的仪器和长期的数据积累。

Based on logarithm law of wind profile under neutral stratification,zero-plane displacement d and roughness length z 0 of the mixed forest of broad-leaved and Korean-pine in Changbai Mountain were calculated with Newton iteration according to the 16 months profile measurements of wind speed,air temperature,humidity and pressure.The results showed that d and z 0 had obvious seasonal variation.In growing season was relatively high and z 0 was lower.Normalized values,d/h and z 0/h,were in the magnitude of 0.867,0.764 and 4.47×10 -2,3.59×10 -2 in growing season and dormant season, respectively. d/h and z 0/h were positively and negatively correlated with leaf area indexes of the forest.Sensitive analysis showed that the iteration approach of calculating d and z 0 demanded high precision measurements of wind speed in the profiles.This work should be based on the long term measurements with high-precision instruments.