晋西黄土区单株油松树下穿透雨空间分布特征研究

Spatial Distribution Characteristics of Throughfall Under Pinus Tabulaeformis Single Tree′s Canopy in Loess Region of Western Shanxi Province

为了更好地解析黄土高原森林水文过程,为基于生态过程的森林水文模型的发展与参数化提供基础,在单株尺度上探讨了晋西黄土区典型油松林穿透雨的空间分布特征。在选取的2棵油松标准木的两侧树冠下,根据离树干的不同距离布置自记雨量计各7个,研究期间共观测了15场不同降雨和穿透降雨量。利用统计学方法分析了林外降雨和冠层结构特征与穿透雨之间的关系。结果表明:(1)部分观测点出现穿透雨率大于100%的状况,最大的穿透雨率达155.8%,这主要是因为降雨在冠层的作用下发生了聚集效应;(2)穿透雨量与降雨量呈显著正相关关系(p<0.05),穿透雨率与降雨强度也呈正相关关系,但其影响未达到显著水平;(3)距树干距离对穿透雨的影响是多重因素综合作用的结果,并且在穿透雨的空间分布中起到主导作用;(4)穿透雨率与郁闭度和冠层厚度呈负相关关系。

In order to analyze the forest hydrology processes on the Loess Plateau and provide reference for the development and parameterization of hydrological model, spatial distribution characteristics of throughfall were discussed at the scale of the single tree of Pinus Tabulaeforrnis in the loess region of Western Shanxi Province. 7 rain gauges were settled under 2 sampled trees in accordance with the distance from the stems. The respective throughfall of 15 different rainfall events was measured and the influences of rainfall and cano py characteristics on throughfall were analyzed by statistical method. Results showed that： （1） Throughfall percentage in some sample sites was greater than 100G, with the maximum being 155.8%. The reason for the phenomenon is the evidently concentrated rainfall which might be caused by the canopy. （2） Throughfall was positively correlated to rainfall and rainfall intensity, but the correlation with rainfall intensity was not significant. （3） The influence of the distance between sample site and stem on throughfall was attributed by multiple factors which play a major role in throughfall spatial distribution. （4） Throughfall percentage was negatively correlated to canopy density and canopy thickness.