祁连山鲜黄小檗和甘青锦鸡儿灌丛冠层降雨再分配特征

Characteristics of Rainfall Canopy Partitioning for Berberis diaphana and Caragana tangutica Shrub in the Qianlian Mountains

以祁连山排露沟小流域的鲜黄小檗和甘青锦鸡儿灌丛为研究对象,2014年6—9月观测了38场降雨的林外降雨量、穿透雨量和树干茎流量,分析了鲜黄小檗和甘青锦鸡儿灌丛冠层降水再分配特征及影响因素。结果表明:(1)鲜黄小檗和甘青锦鸡儿灌丛冠下的穿透雨量、树干茎流量、截留量分别为175.2,20.8,182.6mm和239.1,15.1,113.4 mm,分别占总降雨量的46.3%,5.5%,48.2%和65.0%,4.1%,30.9%;鲜黄小檗和甘青锦鸡儿灌丛群落截留量占年降水量的29.3%和18.6%。(2)穿透雨量、树干茎流量和截留量均与降雨量呈显著线性正相关(P<0.01),穿透雨率和截留率均与降雨量呈对数函数关系(P<0.05)。(3)鲜黄小檗和甘青锦鸡儿灌丛产生穿透雨的临界降雨量分别为1.2mm和0.9mm,2种灌丛产生树干茎流均需要2.0mm的前期降雨量。(4)灌丛截留率9月份最大,其次是7月份,6,8月份最小;树干茎流率6—8月份变化平缓,9月份明显减小。

Rainfall can be partitioned into 3parts through the vegetable canopy：throughfall,stemflow,and interception.In this study,an experiment was carried out in the Pailugou watershed in the Qilian Mountains,in the arid region of northwest China.In a Berberis diaphana and Caragana tangutica shrub stand,throughfall,stemflow,and canopy interception of 38 rain events were observed from 1June to 31 September,2014.Then,we analyzed the characteristics of rainfall canopy partitioning and their influence factors.The results showed that：（1）The throughfall,stemflow and canopy interception of individual Berberis diaphana shrub were 175.2mm（46.3%）,20.8mm（5.5%）and 182.6mm（48.2%）,respectively,while those of individual Caragana tanguticashrub were 239.1mm（65.0%）,15.1mm（4.1%）and 113.4mm（30.9%）,respectively.Meanwhile,the interception ratio of Berberisdiaphana and Caragana tangutica community were 29.3% and 18.6%,respectively.（2）The amount of throughfall,stemflow and canopy interception of individual Berberis diaphana and Caragana tangutica shrub showed a significant positive linear correlation with rainfall amount（P〈0.01）.The relationship of throughfall ratio and interception ratio of shrubs with rainfall amount could be fitted with logarithmic curve（P〈0.05）.（3）The critical rainfall amounts for the occurrence of throughfall under Berberis diaphana and Caragana tangutica shrub were 1.2mm and 0.9mm,respectively.Meanwhile,stemflow generated when the rainfall in early period was 2.0mm.（4）The interception ratio for 2shrubs showed that the maximum values were achieved in September,with the second highest values in July,and the minimum values in June and August.In addition,the stemflow ratio changed slightly from June to August,while it decreased obviously in September.