摘要
研究苔藓层的降雨再分配对于认识其实际截持降雨过程及水文循环机理具有重要意义。本文以祁连山排露沟小流域青海云杉林苔藓层为研究对象,利用室内实验和野外观测相结合的办法,对祁连山苔藓层蓄积量、持水量(率)、林外(内)降雨量和苔藓穿透雨量进行测定,分析青海云杉林苔藓层持水特征、降雨再分配特征及其与影响因素的关系。结果表明:(1)苔藓层的厚度为2.8~12.6 cm,蓄积量为18.6~65.7 t·hm^(-2),最大持水率为218.6%~536.1%,最大持水深为8.6~19.2 mm,且苔藓层的最大持水量约为自身干重的3.5倍。(2)青海云杉林苔藓层的穿透雨总量和截留总量分别为156.5 mm和100.0 mm,分别占林内降雨总量的61.0%和39.0%,并在不同降雨量等级之间存在明显的差异。(3)苔藓层降雨再分配各组成要素(穿透雨和截留)与林内降雨量、林外降雨量、降雨历时和空气相对湿度呈极显著的相关性。林内降雨量、林外降雨量和降雨历时与苔藓穿透雨量均呈线性正相关关系(P<0.01),而与穿透雨率、截留水量和截留率均呈对数函数关系(P<0.05)。因此,苔藓层的持水性能及再分配特征,除与苔藓层的厚度、蓄积量和初始含水量相关外,也与林外各气象因子相关。
Throughfall is partitioned into two parts through bryophyte layer： bryophyte throughfall and bryophyte interception. This process plays an important role in water balance for forest ecosystem. The research on rainfall partition in bryophyte layer is very important and necessary for understanding the process of bryophyte interception under the natural rainfall and revealing the mechanism of hydrological function of bryophytes. In this study,an experiment was carried out in Pailugou Watershed in the Qilian Mountains,an arid region in northwest China. Three representative Picea crassifolia forest stands were selected. Accumulation,water holding capacity and rate of bryophyte layer in Picea crassifolia forest were measured. Rainfall outside of stand,throughfall and bryophyte throughfall of 34 rain events were observed from May 1 to September 31,2015. Moreover,the related meteorological factors including air temperature（ T）,air relative humidity（ Rh） and wind speed（ Ws） were simultaneously monitored by an automatic meteorological station in the outside forest. Then the relationships between the water holding capacity and the thickness and accumulation of bryophyte layer,rainfall partition of bryophyte layer and its affecting factors were analyzed. The results showed that：（1） The thickness of bryophyte layer under Picea crassifolia forest varied from 2. 8 cm to 12. 6 cm,its accumulation varied from 18. 6 t ·hm-2to 65. 7 t ·hm^-2,and its water holding capacity ranged from 218. 6% to 536. 1%. The water holding capacity of bryophyte layer was 3. 5 times of its self-dry weight,and its maximum varied in a range from 8. 6 mm to 19. 2 mm;（2） During the whole observation period,the total bryophyte throughfall and bryophyte interception in Picea crassifolia forest were 156. 5 mm and 100. 0 mm,and accounted for61. 0% and 39. 0% of the total throughfall,respectively. Meanwhile,their ratios varied significantly under different rainfall levels;（3） The two parts of rainfall partition of bryophyte layer were significantly correlated with rainfall,throughfall,rainfall duration and relative air humidity. The rainfall,throughfall and rainfall duration showed a significant positive linear correlation with the amount of bryophyte throughfall（ P〈0. 01）,while three meteorological factors showed a logarithmic curve with bryophyte throughfall ratio,bryophyte interception amount and bryophyte interception ratio（ P〈0. 05）. Therefore,it was concluded that rainfall partition and water holding capacity of bryophyte layer had relation with thickness,accumulation,initial water content of bryophyte layer,and they were influenced by the related meteorological factors.
出处
《干旱区研究》
CSCD
北大核心
2017年第5期1149-1156,共8页
Arid Zone Research
基金
国家自然科学基金项目(31360201
91225302
91425301
41461004)
甘肃省科技创新服务平台项目(144JTCG254)资助
关键词
苔藓层
降雨再分配
气象因子
青海云杉林
祁连山
bryophyte layer
rainfall partition
meteorological factor
Picea crassifolia forest
Qilian Mountains
