青海湖流域高寒草甸壤中流水分来源研究  

Study on the Water Sources of Subsurface Flow in Alpine Meadow of the Qinghai Lake Basin

作　　者：肖雄[1] 李小雁[1] 吴华武[1] 蒋志云[1] 李宗超[2] 

机构地区：[1]北京师范大学资源学院,北京100875 [2]北京师范大学减灾与应急管理研究院,北京100875

出　　处：《水土保持学报》2016年第2期230-236,共7页Journal of Soil and Water Conservation

基　　金：国家自然科学基金项目(41130640;41321001);教育部"创新团队发展计划"项目(IRT_15R06)

摘　　要：通过对青海湖流域高寒草甸壤中流水分来源进行研究,以期揭示青海湖流域高寒草甸系统壤中流的产流机制。收集了大气降水、土壤水和壤中流中δ^(18)O和δD及实测降水数据,对比分析了大气降水、土壤水和壤中流的氢氧同位素特征,并使用了二源线性混合模型对壤中流进行了产流来源计算。结果表明:青海湖高寒草甸分布区大气降水线(LMWL)的斜率和截距均高于全球大气降水线(GMWL),降水较多的月份δ^(18)O、d-excess值较低;壤中流的水分来源与地形及其土壤深度密切相关,具体表现为:(1)壤中流在坡下土壤上层(0—40cm)和下层(40—80cm)产流氢氧同位素值相对聚集,并具有较明显的蒸发富集特征,表明该部分壤中流多源于降雨前储存于土壤中的水分,雨前土壤水对于壤中流在坡下土壤上层(0—40cm)和下层(40—80cm)产流的平均贡献率为85.88%和83.48%;(2)坡中壤中流水分来源因土壤深度而异,雨前土壤水对壤中流在坡中土壤下层(40—80cm)产流的平均贡献率为57.59%,表明大气降水和雨前土壤水贡献相当;壤中流在坡中土壤上层(0—40cm)产流与当地大气降水的季节变动基本一致,雨前土壤水对该层壤中流产流的平均贡献率为39.90%,表明其主要受到大气降水的驱动,与坡中金露梅灌丛根系和土壤孔隙分布有关。同时,随着雨前含水量、降水量和降水特征的不同,雨前土壤水和大气降水对于壤中流的贡献特征也会发生变化。Based on the study about the water sources of subsurface flow in alpine meadow of the Qinghai Lake basin,the mechanism of subsurface flow generation in alpine meadow system of the Qinghai Lake basin was expected to be revealed.This paper collected δ^（18）O andδD of atmospheric precipitation,soil water and subsurface flow,as well as the observed atmospheric precipitation data,to make a comparative analysis of hydrogen and oxygen isotopic characteristics of atmospheric precipitation,soil water and of subsurface flow,and used the second source linear mixed models to calculate the water sources of subsurface flow.The results showed that the slope（8.72）and intercept（25.09）of LMWL（local meteoric water line）were evidently larger than those of GMWL（global meteoric water line）;the relatively lower d-excess values and δ^（18）O were observed in months with small precipitation amount;the sources of subsurface flow were closely related to topography and soil depth,and the specific performances were as follows：（1）The hydrogen and oxygen isotope values of subsurface flow relatively aggregated in the upper layer（0—40cm）and lower layer（40—80cm）of downslope soil,and showed obvious characteristics of evaporation and enrichment,which indicated that this part of the subsurface flow mostly came from the water that stored in soil before the rain,and the average contribution rates of the soil water before rain for subsurface flow in the upper layer（0—40cm）and lower layer（40—80cm）of downslope soil were 85.88% and 83.48%,respectively;（2）The water sources of middleslope subsurface flow varied with the soil depth,and the average contribution rate of the soil water before rain for subsurface flow inthe lower layer（40—80cm）of soil was 57.59%,which indicated that the contributions of atmospheric precipitation and soil water before rain were equal.The seasonal changes ofδ^（18）O andδD of middleslope subsurface flow in the upper layer（0—40cm）of soil were similar with tho

关 键 词：青海湖流域 高寒草甸坡地 氢氧同位素 壤中流 土壤水 

分 类 号：P641.3[天文地球—地质矿产勘探]