黑河流域大气降水稳定同位素变化及模拟  

Variations and Simulation of Stable Isotopes in Precipitation in the Heihe River Basin

作　　者：吴锦奎[1,2,3] 杨淇越[4] 丁永建[1] 叶柏生[2] 张明泉[4] 

机构地区：[1]中国科学院寒区旱区环境与工程研究所寒旱区流域水文与应用生态实验室,兰州730000 [2]中国科学院寒区旱区环境与工程研究所冰冻圈科学国家重点实验室,祁连山冰川与生态环境观测研究站,兰州730000 [3]Institute for Landscape Ecology and Resources Management,Justus-Liebig-University Giessen,Giessen 35392,Germany [4]兰州大学资源与环境学院,兰州730000

出　　处：《环境科学》2011年第7期1857-1866,共10页Environmental Science

基　　金：国家重点基础研究发展规划(973)项目(2007CB411502);冰冻圈科学国家重点实验室开放基金项目(SKLCS2010-10);中日合作项目(黑河流域水文过程研究项目)

摘　　要：利用2002～2004年黑河流域6个采样点上的301个降水数据,对黑河流域大气降水中δD和δ18O的变化进行了分析.结果表明,流域降水δ18O和δD的变化范围分别为6.5‰～-33.4‰和59‰～-254‰,这主要是由于降水水汽来源不同和气象条件特别是气温和降水量的较大变化使得降水形成的凝结机制发生变化引起;降水中同位素的变化和气温之间呈现出非常明显的正相关关系,即温度效应明显;在月时间尺度上,降水量效应是不存在的,但在降水事件尺度上,存在降水量效应;δ18O加权平均值随着采样点海拔高度增加而降低,呈现出较好的高度效应,效应梯度为-0.47‰/100 m;区域大气降水线(RMWL)为δD=7.82δ18O+7.63,其斜率和截距与中国北方地区接近;后向轨迹法追踪黑河流域水汽来源结果表明,冷季(10～次年3月)水汽主要来源于西风带而暖季(4～9月)的水汽来源复杂;模拟显示,δ18O随时间呈现明显的正弦趋势.To study the variations of δD and δ^18O in precipitation,301 samples were sampled during 2002-2004 in 6 sites in the Heihe River basin,Northwestern China.The δD and δ^18O values ranged from 59‰ to-254‰ and 6.5‰ to-33.4‰,respectively.This wide range indicated that stable isotopes in precipitation were controlled by different condensation mechanisms as a function of air temperature and varying sources of moisture.δ^18O in precipitation had a close positive relationship with the air temperature,i.e.,a clear temperature effect existed in this area.At a monthly scale,no precipitation effect existed.On the other hand,a weak precipitation effect still accrued at precipitation events scale.The spatial variation of δ18O showed that the weighted average δ18O values decreased with the increasing altitude of sampling sites at a gradient of-0.47‰ /100m.A regional Meteoric Water Line,δD=7.82 δ^18O＋7.63,was nearly identical to the Meteoric Water Line in the Northern China.The results of backward trajectory of each precipitation day at Xishui showed that the moisture of the precipitation in cold season（October to March） mainly originated from the west while the moisture source was more complicated in warm season（April to September）.The simulation of seasonal δ^18O variation showed that the stable isotope composition of precipitation tended to a clear sine-wave seasonal variation.

关 键 词：稳定同位素 大气降水 温度效应 降水量效应 模拟 内陆河流域 

分 类 号：X169[环境科学与工程—环境科学]