Spatio-temporal variation of stable isotopes in precipitation in the Heihe River Basin, Northwestern China
Spatio-temporal variation of stable isotopes in precipitation in the Heihe River Basin, Northwestern China
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DOI：
10.1007/s12665-009-0432-7
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发表时间：
2010-02
影响因子：
2.8
通讯作者：
Jinkui Wu;Jinkui Wu;Yongjian Ding;Baisheng Ye;Q. Yang;X. Zhang;Jingzhong Wang
中科院分区：
文献类型：
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作者：
Jinkui Wu;Jinkui Wu;Yongjian Ding;Baisheng Ye;Q. Yang;X. Zhang;Jingzhong Wang
对黑河流域中国西北部6个站点2002年至2004年降水中δD和δ18O的时空变化进行了深入研究。30 1个降水样本的δD和δ18O值分别为+5 9~−2 5 4和+6.5~−33.4‰。δD和δ18O之间的关系定义了一条与中国北部的大气水线几乎相同的受良好约束的线。这一宽广的范围表明，降水中的稳定同位素主要受不同的凝结机制控制，这是气温和不同水汽来源的函数。对习水各降水日的回溯轨迹分析结果表明，冷季(10~3月)降水的水汽主要来自西部，暖季(4~9月)降水的水汽来源较为复杂。对δ~(18)O季节变化的模拟表明，降水的稳定同位素组成呈现明显的正弦波季节变化。δ18O的空间变化表明，加权平均δ18O值随采样点海拔的升高而减小。气温的巨大差异导致凝结机制和局地循环大陆湿度的差异，可能对不同地点降水事件的同位素组成产生影响。
An intensive investigation of the spatial and temporal variations ofδD andδ18O in precipitation was conducted during 2002–2004 in six sites in the Heihe River Basin, Northwestern China. TheδD andδ18O values for 301 precipitation samples ranged from +59 to −254 and +6.5 to −33.4‰, respectively. The relationship betweenδD andδ18O defines a well-constrained line given by, which is nearly identical to the meteoric water line in the Northern China. This wide range indicates that stable isotopes in precipitation were primarily controlled by different condensation mechanisms as a function of air temperature and varying sources of moisture. The results of backward trajectory of each precipitation day at Xishui show that the moisture of the precipitation in cold season (October–March) mainly originated from the west while the moisture source was more complicated in warm season (April–September). The simulation of seasonalδ18O variation shows that the stable isotope composition of precipitation tended to a clear sine-wave seasonal variation. The spatial variation ofδ18O shows that the weighted averageδ18O values decreases with the increasing altitude of sampling sites. The great difference of air temperature which led to the differences of condensation mechanisms and local recycled continental moisture may have influence upon the isotopic composition of rain events in different sites.