To better understand the source changes and the response of river water to climate change, waters in mainstream and tributaries in Yellow River Basin were sampled from July to August 2012, and temporal and spatial variations of hydrogen and oxygen isotope values in water samples were analyzed. The results showed that (1) Excluding source water, the values for hydrogen, oxygen isotope, andd excess in mainstream waters in Yellow River ranged from-97.2‰ to-62.9‰ with mean value of-72.2‰, and from-13.0‰ to-8.7‰ with mean value of-9.9‰, and from 4.1‰ to 11.0‰ with mean value of 7.0‰, respectively. For tributary water, the values for hydrogen and oxygen isotope varied from-103.8‰ to-30.5‰ with mean value of-68.9‰ and from-13.7‰ to-1.5‰ with mean value of-9.2‰, respectively, and thed excess varied between-18.5‰ and 13.2‰ with mean value of 4.5‰; (2) The hydrogen and oxygen isotope values in water from the upper-stream of Lanzhou station and middle-stream of Yellow river were more negative than those of water from upper-stream between Lanzhou station and Toudaoguai station and the low-stream, while thed excess values decreased gradually along the flow path; (3) The Na+/Cl- molar ratios varied from 0.94 to 3.02. The mean value of Na+/Cl- molar ratio was 1.02 in source water, and 1.58 in mainstream water above Lanzhou station, and 1.30 in mainstream water between Lanzhou station and Toudaoguai station, and 1.79 in middle-stream water and 1.41 in low-stream water. The negative correlation between Na+/Cl- molar ratio and oxygen isotope values of river water indicated that the Yellow River waters were mainly controlled by atmospheric deposition, groundwater recharge and evaporation; (4) Compared with results of previous studies, it was found that since 2000, the annual water flux of Yellow River increased gradually, the second-evaporation effect on the upper-stream river water decreased, and the evaporation effect on middle and low stream water also decreased, indicating that the climate in Yellow River Basin was becoming less dry.%于2012年7~8月采集黄河流域干流和支流河水样品,通过分析水体氢氧同位素组成的时间和空间变化特征,研究了河水主要来源的变化以及其对流域气候变化的响应.结果表明:除源头河水外,黄河干流河水δD值变化范围为-97.2‰~-62.9‰,均值为-72.2‰,δ18O值范围为-13.0‰~-8.7‰,均值为-9.9‰,d盈余值为4.1‰~11.0‰,均值为7.0‰;支流河水δD值范围为-103.8‰~-30.5‰,均值为-68.9‰,δ18O值范围为-13.7‰~-1.5‰,均值为-9.2‰,d盈余值为-18.5‰~13.2‰,均值为4.5‰.黄河干流兰州段以上以及中游河水氢氧同位素均值均偏负,而兰州至头道拐和下游河水氢氧同位素均值偏正,但河水氘盈余均值呈现由上游到下游逐渐降低的趋势.黄河干流和支流河水Na+/Cl-摩尔比值范围为0.94~3.02,源头区黄河干流河水Na+/Cl-摩尔比均值为1.02,兰州段以上均值为1.58,兰州至头道拐间均值为1.30,中游均值为1.79,下游均值为1.41.河水Na+/Cl-摩尔比值与河水δ18O值呈较好的负相关关系,表明黄河河水受大气降水补给,地下水补给以及蒸发作用等控制.与前人研究结果对比发现,2000年以来黄河河水年径流量逐渐增加,上游河水受二次蒸发过程影响在降低,中游和下游河水受蒸发作用影响在减弱,显示区域气候干旱状况有所降低.
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