艾比湖流域降水、地表水和地下水稳定同位素特征

Stable isotopes characteristics of precipitation,surface water and groundwater in Ebinur Lake Basin

选取艾比湖流域降水、地表水和地下水为研究对象,结合流域水文地质资料,利用野外调查、室内试验和统计分析等方法分析了流域不同水体氢氧稳定同位素的时空变化特征。结果表明:(1)艾比湖流域降水δ^(2)H和δ^(18)O变化范围分别为-148.2‰~-34.5‰和-20.16‰~1.20‰,流域大气降水线斜率为6.69。降水δ^(18)O值与气温呈正相关关系,与降水量在夏季表现出显著的负相关关系。(2)地表水δ^(2)H和δ^(18)O变化范围为-101.0‰~-17.0‰和-14.54‰~0.29‰,其中8月最大,其次为5月和10月。博尔塔拉河同位素值从上游到下游沿流程逐渐增加,而精河沿流程变化趋势不明显,河水δ^(18)O与气温存在正相关关系。(3)地下水δ^(2)H和δ^(18)O值的范围分别为-85.0‰~-65.5‰和-12.18‰~-9.05‰,平均值分别为-75.5‰和-11.00‰。博尔塔拉河区地下水同位素值从上游到下游沿流程逐渐增加,精河区沿流程变化趋势不明显。艾比湖流域水体稳定同位素的测定,为阐明流域水文过程提供同位素证据,对变化环境下有效利用水资源,维护流域生态安全具有重要意义。

The study considered the precipitation,surface water,and groundwater of the Ebinur Lake Basin,Xinjiang,China as the research object.Combining the hydrogeological data,the temporal and spatial variation characteristics of hydrogen and oxygen isotopes of different water bodies in the basin were analyzed using field study,laboratory tests,and statistical analysis.The results show that:(1)the δ^(2)H and δ^(18)O of precipitation in the Ebinur Lake Basin range from −148.2‰ to −34.5‰ and −20.16‰ to 1.20‰,respectively.The slope of the local meteorological water line is 6.69,precipitation δ^(18)O has a significant positive correlation with air temperature and a negative correlation with precipitation in summer.(2)Surface water δ^(2)H and δ^(18)O vary from −101.0‰ to −17.0‰ and −14.54‰ to 0.29‰,with the largest change in August,followed by May and October.The isotopic value of the Bortala River gradually increases from upstream to downstream,but the change in the trend of the Jinghe River is not obvious. δ^(18)O is positively correlated with temperature and negatively correlated with altitude.Compared with river water,the isotopic values of lake water increase significantly in different seasons,reflecting the high evapotranspiration and concentration of lake water.(3)The groundwater δ^(2)H and δ^(18)O range from −85.0‰ to −65.5‰ and −12.18‰ to −9.05‰,respectively,and the average values are −75.5‰ and −11.00‰,respectively.The isotopic value of groundwater in the Bortala River region increases gradually from upstream to downstream,but it is not obvious in the Jinghe River region,which can be attributed to the different recharge sources and evaporation intensity in different sections of the river.The determination of stable isotopes in the Ebinur Lake Basin provides a basis for clarifying the hydrological process of the basin,which is of great importance for the effective use of water resources and the maintenance of ecological security in the face of environmental changes.