呼图壁河流域水体氢氧稳定同位素特征及转化关系

在气候变化和人类活动影响下，水资源短缺是干旱区面临的一个严峻问题.解决问题的关键是要深入了解干旱区独特的水循环机理，而分析不同水体中氢氧同位素特征及转化关系，是应用同位素示踪技术研究水循环机理的基础。以呼图壁河流域为研究区，分析了大气降水、河水、地下水和积雪融水氢氧同位素变化特征及不同水体的δD~δ¹⁸O关系，探讨了地表水对地下水的补给关系。结果表明：呼图壁河流域大气降水、河水、地下水和积雪融水中δD、δ¹⁸O的组成和季节变化差异较大，δD值分别为-86.25‰、-66.66‰、-69.82‰和-150.79‰，而δ¹⁸O值依次为-12.42‰、-9.94‰、-10.23‰和-19.42‰；河水受大气降水和冰雪融水的混合补给导致同位素的贫化，积雪融水主要受蒸发的影响导致同位素的富集，而河水和积雪融水对地下水有密切的水力联系，导致地下水同位素的贫化；呼图壁河上游地区河水对地下水的补给仅占到18.45%，而中下游区域的地下水补给占到90%以上。

Characteristics of Water Stable Isotopes (18O and 2H) in the Hutubi River Basin,Northwestern China

Water resources are the most critical factors to ecology and society in arid basins, such as the Hutubi River Basin. Isotope technique was convenient to trace this process and reveal the in uence from the environment. In this paper, we try to investigate the temporal and spatial characteristics in stable isotope (¹⁸O and D) of surface water and groundwater in the Hutubi River. Through the water stable isotope composition measurement, the characteristics of deuterium (δD) and oxygen 18 (δ¹⁸O) were analyzed. It is revealed that:(1) comparing the stream water line with the groundwater line and local meteorological water line of Urumqi, it is found that the contribution of precipitation to surface water in stream runoff is the main source, whereas the surface water is the main source of groundwater. Groundwater is mainly drainage of surface runoff in the river; (2) in the main stream of the Hutubi River, the spatial variability of river water showed a heavier-lighter-heavier' change along with the main stream for δ¹⁸O, and temporal variability showed higher in summer and lower in winter; (3) the δ¹⁸O value of Precipitation, surface water; groundwater and snowmelt were -12.42‰, -9.94‰, -10.23‰ and -19.42‰, respectively. the δ²H values of Precipitation, surface water; groundwater and snowmelt were -86.25‰, -66.66‰, -69.82‰ and -150.79‰, respectively.