青藏高原那曲河流域降水及河流水体中氧稳定同位素研究

Study on stable isotope in river water and precipitation in Naqu River basin, Tibetan Plateau

根据青藏高原中部那曲河流域 1 998年夏季测得的上下游中稳定同位素的日变化 ,并与同期观测的流域降水中稳定同位素比较 ,分析了河水中δ18O的变化特征 ,初步研究了该流域的稳定同位素水文循环过程。河水中δ18O的变化幅度远小于降水 ,它是降水中δ18O、降水量以及地表蒸发过程共同作用的结果。研究发现湖水对于稳定同位素变化起着显著的调节作用。

The stable isotope hydrological processes in Naqu River basin, middle of the Tibetan Plateau, was studied based on the observations of δ 18O in both river water and precipitation during the summer in 1998. The fluctuation amplitude of δ 18O is much smaller in river water than in precipitation. The variation of δ 18O in river water is a combined effect of δ 18O in river water, precipitation amount and surface evaporation. The study also found the obvious impact of lake water on stable isotope homogeneity in river water. The difference between the weighted δ 18O in river water and lake water reflects the strong soil surface and lake surface evaporation in the research basin.