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

摘要: 根据青藏高原中部那曲河流域1998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.河水中δ¹⁸O与流域降水中δ¹⁸O的差异可能反映了该流域强烈的地表和湖面蒸发作用.

Abstract: The stable isotope hydrological processes in Naqu River basin,middle of the Tibetan Plateau, was studied based on the observations of δ¹⁸O in both river water and precipitation during the summer in 1998. The fluctuation amplitude of δ¹⁸O is much smaller in river water than in precipitation. The variation of δ¹⁸O in river water is a combined effect of δ¹⁸O 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 δ¹⁸O in river water and lake water reflects the strong soil surface and lake surface evaporation in the research basin.