祁连山古浪河流域径流组分特征

为了探究气候变暖、冰冻圈急剧萎缩背景下祁连山内陆河的水文状况，依据古浪河流域所采集的各类水体样品和相关观测数据，分析了各水体稳定同位素特征及其所指示的环境意义，并进行了径流分割。结果表明：（1）与降水相比，河水稳定同位素年际变化较小，从季节变化角度来看，河水δ¹⁸O值夏季 > 秋季 > 春季 > 冬季，反映了不同季节蒸发强度的差异。（2）泉水稳定同位素特征与河水相似，年际变化较为稳定，表明山区河水与泉水之间可能存在转换过程。（3）由于土壤水分交换、地表土壤蒸发、植被蒸腾以及土壤水和地下水之间的同位素差异，引起土壤水同位素组成的梯度差异比较明显，土壤水δ¹⁸O由地表向下经历了富集―贫化―富集的过程，d-excess变化则与之相反。（4）径流分割结果显示大气降水对古浪河流域出山径流的补给率高达76%±2.4%，冻土层上水补给为24%±2.4%。

Characteristics of runoff components in the Gulang River basin of the Qilian Mountains

In order to explore the hydrology of inland rivers in the Qilian Mountains under the background of global warming and cryosphere shrinking,based on the samples of various waters collected in the Gulang River basin and relevant observation data,the stable isotope characteristics of each water and the environmental significance indicated by them were analyzed,and runoff segmentation was conducted. The main conclusions are as follows:(1)Compared with that in precipitation,the annual variation of stable isotope in river is relatively small. The value of δ¹⁸O in river is in summer > in autumn > in spring > in winter,reflecting the difference of intensity in various seasons. (2)The stable isotope characteristics of spring water are similar to those in river which the annual variation is relatively stable,showing that there are many conversion processes between river water and spring water in mountainous areas. (3)Due to the isotope differences among soil water recharge,surface soil evaporation and vegetation transpiration,as well as between soil water and ground water,the gradient differences of soil water isotope composition are relatively obvious. (4)The result of the segmentation of runoff of the mean runoff shows that the recharge ratio of precipitation in the Gulang River basin is up to 76%±2.4%, and that of supra-permafrost water is 24%±2.4%.