多年冻土区风火山流域降水河水稳定同位素特征分析  

Variation characteristics of stable isotopes in precipitation and river water in Fenghuoshan permafrost watershed

作　　者：刘光生[1,2] 王根绪[1] 孙向阳[1,2] 高洋[1,2] 

机构地区：[1]中国科学院成都山地灾害与环境研究所山地表生过程与生态调控重点实验室,四川成都610041 [2]中国科学院大学,北京100049

出　　处：《水科学进展》2012年第5期621-627,共7页Advances in Water Science

基　　金：国家自然科学基金资助项目(40730634;40925002)~~

摘　　要：由于多年冻土区流域土壤冻融过程对水循环影响的复杂性,水循环物理过程观测存在困难和不足,而利用稳定同位素方法可以有效地解决该问题。因此,基于2009年长江源风火山流域夏季定点降水和河水δD和δ18O,对研究区降水河水稳定同位素特征进行分析。结果表明,研究区夏季降水δD和δ18O受到降水量和温度的双重影响,即受海洋性和大陆局地气团的交替影响。河水氢氧同位素的季节变化和空间差异与壤中流、地下水补给河流的季节差异和植被覆盖的空间差异有关。随着地温升高和土壤冻融锋面的迁移,河水补给来源和同位素特征发生改变,表明土壤冻融变化对多年冻土流域径流过程起到重要作用。此外,蒸发分馏作用是研究区河水同位素的重要影响因素。Due to the complexity of the influence of freeze-thaw of active soil layer on water cycle, the hydrological observation is rare and difficult in permafrost watershed. In order to improve hydrological understanding in permafrost watershed, stable isotopes have proven utility since they reflect the integration of processes at smaller scales. There-fore, the spatial-temporal variation of stable isotopes in precipitation and river water of Fenghuoshan permafrost water-shed was investigated, on the basis of variations in stable hydrogen and oxygen isotopes ratios （δD and δ^18O） for pre-cipitation and river water during June to October, 2009. The seasonality of stable isotopes for rain water suggests that tlhe alternative influence of both continental air mass and monsoon air mass to local precipitation. The temporal-spatial distribution of stable isotopes for river water was influenced by the seasonality variation of river recharge from soil water and underground water and spatial difference of vegetation coverage. Along with the migration of freeze-thaw front of active soil layer, the source of river water and the variation characteristics of stable isotopes for river water changed. This suggests that the freeze-thaw of active soil layer plays an important role in rainfall-runoff process in permafrost wa- tershed. In addition, evaporation played important role in the fractionation of water isotopes.

关 键 词：Δ18O 风火山流域 同位素 降水 多年冻土 河水 

分 类 号：P402[天文地球—大气物理学与大气环境]