摘要
以呼伦湖流域为例研究该区域氢氧稳定同位素在不同水体中的分布特征,并探讨氢氧稳定同位素对在该区域水文过程的指示作用.流域湖水、入湖河水、周边地下水水样的氢氧稳定同位素分析结果表明,夏季8月份湖水中的重氢氧稳定同位素比7月份的更加富集.而河水中氢氧稳定同位素在同一时间内的河流沿程上存在明显的差异,下游水体中的氢氧稳定同位素要比上游更加富集.研究区的河水和湖水的δ^(18)O-δD关系特征显示,河水和湖水的δ^(18)O-δD的关系点全部位于当地降水线的右下方,说明流域河水和湖水水体受到明显的蒸发作用.而井水的δ^(18)O-δD的关系点大都靠近当地大气降水线,说明这一区域的地下水主要是大气降水渗入地下形成.利用氢氧稳定同位素分馏过程中的氢氧稳定同位素的比率与剩余水体的关系,并在考虑湿度因子的动力分馏模拟下,计算出河水的剩余水体比例在0.85~0.96之间,而湖水的剩余水体比例在0.71~0.77之间.最后,利用氢氧稳定同位素质量平衡法对呼伦湖多年平均蒸发量进行了估算,估算的湖泊蒸发量结果与实测值相近,相对误差为5.4%,说明方法可靠.氢氧稳定同位素对于研究区域水文过程有着重要的作用,在今后呼伦湖流域水文研究中有着更加广泛的应用空间.
The aim of this paper is to analyze water stable isotopes( δD and δ^(18)O) in Lake Hulun Basin,and to explore the indicative function of stable isotopes in hydrological cycle in this region. The analytical results of lake water,river water and well water around Lake Hulun indicate that there are temporal variations of stable isotopes in lake and river water and spatial variations in river water along the flow path. Furthermore,the relationship between δ^(18)O and δD in lake water,river water and groundwater in Lake Hulun Basin shows the crossing points of lake and river water are located in the lower right of local meteoric water line,suggesting lake water and river water have suffered from evaporation. However,the crossing points of well water are located closely to the local meteoric water line except southwestern area( W1) around the lake,indicating all groundwater except W1 reflects a precipitation origin,and the weird high isotope values in W1 may have connections to the lake water and well water. Using the relationship between stable isotopic ratio in residual water and residual water proportion with consideration of the effect of temperature and humidity,the proportions of modern lake water and river water after evaporation are calculated as 0. 85-0. 96 for river water,and 0. 71-0. 77 for lake water. Obviously,the extent of lake water evaporation is greater than that of river water,with 4%-15% water loss for rivers and 23%-29% water loss for the lake. In addition,the annual lake water evaporation was calculated based on isotopic mass balance method,the low relative error( 5. 4%) compared with measured data indicates this model is appropriate to calculate water evaporation for Lake Hulun. Using stable isotope( δD and δ^(18)O) is an essential method to study on hydrological cycle in a basin,thus stable isotope still has a wide application space in hydrological cycle in Lake Hulun Basin.
出处
《湖泊科学》
EI
CAS
CSCD
北大核心
2018年第1期211-219,共9页
Journal of Lake Sciences
基金
国家自然科学基金项目(51339002
51409288
51509133
51569019)
内蒙古农业大学优秀青年科学基金项目(2014XYQ-10)
国家留学基金委项目(201408150013)联合资助
关键词
氢氧稳定同位素
分馏
蒸发
地下水
水文过程
呼伦湖
Hydrogen and oxygen stable isotopes
fractionation
evaporation
underground water
hydrological process
Lake Hulun
