Song Yang, Wang Sheng-Jie, Zhang Ming-Jun, Shi Yu-Dong
College of Geography and Environmental Science, Northwest Normal University, Lanzhou 730070, China.
Key Laboratory of Resource Environment and Sustainable Development of Oasis, Gansu Province, Lanzhou 730070, China.
Huan Jing Ke Xue. 2022 Jan 8;43(1):199-209. doi: 10.13227/j.hjkx.202104210.
The in-situ monitoring of stable hydrogen and oxygen isotopes (O and H) in precipitation is helpful to understand the processes of water phase change, mixing, and transportation. Due to the arid climate in the eastern Tarim River basin, water resources are the key factor affecting the regional sustainable development. However, the understanding of stable hydrogen and oxygen isotopes in precipitation is still limited for this region. Based on the isotope data of 103 precipitation samples collected at four stations in the eastern Tarim River basin from June 2019 to September 2020, the spatial and temporal characteristics of stable hydrogen and oxygen isotopes in precipitation were analyzed, and the connections between stable isotopes and moisture sources were discussed. The findings provide a reference for the application of environmental isotope tracers in arid areas. The results show that, ① the four sampling stations generally presented an increasing trend in precipitation stable isotopic values from north to south, and the isotopic values were higher in summer and lower in winter. The -excess value in the study region was smaller than the national average, and the slope of the local meteoric water line exhibited a significant arid characteristic. ② There was a positive correlation between precipitation stable isotopes and air temperature in the study region, whereas a weak negative relationship was seen between -excess and air temperature. The negative correlation occurred between O and relative humidity, and the -excess value exhibited a positive correlation with relative humidity. ③ The backward trajectory showed that the eastern Tarim River basin is mainly controlled by the westerlies paths. The proportion of air mass that comes from the middle and short distance is relatively large. The concentration weighted trajectory method showed that the farther from the precipitation sampling site, the more stable the -excess value was. The closer to the sampling site, the more frequently the concentration changed, indicating that the -excess value was greatly affected by the local water vapor recycling.
对降水中稳定氢氧同位素（O和H）进行原位监测，有助于了解水的相变、混合及运移过程。由于塔里木河流域东部气候干旱，水资源是影响区域可持续发展的关键因素。然而，该地区对降水中稳定氢氧同位素的认识仍较为有限。基于2019年6月至2020年9月在塔里木河流域东部4个站点采集的103个降水样品的同位素数据，分析了降水中稳定氢氧同位素的时空特征，并探讨了稳定同位素与水汽源的联系。研究结果为环境同位素示踪剂在干旱地区的应用提供了参考。结果表明，①4个采样站点的降水稳定同位素值总体上呈现出从北向南递增的趋势，且同位素值夏季较高、冬季较低。研究区域的氘盈余值小于全国平均值，当地大气降水线的斜率呈现出明显的干旱特征。②研究区域内降水稳定同位素与气温呈正相关，而氘盈余与气温呈弱负相关。氧同位素与相对湿度呈负相关，氘盈余值与相对湿度呈正相关。③后向轨迹显示，塔里木河流域东部主要受西风带路径控制。来自中短距离的气团比例相对较大。浓度加权轨迹法表明，距离降水采样点越远，氘盈余值越稳定。距离采样点越近，浓度变化越频繁，表明氘盈余值受当地水汽再循环的影响较大。
