上海地区大气水汽氢氧同位素特征及其环境意义  

Characteristics of hydrogen and oxygen isotope in water vapor and its environmental significance in Shanghai

作　　者：杨言[1] 陈雪莹 朱志鹏[1] 周立旻[1] 郑祥民[1] YANG Yan;CHEN Xueying;ZHU Zhipeng;ZHOU Limin;ZHENG Xiangmin(Key Laboratory of Geographic Information Science of the Ministry of Education,School of Geographical Sciences,East China Normal University,Shanghai 200241,China)

机构地区：[1]华东师范大学地理科学学院,地理信息科学教育部重点实验室,上海200241

出　　处：《地球环境学报》2021年第3期288-300,共13页Journal of Earth Environment

基　　金：国家自然科学基金项目(40701195,41271054,41571040)。

摘　　要：大气水汽作为降水的前体物质,对降水同位素有直接的影响,且水汽同位素研究相对于降水有其独特的优势,因此研究大气水汽的同位素组成对分析本地水汽来源及本地蒸发贡献具有重要的意义。本研究使用低温冷阱法,采集了上海地区2019年冬、春、夏三季的大气水汽,并对水汽氢氧同位素进行测试,分析了D、18O和17O的分布特征,并探讨了环境因素与同位素值的关系。结果表明:上海地区大气水汽氢氧同位素值的季节变化小于降水氢氧同位素;水汽同位素值在冬、春季节与绝对湿度的相关性较好,而在夏季不明显;水汽同位素中δ18O和δD拟合曲线斜率与截距,依次为冬季<春季<夏季,水汽氘盈余(d)值明显高于降水d值,且与相对湿度负相关,相关性冬高夏低;δ18O和δ17O基本符合质量分馏效应,但在冬季略有异常;δD实测值与平衡分馏理论值的差异不大,δ18O的实测值小于理论值,d值实测值明显大于理论值且二者差值与相对湿度有一定的负相关关系。上海地区冬季水汽来源以本地蒸发为主,而夏季受东南及西南季风影响,水汽主要来自海洋输送。Background,aim,and scope As the atmospheric water vapor is the main source of precipitation,water vapor isotope has a direct impact on precipitation isotope.The research on hydrogen and oxygen isotopes of atmospheric water vapor can directly reflect the isotopic transformation mechanism in the process of water circulation and has the unique advantages that isotopes of precipitation do not have.The precipitation isotope characteristics of Shanghai were different from those of other regions,and the seasonal fluctuation was also obvious,especially the hydrogen and oxygen isotopes of winter precipitation were significantly heavier.Therefore,further analysis of atmospheric water vapor in Shanghai area and exploration of seasonal variation characteristics of water vapor isotopes were of great significance for in-depth understanding of the source of water vapor in this region and local evaporation contribution.Materials and methods The atmospheric water vapor in Shanghai in winter,spring and summer of 2019 was collected by using an AWVCT04 four channels low-temperature cold trap with the air velocity at 1 L∙min−1.The sampling interval was 3 h in winter and 2 h in spring and summer.TheδD,δ18O,δ17O values of water vapor were measured by an LGR Liquid-Water Isotope Analyzer and their distribution characteristics were analyzed,along with the relationship between environmental factors and isotope values,which were calculated by the SPSS software.Results The average values ofδD,δ18O,δ17O and deuterium excess(d)in winter(2 sampling periods)were−105.36‰±7.92‰,−17.84‰±1.57‰,−9.30‰±0.83‰,37.37‰±6.20‰and−111.43‰±6.62‰,−18.09‰±1.20‰,−9.61‰±0.69‰,−33.32‰±3.86‰.The average values ofδD,δ18O,δ17O and d in spring were−94.26‰±17.70‰,−15.17‰±2.59‰,−8.06‰±1.37‰,27.08‰±5.51‰.The average values ofδD,δ18O,δ17O and d in summer were−115.08‰±14.78‰,−17.60‰±1.98‰,−9.28‰±1.04‰,−25.75‰±3.38‰.Discussion The results showed that

关 键 词：氢氧同位素 大气水汽 降水 水循环 上海地区 

分 类 号：P426[天文地球—大气科学及气象学]