南京地区降水稳定同位素场季节尺度变化特征  

Characteristics of stable isotope in precipitation of Nanjing in variable scale

作　　者：刘建伟 孔兴功[1,2,3] 赵侃[1,2,3] 梁怡佳 王权[4] 汪永进 Liu Jianwei;Kong Xinggong;Zhao Kan;Liang Yijia;Wang Quan;Wang Yongjin(School of Geography,Nanjing Normal University,Nanjing 210023,Jiangsu;Key Laboratory of Virtual Geographic Environment(Nanjing Normal University),Ministry of Education,Nanjing 210023,Jiangsu;Jiangsu Center for Collaborative Innovation in Geographical Information Resource Development and Application,Nanjing 210023,Jiangsu;Key Laboratory of Surface Process and Environment Remote Sensing in Three Gorges Reservoir Area,School of Geography and Tourism,Chongqing Normal University,Chongqing 401331)

机构地区：[1]南京师范大学地理科学学院,江苏南京210023 [2]虚拟地理环境教育部重点实验室(南京师范大学),江苏南京210023 [3]江苏省地理信息资源开发与利用协同创新中心,江苏南京210023 [4]重庆师范大学地理与旅游学院,三峡库区地表过程与环境遥感重庆市重点实验室,重庆401331

出　　处：《第四纪研究》2020年第4期1025-1036,共12页Quaternary Sciences

基　　金：国家自然科学基金项目(批准号:41672164、41572151和41571102)资助。

摘　　要：基于1987年6月至1992年12月全球大气降水同位素观测网(GNIP)数据和2015年1月至2019年6月南京地区大气降水的连续采样数据,探究场降水和月降水 δ^18O变化的水汽源指示意义.结果表明,南京地区的降水稳定同位素δD的变化范围为-142.50‰^+42.91‰,δ^18O的变化范围为-19.16‰^+3.94‰,并且利用场降水稳定同位素数据建立了南京地区大气降水方程:δD=7.42δ^18O+8.07(n=330,R^2=0.95).天气尺度上,对单一水汽源场降水氧同位素分析,将水汽来源地主要分为五类(A^E),其降水 δ^18O平均值分别为-3.66‰、-6.65‰、-6.45‰、-1.64‰和-8.97‰;在持续性降水过程中,受雨除效应影响,δ^18O值呈现逐渐负偏的趋势,水汽源地的变化可能使降水δ^18O值波动加剧,其振幅可达11.14‰,而水汽源稳定的降水δ^18O值波动要相对小的多.在月尺度上,降水δ^18O值呈现春季偏正,夏季偏负的特征,d-excess与温度和降水均呈明显反相位关系;这种现象的原因是南京地区不同季节降水水汽来源存在差异,即夏季以印度洋、南海和西太平洋水汽源(B、E类)为主,冬季降水主要来源于欧亚大陆和西风带来的水汽(A、C类),而春季则是西风远源和局地水汽源(C、D类)占优势,这与上述五类降水的 δ^18O具有很好的对应.Nanjing(32.1°N,118.9°E)is located on the lower reaches of the Yangtze River with an average altitude of 26 m.The mean annual air temperature is 16.9℃and the average annual precipitation is 1240 mm.It is strongly influenced by Asia monsoon climate characterized with seasonal variations of the wind reversal and alternation of dry and rainy periods.Temperature,the relative humidity and precipitation are monitored in Nanjing Normal University campus,which is located 13 km northwest from Hulu Cave.Based on 454 stable hydrogen and oxygen isotope data(δ^18O,δD),including 67 data for monthly precipitation from 1987 to 1992 and 387 data for daily and monthly precipitation from 2015 to 2019 in Nanjing,the stable isotope in precipitation and water vapor sources in this region were studied.The values ofδ^18O ranges from-19.16‰to+3.94‰,while values ofδ^18O ranges from-142.50‰to+42.91‰.The established Local Meteoric Water Line(LMWL)δD=7.42δ^18O+8.07(n=330,R^2=0.95)based on 330 obtained samples of separate events is similar to the LMWL of Eastern Monsoon China from previous studies.To study changes in water vapor sources during precipitation events,stable isotope data,NCEP/NCAR data and Hybrid Single Particle Lagrangian Integrated Trajectory(HYSPLIT)backward trajectory results during 87 single-source precipitation events and 18 continuous precipitation events in Nanjing were analyzed.The results indicate that there are five different water vapor types(A^E)for the 87 single-source precipitation events:Eurasia continental vapor,Western Pacific and South China Sea vapor,remote westerly vapor,vicinal vapor and Indian Ocean vapor.The averageδ^18O values of the five types are-3.66‰,-6.65‰,-6.45‰,-1.64‰and-8.97‰.According to the water vapor sources,precipitation events can be classified into 2 types:single-source precipitation events and multi-sources precipitation events.The oscillation amplitude ofδ^18O in multi-sources precipitation events may be much larger than it of the other one.On the monthly scal

关 键 词：南京 大气降水 Δ^18O 水汽源 

分 类 号：P597.2[天文地球—地球化学] P426.6[天文地球—地质学]