中国东部地区大气水汽稳定同位素的影响因子追踪研究  

A Tracing Study on Influence Factors of East Asian Stable Isotopes in Atmospheric Water Vapor

作　　者：刘宇佳 满文敏 周天军[1,2] 彭冬冬 Yujia LIU;Wenmin MAN;Tianjun ZHOU;Dongdong PENG(State Key Laboratory of Numerical Modeling for Atmospheric Sciences and Geophysical Fluid Dynamics,Institute of Atmospheric Physics,Chinese Academy of Sciences,Beijing 100029;College of Earth and Planetary Sciences,University of Chinese Academy of Sciences,Beijing 100049;Institute of Tropical and Marine Meteorology,China Meteorological Administration,Guangzhou 510641)

机构地区：[1]中国科学院大气物理研究所大气科学和地球流体力学数值模拟国家重点实验室(LASG),北京100029 [2]中国科学院大学地球与行星科学学院,北京100049 [3]中国气象局广州热带海洋气象研究所,广州510641

出　　处：《大气科学》2023年第3期616-630,共15页Chinese Journal of Atmospheric Sciences

基　　金：国家重点研发计划项目2017YFA0604601;国家自然科学基金项目42075041。

摘　　要：大气水汽稳定同位素是现代水循环的重要示踪剂,可以有效地追踪水汽来源及其输送过程。在中低纬度季风区,局地“降水量效应”是大气水汽稳定同位素的主要特征,但是近期研究表明,水汽来源及其输送过程等非局地因素也有重要影响。因此,本文基于拉格朗日粒子扩散模式和卫星遥感观测的大气水汽稳定氘同位素数据(数值表示为千分差,δD),针对前人研究较少的中国东部石笋氧同位素区域,进行水汽源地追踪,并在季节和年际尺度上分析水汽δD的主要影响因素。结果表明,在季节尺度上,水汽δD在夏末秋初较低,冬春季较高,这种特征与局地气象因子、水汽源地贡献的关系较弱,水汽输送路径上的累积降水是影响水汽δD季节变化的主要因素,两者为显著的负相关关系。在年际尺度上,厄尔尼诺(El Nino)年夏季中国东部水汽δD较高,拉尼娜(La Nina)年夏季水汽δD较低。水汽源地贡献在ENSO(厄尔尼诺—南方涛动)不同位相的变化较小,而水汽输送路径上的累积降水在La Nina年较之El Nino年偏多,表明La Nina年热带对流活动和水汽输送过程的贫化作用更强,导致目标区域的水汽δD更低。因此,代表热带对流活动的累积降水是水汽δD季节和年际变化的主要影响因素,热带对流活动增强(减弱)将降低(增加)目标区域的水汽δD。Stable isotopes in atmospheric water vapor,which can track moisture sources and water vapor transport,are extensively used as a crucial tracer of the present-day water cycle.To interpret water vapor stable isotopes in the mid-low latitude monsoon region,the“amount effect”is invoked.However,recent studies have demonstrated that nonlocal factors,such as moisture sources and water vapor transport,have a significant effect on stable isotopes.Thus,the Lagrangian Particle Dispersion Model and Satellite remote sensing deuterium isotope data(expressed by parts per thousand of their deviation,δD)in water vapor are used to investigate the primary factors affecting water vaporδD in the region with abundant Chinese stalagmiteδ18O records.On the seasonal scale,water vaporδD is more depleted in late summer and early autumn and enriched in winter and spring.This characteristic is difficult to interpret in terms of“temperature effect”or“amount effect.”However,accumulated rainfall over water vapor transport paths is the dominant factor of water vaporδD,and there is a significant negative correlation between them.On an interannual scale,water vaporδD is enhanced in the summer of the El Niño year and depleted in the summer of La Niña year.The contribution of moisture sources to water vaporδD is small;however,the accumulated rainfall over water vapor transport paths increased substantially in the La Niña year compared with the El Niño year.This shows that in the La Niña year,tropical convection and depletion in water vapor transport paths are significant,resulting in depleted water vaporδD in the study area.Finally,on a seasonal to interannual scale,upstream convection,as measured by accumulated rainfall,is the primary driver of water vaporδD variations.In the study area,enhanced convection will depleteδD,whereas the weakened convection will enrichδD.

关 键 词：大气水汽同位素 拉格朗日水汽追踪 水汽源地贡献 对流活动 

分 类 号：P467[天文地球—大气科学及气象学]