重庆地区大气场降水中氢氧同位素变化特征及与大气环流的关系  

Variations of Stable Isotope in Precipitation and Its Atmospheric Circulation Effect in Chongqing

作　　者：温艳茹 王建力[1] 

机构地区：[1]西南大学地理科学学院,重庆404100

出　　处：《环境科学》2016年第7期2462-2469,共8页Environmental Science

基　　金：国家自然科学基金项目(40971122);重庆市教委项目(yjg122019)

摘　　要：根据2015年4~10月重庆地区61场降水稳定同位素资料与相关气象资料,分析了不同时间尺度下重庆大气降水中氢氧同位素(δD、δ^(18)O)、过量氘(d)的变化特征以及它们与降水量、温度及厄尔尼诺/拉尼娜和南方涛动(ENSO)的关系.结果表明:1研究区大气降水线方程为:δD=8.28δ^(18)O+12.34(r=0.99,n=61),其斜率和截距与中国东部季风区的多处南方地区大气降水线方程的斜率和截距相似.2研究区大气降水中氢氧同位素和d均出现夏半年低、冬半年高的季节变化,影响重庆降水中氢氧同位素变化的主要原因为不同季节降水的水汽来源及气团性质的差异.3监测时段内研究区大气降水中δ^(18)O与温度、降水量相关性不显著(r=0.03;r=0.12),但却敏感响应了大气环流过程,表现出与ENSO正相关.大气降水中δ^(18)O和过量氘(d)清晰记录了2014~2015年LaNia和ElNio的转换过程.ElNio期间研究区域大气降水中δ^(18)O和d明显偏重;而在LaNia期间,δ^(18)O和d偏轻.Variations of hydrogen and oxygen in stable isotopes and deuterium excess in precipitation as well as their relationship with precipitation,temperature and ENSO（ ElNio / LaNia-Southern Oscilation） were analyzed by using 100 daily precipitation stable isotope data from April to October,2015. The result showed that： 1The equation of local meteoric water line（ LMWL） was established： δD =8. 28 δ^（18）O ＋ 12. 34,the intercept and slope of which were greater than the global meteoric water 1ine（ GMWL） but was similar to most of the southern China monsoon region. 2Both stable isotopes and deuterium excess in precipitation indicated obvious seasonal variation in the monsoon region,high in summer and low in winter. This was attributed to the difference in moisture sources in different seasons. 3In addition,no significant correlation was detected between δ^（18）O values in precipitation with temperature and precipitation（ r = 0. 03; r =0. 12）. But it was sensitive to atmospheric circulation effect,and was positively correlated with ENSO. δ^（18）O values in precipitation and deuterium excess in precipitation clearly recorded the LaNia and ElNio conversion process between 2014 and 2015. During the ElNio event,the δ^（18）O and d values became obvious on the high side,and the changes were the opposite during LaNia.

关 键 词：大气降水 Δ18O δD 过量氘 ENSO 重庆地区 

分 类 号：X142[环境科学与工程—环境科学] X16