摘要
通过对2011年4月至2012年12月期间重庆市芙蓉洞外大气降水氢氧稳定同位素、降水量、温度和洞穴滴水、池水中δD,δ18 O的连续监测,分析了芙蓉洞地区降水中δD,δ18 O的变化特征及其与ENSO事件和季风指数的关系.当地大气降水线方程的截距和斜率均大于全球大气降水线,大气降水中δD和δ18 O值与大气温度成负相关关系,δ18 O与温度的相关系数为r=-0.693(n=20);与降水量的相关系数为r=-0.121(n=20);过量氘(d)也体现出夏季低冬季高的特点.不同季节的水汽源地差异是导致该地区大气降水中δD和δ18 O值出现季节差异的主要原因.芙蓉洞所在的中国南方季风区大气降水中氢氧稳定同位素组成与ENSO有密切联系.当厄尔尼诺发生时,西太平洋副热带高压势力强盛,西北太平洋季风指数高,导致中国南方地区大气降水中氢氧稳定同位素值偏重;拉尼娜发生时,东南信风强,印度洋季风指数高,降水稳定同位素偏轻.
Continuous monitoring was made over the hydrogen and oxygen stable isotopes,precipitation,temperature andδD andδ18 O in the drip water and pool water in Furong cave,Chongqing,China from April 2011 to December 2012,and the characteristics ofδD andδ18 O variation in precipitation and the correlation with atmospheric circulations,such as ENSO and monsoon index,were investigated in this study.An equation of local meteoric water line（LMWL）was established,which indicated that both its intercept and slope were significantly greater than those of global meteoric water line（GMWL）.In addition,a negative correlation was detected between theδD andδ18 O values of local precipitation and the air temperature.The correlation coefficient betweenδ18 O values and temperature was r=-0.693（n=20）,while the correlation coefficient betweenδ18 O values and rainfall was r=-0.121（n=20）.The seasonal change in deuterium excess（d）values also showed the characteristics of being high in summer and low in winter.All the seasonal changes in d,δD andδ18 O values of precipitation could be attributed to the difference in moisture sources in different months.The hydrogen and oxygen stable isotope compositions in precipitation out of Furong cave,a typical site in Southern China monsoon area,were closely associated with the atmospheric circulation in tropical Pacific Ocean,such as the ENSO.When El Nino occurred,the west Pacific subtropical high（WPSH）became stronger,and the northwest Pacific monsoon index was high,leading to an increase in stable isotope values in precipitation in southern China.On the other hand,when La Nina happened,the southeast trade wind was strengthened and Indian monsoon index was also high,resulting in a decrease in stable isotope values in precipitation.
出处
《西南大学学报（自然科学版）》
CAS
CSCD
北大核心
2015年第9期133-139,共7页
Journal of Southwest University(Natural Science Edition)
基金
国家自然科学基金资助项目(41172165,41030103,41302138)
中央高校基本科研业务费专项资金资助项目(XDJK2013A012,XDJK2009B016,XDJK2014C010)
黄土与第四纪地质国家重点实验室开放基金资助项目(SKLLQG1310)
作者简介
袁娜（1988-），女，山东滨州人，硕士研究生，主要从事第四纪地质学专业方面的研究．
通信作者：李廷勇，副研究员，硕士研究生导师．
