降水滴水的δ18O／δD年季变化及与大气环流的关系--以重庆芙蓉洞地区为例
- 国土资源部/广西岩溶动力学重点实验室 中国地质科学院岩溶地质研究所,广西桂林541004; 西南大学地理科学学院,重庆400715; 国土资源部岩溶生态环境 重庆南川野外基地,重庆408435 国土资源部/广西岩溶动力学重点实验室 中国地质科学院岩溶地质研究所,广西桂林541004; 西南大学地理科学学院,重庆400715 中国气象科学研究院,北京,100081
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．
Annual and Monthly Variations of δD andδ18 O Values in Precipitation and Drip Water and Their Relationship with Atmospheric Circulation---A Case Study in Furong Cave Area
- 国土资源部/广西岩溶动力学重点实验室 中国地质科学院岩溶地质研究所,广西桂林541004; 西南大学地理科学学院,重庆400715; 国土资源部岩溶生态环境 重庆南川野外基地,重庆408435 国土资源部/广西岩溶动力学重点实验室 中国地质科学院岩溶地质研究所,广西桂林541004; 西南大学地理科学学院,重庆400715 中国气象科学研究院,北京,100081
Keywords:
- 季风区 /
- 大气降水 /
- δD /
- δ18O /
- ENSO /
- 季风指数
Abstract: 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 A‐pril 2011 to December 2012 ,and the characteristics of δD andδ18 O variation in precipitation and the corre‐lation 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 nega‐tive 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 cor‐relation coefficient betweenδ18 O values and rainfall was r= -0.121 (n=20) .The seasonal change in deu‐terium 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 mois‐ture 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 atmos‐pheric 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 ,w hen 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 .
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