摘要
大气降水中δD、δ18 O主要受到温度、纬度、高程、降雨量等多种环境因素影响。通过对桂林地区2010年大气降水进行δD、δ18 O分析测试,获得δD的分布范围:29.05‰～-96.27‰;δ18 O的分布范围:-0.2‰～-12.96‰。研究结果表明桂林地区大气降水的δ18 O与所受季风类型存在明显联系:由于夏季研究地区主要受到东亚(东南)夏季风影响,水汽团在运移过程中因强烈降水导致水汽中δD、δ18 O连续被贫化,其结果是夏季降水的δD、δ18 O普遍偏轻于冬季降水。通过建立该地区大气降水线方程:δD=8.87δ18 O+15.49,揭示出该区域温润多雨的气候特征。此外,过量氘(d=δD-8δ18 O)在夏季和冬季呈现不同的变化特征指示了研究区夏季大气降水水汽源主要来源于低纬度海洋,而冬季大气降水水汽源主要为内陆或者局地蒸发和冬季风(西风带)的输送。该研究结果为解译石笋和洞穴滴水中所蕴含的环境信息提供有力的科学依据。
This study investigated the factors controlling the δ18O composition of the precipitation in Guilin. Daily precipitation samples for stable isotope analysis were collected in Guilin during 2010. The stable isotope （6D and 6-80） in precipitation displayed obvious spatial and temporal variation,and thus could be used for providing： （1）the best natural tracer for studying the hydrological cycle; （2）the ambient temperature and amount at time of precipitation; （3）the ground surface elevation; （4）the distance between precipitation event and its water vapor source region in the ocean; （5）water vapor source migration pathway. Empirical relations between isotope of precipitation and climate were used in numerous studied aimed to reconstructing past climate from various environmental archives. 6D and δ18O in atmospheric precipitation were tested and analyzed,and the results showed： the values of 6D distribution ranged from 29.05% to 96.27%;δ18O values distribution ranged from -0. 2% to --12.96%0. The tested result of stable isotope showed significantly seasonal variability. The research results indicated that there was a significant relationship between δ18O values and the types of monsoon winds. δ18O values of the researched area were mainly affected by summer monsoon of east and southeast area in summer. During the transportation of atmospheric precipitation,the 6D and δ18O in vapor caused by intense precipitation became more negative. Thus,6D and δ18O values of precipitation in summer were more negative excursion than that in winter. The Local Meteoric Water Line：SD=8. 87818Oq-15.49 was established by using the relationship between 6D and δ18O. This result re- flected climate character of Guilin： the warm and rainy. In addition, Deuterium Excess （d=SD--88180）presented different characters during summer and winter. At the same time,the equation showed that in the researched area, the vapor source of atmospheric precipitation were mainly from ocean of low latitude in summer,while in winter the vapor source of atmospheric precipitation were mainly from the evaparation of inland and part areas and the transportation of winter monsoon（westerlies）. In 2010,the δ18O value of atmospheric precipitation in September was more negative than that in June. This result indicated summer monsoon was extremely strong in September. But the total precipitation in September was far less than that in June. The reason might be that summer wind was strong and caused atmospheric precipitation zone reached to monsoon marginal zone. All of this contributed to the relatively decrease of atmospheric precipitation in the researched area. This study provides significant information to understand present-day seasonality of precipitation and its isotopic composition in Guilin,and strong scientific basis for constructing environment temperature with the use of stalagmites and dripping water.
出处
《长江流域资源与环境》
CAS
CSSCI
CSCD
北大核心
2013年第2期182-188,共7页
Resources and Environment in the Yangtze Basin
基金
中国地质科学院重点开放实验室专项资金(2010-sys-14)
国家自然科学基金项目(40772216)
广西青年科学基金项目(桂科青0640076)
科技部所控项目(200903)
中国地质调查项目(水[2010]矿评03-06-02)
中国地质科学院岩溶地质研究所基金(2012006)联合资助
关键词
大气降水
氢同位素
氧同位素
季节性变化
precipitation
hydrogen isotope
oxygen isotope
seasonal variation
作者简介
吴夏（1984-），男，湖北省荆州人，助理研究员，硕士，主要从事同位素地球化学．E—mail：wuxia@karst．ac．cn
