摘要
大气降水中δD、δ^(18)O值具有规律性变化特征,与诸多气象要素及水汽来源之间存在密切联系.根据2009年1月至2011年12月对滇南蒙自地区大气降水的连续性采样,结合欧洲中期数值预报中心(ECMWF)以及美国国家环境预报中心/美国国家大气研究中心(NCEP/NCAR)的再分析资料,并利用HYSPLIT_4.8后向轨迹追踪模型,分析了天气尺度下蒙自地区大气降水中δD、δ^(18)O的变化特征,探究了降水稳定同位素与温度、降水量、风速及水汽来源之间的关系.结果表明,蒙自地区降水中δD、δ^(18)O值表现出明显的季节变化,即干季偏高,湿季偏低;降水中δ^(18)O与温度、降水量之间存在显著负相关,但与不同气压层(300、500、700、800 h Pa)风速之间呈现出显著正相关,表明风速也是影响降水中δ^(18)O变化的一个重要因素;随着降雨等级的增加,其大气水线的斜率与截距也增大,说明降水稳定同位素存在一定程度的云底二次蒸发效应;水汽输送轨迹显示,干季降水的水汽主要来自于西风带输送及局地再蒸发水汽,而湿季降水的水汽主要来源于远源海洋水汽的输送,并且在受台风影响期间,降水中δD、δ^(18)O值更加偏负.
The δD and δ^18Ovalues in precipitation have disciplinary variations,and they have close connections with meteorological parameters and moisture sources. Based on the continuously collected precipitation samples in Mengzi from Jan. 2009 to Dec. 2011,the reanalysis data from the European Centre for Medium-Range Weather Forecasts（ ECMWF） and the National Centre for Environmental Prediction / National Centre for Atmospheric Research（ NCEP / NCAR）,and the Hybrid Single-Particle Lagrangian Integrated Trajectory for 4. 8（ HYSPLIT4. 8） model,we analyzed the variations of δD and δ^18Oin precipitation at synoptic scale in Mengzi,and the relations between δ^18Oin precipitation and air temperature,δ^18Oin precipitation and amount,δ^18Oin precipitation and wind speed,δ^18Oin precipitation and moisture sources. The results showed that the variations of δD and δ^18Ovalues in precipitation exhibited remarkable seasonal variability. The stable isotopic values in precipitation were higher during dry season than those during wet season. The relations between δ^18Oin precipitation and air temperature,δ^18Oin precipitation and amount indicated significant negative correlations. However,it exhibited significant positive correlation between precipitation δ^18Oand wind speed at different pressure levels（ 300 hPa,500 hPa,700 hPa,and 800 hPa）,and this result indicated that the wind speed was an important influencing factor for the variations of precipitation δ^18O With the increasing rainfall levels,the intercept and slope of meteoric water line also increased,and this phenomenon suggested that there was a secondary evaporation effect under sub-cloud in stable isotopes of precipitation. The backward trajectory model showed that the main moisture sources during dry season came from the westerly and the inland. However,during wet season,the remote ocean vapor was the main moisture source in Mengzi,and the δ^18Ovalues in precipitation were much lower during typhoon period.
出处
《环境科学》
EI
CAS
CSCD
北大核心
2016年第4期1313-1320,共8页
Environmental Science
基金
国家自然科学基金项目(41571021)
水利部水利公益性行业科研专项(201301075-03)
中央高校基本科研业务费专项(020914380011)
江苏省普通高校研究生创新计划项目(KYLX15_0041)
关键词
大气降水
稳定同位素
大气水线
二次蒸发
水汽来源
蒙自地区
precipitation
stable isotopes
meteoric water line
secondary evaporation
moisture sources
Mengzi region
