ENSO事件对上海降水中氢氧同位素变化的影响

Influence of ENSO Events on the Hydrogen (δ~2H) and Oxygen (δ^(18)O) Isotopic Values of Precipitation in Shanghai

根据2012年1月至2017年2月上海206个降水样品实测数据,结合全球大气降水同位素网络(GNIP)提供的南京、武汉、福州、香港1961~2012年大气降水同位素数据分析不同强弱程度的ENSO事件对降水中同位素组成影响的差异性.研究时段内上海降水中δD与δ^(18)O夏秋为低值,冬春为高值.El Nino事件期间大气降水线的斜率与截距均大于非El Nino事件期间,La Nina事件期间反温度效应、降水量效应、水汽压效应较非La Nina事件期间显著.不同强弱程度的El Nino和La Nina事件影响下的上海降水中δ^(18)O、d值与海洋尼诺指数(ONI)、海表温度距平值(SSTA)、ONI极值、累积值ΣONI这4个指数具有明显的负相关关系,并且降水中δ^(18)O与ONI、SSTA两个指数相关性大小受ENSO事件的影响较大.

An analysis of the effect of ENSO events with different strengths on the isotopic composition of precipitation is conducted based on test data for 206 precipitation samples collected from January 2012 to February 2017 in Shanghai coupled with the archives for Nanjing, Wuhan, Fuzhou, and Hong Kong from 1961 to 2012 from the Global Network of Isotopes in Precipitation （GNIP） database. During the research periods, the δD and δ18O values in precipitation are lower in summer and autumn but higher in winter and spring. The slope and intercept of the atmospheric precipitation lines during El Ni-o events are larger than during other times, while anti-temperature, precipitation amount, and vapor pressure effects are more significant than during La Ni-a events. The δ18O and deuterium excess values （value of d） of rainfall in Shanghai during El Ni-o and La Ni-a events of varied strengths have an obvious negative correlation with the oceanic Ni-o index （ONI）, sea surface temperature anomaly （SSTA）, and the extreme and cumulative values of ONI. Moreover, ENSO events are closely intertwined with the correlation between δ18O isotopic value in precipitation, ONI, and SSTA.