Characteristics of Stable Isotope in Precipitation and Its Relationship with ENSO in Shanghai

A total of 70 precipitation samples were collected from August 2014 to August 2015 in Shanghai and the oxygen and hydrogen isotope of precipitation were analyzed. The relationship between the δ¹⁸O and deuterium excess of precipitation and ENSO events was addressed. The results showed that δD and δ¹⁸O of precipitation in Shanghai were higher in winter and spring than in summer and fall. The slope of meteoric water line with these data was a little smaller than the global meteoric water line. The main reason could be the unbalanced secondary evaporation in the process of precipitation. The correlation between the δ¹⁸O in precipitation and temperature and precipitation varied in different time scales. On a seasonal scale, this work revealed that there was no significant temperature effect in winter, but significant precipitation effect was found in the annual scales, which was obviously affected by the atmospheric circulation. δ¹⁸O values and deuterium excess in precipitation recorded the La Niña and El Niño conversion process. During the La Niña event, the δ¹⁸O and d values were more negative than those in the El Niño event.