Water vapor and precipitation isotope ratios in Beijing, China

摘要

The objective of this study is to investigate the characteristics of SD,10Oanddeuterium excess (d) of precipitation and water vapor in surface air in Beijing, China. TheSD, 6180, and d of atmospheric water vapor in surface air were measured continuouslywith an in situ technique. Much less day-to-day and diurnal variations in the vaporisotopic contents wereobserved in the summer monsoon season (June–August) than inthe rest of the year. Outside the monsoon season, the vapor SD and 6180 showed a loglinear dependence on the vapor mixing ratio, and d showed a negative correlation withthe local relative humidity (RH). Both relationships were statistically significant. Thevapor mixing ratio and RH were poor predictors of the vapor isotopic temporal variabilityduring the peak summer monsoon activities. In addition, an analysis was presented ofthe interaction of the isotopic exchange between the vapor and the condensed phase. TheSD and 6180 departure from the equilibrium state was positively correlated with RH, andthe d departure from the equilibrium state was negatively correlated with RH.