Temporal and Spatial Variations of Precipitation δ18O and Controlling Factors on the Pearl River Basin and Adjacent Regions

Based on the precipitation delta O-18 values from the datasets of the Global Network of Isotopes in Precipitation (GNIP), the National Centers for Environmental Prediction/National Center for Atmospheric Research (NCEP/NCAR) Reanalysis data, and previous researches, we explored the temporal and spatial variations of precipitation delta O-18 in a typicalmonsoon climate zone, the Pearl River basin (PRB), and adjacent regions. The results showed that the temporal variations of precipitation delta O-18 for stations should be correlated with water vapor sources, the distance of water vapor transport, the changes in location, and intensity of the intertropical convergence zone (ITCZ) rather than "amount effect." Meanwhile, local meteorological and geographical factors showed close correlations with mean weighted precipitation delta O-18 values, suggesting that "altitude effect" and local meteorological conditions were significant for the spatial variations of precipitation delta O-18. Moreover, we established linear regression models for estimating the mean weighted precipitation delta O-18 values, which could better estimate variations in precipitation delta O-18 than the Bowen and Wilkinson model in the PRB and adjacent regions.