Precipitation Stable Isotope Variability in Tropical Monsoon Climatic Zone of Asia

The temporal and spatial variability of precipitation stable isotopes in tropical climatic zone of Asia are analyzed based on the data provided by GNIP during the study period, which is from January 2015 to December 2016. Results indicate that the monsoon activities are the major parameters that control the characteristics of precipitation stable isotopes on both temporal and spatial scale. On the annual scale, the extreme values, average values and the variation ranges of δ18O and d-excess vary considerably among stations, showing differences of the controlling air masses. The monthly variation of δ18O and d-excess have significant regularities, which are strongly correlated to the distance of water transport and the location of moisture sources respectively. The spatial distribution of stable isotopes in months of different seasons is generally consistent with the tropical monsoon circulation during the four seasons, as values decrease along the path of monsoon flow in summer and winter, and show features of transition periods in spring and autumn as a result of barometric movement. It can serve as a useful tool to contribute valuable information for the research of regional monsoon and water circulation.