Oxygen and hydrogen isotope analysis of summer and autumn precipitation, Bucheon, Korea

Abstract

Water stable isotope composition of precipitation has been used to understand the global and regional water cycles. To investgate the regional water cycle, previous studies have relied mostly on changes in daily- to monthly-averaged isotope composition of precipitation. Figure 1 displays an isotopic scheme during evaporation and precipitation. In the figure, however, the exact numbers can vary depending on meteorological factors such as temperature and precipitation rate, even within a single rainfall event. In this study, we monitored the changes in water isotope composition over the course of rainfall events. The results showed that the δD and δ18O values varied widely from -11.94‰ to -2.18？‰ and from -91.44‰ to -14.40？‰, respectively. The δD-δ18O slope for entire samples was 8.18, but those for single events were 6.51, 7.43 and 9.93. Our study stresses the need for high-resolution sampling of precipitation to better understand the regional water cycle.