Isotopic signals of different rainfall types revealed by intra-event rainfall analysis

The precipitation types (convective, stratiform, and mixed precipitation) are related to different atmospheric processes. To understand the isotopic characteristics of different types of precipitation, we collected 121 intra-event precipitation samples in Lanzhou of China from June to October 2021. These precipitation events were divided into mixed precipitation and stratiform precipitation using radar images. In the mixed precipitation events, the δ 1 8 O values show a similar variation trend. In contrast, the δ 18 O values of stratiform precipitation events have no coherent trend and are associated to local meteorological factors. The slope and intercept of local meteoric water line indicate that stratiform precipitation is more susceptible to evaporation. Our results provide observational constraints for understanding of isotope variations in different types in mid-latitude semi-arid region.