The study looked at how different sources of water vapor and local evaporation affect the isotopic composition of rainwater. They collected rain samples from four sites in 2016 and found that the isotopic composition of rainwater varied between summer and winter due to different water vapor sources. During summer, evaporation from Lake Taihu influenced the isotopic composition of rainwater, while in winter, local evaporation had less impact. The researchers also found that the isotopic composition of rainwater in the study area differed from the global average due to moisture recycling and varying water vapor sources between seasons.