The study looked at two different rain events in Lanzhou City in 2019 to understand how stable isotopes in rainwater change over short periods. By analyzing rain samples and using a computer model, the researchers found that the isotopes in rainwater can show where the moisture came from and how it moved. They discovered that the isotopes in rainwater can be affected by evaporation and recycling of moisture. The researchers also found that the source of moisture for a rain event can influence the isotopes in the rainwater.