Stable isotope record of super typhoon Lekima (2019)

Stable isotope ratios (delta O-18 and delta D) in atmospheric precipitation and water vapor have the potential to diagnose synoptic-scale weather processes. Here we present high-frequency measurements of stable isotopes in water vapor and rainfall during super typhoon Lekima of 2019 in Shanghai, Eastern China. Our results indicate that both water vapor and rainfall exhibit large fluctuations in delta D, with the magnitude of 94.69 parts per thousand and 57.88 parts per thousand, respectively. These fluctuations reflect changes in typhoon-induced atmospheric and precipitation processes. Water vapor content and its dD values before Lekima are generally high due to stable atmospheric conditions that effectively suppress vapor condensation and isotope fractionation. During Lekima, isotope ratios in both water vapor and rainfall are complex and generally follow an inverted U-shaped pattern due to the combined effects of convection intensity, moisture convergence and rain evaporation. After Lekima, dry continental (northerly) air mass and subsidence cause a substantial decrease in both water vapor content and delta D over the study region. Our study sheds light on the influence of super typhoon on isotope behaviors of water vapor and rainfall, and may have some implications for paleoclimate reconstruction of typhoon activity.

Automated summary

This study demonstrates the complex variations in stable isotope ratios in water vapor and rainfall during a super typhoon, showing the influences of convection intensity, moisture convergence, and rain evaporation. After the typhoon, dry continental air masses and subsidence lead to a significant decrease in both water vapor content and delta D values in the study region.