Monitoring Surface ¹⁰Be/⁷Be Directly Reveals Stratospheric Air Intrusion in Sichuan Basin, China

Stratospheric air intrusion can break the balance of atmospheric properties such as chemicals and radiation affecting the atmosphere. The meteoric cosmogenic ⁷Be and ¹⁰Be are mainly produced between the lower stratosphere and the upper troposphere and then adsorbed on aerosols for transport, they are good tracers of the atmospheric mass transport. Here, ⁷Be and ¹⁰Be in aerosols were measured simultaneously by accelerator mass spectrometry, and after removing dust ¹⁰Be interference, daily resolution ⁷Be and ¹⁰Be for the whole year in Chengdu (a major city in the Sichuan Basin of China) was obtained. The long-period tracing of stratospheric air intrusion in the Sichuan Basin area is realized by directly observing the surface ¹⁰Be/⁷Be ratio. This work confirms the influence of stratospheric air intrusion on the surface O₃ and atmospheric water vapor in the Sichuan Basin and finds that the stratospheric air intrusion degree in spring and summer is significantly higher than that in autumn and winter. The results indicate that high-resolution ¹⁰Be/⁷Be can provide effective and refined tracers for the atmospheric vertical motion. The new ⁷Be and ¹⁰Be observation records contribute to evaluating the impact on the environment and climate during the stratospheric air intrusion in the Sichuan Basin.