To what extent can the ozone valley over the Tibetan Plateau influence the East Asian summer precipitation?

The ozone valley over the Tibetan Plateau (OVTP) has experienced significant interannual variations during the past decades. Previous studies have primarily focused on the origins of OVTP rather than its climate impact. This study reveals that OVTP during its peak season (May-July) explains up to 15% of the summer precipitation variability in East Asia. The results suggest that the surface temperature (Ts) anomaly over the Tibetan Plateau (TP) acts as a link between OVTP and East Asian precipitation. Through the positive land-atmosphere feedback, the Ts anomaly over the TP is amplified. The anomalous Ts pattern persists into summer (June-August) due to the land memory effect and impacts the East Asian precipitation by modulating the local circulation. The Specified-Chemistry version of the Whole Atmosphere Community Climate Model is employed to validate that MJJ OVTP results in a substantial increase of Ts over TP and induces an anomalous anti-cyclone centered over the Yangtze-Huaihe River Basin during summer. Consequently, negative precipitation anomalies are observed in the Yangtze River Basin, while positive precipitation anomalies occur in Southern China. The linear baroclinic model further demonstrates that the diabatic heating over the TP serves as the link between MJJ OVTP and East Asian summer precipitation patterns. Our analysis of Coupled Model Intercomparison Project Phase 6 models reveals that a more accurate prediction of East Asian precipitation requires an improved understanding of the relationship between OVTP and TP Ts.

Automated summary

This study reveals that the ozone valley over the Tibetan Plateau (OVTP) has a significant impact on summer precipitation variability in East Asia, explaining up to 15% of the variation. The link between OVTP and East Asian precipitation is through the surface temperature anomaly over the Tibetan Plateau (TP), which is amplified by positive land-atmosphere feedback. The abnormal TP Ts pattern affects East Asian precipitation by modulating the local circulation, resulting in negative anomalies in the Yangtze River Basin and positive anomalies in Southern China.