The Impact of the Vertical Structure of Stratospheric Zonal Wind on Interannual Variability of Precipitation in the Tropics

Previous studies have emphasized the role of the stratospheric Quasi‐Biennial Oscillation (QBO) in modulating tropical precipitation. However, the relationship between precipitation and QBO index at different stratospheric levels is inconsistent. This study identifies two distinct vertical structures of stratospheric zonal wind that influence precipitation in the tropics: (a) westerlies at 50 and 70 hPa combined with easterlies above 50 hPa generate warm anomalies near the tropopause; (b) easterlies at 20–70 hPa paired with westerlies at 10 hPa induce strong cold anomalies near the tropopause. Temperature anomalies affect atmospheric static stability, with negative anomalies increasing high cloud cover and strengthening convection. Additionally, the large‐scale circulation links stratospheric zonal winds to deep convection. The vertical structure of the stratospheric zonal wind influences the intensity and positioning of the Hadley and Walker circulations, thereby shaping the spatial distribution of tropical precipitation. A linear combination of time series from these two wind structures explains a significant part of interannual tropical precipitation variability after removing the El Niño‐Southern Oscillation signal. Evaluation of 15 Phase 6 of the International Coupled Model Intercomparison Project models shows that eight reproduce the observed relationship between stratospheric wind structures and tropical precipitation with reasonable accuracy. The vertical structure of stratospheric zonal wind exerts a significant influence on tropical precipitation patterns.