What Controls the Interannual Variability of Extreme Precipitation?

Abstract The controlling factors of the interannual variability of extreme precipitation (EP) are examined on a global scale. We quantify the moisture (thermodynamic) and vertical motion (dynamic) contributions to the interannual variability of EP by applying a physical scaling diagnosis. The thermodynamic contribution is small and the dynamic contribution dominates the interannual variability of EP. We further apply a quasi‐geostrophic diagnosis on EP to decompose the vertical motion and its variability into components due to the large‐scale adiabatic perturbations (dry dynamics) and the diabatic heating feedback (moist dynamics). The variability of vertical motion associated with large‐scale adiabatic perturbations is approximately twice that of the diabatic heating feedback. These results highlight the dominant role of the large‐scale adiabatic perturbations on the year‐to‐year variability of EP, in contrast to the responses of EP to global warming, in which both the large‐scale adiabatic perturbations and diabatic heating feedback are important.