Tropospheric Mass Flux Reduction with warming and its impact on the frequency and intensity of convective precipitation

Tropical precipitation will change with warming. Some results suggest that tropical precipitation extremes will increase at rates higher than Clausius-Clapeyron scaling of 7% per Kelvin. As a first step in building physical understanding of tropical precipitation changes, we apply the framework established by Pendergrass and Hartmann in their 2014 (PH14) trilogy to idealized cloud-resolving models in radiative convective equilibrium. PH14 introduce a way to understand changes to precipitation distributions in two modes: the shift and the increase mode. We explain the values of the shift and increase modes in terms of physical principles. The shift mode is captured to first order by Clausius Clapeyron scaling, while the increase mode is a combination of Clausius-Clapeyron scaling and the decrease of mass flux expected with climate change.