Aerosol-Induced Invigoration Effects in Deep Convection

Aerosols are known to play a role in cloud droplet activation by acting as cloud condensation nuclei. Through aerosol indirect effects, they can have an enhancing or suppressing effect on the formation of deep convective clouds (DCCs). The behavior of DCCs, which are structurally more complicated than their shallow counterparts, depends on the stage of the cloud’s lifetime and aerosol properties owing to feedback loops caused by the coupling of complex dynamics and microphysics. In this study, the dynamical and microphysical effects aerosols have on the convective strength of deep clouds are explored in detail. In particular, simulations of the early stages of a deep convective storm are conducted with varying aerosol concentrations using RAMS. Consistent with other modeling studies, the simulations show that the vertical velocity increases in response to aerosol loading. Additional tests are run to identify the mechanisms leading to this invigoration. Comparative analysis of the simulations indicate supersaturation is strongly tied to the aerosol-induced invigoration of deep convection. The supersaturation modulates both the condensation rate and the nucleation rate of cloud droplets both of which are shown to feedback on the storm dynamics.