Examination of Aerosol-induced Convective Invigoration using Idealized Simulations

Abstract

Idealized large eddy simulations (LES) are performed of deep convective clouds over south Florida to examine the relative role of aerosol-induced condensational versus mixed-phase invigoration to convective intensity and rainfall. Aerosol concentrations and chemistry are represented by using output from the GEOS-Chem global atmospheric chemistry model run with and without anthropogenic aerosol sources.The results clearly show that higher aerosol concentrations result in enhanced precipitation, larger amounts of cloud liquid water content, enhanced updraft velocities during the latter part of the simulation, and a modest enhancement of the latent heating of condensation.Overall our results are consistent with the concept that convective cloud invigoration is mainly due to condensational invigoration and not primarily to mixed-phase invigoration. Furthermore, our results suggest that condensational invigoration can result in appreciable precipitation enhancement of ordinary warm-based convective clouds such as are common in locations like south Florida.