Aerosol-Induced Feedbacks within Tropical Anvil Clouds

Enhanced concentrations of aerosols serving as cloud condensation nuclei tend to suppress collision coalescence processes, thereby reducing warm rain precipitation rates and leaving more cloud water suspended within the cloud system. The availability of greater cloud water amounts for lofting into the mixed-phase regions of convective systems subsequently results in the production of greater ice amounts. The greater amounts of available cloud water together with higher concentrations of aerosols that can serve as ice nuclei, can produce significant changes in ice crystal number concentrations and sizes. As cloud radiative forcing is highly sensitive to ice crystal sizes and number concentrations, variations in aerosol concentrations could thus be expected to significantly influence the cloud radiative forcing of convective anvils, which in turn can have feedbacks to storm organization, stratiform precipitation, atmospheric stability and local and large-scale circulations. These aerosol-induced relationships within convective anvils will be investigated using cloud-resolving model simulations of tropical convective anvils under a framework of radiative convective equilibrium.