Aerosol Indirect Effects on Idealized Tropical Cyclone Dynamics

The desire to improve the forecasting skill of the intensity and size of tropical cyclones has prompted the investigation into numerous physical processes that can impact these quantities. The modification of cloud properties via aerosols injected into a tropical cyclone can initiate interactions between cloud microphysics and storm dynamics that ultimately lead to appreciable changes in the large-scale features of the storm. In this modeling study it is shown that the introduction of aerosols at the periphery of an idealized tropical cyclone can impact both the intensity and size of the storm. In general, the storm intensity increases and the storm size decreases with increasing aerosol number concentration. Results from a sensitivity study to the aerosol number concentration in a source located at the storm periphery reveal that the storm intensity is increased up to 17%, and the storm size is reduced up to roughly 16% for aerosol concentrations ranging from 100 to 2000 cm(-3). The storm response is approximately a monotonic function of the aerosol concentration amounts. Despite the increase in storm intensity for the heavily polluted case, the overall destructive potential of this case is reduced due to the significant decrease in the storm size.