The Potential Impact of Aerosols on Severe and Tropical Storms

Convective storm dynamics is sensitive to precipitation forming processes and the vertical redistribution of the latent heating and cooling. The question is: how sensitive are microphysical processes to changes in aerosol concentrations? Theory and observational evidence suggests that the microphysical effects of aerosols can impact the self-organization of convective clouds into squall lines and super-cells. This can lead to changes in the the distribution of hydrometeor concentrations, atmospheric moisture, as well as rainfall intensity and lightning. Moreover, aerosol modulated changes in convection could impact the intensity of tropical cyclones. We will examine these issues using a highly sophisticated microphysical scheme embedded in WRF, called Spectral (bin) Microphysics. Case study examples are simulated with different aerosol concentrations to elucidate the possible role of aerosols in convective and tropical storms. The accuracy of the re-forecasts is found to depend upon these assumed distributions. The results suggest the utility of assimilating aerosol concentrations into operational forecast models for improving predictions of hurricane initiation and intensity changes, convective mesoscale complexes, and squall lines.