The Impact of Saharan Dust on the Genesis and Evolution of Hurricane Earl (2010)

Dust, one of the most abundant natural aerosols, can exert substantial radiative (direct) and microphysical (indirect) effects on the regional climate and has potential impacts on the genesis and intensification of tropical cyclones (TCs). Dust can act both as Cloud Condensation Nuclei (CCN) and Ice Nuclei (IN). A new dust module has been implemented to the TAMU two-moment microphysics scheme in the Weather Research and Forecasting (WRF) model, accounting for both dust as CCN and IN. The Weather Research and Forecasting Model and the Regional Oceanic Modeling System coupled model (WRF-ROMS) is used to simulate the evolution of Hurricane Earl (2010), of which Earl was interfered by Saharan dust at the TC genesis stage. The hurricane track, intensity and precipitation have been compared to the best track data and TRMM precipitation, respectively. The influences of Saharan dust on Hurricane Earl are investigated with dust-CCN, dust-IN, and dust-free scenarios. The analysis shows that Saharan dust changes the latent heat and moisture distribution, invigorates the convections in the hurricane’s eyewall, and suppresses the development of Earl. These findings addresse the importance of accounting dust microphysics effect on hurricane predictions.