The potential Impact of African Dust on the Simulation of North Atlantic Hurricanes in High-Resolution CAM5

The focus of this study is to explore the potential impact of African dust on topical cyclone (TC) genesis, frequency and intensity in the North Atlantic. For this work the Community Atmosphere Model version 5 (CAM5), a comprehensive atmospheric general circulation model, is configured with a global horizontal grid spacing of approximately 28 km to permit the direct simulation of TCs. While the simulations are forced with prescribed sea-surface temperatures (SSTs) and greenhouse gases from 1980 to 2012, two different aerosol treatments are used within the CAM5 framework. In particular, we explore the impact of African dust on the formation and development of TCs by modifying the prognostic aerosol formulation to inhibit dust emissions (i.e., no airborne dust). In general, we find an increase in overall TC activity in the North Atlantic due to a more favorable environment for tropical cyclogenesis in the CAM5 simulation with no dust. Furthermore, the ability of CAM5 to reproduce observed interannual variability is reduced in the no dust simulation. These changes in TC characteristics are investigated in detail in this study.