Impacts of Saharan Dust on Atlantic Regional Climate and Implications for Tropical Cyclones

AbstractThe radiative and microphysical properties of Saharan dust are believed to impact the Atlantic regional climate and tropical cyclones (TCs), but the detailed mechanism remains uncertain. In this study, atmosphere-only simulations are performed from 2002 to 2006 using the Community Atmospheric Model version 5.1 with and without dust emission from the Sahara Desert. The Saharan dust exhibits noticeable impacts on the regional longwave and shortwave radiations, cloud formation, and the convective systems over the West Africa and tropical Atlantic. The African Easterly Jet and West African Monsoon are modulated by dust, leading to northward shifts of the Intertropical Convergence Zone and the TC genesis region. The dust events induce positive mid-level moisture and entropy deficit anomalies, enhancing the TC genesis. On the other hand, the increased vertical wind shear and decreased low-level vorticity and potential intensity by dust inhibit TC formation in the genesis region. The ventilation index sh...