Exploring the Impact of Dust on North Atlantic Hurricanes in a High-Resolution Climate Model

The relationship between African dust and the climatology of tropical cyclones (TCs) in the North Atlantic is explored using the Community Atmosphere Model at a global horizontal resolution of 28 km. A simulation in which the aerosol model is modified to significantly reduce the amount of airborne dust is compared to a standard simulation. The simulation with reduced dust increases TC frequency globally, with the largest increase occurring in the North Atlantic. The increase in TC activity in the North Atlantic is consistent with an environment that is more conducive for the genesis and intensification of storms. TCs are more frequent (27%) and on average significantly longer lived (13%) in the low dust configuration but only slightly stronger (3%). This results in a 57% increase in accumulated cyclone energy per hurricane season on average. This work has implications for projections of future climate and resulting changes in TC activity. Plain Language Summary Dust from the Sahara desert in Africa can impact hurricane formation and development in the North Atlantic. Carried by the wind over the North Atlantic and around the globe, the dust contributes to dry and stable air that can make it harder for thunderstorms over the ocean to develop into stronger tropical cyclones or hurricanes. In this study, we look at how this effect shows up in a climate model with sufficient resolution to represent hurricanes. After the control experiment (1980-2012), we reduced the amount of airborne dust in the model over the same historical period as a low dust experiment. In the low dust simulation, tropical cyclone frequency increases globally. In the North Atlantic where storms can be impacted directly by African dust, storms become more frequent, longer lived, and slightly stronger, increasing their destructive potential. Understanding how dust interacts with tropical cyclones in climate models will help us understand and prepare for the potential changes in hurricanes of the future.