Evaluating the Microphysical and Dynamical Impacts of Saharan Dust Plumes on Tropical Cyclones across the Tropical Atlantic Basin

Over the past few decades, there has been a substantial increase in the density of research focused on investigating the impacts of Saharan dust on tropical cyclones across the Tropical Atlantic Ocean basin. Over that time, there have been evolving (but contrasting) viewpoints on how and why Saharan dust plumes affect the intensity and tracks of tropical cyclones. It is well understood that the premiere issues tied to Saharan dust plumes with respect to tropical cyclones are associated with the impacts of the Saharan Air Layer (SAL). More specifically, the increased vertical wind shear, the locally drier deep-layer moisture profile within the SAL, and the variable impacts from the direct and indirect effects of Saharan dust particles on in-situ and storm dynamics. Much research has strived to investigate how and to what extent the SAL and Saharan dust plumes (which are typically contained within the SAL as they eject from western Africa) physically influence the track, intensity, development and/or maturation of tropical cyclones across the tropical Atlantic basin.

The primary goal of this work is to investigate the extent to which the direct and/or indirect effects of aerosols as well as other associated dust particle transport processes may be assessed for better future predictability in different SAL scenarios. Through integrating ERA5 Reanalysis data from various case studies over a 20 yr dataset into WRF numerical model simulations both with and without aerosol considerations, the results presented here update the progress of a critical issue associated with seasonal tropical cyclogenesis hazards. A major focus is placed on studying how Saharan dust plumes of varying areal extent and concentrations may correspond to different outcomes with respect to peak tropical cyclone intensity as well as tropical cyclone tracks. A combination of satellite data, tropical cyclone best track data, and various satellite-derived products are collectively used to build statistics towards assessing whether certain tropical cyclone SAL influence theories (e.g., theories involving cloud condensation nuclei enhancement vs. dry air intrusion) may or may not be reliable based on this research.