Radiative Influence of Dust Aerosols on the Evolution of Tropical Storm Hermine

Abstract. This study investigates the impact of dust aerosols on the evolution of Tropical Storm Hermine (2022) using the Weather Research and Forecasting model coupled with Chemistry (WRF-Chem) and observational data from the NASA Convective Processes Experiment – Cabo Verde (CPEX-CV). The objective is to evaluate how varying initial dust aerosol conditions influence storm development and to uncover the mechanisms behind these effects. Three WRF-Chem simulations were conducted with different initial aerosol concentrations: one with no aerosols, one with realistic dust concentrations, and one with intermediate aerosol levels. The simulations were compared against observational data from CPEX-CV and the best track data from the United States' National Hurricane Centre, focusing on parameters such as wind, pressure, aerosol optical depth, and radar reflectivity. The results indicate that the radiative effect of dust aerosols led to a weaker and more disorganized storm system compared to simulations without the inclusion of dust, highlighting the critical role of dustradiation interactions in modifying storm intensity. Furthermore, the study found that the ECMWF's Atmospheric Composition Reanalysis 4 (CAMS) underestimated atmospheric dust concentrations, in comparisons to observations, underlining the necessity for accurate observational data to validate aerosol-related processes and improve model predictions. These findings emphasize the complexity of dust aerosol-storm interactions and the importance of improving aerosol representations in simulations of tropical cyclones.