Influence of atmospheric dust on the equatorial Atlantic Variability

Northern tropical and subtropical North Atlantic Ocean is exposed to large plumes of atmospheric dust mostly from Saharan dust outbreaks. The scattering and absorbing radiation in the dust air layer modifies the air column temperature. These temperature changes strongly impact the atmospheric wind forcing and deep atmospheric convection resulting in changes in the latitudinal position of the Intertropical Convergence Zone and the distribution of sea surface temperature anomalies (SSTA). In this study, we analyze the interaction between the interannual variability of Aerosol Optical Depth (AOD) in the North Tropical Atlantic (NTA) and SSTA in the equatorial Atlantic in the period 1996-2020. Observational results show that AOD-induced SSTA in the north tropical Atlantic may impact the equatorial Atlantic variability by different mechanisms such as an intensification of cross-equatorial winds and the excitation of oceanic waves. In particular, the AOD in NTA in boreal winter/spring seems to impact on the onset, intensity and spatial configuration of the Atlantic Zonal Mode, also known as Atlantic Niño. Our findings suggest that atmospheric dust can be a potential precursor for equatorial Atlantic Variability.