Extratropical cyclones drive the spatial heterogeneity distribution of Sea Salt Aerosol (SSA) and vertical transport in the Southern Ocean

Abstract. Sea salt aerosols (SSA) were emitted via bubble bursting during wave breaking, exhibiting a strong positive correlation with wind speed. However, the generation and emission of SSA driven by cyclones was still lack of knowledge. In this study, we combine cruise observations and GEOS-Chem simulations to investigate the contribution of extratropical cyclones to SSA dynamics. During the R/V Xuelong cruise, observed SSA concentrations were consistently lower in cyclonic periods compared to non-cyclonic periods, a pattern probably linked to updraft transport within cyclone systems. Model results revealed that SSA concentrates predominantly north of cyclone centers. As altitude increases, these high-concentration zones gradually shifted northwestward. Cyclone-associated high-wind regions accounted for 63 % of total SSA emissions across the Southern Ocean. The maximum upward SSA transport flux occurred at 450 m altitude within Warm Conveyor Belt regions, with stronger and longer-lasting cyclones generating greater transport intensities. Our results demonstrate that cyclones modulate SSA distribution primarily through turbulent mixing, with synergistic effects from wet deposition and advective transport. This study highlights the spatial heterogeneity of SSA distribution during cyclones and elucidates how combined physicochemical processes regulate SSA transport under cyclonic conditions.