Shipborne Measurements of Mineral Dust and Black Carbon Aerosols Over the Southern Ocean in the Austral Summer

Atmospheric mineral dust and black carbon (BC) aerosols play important roles in the Earth's climate system, yet direct observations over the Southern Ocean (SO) are scarce. In this study, we present the characteristics of airborne water‐insoluble particles (WIPs) collected during a cruise of the R/V Shirase in the Australian and Indian sectors of the SO from December 2022 to March 2023. Using a complex amplitude sensor, we measured complex scattering amplitude of individual WIPs to classify into dust‐like (0.50–2.5 μm in diameter) and BC‐like (0.15–0.50 μm in diameter) particles. The mass concentrations of dust‐like and BC‐like aerosols were 0.0–6.4 ng m −3 and 0.079–3.8 ng m −3 , respectively. The highest concentrations of both were observed when the R/V Shirase was located in a mid‐latitude region closest to Australia, indicating strong influence of the emission from mid‐latitude sources. The lowest concentration of BC‐like aerosols was observed in a sample collected when the ship was near the Antarctic coast and the air mass would be rarely influenced by mid‐latitude emissions. However, the dust‐like aerosol concentration in the same sample was relatively higher than that collected in the most remote offshore region away from both mid‐latitude and Antarctic continents, suggesting a potential source of dust aerosols. Despite a case study based on a limited number of samples, this study fills an observational gap by providing quantitative data of mineral dust and BC aerosols over the SO, providing new insights into their sources and climate effects.