Characterization of AOD anomalies in September and October 2022 over Skukuza in South Africa

Abstract. This case study presents the evolution of aerosol optical properties during Intensive Observational Period (IOP) of the Biomass Burning Aerosol Campaign (BiBAC) in the Kruger National Park at Skukuza, between 18 and 23 September (Event 1) and 9 and 17 October (Event 2) 2022. The aerosol classification from sun-photometer data is consistent with the CALIOP, showing a predominance of biomass burning aerosols. The transport of CO and aerosols shows a southeastward transport over Southern Africa and toward the SWIO basin. The vertical distribution of aerosols spans vertically from the surface to 6 km (Event 1) and until 10 km (Event 2). The study discusses the synoptic conditions that have favored the significant perturbation of aerosol loading from September to October 2022. During Event 1, the "river of smoke" phenomenon was driven by surface ridge tongues with the westerly wave not being converted into a COL. During Event 2, a surface heat low, mid-tropospheric anti-cyclonic system, and warm air column resulted in stable conditions, which was also influenced by strong subsidence. The study investigates the long-range transport of biomass burning from South America to Southern Africa, with the plume exiting over southern Brazil, likely driven by the Southern American low-level jet (SALLJ), which is driven by climate forcings like El Niño–Southern Oscillation (ENSO) and Madden-Julian Oscillation (MJO). Further research addresses to the contribution of biomass burning plumes from Southern Africa and South America to those observed during both events and determines the atmospheric pattern.