Variation, distribution and trends of aerosol optical properties in Africa during 2000-2022

Global anthropogenic emissions have been on the increase causing environmental and climatic concerns. To this end, aerosol properties influenced by these anthropogenic activities from satellite and ground remote sensing were examined for distribution, variation, and trends over Africa during 2000–2022. Furthermore, the response of temperature to the interaction of aerosols with solar radiation was investigated in the region. The spatial distribution of the aerosol properties were characterized as high (towards maximum values), moderate (around middle values), and low (towards least values) which varied with time and local emissions dependence. In addition, trends in Aerosol Optical Depth (AOD) show a significant decrease in the arid areas of the northern and southern regions, while an increase in the arid Sahel and central Africa. Angstrom Exponent (AE) is on a decreasing trend as well as Absorption Aerosol Optical Depth (AAOD), except for southern central Africa, which has a significant positive trend of AAOD attributed to intense bush burning. A dust hotspot in the central Sahara and central South Africa smoke experienced positive and neutral trends in Single Scattering Albedo (SSA) respectively indicating an increase in scattering aerosol (pure dust) and a uniform level of smoke emission in the areas, with other areas negatively trending. A strong relationship exists between air temperature with AOD, AAOD, and SSA and negative ones with AE based on the level of aerosol composition and types. The study forms the basis for climate change impact study in Africa region.