Abstract:
In this paper, we present a detailed study of the spatial and seasonal aerosol climatology
over South Africa (SA), based on Multiangle Imaging Spectroradiometer (MISR) data.
We have used 10 years (2000–2009) of MISR monthly mean aerosol extinction (text),
absorption (ta) optical depths at 558 nm, Angstrom exponents in visible (VIS; 446–672 nm)
and near‐infrared (NIR; 672–866 nm) spectral bands, and the extracted spectral curvature.
The study has shown that, in terms of aerosol load level spatial variation, SA can be classified
into three parts: the upper, central, and lower, which illustrate high, medium, and low
aerosol loadings, respectively. The results for the three parts of SA are presented in detail.
The prevailing sources of aerosols are different in each part of SA. The lower part is
dominated by the air mass transport from the surrounding marine environment and other
SA or neighboring regions, while the central and upper parts are loaded through windablated
mineral dust and local anthropogenic activities. During the biomass burning seasons
(July–September), the central part of SA is more affected than the rest of SA by the biomassburning
aerosols (based on ta, ∼20% higher than the rest of SA). In alignment with the
observed higher values of text, aerosol size distributions were found to be highly variable
in the upper part of SA, which is due to the high population and the industrial/mining/
agricultural activities in this area.
