[1] 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 (t ext ), absorption (t a ) 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 t a , ∼20% higher than the rest of SA). In alignment with the observed higher values of t ext , 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.

No abstract

No abstract

No abstract

No abstract

The present study evaluates the aerosol optical property computing performance of the Regional Climate Model (RegCM4) which is interactively coupled with anthropogenic-desert dust schemes, in South Africa. The validation was carried out by comparing RegCM4 estimated: aerosol extinction coefficient profile, Aerosol Optical Depth (AOD), and Single Scattering Albedo (SSA) with AERONET, LIDAR, and MISR observations. The results showed that the magnitudes of simulated AOD at the Skukuza station (24 ∘ S, 31 ∘ E) are within the standard deviation of AERONET and ±25% of MISR observations. Within the latitudinal range of 26.5 ∘ S to 24.5 ∘ S, simulated AOD and SSA values are within the standard deviation of MISR retrievals. However, within the latitude range of 33.5 ∘ S to 27 ∘ S, the model exhibited enhanced AOD and SSA values when compared with MISR observations. This is primarily associated with the dry bias in simulated precipitation that leads to the overestimation of dust emission and underestimation of aerosol wet deposition. With respect to LIDAR, the model performed well in capturing the major aerosol extinction profiles. Overall, the results showed that RegCM4 has a good ability in reproducing the major observational features of aerosol optical fields over the area of interest.

No abstract

A-