loading page

Atmospheric aerosol optical properties and radiative forcing over two metros in South Africa
  • Abdulaziz Tunde Yakubu,
  • Naven Chetty
Abdulaziz Tunde Yakubu
University of KwaZulu-Natal

Corresponding Author:[email protected]

Author Profile
Naven Chetty
University of KwaZulu-Natal
Author Profile


Aerosol Robotic Network (AERONET) measurement data is used in the validation of two prominent satellite aerosol property retrieval, Multiangle Imaging Spectroradiometer (MISR) and Moderate Resolution Imaging Spectroradiometer (MODIS), then applied to examine the properties of aerosols and the direct influence on radiative forcing (RF) over two metropolitan cities, Cape Town (CPT) and Pretoria (PRT) in South Africa. The synoptic characteristics of aerosols over CPT for 2015-2019 indicate a general low aerosol optical depth (AOD) of an average of 0.08 ± 0.014 and are prevalently sea salt (SS) aerosols. In contrast, a high AOD value with an average of 0.23 ± 0.050 was observed over PRT between 2011-2019 and predominated by sulphate/nitrate aerosols. These two dominant aerosol types are found to be the primary motivator of the net cooling effect of RF due to aerosol in each location. While the average RF over CPT is -16.79 ± 5.61 during the study period, the value over PRT is estimated to be more than two times (-36.55 ± 10.54) of the former. The validation of MISR and MODIS satellite aerosol properties retrieval for the region demonstrated better accuracy over the land than in the maritime environment. Meanwhile, MODIS underestimated AOD by ≈ 32% but generally reported better precision across the board than the MISR instrument. Further investigation into the seasonal variation of aerosols over the two locations identified seasonality changes in the characteristics of aerosols mainly influenced by the transport of high-absorbing biomass-burning aerosols.
06 Sep 2023Submitted to ESS Open Archive
11 Sep 2023Published in ESS Open Archive