Author(s)

Bruno Korgo^1*, Pétronille Kafando², Bernard Zouma¹, Nebon Bado¹, Issa Zerbo¹, Jean-Claude Roger³, Joseph D. Bathiebo¹

¹Laboratory of Thermal and Renewable Energy, Department of Physics, University Joseph KI-ZERBO, Ouagadougou, Burkina Faso.
²Laboratory of Environmental Physics and Chemistry, Department of Physics, University Joseph KI-ZERBO, Ouagadougou, Burkina Faso.
³Department of Geographical Sciences, University of Maryland, College Park, MD, USA.

This paper is an assessment of radiative forcing caused by atmospheric aerosols in an urban city in West Africa. It is carried out in Ouagadougou in Burkina Faso and is an illustration of the radiative impact in most of the large Sahelian urban cities which are under the same climatic influences and whose populations present similarities in their socio-economic aspects. Using the GAME code, the radiative forcing was calculated at the top of the atmosphere, in the atmospheric layer and at the earth’s surface. The results showed overall a cooling effect at the top of the atmosphere due to the backscattering in space of the incident radiation, a heating in the atmospheric layer due to the absorption effect and a surface cooling justified by the attenuation of radiation crossing the atmosphere. Using monthly average values of optical properties, vertical temperature and humidity profiles, daily temperatures and surface albedo, the simulation yielded forcing values ranging from -6.77 W/m² to -2.56 W/m² at the top of the atmosphere, from 15.8 W/m² to 34.7 W/m² in the atmospheric layer and from -41.00 W/m² to -21.68 W/m² at the earth’s surface. In addition, the warming was simulated in the first atmospheric layer (in contact with the surface), and the results show values ranging from 0.8°C to 1.8°C. The study of the annual variability of the results showed a strong correlation between the radiative forcing and the seasonal succession characteristic of the climate in West Africa with the extreme values in the month of March (characteristic of the dry and hot season) and in the month of August (characteristic of the rainy season).

Aerosols, Radiative Forcing, Scattering, Absorption, GAME Code, AERONET

Korgo, B. , Kafando, P. , Zouma, B. , Bado, N. , Zerbo, I. , Roger, J. and Bathiebo, J. (2021) The Radiative Forcing of Aerosols in a West Africa Sahelian Urban City: Case Study of Ouagadougou. Atmospheric and Climate Sciences, 11, 73-85. doi: 10.4236/acs.2021.111005.