Author(s)

Nébon Bado^1,2*, Adama Ouédraogo^1,3, Hassime Guengané¹, Thierry Sikoudouin Maurice Ky¹, Serge Dimitri Bazyomo^1,4, Bruno Korgo¹, Mamadou Simina Dramé², Saidou Moustapha Sall², Florent P. Kieno¹, Dieudonné Joseph Bathiebo¹

¹Laboratoire d’Energies Thermiques Renouvelables (L.E.T.RE), Université Joseph Ki Zerbo, Ouaga, Burkina Faso.
²Laboratoire de Physique de l’Atmosphère et de l’Océan Siméon Fongang, Université Cheikh Anta Diop, Dakar-Fann, Sénégal.
³Centre Universitaire Polytechnique de Kaya (CUP-K), Kaya, Burkina Faso.
⁴Institute of Mathematics and Physical Sciences, University of Abomey-Calavi, Porto-Novo, Benin.

This paper deals with the climatology of aerosols in West Africa based on satellite and in situ measurements between 2001 and 2016 and covers four sites in the Sahelian zone. There are indeed Banizoumbou (13.541°N, 02.665°E), Cinzana (13.278°N, 05.934°W), Dakar (14.394°N, 16.959°W) and Ouagadougou (12.20°N, 1.40°W) located respectively in Niger, Mali, Senegal and Burkina Faso. Thus, an intercomparison between the satellite observations and the in situ measurements shows a good correlation between MODIS and AERONET with a correlation coefficient R = 0.86 at Cinzana, R = 0.85 at Banizounbou, R = 0.84 at Ouagadougou and a low correlation coefficient R = 0.66 calculated on the Dakar site. Like MODIS, SeaWiFS shows a very good correspondence with measurements of the ground photometer especially for Banizoumbou (R = 0.89), Cinzana (R = 0.88) and Dakar (R = 0.75) followed by a low correlation coefficient calculated on the Ouagadougou site (R = 0.64). The performance of these airborne sensors is also corroborated by the calculation of root mean square error (RMSE) and the mean absolute error (MAE). Following this validation, a climatological analysis based on aerosol optical depth (AOD) shows the seasonality of aerosols in West Africa strongly influenced by the climate dynamics illustrated by the MERRA model reanalysis. This seasonal spatial distribution of aerosols justifies the temporal variability of the particles observed at the different sites in the Sahel. In addition, a combined analysis of AOD and Angstrom coefficient indicates the aerosol period in the Sahel in spring (March-April-May) and summer (June-July-August). However, these aerosols are strongly dominated by desert dust whose main sources are located north in the Sahara and Sahel.

West-Africa, Aerosols, Airborne Sensors, Aeronet, MERRA Model

Bado, N. , Ouédraogo, A. , Guengané, H. , Maurice Ky, T. , Bazyomo, S. , Korgo, B. , Dramé, M. , Sall, S. , Kieno, F. and Bathiebo, D. (2019) Climatological Analysis of Aerosols Optical Properties by Airborne Sensors and in Situ Measurements in West Africa: Case of the Sahelian Zone. Open Journal of Air Pollution, 8, 118-135. doi: 10.4236/ojap.2019.84007.