Daily and Seasonal Variation of Aerosol Optical Depth and Angstrom Exponent over Ethiopia using MODIS Data

Document Type : Original Research Paper


Department of Physics, College of Science, Bahir Dar University, P.O.Box 79, Bahir Dar, Ethiopia


Aerosols are tiny particles (liquid or solid) suspended in the atmosphere. They play a significant role
in climate dynamics directly or indirectly. Aerosol Optical Depth (AOD) and Angstrom Exponent
(AE) are significant parameters to study the concentration and size or type of aerosol over an area,
respectively. In this article, we utilized three years of AOD and AE parameters derived from moderate
resolution imaging spectroradiometer (MODIS) satellite during the period January, 2013 to December,
2015 over Ethiopia. In order to study the spatiotemporal pattern of aerosols, we choose three areas
(Debretabour, Gojjam and Addis Ababa) over Ethiopian highlands, which are representative of nonindustrial, agricultural and industrial areas respectively. Further we compare continental aerosols with
marine aerosols from Djibouti. Our results clearly depicts the aerosol distribution over Ethiopia is
highly variable spatially and temporally. The results indicates that the urban and biomass aerosols are
dominate over Addis Ababa, and Gojjam respectively, whereas dust and biomass aerosols are present
over Debretabour, while Djibouti is loaded by sea spray aerosols. The seasonal variability of AOD is
found to be maximum during the kiremt (summer) and minimum during bega (winter) over all areas
(continental and marine).


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