keywords: Aerosol, aeronet, desertification, shaping constant, scaling constant, precipitation
Aeronet Aerosol Optical Depth (AOD) data of Ilorin in the Savannah belt of Nigeria (80, 32’N: 40, 34’E) for a five year period (2005-2009) were graphically analyzed with a view to deduce the trend and level of aerosols load in the region. Shaping and scaling constants were determined to classify the prevalent aerosols in the region and determine the concentration of aerosol load in the region respectively. The annual variation of the shaping constant showed prevalence of coarse mode aerosols (soil particles) indicating activeness of desertification in the region. Maximum and minimum average aerosol sizes were recorded in the month of March and August, respectively showing the impact of dry season dust and wet season precipitation on aerosol load in the atmosphere. Annual average scaling constant showed a moderate aerosol concentration in the atmosphere of the region. An analysis of the inter-annual variation of the scaling constant showed a 6.8% increase in aerosol concentration between 2005 and 2007 and a 10.6% decrease between 2007 and 2009 indicating that the activeness of desertification in the region can be contracted by controlled anthropogenic activities since aerosols concentration in the region did not increase continuously over the five year period under investigation.
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