Browsing by Author "Ibrahim, B. B."

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    TREND ANALYSIS OF AOD AND AE IN ILORIN AND CAPO VERDO, WEST AFRICA
    (IKSAD GLOBAL Publishing House, 2021) Sharafa, S. B.; Aliyu, R.; Ibrahim, B. B.
    Analysis of atmospheric aerosols enhances confidence in the evaluation of its effects on both local and regional climate change. To accomplish this over West Africa, it is vital to be familiar with aerosols' temporal characteristics over the area. West Africa has witnessed more frequent and intensified dust storms in the past. Trend analysis of aerosols in this region requires observational data regarding its physical and optical properties. For this, the Statistical Package for the Social Sciences (SPSS) software has been used. Monthly averaged measurements of aerosol optical depth at 550 nm (AOD, τ) and Angstrom exponent at 470 - 660 nm (AE, α) data from Moderate Resolution Imaging Spectroradiometer (MODIS) over Capo Verdo and Ilorin Aerosol Robotic Network (AERONET) stations were analyzed in this study. The satellite dataset collected for a period from 2000 to 2015 were examined in relation to their trends. It was discovered that the Ilorin and Capo Verdo stations were dominated by fine mode and coarse mode particles, respectively. Also, an increasing trend in aerosol loading was noticed in Ilorin while a reduction was noticed in Capo Verdo. It was also deduced that fine mode aerosols are on the increase in the two stations. The analysis for the seasonal variation shows that during the dry season, both aerosol loading and fine mode aerosols are on the increase in both stations. In the rainy season, Ilorin station recorded increasing aerosol loading and an increase in dust pollution. On the other hand in Capo Verdo, a reduction in aerosol loading was noticed while fine mode aerosols are on the increase. Seasonal contribution of aerosols show that dry seasons has the highest pollution recorded in Ilorin while Capo Verdo record the least during the same dry season. The highest contribution of fine mode aerosols in both stations was noticed in the rainy season.
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    Trend and variability of aerosol optical depth at UV wavelength (340 nm) over Ilorin AERONET site in the North Central State of Nigeria
    (School of Science and Technology Education, Federal University of Technology, Minna, Nigeria, 2020-12-03) Ibrahim, B. B.; Sharafa, S. B.; Usman, A.
    Aerosols are small solid or fluid airborne mass, or particles, that remain suspended in the air and move with the motion of the air within broad limits. The extinction of sunlight reaching the ground by a vertical column of atmosphere due to aerosol is often termed as aerosol optical depth. This research work investigates the trend of Aerosol Optical Depth (AOD) at 340 nm and its variability over 13 years (2002-2014) using AERONET data for Ilorin, Nigeria. Daily and monthly mean, maximum, minimum and range of AOD values and their trends were investigated using regression analysis. The result shows that on annual basis, the minimum value of AOD occurred in the year 2008 with a value of 0.096 in August while the maximum value of AOD occurred in 2006 with a value of 3.878. The highest range of AOD also occurred in the year 2006 with a value of 3.663 in March. On year by year monthly average,the minimum value of AOD occurred in year 2008 with a value of 0.293 in August while the maximum occurred in year 2007 with a value of 1.6747 in January. Year 2008 has the highest value of range with a value of 1.3068. The result further shows that the yearly representation of daily mean, maximum, minimum and range behave similarly in trend with AOD rising from November up to March of the following year. There is a drop in AOD in May until a minimum in August of the year before another rise in the value. A quadratic fit best described the plot of daily mean, maximum, minimum and range of AOD with days of the year. AOD shows positive and negative value of monthly trend throughout the study period. No year with similar monthly trend. This analysis will be useful for air quality assessment studies.