Spatiotemporal Variabilty of Aerosol Optical Depth Over Nigeria Based on Modis Satellite Observations (2004–2023)

Abstract

Aerosol optical depth is a key parameter and important factor for understanding climatic change and environmental pollution. This study presents long term (2004-2023) investigation of spatial and temporal variation and trends in AOD over Nigeria retrieved from Moderate Resolution Imaging spectroradiometer (MODIS) Aqua [dark target (DT) and deep blue (DB)]. Monthly mean data was utilized. The spatial variability of AOD in the North West (NW) and South West (SW) regions is large then followed by South East (SE) and North Central (NC) and the least is North East (NE) and South South (SS). The mean AOD values ranged from 0.252 to 0.851. Three out of six major political zones had the highest AOD values in winter, while the remaining three had the highest AOD in spring. Such differences might be attributed to different driving forces, the South and some part of the North West had high level of AOD in winter. In addition, the AOD values show that there are obvious regional differences in the study area, with decreasing value from winter to autumn. Among them, the level of mean AOD in South-South reduces from 1.2 in winter to 0.2 in autumn. The spatial distribution of AOD also varies slightly among seasons, which may be related to meteorological factors, elevation and population.