An EOT Approach to Analyze the Temporal Variability of Rainfall Data and Some Aerosol Properties over Ilorin using MODIS Data
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Date
2019-05-01
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Publisher
Nigerian Geophysical Society
Abstract
Many remote sensing techniques and passive sensors have been developed to measure global aerosol properties.
In this paper, aerosol properties in Ilorin, like optical depth (τ550), Angstrom exponent (α470-660), single
scattering albedo (ωo), and ne mode fraction (FMF), together with cloud fraction (Ncloud) from the
Moderate Resolution Imaging Spectroradiometer (MODIS), as well as Rainfall (RF) data were analyzed using
Empirical Orthogonal Transformation (EOT) analysis. The EOT is used to check for underlying constructs that
may have characterized the atmosphere in the study area. The data set covers the period from March 2000 to
June 2015. Analysis results show that four (4) principal components with eigenvalues greater than one (1),
were extracted. These components explained 89.118% of the total variance. The first component is extracted
most strongly on RF and Ncloud. This indicates a cloudy-rainy season. The second component is extracted on
τ550 and α470-660. These also indicate a rainy season. The third component is extracted on ωo. This
indicates a dry and cold dry. The fourth component had only FMF, and it indicates a dry and warm. This
shows that the structure of the atmosphere in the study area during this period is strongly characterized by
cloudiness, clear sky, scattering and absorption of electromagnetic radiation. The climatology of the station
also shows the predominance of coarse and reflecting aerosols.
Description
Keywords
Basement Complex, Conductive Zones, Road Instability, Electrical Resistivity