Evaluation of Landsat OLI data for estimating Aerosol Optical Thickness over deserts

Dust is one of the most important effective factor on solar radiation forcing and reflection on earth's atmosphere, and in this point, it has a significant impact on local climate. Detection of aerosols on desert zones, despite the sea and oceans (dark surfaces), is difficult because of reflectometric interference spectroscopy of bright surfaces. Representing a simple and low costs method for detecting dusts and predicting their effects is essential. One of the most important indexes for dust and smoke detection is the AOT (Aerosol Optical thickness), which provided in large-scale (10x10 km) which is not suitable for local dust scales detection. The purpose of this study is using visible and mid-infrared spectrum of OLI sensor for detection dust of deserts. In this study, by using of mid-wave infrared (2.1 μm), red and blue wavelengths the AOT was calculated. The results indicated that ratio between the red and mid-wave infrared wavelengths is 0.95 and blue wavelengths and mid-wave infrared is 1.05 respectively. The comparison results of AOT index by radiometer showed that the correlation between computational method for data and the direct measurement for the red and blue wavelengths were 0.83 and 0.95 with root-mean-square deviation (RMSE) were 0.91 and 9.4 respectively. Therefore, it can be said that this method for estimating the Aerosol optical thickness at 0.65 μm (AOT 0.65μm) is enough accuracy and is not suitable to measure Aerosol optical thickness at 0.47 μm (AOT 0.47μm).