Estimation of aerosol optical depth over ocean: Intercept technique

The study of atmospheric aerosols is an important element to understand the earth's solar radiation budget, water cycle balance, and climate change dynamics. Estimating aerosol properties is also one of the first steps in generating high-level land and ocean surface products from satellite observations. In this paper, a simple method to estimate the aerosol optical depth (AOD) over ocean is proposed. The method is based on the intercept of the line connecting the 0.47, 1.24, 1.64 and 2.14 µm. The lines that intercept the apparent reflectance axis are higher over the high aerosol contribution area and lower over low aerosol contribution area. The comparison of the intercept map line and AOD map distributed by MODIS ocean color team are in high correlation with R>0.90. The AOD map from the applications of the algorithm was constructed. The sample result of AOD map from several MODIS datasets acquired over the Gulf of Martaban is presented.