Satellite remote sensing of Asian aerosols: a case study of clean, polluted, and Asian dust storm days

摘要

In East Asia, satellite observation is important because aerosols fromnatural and anthropogenic sources have been recognized as a major source ofregional and global air pollution. However, retrieving aerosols propertiesfrom satellite observations over land can be difficult because of thesurface reflection, complex aerosol composition, and aerosol absorption. Inthis study, a new aerosol retrieval method called as the Moderate ResolutionImaging Spectroradiometer (MODIS) satellite aerosol retrieval (MSTAR) wasdeveloped and applied to three different aerosol event cases over East Asia.MSTAR uses a separation technique that can distinguish aerosol reflectancefrom top-of-atmosphere (TOA) reflectance. The aerosol optical thickness(AOT) was determined by comparing this aerosol reflectance withpre-calculated values. Three case studies show how the methodologyidentifies discrepancies between measured and calculated values to retrievemore accurate AOT. The comparison between MODIS and the Aerosol RoboticNetwork (AERONET) showed improvement using the suggested methodology withthe cluster-based look-up-tables (LUTs) (linear slope = 0.94, R = 0.92) thanusing operational MODIS collection 5 aerosol products (linear slope = 0.78,R = 0.87). In conclusion, the suggested methodology is shown to work wellwith aerosol models acquired by statistical clustering of the observationdata in East Asia.