Analysis of the Spatial and Temporal Variability of Aerosol Optical Thickness and Columnar Water Vapor from Meris Data

The SCAPE-M method has been developed for the retrieval of aerosol optical thickness (AOT), columnar water vapor (CWV) and surface reflectance from MERIS data. The retrieval of the three products is performed on a coupled manner taking profit of a common basis in which variations in surface elevation, topography and atmospheric state are considered pixel-by-pixel. More than 200 MERIS images have been processed by SCAPE-M. This results in a large data base of AOT, CWV and reflectance data to be validated and analysed. Comparison of SCAPE-M AOT retrievals with data from AErosol RObotic NETwork (AERONET) stations showed typical Root Mean Square Errors (RMSEs) of 0.05, an average correlation coefficient R of about 0.7–0.8. The R values grow up to more than 0.9 in the case of CWV after comparison with the same stations. Retrieved surface reflectance maps have been successfully compared with reflectance data derived from CHRIS-PROBA images and with ground-based measurements over water.