At short wavelengths, the reflectance observed by a satellite sensor is a combination of surface and atmospheric signals, the latter – under clear conditions – being dominated by aerosols. In order to accurately estimate the terrestrial surface dynamics, the observed Top-of-Atmosphere (TOA) reflectances should be corrected for the influence of the aerosol contribution. The current operational Atmospheric Correction applied to PROBA-V TOA observations (Sterckx et al. 2014) uses the Simplified Model for Atmospheric Correction (SMAC) v4.2 (Rahman and Dedieu 1994, Berthelot and Dedieu, 1997). The aerosol optical thickness (AOT) is estimated with an optimization method that utilises a relation between TOA NDVI and the observed SWIR / BLUE reflectance ratio (Maisongrande et al. 2001).
The objective of the ATMO Activity was to investigate the added value of a joint surface reflectance – aerosol retrieval algorithm to improve the land surface reflectance characterization derived from PROBA-V observations. The suggested method took advantage of previous work (Govaerts et al. 2010), using an Optimal Estimation method originally developed for usage on Meteosat Spinning Enhanced Visible and Infrared Imager (SEVIRI) observations, which was adapted to enable application to PROBA-V observations.