A synergetic approach for the retrieval of aerosol optical thickness from both AATSR data and MODIS BRDF data over Land

Abstract

As is known that multi–angle sensor can provide more information to characterize the angular spectral reflectance, which is important for the inversion of most geophysical parameters, including aerosol optical thickness (AOT). In this paper, a synergetic approach for simultaneous retrieval of AOT over land at a 1 km spatial resolution for 0.55, 0.66 and 0.87 μm from Advanced Along–Track Scanning Radiometer (AATSR) TOA radiance is presented which exploits the synergy of AATSR dual–angle view capabilities and semi–empirical linear kernel–driven bi-directional reflectance distribution function (BRDF) model product from NASA. In this approach, the BRDF characteristics of land surface are used to retrieve AOT by combining the geometrical information extracted from AATSR and linear kernel–driven BRDF parameter product. No assumptions are required about the land surface spectral properties, thus allowing for quantitative retrieval of aerosol particles over virtually arbitrary land surface. A retrieval example is given by validating against AERONET Beijing in–situ AOT measurements with the maximum standard deviation of 0.06, which suggests that the retrieval precision of AOT be favorable by accounting for BRDF effects through this synergetic approach developed in this paper.