Influence of aerosol and surface reflectance variability on hyperspectral observed radiance Aerosol Optical Retrieval and Surface Reflectance from Airborne Remote Sensing Data over Land.

Physically based retrievals of aerosol properties from remotely sensed data usually requires extensive assumptions on particulate type and vertical distribution, and ground surface reflectivity. New satellite missions, based on high spectral resolution instruments, such as PRISMA (Hyperspectral Precursor and Application Mission), represent a valuable opportunity to mitigate the dependency of the retrieval accuracy from the such (a-priori) information. This paper aims to address the potential of these new observing systems in retrieving aerosol properties specifically over coastal areas. Goal has been achieved by using simulated radiances obtained combining two aerosol models (urban and continental), and two reflecting surfaces, dark (water) and bright (sand) for the PRISMA instrument. Results showed that, in the continental regime, the expected instrument sensitivity would allow for retrieval accuracy of the optical thickness at 550 nm of 0.02 or better, with a dark surface surrounded by dark areas. Study also showed that for the urban regime, the surface plays a more significant role, with a bright surface surrounded by dark areas providing the best conditions for the aerosol load retrievals, and dark surfaces representing less suitable situations for accurate retrievals independently of the surroundings. Moreover the results obtained, led the authors to the conclusions that high resolution observations of Earth spectrum between 400 and 1000 nm, through the use of a physically based inversion system, would allow for a significant improvement of the retrieval accuracy for anthropogenic/natural aerosol, over coastal regions.