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GRASP is a highly accurate aerosol retrieval algorithm that processes properties of aerosol- and land-surface-reflectance. It infers nearly 50 aerosol and surface parameters including particle size distribution, the spectral index of refraction, the degree of sphericity and absorption. The algorithm is designed for the enhanced characterization of aerosol properties from spectral, multiangular polarimetric remote sensing observations. GRASP works under different conditions, including bright surfaces such as deserts, where the reflectance overwhelms the signal of aerosols. GRASP is highly versatile and allows input from a wide variety of satellite and surface measurements.
Examples of aerosol optical thickness (AOT) at 0.67μm retrieval during two consecutive POLDER/PARASOL observations on 21 and 23 February 2008 over an 1800×1800km area centered at the Banizoumbou, Niger, AERONET site (indicated by an arrow).
Left: The variability of aerosol ω0(0.67μm) retrieved from POLDER/PARASOL on 1 September 2008 over an area of 1800×1800km around the AERONET site at Mongu, Zambia. Right: Map of fire locations retrieved from MODIS (Moderate-resolution Imaging Spectroradiometer) over the same area (the white rectangle circumscribes the area corresponding to the map shown at left).
Diagram illustrating the principle of combined synergetic processing of complementary observations using a multi-pixel2 retrieval approach. CALIPSO is a joint lidar mission of NASA and the French Space Agency, which also manages the PARASOL imager. AERONET is a worldwide network of radiometer sites.
Results of the GaRRLiC (Generalized Aerosol Retrieval from Radiometer and Lidar Combined data)/GRASP retrieval of aerosol vertical profiles from the coincident observations of AERONET radiometer and multi-wavelength lidar (transported smoke over Minsk, Belarus, on 13 August 2010). Left: Profiles c(h) show vertical distribution of aerosol volume concentrations of fine and coarse aerosol modes; c(h) are normalized to 1. Right: Retrieved vertical distributions of aerosol single-scattering albedo ω0(λ) (ratio of scattering to scattering plus absorption).What is the GRASP Algorithm?
GRASP (Generalized Retrieval of Aerosol and Surface Properties) is the first unified algorithm to be developed for characterizing atmospheric properties gathered from a variety of remote sensing observations
(Dubovik, O. et al., 2014, GRASP: a versatile algorithm for characterizing the atmosphere, SPIE Newsroom. DOI: 10.1117/2.1201408.005558, doi: http://spie.org/x109993.xml)
What are Aerosols?
What are the sources of aerosols and what effects do they have?
Interested in GRASP Algorithm
Acknowledgement
