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JOURNAL OF GEOPHYSICAL RESEARCH, VOL. 112, D13211, doi:10.1029/2006JD007811, 2007

Second-generation operational algorithm: Retrieval of aerosol properties over land from inversion of Moderate Resolution Imaging Spectroradiometer spectral reflectance

Robert C. Levy

Science Systems and Applications Inc., Lanham, Maryland, USA
Laboratory for Atmospheres, NASA Goddard Space Flight Center, Greenbelt, Maryland, USA
Department of Atmospheric and Oceanic Science, University of Maryland, College Park, Maryland, USA


Lorraine A. Remer

Laboratory for Atmospheres, NASA Goddard Space Flight Center, Greenbelt, Maryland, USA


Shana Mattoo

Science Systems and Applications Inc., Lanham, Maryland, USA
Laboratory for Atmospheres, NASA Goddard Space Flight Center, Greenbelt, Maryland, USA


Eric F. Vermote

Department of Geography, University of Maryland, College Park, Maryland, USA


Yoram J. Kaufman

Laboratory for Atmospheres, NASA Goddard Space Flight Center, Greenbelt, Maryland, USA


Abstract

Since first light in early 2000, operational global quantitative retrievals of aerosol properties over land have been made from Moderate Resolution Imaging Spectroradiometer (MODIS) observed spectral reflectance. These products have been continuously evaluated and validated, and opportunities for improvements have been noted. We have replaced the surface reflectance assumptions, the set of aerosol model optical properties, and the aerosol lookup table (LUT). This second-generation operational algorithm performs a simultaneous inversion of two visible (0.47 and 0.66 μm) and one shortwave-IR (2.12 μm) channel, making use of the coarse aerosol information content contained in the 2.12 μm channel. Inversion of the three channels yields three nearly independent parameters, the aerosol optical depth (τ) at 0.55 μm, the nondust or fine weighting (η), and the surface reflectance at 2.12 μm. Retrievals of small-magnitude negative τ values (down to −0.05) are considered valid, thus balancing the statistics of τ in near zero τ conditions. Preliminary validation of this algorithm shows much improved retrievals of τ, where the MODIS/Aerosol Robotic Network τ (at 0.55 μm) regression has an equation of: y = 1.01x + 0.03, R = 0.90. Global mean τ for the test bed is reduced from ∼0.28 to ∼0.21.

Received 20 July 2006; accepted 26 February 2007; published 13 July 2007.

Keywords: MODIS; aerosol; land.

Index Terms: 0305 Atmospheric Composition and Structure: Aerosols and particles (0345, 4801, 4906); 0480 Biogeosciences: Remote sensing; 0360 Atmospheric Composition and Structure: Radiation: transmission and scattering; 0394 Atmospheric Composition and Structure: Instruments and techniques; 0365 Atmospheric Composition and Structure: Troposphere: composition and chemistry.

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Citation: Levy, R. C., L. A. Remer, S. Mattoo, E. F. Vermote, and Y. J. Kaufman (2007), Second-generation operational algorithm: Retrieval of aerosol properties over land from inversion of Moderate Resolution Imaging Spectroradiometer spectral reflectance, J. Geophys. Res., 112, D13211, doi:10.1029/2006JD007811.