Validation of atmospheric scattering functions used in atmospheric correction over the ocean

A new approach has been developed to validate atmospheric correction (AC) over the ocean. The latter has been applied to the ground-segment data from the Medium Resolution Imaging Spectrometer (MERIS) on board the Environmental Satellite (Envisat) platform. An atmospheric validation database has been built up with a ground-based instrument, i.e. the Cimel radiometer from the Aerosol Robotic Network (AERONET). The aim of this work is to assess the atmospheric scattering functions needed to perform AC of remotely sensed data. The inputs to this new methodology were provided by AERONET, after inversion of radiometric measurements (i.e. solar direct extinctions and sky diffuse radiances) to get the inherent optical properties (IOPs) of the aerosols. The successive orders (SOs) of scattering code have been used as the radiative transfer tool in this study. This new concept for the validation of AC has been illustrated with the MERIS level-2 data extracted from the Meris Matchup In-situ Database (MERMAID) over the Acqua Alta Oceanographic Tower (AAOT, Venice – Italy). Results indicate first, an overestimate of the MERIS aerosol optical thickness (AOT) at 865 nm, and second, a marine reflectance affected by a negative bias of about 13% at 412.5 nm. This yields to an overestimate of the MERIS algal-1 pigment index, which may exceed 50%, over AAOT. The same trend is also observed in the determination of the algal-2 pigment index.

[1]  R. Santer,et al.  A new climatology for atmospheric correction based on the aerosol inherent optical properties , 2007 .

[2]  Oleg Dubovik,et al.  Non‐spherical aerosol retrieval method employing light scattering by spheroids , 2002 .

[3]  Jim Aiken,et al.  The atmospheric correction of water colour and the quantitative retrieval of suspended particulate matter in Case II waters: Application to MERIS , 1999 .

[4]  Menghua Wang,et al.  Retrieval of water-leaving radiance and aerosol optical thickness over the oceans with SeaWiFS: a preliminary algorithm. , 1994, Applied optics.

[5]  Michael D. King,et al.  A flexible inversion algorithm for retrieval of aerosol optical properties from Sun and sky radiance measurements , 2000 .

[6]  P. Deschamps,et al.  Description of a computer code to simulate the satellite signal in the solar spectrum : the 5S code , 1990 .

[7]  André Morel,et al.  A multiple scattering algorithm for atmospheric correction of remotely sensed ocean colour (MERIS instrument): Principle and implementation for atmospheres carrying various aerosols including absorbing ones , 1999 .

[8]  A. Goetz,et al.  Atmospheric correction algorithms for hyperspectral remote sensing data of land and ocean , 2009 .

[9]  Maurice Herman,et al.  Fourier series expansion of the transfer equation in the atmosphere-ocean system , 1989 .

[10]  Alexander Smirnov,et al.  Cloud-Screening and Quality Control Algorithms for the AERONET Database , 2000 .

[11]  Didier Tanré,et al.  A successive order of scattering code for solving the vector equation of transfer in the earth's atmosphere with aerosols , 2007 .

[12]  David J. Diner,et al.  Simultaneous retrieval of aerosol and surface properties from a combination of AERONET and satellite data , 2007 .

[13]  Jean-François Léon,et al.  Application of spheroid models to account for aerosol particle nonsphericity in remote sensing of desert dust , 2006 .

[14]  B. Holben,et al.  Validation of MODIS aerosol retrieval over ocean , 2002 .

[15]  M. Rast,et al.  The ESA Medium Resolution Imaging Spectrometer MERIS a review of the instrument and its mission , 1999 .

[16]  M. Schaepman,et al.  Retrieving sup-pixel land cover composition through an effective integration of the spatial, spectral, and temporal dimensions of MERIS imagery , 2005 .

[17]  G. Zibordi,et al.  Assessment of MERIS ocean color data products for European seas , 2013 .

[18]  Hui Feng,et al.  AERONET-OC: A Network for the Validation of Ocean Color Primary Products , 2009 .

[19]  W. Munk,et al.  Measurement of the Roughness of the Sea Surface from Photographs of the Sun’s Glitter , 1954 .

[20]  R. Santer,et al.  MERIS atmospheric correction over coastal waters: validation of the MERIS aerosol models using AERONET , 2009 .

[21]  J. Hansen,et al.  Light scattering in planetary atmospheres , 1974 .

[22]  A. Smirnov,et al.  AERONET-a federated instrument network and data archive for aerosol Characterization , 1998 .

[23]  Ziauddin Ahmad,et al.  New aerosol models for the retrieval of aerosol optical thickness and normalized water-leaving radiances from the SeaWiFS and MODIS sensors over coastal regions and open oceans. , 2010, Applied optics.

[24]  J. T. Houghton.  Atmospheric radiative transfer , 1977, Nature.