Atmospheric correction of visible to middle‐infrared EOS‐MODIS data over land surfaces: Background, operational algorithm and validation

The NASA moderate resolution imaging spectroradiometer (MODIS) instrument will provide a global and improved source of information for the study of land surfaces with a spatial resolution of up to 250 m. Prior to the derivation of various biophysical parameters based on surface reflectances, the top of the atmosphere signals need to be radiometrically calibrated and corrected for atmospheric effects. The present paper describes in detail the state of the art techniques that will be used for atmospheric correction of MODIS bands 1 through 7, centered at 648, 858, 470, 555, 1240, 1640, and 2130 nm, respectively. Previous operational correction schemes have assumed a standard atmosphere with zero or constant aerosol loading and a uniform, Lambertian surface. The MODIS operational atmospheric correction algorithm, reported here, uses aerosol and water vapor information derived from the MODIS data, corrects for adjacency effects and takes into account the directional properties of the observed surface. This paper also describes the operational implementation of these techniques and its optimization. The techniques are applied to remote sensing data from the Landsat Thematic Mapper (TM), the NOAA advanced very high resolution radiometer (AVHRR), and the MODIS airborne simulator (MAS) and validated against ground‐based measurements from the Aerosol Robotic Network (AERONET).