An Assessment of Atmospherically-corrected Aster Evi from Geo Grid

We developed an on-demand processing service on the GEO Grid system to generate Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) Digital Elevation Model (DEM) and ortho-rectified images. The latest algorithms of radiometric and atmospheric corrections are also supported on this system (Sekiguchi et al., 2008). We implemented the MODTRAN3.7-based atmospheric correction for ASTER visible and near Infrared (VNIR) and short wavelength infrared (SWIR) bands on our system. Atmospheric correction algorithm is able to remove Rayleigh scattering, water vapour absorption, and aerosol effects with terrain effects by using ASTER DEM and Moderate Resolution Imaging Spectroradiometer (MODIS) Atmosphere L3 gridded product (MOD08_D3). On the other hand, recent researches confirm the superiority of relationships between Enhanced Vegetation Index (EVI) and biophysical parameters. Yamamoto et al. (2010) evaluates three kinds of ASTER EVIs, which include two forms of the two-band EVI with ASTER red and NIR bands but without a blue band and the original, three-band EVI computed with ASTER red/NIR and MODIS blue reflectances generated by the previous GEO Grid system. The atmospheric correction on the previous system does not include the aerosol correction and terrain effect. This research shows the ASTER EVI using new surface reflectance products generated on GEO Grid. MODIS surface reflectance is also generated by the common atmospheric correction, and then ASTER EVIs are compared with MODIS EVI. * Corresponding author.