Irradiance-based calibration and validation of MODIS visible and near-infrared channels

Radiometric calibration is the key of improving quality and quantitative applications of the remote sense data. A irradiance-based radiometric calibration campaign was performed by National Spaceborne Demonstration at the Erenhot test site on June 1, 2007, in which Terra MODIS was the object. It showed that the irradiance-based calibration results were in good agreement with both the MODIS on-board calibration and reflectance-based calibration results with the variations less than 3.3% at the site. It was concluded that the irradiance-based calibration method was performed correctly, while the differences among the coefficients showed that the measurement of the ratio of diffuse-to-global ratio has crucial impact on results of irradiance-based calibration. The results from different aerosol modes confirmed that the irradiance-based radiometric calibration can reduce the error caused by the assumption of the aerosol mode.