This paper describes another in flight method for satellite sensor absolute radiometric calibration

named irradiance based method which was used to calibrate the VIR channels of FY 1C with Dunhuang site. The inaccuracies of apparent reflectance computed by usual reflectance based method can be dependent on the aerosol scattering by assuming aerosol model. Irradiance based method substitute the measured ratio of diffusion to global irradiance to the aerosol scatter computed by radiance transfer code. Calibration results in five times show that the very good agreement with the reflectance based method for most dates confirm the validity of the irradiance based method. But the higher accuracy of the irradiance based method appears in the day when there is high aerosol.