Spectral band adjustment factors for cross calibration of GF-1 WFV and Terra MODIS

Cross calibration is critical to provide consistent measurements from multiple sensors. The intrinsic varieties between the Gao Fen (GF)-1 Wide Field of View (WFV) and Terra MODIS are caused by the relative spectral responses, sensor and solar zenith angle, azimuth angle. The sensor and solar observation conditions combined with the typical reflectance spectrum over Dunhuang test site were used to calculate the spectral band adjustment factors (SBAFs). A total of 32 image pairs between WFV and MODIS over Dunhuang site are available considering the cloud contamination. The SBAFs have the similar changing tendency in both 4 bands. According to the SBAFs, the gain of WFV can be calculated. TOA radiance products of MODIS and WFV are compared which shows that the accuracy of cross calibration coefficients is depending on the SBAF.