RESUMO
A field calibration campaign of ZY-3 multispectral sensor (MUS) was performed by the China Center for Resources Satellite Data and Application at the Dunhuang site. The reflectance-based method with two-point sites was used to obtain MUS absolute calibration coefficients in 2013. Compared to the calibration results in 2012, the calibration coefficients in 2013 changed by about 1%-8.5% in different bands. The results were also validated by intercalibration method using the Landsat 8 Operational Land Imager (OLI) data. It shows largely good consistency between field calibration and intercalibration. It was concluded that the absolute calibration coefficients were highly reliable.
RESUMO
The resolution of the ZY-3 MUX data is 5.8 meter, which is used to the subject classification. It is very difficult to use the dark target method for the atmosphere correction due to the lack of near infrared band in ZY-3 MUX data. The present paper uses the atmospheric correction coefficient look-up table (LUT) constructed by the radiation transmission model 6S based on the aerosol optical depth retrieved from the MODIS data for the atmospheric correction of ZY-3 image. To validate the results, the paper compares the surface spectral curves of the gypsum mine and Gobi and the NDVI values from the corrected and TOA reflectance, the relative error of the atmosphere corrected and the ground-based surface reflectance is less than 6%; the atmospheric correction increases the difference between vegetation NDVI and other features NDVI, highlights vegetation monitoring application ability.
