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RADIOMETRIC CALIBRATION COEFFICIENTS OF WATER-BODY FOR “HJ-1” SATELLITE MULTI-SPECTRAL CCD SENSORS BY CROSS-CALIBRATION BASED METHOD

In this paper, the four visible and near-infrared spectral bands of HJ-1/CCD1, HJ-1A/CCD2, HJ-1B/CCD1 and HJ-1B/CCD2 were calibrated respectively using cross-calibration methods based on the EOS/MODIS. The latter has the high radiation precision, and simultaneously passed through the South China Sea. The radiometric calibration coefficients of water-body targets for “HJ-1” satellite multispectral CCD sensors were obtained and validated. The results showed that (1) there were a larger difference in cross-calibration coefficients on all bands of the four sensors of the CCD camera in HJ-1A/B, in which the cross-calibration coefficients on band 1 and 2 (blue and green bands) were relatively stable, while the calibration coefficients on band 3 and 4 (red and near-infrared band) appear obvious difference.(2) by comparison of the water-leaving radiance between the inversion of cross-radiometric calibration coefficients in this paper with the inversion of the absolutely radiometric calibration coefficients which were obtained in DunHuang land radiometric calibration field in China, it was found that the water-leaving radiance of the latter were much larger than the former, which indicates that the high reflectivity of the land field led to a higher water-leaving radiance from inversion. Therefore we recommend that on the research of water quality in quantitative remote sensing be very cautious by using the absolutely radiometric calibration coefficients from the land calibration field.