Vicarious calibration for GLI ocean color channels by ground observation data

The Global Imager (GLI) was launched on board the Advanced Earth Observing Satellite 11 (ADEOS-H) on December 14, 2002. We conducted vicarious calibration of the GLI ocean color channels in visible to near-infrared channels. For the calibration we used the normalized water-leaving radiance derived from the Marine Optical Buoy (MOBY), and the aerosol optical properties (aerosol optical depth, size distribution, and refractive index) released in the Aerosol Robotic Network (AERONET). The following GLI characteristics are recognized from the calibration results. First, GLI underestimates the radiance in channels 1, 2, 4, and 5. Next, in near-infrared channels, it is suggested that GLI overestimates the radiance on the order of 15% in channels 18 and 19. Furthermore, the comparison of the result with other vicarious calibration results suggests the possibility that the GLI observed radiance has offset radiance versus the simulated radiance. The estimated offset is about 0.4 W/m boolean AND 2/um/sr in channel 19, which is considered appropriate by the adaptation test to the GLI standard atmospheric correction algorithm.