Abstract
The three-axis stabilized Geostationary Operational Environmental Satellites (GOES) have been observing the US and its neighbor environs for about two decades, providing valuable information for the weather forecast and climate change studies. Yet, due to the lack of on-board calibration device for the visible channels, accurate radiance of the Imager visible channel data depends on vicarious post-launch calibration methods which use not on-orbit references to characterize the instrument responsivity. Results of recent researches show that well characterized stable desert can be used not only to monitor sensor degradation trending, but also to facilitate sensor cross-comparisons. In the Global Space-based Inter-Calibration System (GSICS) project, it is recommended the vicarious calibration should be traceable to Aqua MODIS C6 observations to harmonize the global satellite observation quality of the solar reflected channels. This work is therefore to inter-calibrate the GOES 8 through GOES 15 Imager visible channels traceable to Aqua MODIS C6 Band 1 data using the Sonoran desert [32.05N-32.35N, 114.4W-114.7W] as the transfer. The desert is reported stable at decadal scale. Hyperion data is used to provide spectral band adjustment factors for the GOES visible and MODIS Band 1 data. In spite of occasional disturbances of the desert target reflectance and its spatial variability due to the ENSO events, the absolute calibration accuracy of the desert-based GOES visible calibration is estimated to be 2-3% with several assumptions.
Inter-calibration of GOES Imager Visible Channels Over the Sonoran Desert
The three-axis stabilized Geostationary Operational Environmental Satellites (GOES) have been observing the US and its neighbor environs for about two decades, providing valuable information for the weather forecast and climate change studies. Yet, due to the lack of on-board calibration device for the visible channels, accurate radiance of the Imager visible channel data depends on vicarious post-launch calibration methods which use not on-orbit references to characterize the instrument responsivity. Results of recent researches show that well characterized stable desert can be used not only to monitor sensor degradation trending, but also to facilitate sensor cross-comparisons. In the Global Space-based Inter-Calibration System (GSICS) project, it is recommended the vicarious calibration should be traceable to Aqua MODIS C6 observations to harmonize the global satellite observation quality of the solar reflected channels. This work is therefore to inter-calibrate the GOES 8 through GOES 15 Imager visible channels traceable to Aqua MODIS C6 Band 1 data using the Sonoran desert [32.05N-32.35N, 114.4W-114.7W] as the transfer. The desert is reported stable at decadal scale. Hyperion data is used to provide spectral band adjustment factors for the GOES visible and MODIS Band 1 data. In spite of occasional disturbances of the desert target reflectance and its spatial variability due to the ENSO events, the absolute calibration accuracy of the desert-based GOES visible calibration is estimated to be 2-3% with several assumptions.