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3 October 1998 Calibrating the GOES Imager visible channel using the moon as an irradiance source
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An activity is underway to establish the feasibility of using the Moon as an irradiance standard to calibrate the visible channel of the GOES Imagers. This channel is calibrated prior to launch but there are no facilities in the instrument for in-flight calibration of the visible band. The Moon is with in the Imager field of view for a few days disturbance of the operational observations. This makes it relatively easy to compare instruments on different GOES separate NASA-sponsored program, ground-based telescopic measurements of the Moon are being made in several spectral bands between 0.34 and 0.95 micrometers to establish the Moon as a spectral radiance standard over a wide range of illumination and liberation angles. Histograms of images of the Moon can be converted to total lunar irradiance using prelaunch calibration. This will eventually be compared with the predicted total radiance for the Moon from ground measurement to update the calibration. There are over 100,000 pixels in a GOES image of a full Moon, which enables a precise measurement. Imager test data from GOES 10 was analyzed and preliminary estimates of the performance of the two different analysis approaches are presented. This paper includes a comparisons of the relative calibration of the Moon at two times, a few days apart, which have significant changes in the Moon's illumination. This data is used to assess the ability of the model to track these changes assuming the instrument was stable over these few days. Further work will be required to improve performance of the analysis of these space data, in the ground model and in the use of this type of data to make an absolute calibration of the Imager.
© (1998) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Marvin S. Maxwell and Hugh H. Kieffer "Calibrating the GOES Imager visible channel using the moon as an irradiance source", Proc. SPIE 3439, Earth Observing Systems III, (3 October 1998);

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