Operational Calibration of the Imagers and Sounders
on the GOES-8 and -9 Satellites, Page 15
Michael Weinreb, Michael Jamieson, Nancy Fulton, Yen Chen, Joy Xie Johnson,
James Bremer, Carl Smith, and Jeanette Baucom
7.1 Infrared-channel data
Calibration processing for the infrared channels takes place at the CDA in real
time. In the processing, the calibration coefficients are computed and are
applied to the raw data, converting them to radiances, as previously discussed.
The radiances are scaled linearly so that they utilize the full 10-bit (imager)
or 16-bit (sounder) word length of the GVAR. The calibration coefficients (three
per channel/detector) and the scaling coefficients (two per channel) are also
transmitted in the GVAR. Users can derive the radiances from GVAR counts by
inverting the scaling operation. The procedure for converting GVAR counts to
radiances, temperatures, and eight-bit "mode-A" counts15 is described
in detail in Appendix A. For the sounders, the GVAR will contain both radiances
and raw data. For the imagers, it will only contain the radiances, because the
GVAR does not have enough bandwidth for both. The GVAR also contains statistical
data and telemetry information for monitoring the calibration and instrument.
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Contact Michael P. Weinreb at michael.weinreb@noaa.gov
Latest Revision: July 9, 1997
