Calibration of the Eighth Geostationary Observational Environmental Satellite (GOES-8) Imager Visible Sensor

Abstract

The GOES-8/Imager has provided scientifically valuable imagery since its launch in April of 1994. However, without an onboard calibration source most research applications involving its data have been limited to qualitative analysis of the imagery. Presented herein is a review of previous quantitative work, including the prelaunch calibration information, and results of a new calibration effort that compares GOES-8/Imager raw counts of clear ocean scenes to theoretical satellite-detected radiance values from a radiative transfer model. Monthly averages of the calibration coefficient are presented at 6-month intervals from August 1995 through August 1999. Although the technique differs from previous calibration efforts, which compare Geostationary Operational Environmental Satellite observations to some reference instrument, the new calibration results agree well with previous results. The calibration suggests a one-time decrease of 7.6% shortly after launch, and an ongoing annual degradation of 5.6% thereafter.