A GOES-10/8 imager visible channel cross calibration procedure

A GOES-10/8 Imager Visible Channel Cross Calibration Procedure

Byron Raines

Raytheon Information Technology and Scientific Services

Lanham, Maryland 20706

Dan Tarpley

Climate Research and Applications Division, NOAA/NESDIS

Washington, D.C. 20233

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The Geostationary Operational Environmental Satellite (GOES) series of meteorological satellites do not employ an on-board calibration system for the visible channel data.   The post-launch sensor degradation is difficult to quantify and causes inaccuracy in measurements derived from the visible band.   Comparison of quantitative products from different satellites of this series requires estimation and correction of the signal deterioration.   The National Environmental Satellite Data and Information Service (NESDIS) now maintains coverage of North America from two GOES spacecraft, GOES-10 and GOES-8, in fixed orbital geometry.   The overlap in view from the two spacecraft now exceeds a year of data coverage.

The dual east and west GOES viewing positions, with stable geometry, present the opportunity to evaluate and correct the visible channel degradation of the two satellites through a method of cross-comparison.   The calibration estimates for both GOES-10 and GOES-8, as derived from time and space coincident observations, are the focus of this study.   Scenes selected along the meridian midway between the spacecraft, and taken near solar noon, provide a similar sun-target-sensor geometry from both views.   The individual visible channel deterioration rate estimates are derived for computing measured albedos which are identical over the period of observation from the two GOES.   Several months of observations of the signal variation between the two platforms are studied to form the basis for the derivations.   The results provide a temporally-uniform measure of the degradation rates of the two sensors that are used to correct the visible data.