Optical Degradation Due To Contamination On The SAGE/SAGE Ll Spaceflight Instruments

An optical model for contamination effects has been developed for the SAGEII/ERBS instru-ment. This model describes instrument throughput efficiency and response characteristics as a function of molecular contamination thickness for indexes of refraction representative of Shuttle/ERBS/SAGE II contaminants at seven spectral wavelengths between 0.385 and 1.02 micrometers. Contamination effects are treated as thin film coatings on selected optical elements which cause changes in those elements reflection/transmission/absorption characteristics. SAGE/AEM in-orbit performance data were used to estimate the optical constants for the contaminants. SAGE and SAGE II are radiometers that spatially scan the sun through the Earth's atmosphere with a narrow field-of-view in spectral intervals from visible to the near infrared.