Atmospheric Transmittance Determination from a Two-Angle Measurement of Radiance Change.

摘要

This report describes an experimental technique for estimating atmospheric transmittance to space from the ground. Using an idealized model for atmospheric absorption, it is shown that the measurement of the ratio of radiance gradients at two different zenith angles can be used to estimate the clear-sky transmittance. Transmittance obtained with this technique were compared with LOWTRAN 6 calculations using measured profiles of meteorological parameters. Results show the modeled transmittances to be in agreement with 10 percent for zenith angles above the horizon. Keywords: Radiance; Zenith angle; Aerosol scattering; Atmospheric transmittance; Thermogram. (jhd)