||Photographic Method for Visibility Monitoring.
Richards, L. W. ;
Stoeiting, M. ;
Hammarstrand, R. G. M. ;
||Sonoma Technology, Inc., Santa Rosa, CA.;Environmental Protection Agency, Research Triangle Park, NC. Atmospheric Sciences Research Lab.
Atmospheric density ;
Optical properties ;
Optical density ;
Light scattering ;
Light transmission ;
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A visibility monitoring method is described in which photographs are taken at two distances from a scene and the data are reduced to determine the atmospheric transmittance and path radiance for the sight path between the two cameras. Data from the magenta-forming layer of color slide film are used to determine the transmittance and path radiance for green light, and these results are compared with transmittance data for the same sight path measured by teleradiometers and by a transmissometer. A film calibration method which makes it possible to determine radiances from film densities is described. It is recommended that the radiance calibration data and time of the photograph be recorded on each frame to minimize the need for special film handling and for auxiliary data records. (Copyright (c) 1989, American Chemical Society.)