Optical depth
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In physics, optical depth or optical thickness is the natural logarithm of the ratio of incident to transmitted radiant power through a material. Thus, the larger the optical depth, the smaller the am
Aerosol Optical Depth (AOD) at 830 nm measured with the same LED sun photometer from 1990 to 2016 at Geronimo Creek Observatory, Texas. Measurements made at or near solar noon when the Sun is not obstructed by clouds. Peaks indicate smoke, dust and smog. Saharan dust events are measured each summer.
Sun photometer
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A Sun photometer is a type of photometer conceived in such a way that it points at the Sun. Recent sun photometers are automated instruments incorporating a Sun-tracking unit, an appropriate optical s
Optical depth
…into several components, ascribed to Rayleigh scattering, aerosols, and gaseous absorption. The optical depth of the atmosphere can be measured with a Sun photometer. The optical depth with respect to the height within the atmosphere is given by τ ( z ) = k a w 1 ρ 0 H e − z / H and it follows that the total atmospheric…
Sun photometer CIMEL 318A in Tõravere