How does a visibility meter work?

A visibility meter, often used in meteorology and aviation, measures the distance at which objects can be clearly seen. It typically employs a light source and a receiver; the light is directed toward a target, and the meter calculates visibility based on the intensity of the light that reaches the receiver after passing through the atmosphere. Factors like fog, rain, or pollution can scatter or absorb the light, affecting the reading. The results are often expressed in meters or kilometers, indicating how far one can see under current conditions.