THE Fog – or Fog – is, basically, the formation of clouds in proximity to the ground through the condensation of water present in the atmosphere in the form of moisture. By definition, it can only be considered fog when horizontal visibility is impaired at a distance of up to 1000 meters.
We know that condensation (or liquefaction) is the transformation of matter from a gaseous state to a liquid state. Therefore, we can conclude that fog forms when the air temperature is low enough to make water vapor liquid. For this to happen, of course, the environment must be very humid, that is, with a large amount of water droplets suspended in the air.
This phenomenon usually occurs in mountainous regions, where the altitude acts to reduce temperatures and to intercept humid air masses coming from other locations. Therefore, during the coldest hours of the day, fog is bound to form in these regions.
Example of fog in the area of a mountain range
Other points where fog occurs are in areas close to water courses, such as rivers and, especially, lakes. During the day, they emit a large amount of moisture in the form of vapor, which condenses during the night or early morning, forming the densest mists in the morning.
Example of a fog forming near a lake
When fog or fog occurs without a major obstruction of vision or when visibility is impaired at a distance greater than 1000 meters, meteorologists call it a mist, that is, the difference between fog and fog lies in the distance from the affected field of view and the intensity at which the phenomenon occurs.
By Rodolfo Alves Pena
Graduated in Geography
Source: Brazil School - https://brasilescola.uol.com.br/geografia/como-se-forma-neblina.htm
