What is the phenomenon of fog?

Fog is a kind of natural weather phenomenon, which refers to the phenomenon that when the air near the ground is cooled to a certain extent under the condition of sufficient water vapor, breeze and stable atmosphere, the water vapor in the air will condense into fine water droplets suspended in the air, which will reduce the visibility of the ground.

The essence of fog is water vapor condensation. Therefore, as long as the air temperature reaches or is quite close to the dew point, the water vapor in the air will condense and produce fog. When the temperature is above freezing point, water vapor condenses into water droplets. When the temperature is below freezing point, water vapor condenses directly into solid ice crystals, such as ice fog.

Because the dew point is only affected by air temperature and humidity, there are two main reasons for the formation of fog: first, the water vapor in the air increases greatly, which makes the dew point rise to the air temperature, thus forming fog, such as steam fog and frontal fog; Second, when the temperature drops below the dew point, fog is generated, such as advection fog and radiation fog.

The reason why the fog dissipates:

1. As the underlying surface gets warmer, the fog drops evaporate.

2. With the increase of wind speed, the fog will dissipate or dissipate into clouds; Then turbulent mixing, water vapor upload, heat transfer, and evaporation of droplets near the ground.