How is the fog formed? Why do you have it sometimes in the morning and sometimes not?

1, formed by radiation cooling, mostly occurs at night and early morning when the sun is shining, the breeze and the water vapor near the ground are rich and stable or there is inversion, which is called radiation fog in meteorology;

2. Warm and humid air moves horizontally. After passing through the cold ground or water surface, the water vapor in the air is gradually liquefied by cold, which is called advection fog in meteorology.

3. Sometimes the fog formed by two reasons is called mixed fog. It can be seen that it is late autumn and early winter that can meet these conditions, especially in the morning of late autumn and early winter.

There is actually a difference between extended data "fog" and "haze". Fog refers to the weather phenomenon that the visibility is lower than 1 km due to the condensation of suspended water vapor in the atmosphere; The formation of smog is mainly the result of a large number of suspended particles in the air and meteorological conditions. There are three reasons:

First, the phenomenon of static wind in the horizontal direction has increased.

The higher the buildings are built in the city, the obstruction and friction of airflow passing through the urban area will be obviously weakened. The increase of static wind phenomenon is not conducive to the diffusion and dilution of suspended particles in the atmosphere, and it is easy to accumulate around urban areas and suburbs.

Second, the vertical direction is reversed.

The inversion layer is like a pot cover over a city. This inversion phenomenon that the upper air temperature is higher than the lower air temperature limits the vertical movement of the lower air, making it difficult for suspended particles in the air to drift to the upper air and be blocked at the lower air and near the ground.

Third, the increase of suspended particulate matter and organic pollutants in the air.

With the growth of urban population and industrial development, the number of motor vehicles has surged, resulting in a large increase in pollutant emissions and suspended solids.

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