Zhejiang is a foggy city. How did the foggy weather come about?

If the air contains more water vapor than saturated water vapor at a certain temperature, the excess water vapor will condense out. When enough water molecules combine with tiny dust particles in the air, the water molecules themselves will combine with each other and become small water droplets or ice crystals, thus forming fog.

If the ground heat is lost, the temperature drops and the air is quite humid, then when it is cooled to a certain extent, some water vapor in the air will condense out and become many small water droplets suspended in the air layer near the ground to form fog. Both it and clouds are caused by temperature drop, and fog can actually be said to be a cloud near the ground.

The temperature is higher during the day, so the air can hold more water vapor. But at night, the temperature drops and the capacity of water vapor in the air decreases. Therefore, some water vapor will condense into fog. Especially in autumn and winter, due to the long nights, there are not many opportunities without Feng Yun, and the ground heat dissipation is faster than that in summer, which makes the ground temperature drop sharply, so that the water vapor in the air near the ground can easily reach saturation in the middle of the night, condense into small drops and form fog. In autumn, winter and spring, when the temperature is lowest in the morning, the fog is thickest.

Formation conditions of fog Fog is a weather phenomenon, which reflects a weather condition.

The conditions of fog formation are cooling, humidification and condensation to increase water vapor content.

A kind of fog is formed by radiation cooling, which mostly appears at night and early morning, when the weather is clear, the breeze is light, the water vapor near the ground is rich and stable, or there is inversion. Meteorology is called radiation fog;

The other is that warm and humid air moves horizontally, passing through the cold ground or water surface, and the water vapor in the air is gradually liquefied by cold to form fog, which is called advection fog in meteorology;

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.

The smog in the city is caused by another reason, and that is human activities. Morning and evening are the peak hours of heating boilers. Under the condition of low air pressure and low wind speed, a large number of pollutants, such as smoke, suspended solids and automobile exhaust, are difficult to diffuse, and it is easier to form smoke (fog) when combined with water vapor in the lower air, and this smoke (fog) often lasts for a long time. What is it called? Fog capital? London (note: there is no serious smog in London now).