There is often foggy weather in autumn and winter. Why?

In the morning of autumn and winter, when you open the window, you can see large tracts of white fog. Walking on the road, I feel the air is wet, and tiny water drops will fall down. But why do heavy fog appear frequently only in autumn and winter? Because the temperature difference between day and night is too large, water vapor condenses.

1, causes of fog in autumn and winter

The temperature difference between autumn and winter is still very large. During the day, the temperature rises under the sunshine, and the air contains a lot of water vapor that we can't see with the naked eye. At night, due to insufficient temperature supply, the ground heat is lost, which makes the ground temperature drop by two times. At the same time, the air near the ground will drop sharply under this influence. When the water vapor in the air sinks to the ground, it will be tightly squeezed together to form small water droplets. Too many small water droplets gather together, blocking our sight and forming white fog. Especially in autumn and winter, due to the long night time and the cloudless and windless conditions in Wan Li, the heat dissipation on the ground is rapid, and the condensation speed of water vapor near the ground is particularly fast from midnight to morning, which is also the reason why fog often forms in autumn and winter morning.

2. Formation conditions of fog

The conditions for fog formation in autumn and winter are specifically the cooling, humidification and condensation of air near the ground. There are several types of fog, one is formed by radiation cooling, also called radiation fog. The required conditions are sunny, breezy, sufficient water vapor near the ground, and stable inverse temperature difference at night or early morning. The second type is advection fog, which is formed by the cold liquefaction of water vapor in the air. The third kind is mixed fog, which has the characteristics of the above two kinds of fog. It can be seen that the intelligence of meteorological conditions on the formation of these fogs is most obvious in autumn and winter, especially in the early morning of autumn and winter.

In foggy autumn and winter, we should pay attention to protect ourselves, especially the fog contains various harmful substances, which will have a great impact on our health. Casual details can cause respiratory diseases. Therefore, in foggy days, we should reduce our stay outside, wear masks when going out and take more precautions.