What is the state of fog?

Fog is a liquid, a small water droplet condensed in the air. When the relative humidity reaches 100%, the water vapor in the air will condense into fine water droplets suspended in the air, which will reduce the visibility on the ground. This weather phenomenon is called fog. Most of them appear between February and April in spring. Forming conditions: cooling, humidifying and increasing water vapor content. There are radiation fog, advection fog, mixed fog and evaporation fog.

Fog is one of the weather that has the greatest influence on human traffic activities. The deterioration of visibility in foggy days is easy to cause traffic accidents. In highway traffic accidents, traffic accidents caused by bad weather such as dense fog account for about a quarter of the total, which not only hinders traffic, but also causes great losses to the country and people's lives and property. Because the fog is uneven, it will cause visual errors, and the driver's judgment of distance and speed is quite different from the actual situation, and the sight distance is shortened, which is easy to collide with the car in front. Especially on the expressway, once a traffic accident happens, it will often cause a chain reaction and eventually form a serious traffic accident.

Fog is ever-changing and complicated, but it is nothing more than radiation fog and advection fog. Although there are various phenomena, the essence is the same: water vapor condenses when it meets cold. Sometimes fog indicates sunny days, sometimes fog indicates rainy days, and it looks chaotic. However, as long as the characteristics of radiation fog and advection fog are mastered, observed in many aspects and carefully analyzed, the laws of fog, sunny and rainy weather can be accurately grasped, and the weather can be predicted. This is very useful for agriculture, transportation, aerospace and navigation.