What does "smoke" mean in the weather forecast?

Smoke screen refers to the atmospheric phenomenon of a large amount of smoke (a solid particle aerosol, usually caused by grassland or forest fires, factory emissions, volcanic eruptions, etc.). ) exists in the air, making the horizontal visibility less than 10 km.

Formation of smoke screen:

Smoke screen only where there is a smoke source will there be smoke screen. This sign looks simple, but it is very useful, because there are many weather stations in China's vast land without smoke screens to remember.

In addition, the smoke cloud is required to be large, scattered into pieces, covering a certain area, and the effective visibility is reduced to below 10 km. Therefore, the formation of smoke screen also needs three conditions like smog. First, there must be enough smoke sources. Second, if the wind is small, the smoke will not spread quickly. Third, there should be a lower inversion layer, so that smoke can accumulate at low altitude without spreading upward.