Cold air and atmospheric stratification cause haze and fog

Since January 10, severe haze and fog hit central-eastern China and Sichuan Basin. Ma Xuekuan, Chief Forecaster of Central Meteorological Office said that the force of cold air is weak and the wind goes down in North China Plain, the Middle and Lower Yangtze Valley Plain and Sichuan Basin, with stable atmospheric stratification. The precipitation and surface evaporation of the above-mentioned areas increase the relative humidity. Meanwhile, the night sky is clear with more obvious temperature cooling. These reasons are conducive to wet air saturate and condense to form fog.

In this stable weather conditions, the pollutants in the air are not easy for outward diffusion, so that the pollutants accumulate in the atmosphere to make the air worse. This is also an important reason for the severe haze in central-eastern China.

It is forecasted that before January 16, the haze and fog will continue to hit most areas of central-eastern China. Since January 16, a stream of cold air will affect China, and then the fog and haze in central-eastern China will dissipate or significantly reduce from north to south.(Jan. 14)

(Source:China Meteorological News Press)