Why are there more sandstorms in Beijing in spring?

Sandstorms in Beijing usually occur in March and April in spring, December in winter and January of the following year.

Due to the scarcity of vegetation, more sandy soil and frequent cold waves and strong winds in northern and northwestern China, sandstorms are prone to occur in relatively dry spring. Therefore, the sandstorm season in Beijing should be winter and spring. At 7: 25 on March/March/2002 15, Beijing upgraded and issued a yellow warning signal for sandstorms. There is an obvious sandstorm in Beijing. It is estimated that by noon on June 15, the visibility in most areas will be less than 1000 meters.

At 06: 50 on 20021March 16, Beijing Meteorological Observatory lifted the yellow warning signal of sandstorm. Affected by Mongolian cyclone and cold air gale, sandstorm, sand blowing and floating dust weather occurred in a large area from the central and western Inner Mongolia to the northwest of Hebei on the night of March/day of 2002 1 year, with visibility of about 1 km and local area less than 300 meters. On the morning of March, 200218 15, the concentration of PM 10 in Beijing increased obviously, resulting in sandstorm weather.

Causes of sandstorm formation

The weather situation favorable to strong winds or strong winds, favorable distribution of dust sources and favorable air instability conditions are the main reasons for the formation of sandstorms or strong sandstorms. Strong wind is the driving force of sandstorm, and the source of sandstorm is the material basis of sandstorm. Unstable thermal conditions are conducive to the increase of wind power and the development of strong convection, thus carrying more dust and winding it higher.

In addition, drought and lack of rain in the early stage, warming weather and rising temperature are the special weather background for the formation of sandstorms. The convective cells before the ground cold front develop into clouds or squall lines, which is a small and medium-sized system conducive to the development and strengthening of sandstorms. The topographic condition conducive to the increase of wind speed, that is, the narrow tube effect, is one of the favorable conditions for the formation of sandstorms.

Reference to the above content: Baidu Encyclopedia-Beijing