How are sandstorms formed?

Strong wind, strong thermal instability and sand source are the dynamic factors and material basis of sandstorm formation respectively.

Sandstorm:

1 refers to the weather phenomenon that strong winds blow up dust on the ground, making the air very turbid and the horizontal visibility less than 1km.

2. Sandstorm is a weather phenomenon in wind erosion and desertification, and its formation is influenced by both natural factors and human activities. Natural factors include strong wind, decreased precipitation and its sand source. Human activity factor refers to the increase of sandstorm frequency after vegetation destruction in the process of economic development. ?

3. Sandstorm weather mainly occurs in winter and spring. This is because there is little precipitation in winter and spring in semi-arid and arid areas, the surface is extremely dry and loose, and the wind erosion resistance is very weak. When strong winds blow, a lot of dust will be entrained in the air, forming sandstorm weather.

Reasons for formation:

1. The favorable weather situation, 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.

2. In addition, drought and lack of rain in the early stage, warmer 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.

3. The main component of soil and yellow sand is silicate. When there is little rain and the temperature is getting warmer, the silicic acid on the silicate surface loses moisture, which makes the silicate soil micelle and sand surface negatively charged, repel each other, become aerosols, and cannot gather together to form sand blowing, that is, sandstorms. Sandstorms are essentially silicate aerosols with negative charges.