Why are there sandstorms?

The causes of sandstorms include: natural conditions, physical factors, environmental factors, human factors, and meteorological factors.

1. Natural conditions

Weather conditions that are conducive to strong winds or strong winds, favorable dust source distribution and favorable air instability conditions are the main reasons for the formation of sandstorms or strong sandstorms . Strong wind is the driving force for sandstorms, and the dust source is the material basis of sandstorms. Unstable thermal conditions are conducive to the development of wind convection, which entrains more sand and dust and carries it higher.

In addition, drought and lack of rain in the early stage, warm weather, and rising temperatures are the special weather background for the formation of sandstorms; the development of convective cells in front of the ground cold front into clouds or squall lines is conducive to the development of sandstorms And strengthened small and medium-scale systems; the terrain conditions that are conducive to increased wind speed, that is, the narrow tube effect, are one of the favorable conditions for the formation of sandstorms.

2. Physical factors

Under the conditions of extremely favorable large-scale environment, high-altitude dry and cold jet stream, strong vertical wind speed, wind shear and thermally unstable stratification, near the front area The generation and development of medium- and small-scale systems intensifies the pressure and temperature gradients before and after the frontal zone, forming a huge pressure-temperature gradient before and after the frontal zone.

Under the simultaneous action of momentum downward transmission and gradient deviation wind, the near-surface wind speed rises sharply, kicking up surface sand and dust, forming sandstorms or strong sandstorms.

3. Environmental factors

Soil wind erosion is the primary link in the occurrence and development of sandstorms. Wind is the most direct driving force of soil, among which the nature of air flow, wind speed, and related conditions of wind force during soil wind erosion are the most important factors. In addition, soil moisture content is also one of the important reasons affecting soil wind erosion.

4. Human factors

The occurrence of sandstorms is not only the product of specific natural environmental conditions, but also has a corresponding relationship with human activities. Man-made overgrazing, deforestation of forest vegetation, industrial and mining transportation construction, and especially man-made excessive reclamation destroy ground vegetation, disturb the ground structure, and form large areas of desertified land, which directly accelerate the formation and development of sandstorms.

5. Meteorological factors

The formation of sandstorms is based on the special atmospheric circulation in East Asia and is closely related to the winter monsoon. The occurrence is mainly driven by the high pressure in Siberia and Mongolia in the winter half. It is related to the passage of the cold front below and is a cold front type sandstorm.