How are sandstorms formed, and why aren t they so frequent in China?

Sandstorms are the products of specific natural environmental conditions, and have a corresponding relationship with human activities, artificially overgrazing and deforestation of forest vegetation, industrial and mining transportation construction, especially man-made excessive reclamation to destroy ground vegetation and disturb the ground structure, will form a large area of desertified land. Dust storms will form. Sandstorm is due to the strong wind blowing up the sand and dust on the ground, so that the atmospheric visibility is sharply reduced disastrous weather, since the founding of the People's Republic of China shelter forest measures and planting trees and grass at the edge of the desert and other projects, to prevent and control the occurrence of sandstorms have played an important role, so China does not often have sandstorms.

It is the wind in the air that sweeps the sand on the ground, China is a mountainous and watery place, and in many places the wind is relatively small, and the plain area is limited.

Strong wind, strong thermal instability, and sand source are the three important conditions for the formation of sandstorms, respectively.

Favorable weather conditions for the generation of high winds or strong winds, favorable distribution of sand and dust sources and favorable air instability conditions are the main reasons for the formation of sand and dust storms or strong sand and dust storms. Strong wind is the driving force of sandstorms, and the sources of sand and dust are the material basis of sandstorms, and unstable thermal conditions are conducive to the increase of wind and the development of strong convection, so as to entrain more sand and dust and roll higher.

In addition, the drought and lack of rain in the early stage, the warming weather and the rising temperature are the special weather background formed by sandstorms. The development of convective cells in front of the surface cold front into clouds or squall lines is a small and medium-scale system that is conducive to the development and strengthening of sand and dust storms. The topographic conditions that are conducive to the increase of wind speed, i.e., the narrow tube action, are one of the favorable conditions for the formation of sandstorms.

1. Morphological characteristics.

1. The wind and sand wall is towering.

Most of the severe sandstorms on the mainland moved from the northwest or west, and a few from the east. When almost all sandstorms come, we can see black walls of wind and sand moving rapidly in the direction of the wind, getting closer and closer. From a distance, the wind and sand wall is as tall as a mountain, very much like a city wall, and it is the vanguard of the arrival of the sandstorm.

2. It's dark.

When a strong sandstorm occurs, the wind is very strong due to the wind blowing above level 8, which can roll up stones and sand. As more and more sand and dust flew into the air, the dense sand and dust covered the sky, blocking the sun and making it impossible to see anything for a while, as if it were at night.

Causes of the formation of sandstorms.

Sandstorms are generally accompanied by strong winds, and the dust they roll up can instantly make the sky gray and yellow sand, so how is the sandstorm formed?

The formation of sandstorms requires conditions, strong winds and strong winds are favorable factors for the formation of sandstorms, because they are the driving force of sandstorms, and the source of sand and dust is the material basis of sandstorms, and unstable thermal conditions are conducive to the increase of wind and the development of strong convection, so as to entrain more sand and dust, and roll higher.

Summary: Favorable distribution of sand and dust sources and favorable air instability conditions are the main reasons for the formation of sandstorms or strong sandstorms.

In addition to the above reasons, drought is also one of the main reasons for the formation of sandstorms, and the main natural disasters in sandstorm-prone areas such as North China, Inner Mongolia, and Xinjiang are also drought. When there is drought and little rain and the temperature warms, the silicic acid on the surface of the silicate loses its moisture, so that the surface of the silicate soil colloids and sand particles will have a negative charge, which has a repulsive effect on each other, and becomes an aerosol that cannot be condensed together, thus forming a sand storm that is. Dust storms are essentially silicate aerosols with a negative charge.

There are three major conditions for the formation of sandstorms.

One is the sand and dust material on the ground. It is the material basis for the formation of sandstorms.

The second is strong winds. This is the power basis for the formation of sandstorms, and it is also the power guarantee that sandstorms can be transported over long distances.

The third is the unstable air state. This is an important local thermal condition. Sandstorms tend to occur in the late afternoon and evening, which illustrates the importance of local thermal conditions.

The formation of sandstorms requires multiple conditions, the sandstorm material on the ground is the material basis for the formation of sandstorms, the strong wind is the dynamic basis for the formation of sandstorms, the unstable air state is the local thermal conditions for the formation of sandstorms, and the man-made factors such as overgrazing, deforestation and over-reclamation are also important reasons for accelerating the formation and development of sandstorms.

Causes of the formation of sandstorms.

The formation of sandstorms requires three conditions, one is the sand and dust material on the ground, the second is the wind, and the third is the unstable air state, the dust material is the material basis for the formation of the sandstorm, the wind is the dynamic basis for the formation of the sandstorm, and the air state is an important local thermal condition.

In addition, sandstorms not only occur in a specific natural environment, but also have a certain relationship with human activities, such as human overgrazing, deforestation and over-reclamation of the ground, etc., forming a large area of desertified land, which will also accelerate the formation and development of sandstorms.

What is a sandstorm

Sandstorm is a general term for sandbags and dust storms, which is a sign of land desertification, which refers to a disastrous weather phenomenon with strong winds rolling up a large amount of sand and dust from the ground, resulting in horizontal visibility less than 1 km, with the characteristics of suddenness and short duration.

Sandstorms mainly occur in winter and spring, in some semi-arid and arid areas, the precipitation is relatively small, the ground is also very dry and loose, the wind erosion resistance is weak, at this time the wind blows, it will carry a large amount of sand and dust into the air, forming a sandstorm weather.

Sand duststorm is a general term for both sandstorm and duststorm, which refers to a severe sandstorm weather phenomenon in which strong winds blow up a large amount of sand and dust materials on the ground and roll them into the air, making the air particularly turbid and the horizontal visibility is less than 1,000 meters. Sandstorms refer to sandstorms formed by strong winds blowing a large amount of sand into near-surface formations. A dust storm is a storm formed by high winds that sweep large amounts of dust and other fine particles into the air.

Relevant studies have pointed out that there are four conditions for the formation of sandstorms: first, sandand and dust materials on the ground, which are the material basis for the formation of sandstorms; the second is the strong wind, which is the power basis for the formation of sandstorms and the power guarantee that sandstorms can be transported over long distances; The third is the unstable air state, which is an important local thermal condition, and the occurrence of sandstorms in the afternoon and evening shows the importance of local thermal conditions. Fourth, the arid climate environment, sandstorms mostly occur in the spring in the north, and sandstorms do not occur for a period of time after rainfall is good evidence. In the edge area of the desert in spring, due to long-term drought and little vegetation cover on the surface, the sand and dust on the surface are easy to be blown up and transported when there is a strong wind, but due to the large particle size of the sand, it is not easy to form a suspension (suspension movement is a necessary condition for small particulate matter to ensure long-distance transport), so it can not be transported over a long distance, which is also the main reason why there is only dust and sand blowing in areas far away from the dust.

If the wind lasts for a long time, the suspended floating dust can be transported over a long distance, and a sandstorm will occur in the area it passes; When the wind speed weakens to a certain level, the floating dust will fall, and the dust will fall in the area. If it rains at this time, it will form a so-called "mud rain".

From the perspective of the four conditions required for the formation of sandstorms, the Loess Plateau, the vast desert and the land in the process of desertification destroyed by human factors, the land cultivated at the end of spring in the north and the infrastructure in the construction process (such as highways, etc.) provide sufficient material sources for the occurrence of sandstorms. The drought in the northern region in spring increases the possibility of sandstorms. Gale generation is a complex atmospheric phenomenon that is mainly the result of cold front activity or the adjustment of meridional and zonal circulation. It can be seen that the occurrence of sandstorms is the result of the joint action of a variety of complex factors, and the destruction of the natural world by human activities has led to the aggravation of land desertification, which has played an extremely important role in the occurrence of sandstorms, and in recent years, abnormal weather phenomena such as global drought (the cause of which is not yet known) have also played an immeasurable role in the occurrence of sandstorms. Therefore, human activities only play a certain role in the generation of sandstorms, and it cannot be said that sandstorms are caused by human factors.

In addition to reducing visibility, sandstorms also have many hazards, it will erode the soil on the surface, affect the growth of plants, lead to reduced crop yields, and greatly reduce air quality, easy to get upper respiratory diseases, in short, it is a bad thing, so to eliminate sandstorms, afforestation is still very important.

How are sandstorms formed? What are the hazards of sandstorms? How many other benefits can sandstorms bring? Without sandstorms, the earth can't turn?