You can't dry clothes tomorrow. What does the old man mean by wind dragon?
The wind dragon the old man said refers to the sandstorm.
sandstorm refers to the weather phenomenon that strong winds blow up dust and sand on the ground, making the air very turbid and the horizontal visibility less than 1km. 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. The human activity factor refers to the increase in the frequency of sandstorms after the destruction of vegetation in the process of economic development.
Sandstorm weather mainly occurs in winter and spring. This is because there is little precipitation in semi-arid and arid areas in winter and spring, the ground is extremely dry and loose, and the wind erosion resistance is very weak. When a strong wind blows, a large amount of dust will be caught in the air, forming sandstorm weather.
Environmental factors
With the efforts of experts from the Institute of Environment and Engineering in Cold and Arid Regions, Chinese Academy of Sciences, a sandstorm wind tunnel simulation experiment specially set up to explore the start-up and transport mechanism of dust substances was successfully completed.
Through experiments, experts found that 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 airflow, the magnitude of wind speed and the related conditions of wind action in the process of soil wind erosion are the most important factors. In addition, soil water content is also one of the important reasons that affect soil wind erosion.
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, industrial and mining traffic construction, especially man-made excessive reclamation, destroy the ground vegetation, disturb the ground structure, and form a large area of desertified land, which directly accelerates the formation and development of sandstorms.
Meteorological factors
The formation of sandstorm is based on the special atmospheric circulation in East Asia, which is closely related to the winter wind. Its occurrence is mainly related to the cold front crossing driven by the Siberian-Mongolian high pressure in the winter half year, and it belongs to the cold front sandstorm.