The reason why the intensity of sandstorm in Minqin is weaker from night to morning than from afternoon to night.

The reason why the intensity of sandstorm in Minqin is weaker from night to morning than from afternoon to night is geographical. This place is located in arid and semi-arid area, with dry climate and little rain. In spring, due to the rapid temperature rise, windy weather, less precipitation and loose soil, it is easy to be blown by the wind. Furthermore, in spring, it moves northward, the solar radiation increases, the temperature rises, the precipitation is scarce, evaporation is vigorous, the surface is more arid and water-deficient, and the bonding force between sand grains weakens, resulting in loose surface soil. In addition, during this period, the temperature changes rapidly, the cold front activities are frequent, there are many windy days, and sandstorms occur frequently. A sandstorm is a sandstorm. It is a sign of desertification, which refers to a disastrous weather phenomenon in which strong winds roll up a lot of dust on the ground and make the horizontal visibility less than 1 km. It has the characteristics of suddenness and short duration, low probability and great harm.