The number of annual gale days in Northwest Chinese and sandstorm days figure
In the north of China, the westerly belt system of the atmospheric circulation has great
influence, and more cold air activities. When the cold air is active, the air pressure system
is cold and high pressure, and the front is cold front and windy weather. In the mountains
of the northwest, the topographical effect has a positive effect on the strong winds. Therefore,
there are many windy days in the northwest.
There are two reasons for the impact of sandstorm weather. In terms of climate: China's northwestern
region is a temperate continental climate with large temperature differences in winter and summer
and less precipitation throughout the year. In the spring, the temperature rises rapidly, and a lot
of water vapor is taken away during the evaporation process, making the surface dry. And in the
northwest region, controlled by the subtropical high and the west wind, the wind is large, and it is
very easy to form dusty weather. When the wind reaches a certain level, the dust will accumulate and
form a sandstorm.
Vegetation: Due to climatic factors, the northwestern region of China has less precipitation, strong
light and large heat, so the vegetation coverage is extremely small and the desertification is serious.
The vegetation has the function of preventing wind and sand, while the vegetation in the northwestern
part of China is sparse and the soil is desertified, so it is easy to form sandstorm weather.