Causes of Cold Wave, Drought and Sandstorm in Northern China

1, Causes of cold wave in North China: In the Arctic, due to the weak sunlight, the ground and atmosphere get less heat, and it snows all the year round. In winter, the direct sunlight passes through the equator and reaches the southern hemisphere. The arctic region is colder and wider, and the temperature is generally below MINUS 40℃-50℃. Large-scale cold air masses gather to a certain extent, and under the action of suitable high-altitude circulation, they will invade southward on a large scale, forming cold wave weather.

2. The drought in northern China is caused by natural and man-made factors.

Natural reasons: ① Unstable hydrothermal conditions lead to uneven seasonal distribution of precipitation and severe spring drought; (2) the passage of winter wind; ③ Close to sand source; ④ Strong evaporation and low vegetation coverage.

Man-made reasons: ① it is the main agricultural commodity production base, and the irrigation water is increasing; ② The population and cities are dense, and the per capita water resources are scarce; (3) Excessive pumping of groundwater leads to land subsidence, seawater intrusion and lack of water resources.

3. The reasons for frequent sandstorms in northern China are as follows: ① The wind erosion on the soil is more and more serious due to the dry climate and loose soil; (2) Under the increasing population pressure, people have destroyed forests for land reclamation and cut down trees indiscriminately, thus reducing the forest coverage rate. (3) Driven by economic interests, overgrazing and indiscriminate digging of medicinal materials have led to rapid degradation of forests and grasslands, continuous expansion of desertified land area and frequent sandstorms.