Causes of spring drought in northern China.

1. The temperature rises rapidly and evaporates strongly in the northern region in spring.

; The summer monsoon is weak, the rainy season has not arrived, and the precipitation is less; Spring ploughing needs a lot of water, but the rainy season has not yet arrived and the groundwater level is low.

; Less precipitation than at the same latitude, explained by geographical reasons, mainly due to mountain barrier or monsoon leeward slope, affected by "foehn effect". In some areas, the bay mouth effect enables the winter wind to go straight down.

2. Insufficient rainfall is one of the reasons for the serious spring drought. In some places, it rains alternately. The precipitation in most parts of central and eastern Chongqing is more than 25mm, and the total precipitation in most parts of western Chongqing is less than 25mm. The rainfall in Tongnan, Dazu, Rongchang, Yongchuan, Tongliang and Jiangjin is 30% to 80% less than that in the same period of last year.

3. Extraordinary drought has seriously affected the water storage capacity of reservoirs and rice fields. For example, some land is seriously cracked, and it doesn't matter if it rains lightly. The storage capacity of the reservoir is about165438+700 million cubic meters, which is less than 50% of the storage capacity in the same period in history.

4. The cause of drought really lies in climate change, which is driven by human hands. Burning a lot of fossil energy such as coal and oil and emitting greenhouse gases such as carbon dioxide into the atmosphere are the fundamental driving forces of global warming.

5. The height field from Balkhash Lake to Baikal Lake and northeast China is abnormally high compared with the same period of normal years. The frequent occurrence and development of warm high-pressure ridges in this area, the dominant circulation system is high-pressure ridges, which is the main reason for the annual spring drought; The low SST and abnormal solar activity in the equatorial eastern Pacific Ocean are indirect causes of spring drought.

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