Wuzhou historical meteorology

There were heavy rains in 9 provinces and regions, and most city streets were flooded. Why is there so much rain in China this year?

With the arrival of summer, there are heavy rains in Guangdong, Fujian, Guangxi, Zhejiang, Hunan, Guizhou, Yunnan and Jiangxi provinces. In some provinces, heavy rains have also caused huge economic losses, and the personal safety of residents has also been more or less threatened. So everyone must pay more attention to the weather forecast and understand the real-time changes of the weather. So, what caused so much rain this year?

1, surface water evaporates as the temperature rises.

Sunlight shines on the water surface of the earth's surface and converts it into water vapor, which can be evaporated into the air. When water vapor rises and meets cold air at high altitude, the two will combine to form small water droplets with a diameter of only 0.0 1~0.02 mm. Because these small water droplets are small and light, they can be kept in the air by the updraft existing in the air. As time goes on and the temperature rises, more and more such small water droplets gather and interact constantly? Annexation? Let the volume increase and finally fall to form rain.

2. The arrival of the rainy season in the south.

If you are a southerner living in the middle and lower reaches of the Yangtze River, then you must know what it is. Meiyu season? Because there is always a rainy time every year. The rainy season is also called because the air humidity is high and the clothes are easy to get moldy. Mildew rain? . Its formation is mainly due to the convergence of cold air and warm air in South China to form a quasi-static front in South China. With the arrival of mid-May, the warm air from south to north will be strengthened, and the quasi-static front in South China will move northward and reach the Jianghuai area, which is also known as the quasi-static front in Jianghuai. Mei Yufeng?

Because during this period, cold air and warm air are equal. Mei Yufeng? Will stay in the Jianghuai area, and produce a lot of cold and hot air convection activities. Will it finally appear in the middle and late June? Become a plum? , which is a typical plum rain.

3. The arrival of the first flood season in South China.

The flood season in South China is divided into two stages: the pre-flood season and the post-flood season, and there will be rainfall or heavy rainfall in both stages. April-June is usually the first flood season in South China, and the westerly belt on the north side of the subtropical high is the main rainfall belt in this period, which is mostly formed by the collision between cold air and warm air and the onset of monsoon, because the summer monsoon from the ocean will start its journey northward in early April every year.

In the process of going north, the cold air in the north will also move south, but the cold air has insufficient stamina. Just after Nanling, strong warm air was encountered, and the two met to form raindrops, which eventually led to the arrival of the first flood season in South China. Because it is rain formed by the interaction of cold and warm air, it is mainly frontal rain in the first flood season. The latter flood season generally refers to July to September every year, and the rainfall in this period is mainly affected by tropical climate such as typhoon.

These reasons will affect each other. The comprehensive effect led to the emergence of heavy rainfall this year. Heavy rainfall will lead to floods, landslides and other disasters. Be sure to pay more attention to the weather forecast, observe the travel terrain, ensure your own safety and prevent property losses!