What is the origin of Dashui solar terms? On July 23 or 24 every year, the sun reaches the yellow meridian 120? What time? Summer heat? Solar terms? Summer heat? With what? A little hot? Similarly, it is also a festival that reflects the heat in summer. Summer heat? It means extremely hot. Twenty-four solar terms: In mid-June, summer heat was also divided into mild summer heat and severe summer heat, with mild summer heat at the beginning of the month and severe summer heat in the middle of the month, and it is still hot now. ? At this time? Zhongfu? Before and after, most parts of the country entered the hottest period of the year, and it was also the fastest growing period of warm crops. However, natural disasters such as droughts and floods occur frequently, and the tasks of typhoon prevention and field management are very heavy.
The ancient summer heat in China was divided into three periods: first, the rotten grass was firefly; Second, wait for the soil to moisten and cool off the heat; Just when it rains heavily. ? There are more than 2000 species of fireflies in the world, which are divided into aquatic and terrestrial species. Terrestrial fireflies lay eggs on hay, and when it is hot, fireflies ovulate, so the ancients thought fireflies were made of rotten grass. The second weather is that the weather becomes sultry and the land is wet. The third kind of weather is frequent thunderstorm, which weakens the heat and humidity, and the weather begins to transition to beginning of autumn.
We know that under the control of high pressure system, high pressure produces downward flow. In the process of sinking, the temperature rises, making the sky clear, and the solar radiation is strong when it is partly cloudy. The end of July to the beginning of August is the active period of the western Pacific subtropical high, which often occupies the eastern part of China. When it is strong, it can be controlled westward to the eastern part of southwest China, such as eastern Sichuan and Chongqing.
Similarly, in summer, many areas of Chinese mainland are often controlled by continental high pressure, which is also sinking and warming. Part of the cloudy clear sky and the hot ground bake the atmosphere and maintain a high temperature. It can be seen that the high pressure system is the basic condition of high temperature weather, and the maintenance of high pressure means the continuation of high temperature weather. Generally speaking, in hot days when the daily maximum temperature is higher than 35℃ (meteorologically called? Hot weather? ), the number of heatstroke has increased significantly.
When the highest temperature of the day reaches above 37℃ (meteorologically called? Hot weather? ), the number of heatstroke will increase sharply, especially in the middle and lower reaches of the Yangtze River under the control of subtropical high. The sun is like fire, the wind is small and the humidity is high, which makes people feel sultry. Along the Yangtze River? Three stoves? Nanjing, Wuhan and Chongqing, every year? Hot weather? The average is 17 ~ 34 days. Hot weather? There are still 3 to 14 days.
Actually, than? Three stoves? There are also many hot places, Anqing, Jiujiang and Wanxian, among which Guixi in Jiangxi, Hengyang in Hunan and Kaixian in Sichuan have an average annual average? Hot weather? It's been more than 40 days, and the whole middle and lower reaches of the Yangtze River is a big area? A stove? Therefore, it is particularly important to do a good job in heatstroke prevention and cooling.
Generally speaking, the summer solar term is the period with the most sunshine and the highest temperature in South China, the period with the most abundant rainfall, the most common thunderstorm and the most concentrated days of high temperature above 30℃ in western South China, and the period with the most frequent occurrence of high temperature above 35℃ in eastern South China. The summer heat is also the season with the most thunderstorms. There is a proverb that says: East Flash has no drop, but West Flash can't go? It means that in the summer afternoon, if there is lightning in the east, the rain will not come here. If lightning is in the west, the rain will come soon, and it's too late to hide.
What do people often call a thunderstorm in summer afternoon? Northwest rain? And describe it? Northwest rain falls on the driveway. Summer rain leaves the field? And then what? Summer rain separates the cow's back? All this vividly shows that thunderstorms are often rainy here and sunny there, just like the poems of Liu Yuxi, a poet in the Tang Dynasty. It's sunny in the east and rainy in the west, but it's sunny, sunny. ?