Autumn solar terms ppt background
In autumn, the most obvious change of natural landscape is in trees. The city will begin to clean up a lot of fallen leaves, and many tourists will flock to the mountains to watch the red leaves. Autumn, the third season of the year, is a transitional season from summer to winter. The lunar calendar is from beginning of autumn in July to beginning of winter in September, the solar calendar is from 9: 00 to 1 1, and the astronomical vernal equinox starts from the winter solstice. The standard for meteorologists to study phenology is: after the intense summer heat, the average temperature for five days is stable below 22 degrees, which means that it is autumn, and it is over when it is below 10 degrees.
Autumn solar terms:
Beginning of Autumn
It is 13 of the 24 solar terms. On August 7th or 8th every year, beginning of autumn is considered as the time when the sun reaches 135. "Autumn" means that summer is cool, which means the beginning of autumn. But in early autumn, the weather in Jianghuai area is still very hot. According to the standard of dividing seasons according to the average temperature, it must be that the average temperature for five days is below 22℃ to be considered as autumn. According to this standard, the Jianghuai area generally enters autumn in the middle and late September. After beginning of autumn, although the summer heat is hard to disappear for a while, there is still the afterglow of "autumn tiger", but the general trend is that the weather is getting colder and colder. The daily temperature range is gradually obvious, which is often very hot during the day and very cold at night.
The heat is over
Summer is 14 of the 24 solar terms. "Out" means going. In summer, the heat stops here, that is, in summer, the hot summer will pass, the temperature will gradually drop, and the rainfall will gradually decrease. However, this is only a general rule. In the Jianghuai area, the difference is bigger year by year. In some years, the weather during the hot summer is even hotter than that in summer, resulting in the so-called "autumn tiger" weather. Because of this, the intense heat in the Jianghuai area is interpreted as "the intense heat in midsummer". Therefore, remind people to pay attention to heatstroke prevention at this time. The temperature difference between day and night in the north is gradually increasing, so it is necessary to add clothes in time in the morning and evening to prevent colds.
Autumn Equinox
The autumnal equinox is a solar term representing seasonal changes. On the day of the autumnal equinox, the sun is located at longitude 180 degrees, and the sunlight is almost direct to the equator, and day and night are almost equal. At this time, the waiting temperature in the southern region has generally dropped below 22℃, and it has entered a cool autumn. "An autumn rain and a cold". The cold air from the south meets the warm and humid air that gradually decays, resulting in repeated rainfall and the temperature dropping again and again. In the northern part of the northwest plateau, the daily minimum temperature has dropped below 0℃, and you can already see the magnificent snow scene flying all over the sky and the earth wrapped in silver.
Cold Dew
Every year1when the sun reaches 195 on October 8 or 9? Cold dew. "Twenty-four solar terms" said: "In September, the dew is cold and will condense." Cold dew means that the temperature is lower than that of the white dew, and the dew on the ground is colder and will soon condense into frost. In the cold dew season, Nanling and the vast area to the north have entered autumn, and the northeast and northwest regions have entered or are about to enter winter. In the capital Beijing, you can see the first frost in many years. In addition to the perennial snow on the Qinghai-Tibet Plateau, it has generally begun to snow in the northeast and northern Xinjiang.
Frost's Descent
The solar term of the first frost is1October 23rd or 24th every year, 10. According to the "Twenty-four solar terms": "In mid-September, the gas is cold and condensed, and the dew is like frost." It can be seen that the first frost refers to the beginning of frost. However, China has a vast territory, and the climate varies greatly from place to place. "The first frost in the first frost" reflects the climate characteristics of the Yellow River Basin. As far as the annual frost days are concerned, there are frost and snow in some parts of the Qinghai-Tibet Plateau even in summer, and the annual frost days are over 200, which is the place with the largest number of frost days in China. Eastern Tibet, southern Qinghai, Qilian Mountain, Western Sichuan Plateau, Northwest Yunnan, Tianshan Mountain, The annual frost days in Altai mountain area, western mountainous area of northern Xinjiang, northeast China and eastern Inner Mongolia all exceed 100 days, the vast areas south of Huaihe River and Hanshui River and east of Dongpo of Qinghai-Tibet Plateau are all below 50 days, the south of 25 north latitude and Sichuan Basin are only about 10 days, the average annual frost days in south of Fuzhou and coastal areas of Guangdong and Guangxi are less than days, and Xishuangbanna, Hainan, southern Taiwan Province Province and the South China Sea are among them.
Autumn literature:
1. The beauty of autumn is mature-it is not as shy as spring, so open in summer and so introverted in winter.
2. Autumn, harvest season, golden season-as lovely as spring, as enthusiastic as summer, as charming as winter.
3. The sunshine in autumn is warm and quiet, the autumn wind in Dong township is warm and gentle, and the blue sky and white clouds are elegant and melodious.
The golden rice fields in the distance roll like golden waves under the autumn wind, which is very spectacular.
As soon as September comes, autumn comes. It slips away in the foggy dawn and disappears in the hot afternoon. It tiptoed past the top of the tree, dyed a few leaves red, and then left the valley like a gust of wind.