Why is the autumnal equinox still hot?
Why is the autumnal equinox still hot?
Because after the autumnal equinox, the days in the northern hemisphere are short and the nights are long, the direct sunlight position moves south, the temperature difference between day and night increases, and the temperature is still very stuffy. Traditionally, the meteorological autumn refers to the autumn when the average temperature is below 22 degrees after the summer heat, and the day of beginning of autumn is beginning of autumn. The autumnal equinox is still very hot, which may be caused by the subtropical high. With the subtropical high extending to the west and lifting to the north, the "autumn tiger" will flourish in the south for a period of time, and the highest temperature in most areas will last above 30℃.
The autumnal equinox, the fourth solar term in autumn, is the sixteenth solar term among the twenty-four solar terms. The autumnal equinox means "equal share" and "equal share". On the day of the autumnal equinox, the length of day and night in the world is equal, which not only means that day and night are equally divided, but also autumn is equally divided.
According to the standard of climatology, in the "autumnal equinox" season, the average daily temperature in the Yangtze River basin and its northern area drops below 22℃, which is phenological autumn. At this time, the cold air mass from the north has had a certain impact. The rainy season has ended in most parts of the country, and words such as breezy breeze, blue sky and Wan Li, sunny weather, crisp autumn air, sweet osmanthus fragrance and crab fat and chrysanthemum yellow are all descriptions of this scene.
After the autumnal equinox, the direct sunlight moved to the southern hemisphere, and the northern hemisphere got less and less solar radiation, but the ground lost more heat and the temperature dropped significantly. The agricultural proverb says, "an autumn rain and a cold". "In August, the wild goose gate opens, and the foot of the wild goose is frosty." It is not surprising that the temperature in Northeast China drops early and frost appears at the autumnal equinox.
How much do you know about the proverb "vernal equinox"?
First, after eating the autumnal equinox, the day is shorter than the line.
On the autumnal equinox, the sun shines directly on the equator, and the day is as long as the night. However, after the autumnal equinox, the direct point of the sun will continue to move southward, and the phenomenon of shorter days and longer nights in the northern hemisphere will become more and more obvious (from winter to sunrise, the sun is directly on the tropic of Capricorn with the shortest days and the longest nights in the northern hemisphere), and it will get dark earlier and earlier.
"After eating the autumnal equinox, a thread is getting shorter every day", which means that "after the autumnal equinox, when women are sewing, they will use less thread every day than the day before. If they use the same length of wire, it will be dark ",which fully means that tomorrow will be darker and darker."
Second, summer is busy for half a month and autumn is busy for forty days.
As the saying goes, "Grab autumn, grab autumn, don't grab autumn", and the autumn equinox season just happens to catch up with the busy farming season (autumn harvest, autumn ploughing and autumn planting) in Sanqiu. The autumnal equinox is a good time to harvest corn, late rice, cotton and other crops. If you don't harvest in time, it will lead to lodging, mildew and germination in case of continuous rain, so harvest in time when the crops are mature.
"a person is mistaken for a moment, but he is mistaken for a year." After the autumn harvest, he is still busy farming. If he encounters rainy days while farming, he certainly can't. Therefore, he must use cloudy or sunny days to farm in time. There is an old saying: "Wheat is sown early and harvested in ten years and nine years; White dew is early, cold dew is late, and wheat is planted in the autumn equinox. " Timely and early sowing can make use of the heat before winter to cultivate strong seedlings for overwintering crops, which is conducive to the safe overwintering of seedlings and a good harvest in the coming year.
"Sanqiu is busy" and pays attention to the word "early", so farmers will be busy for a long time. If they are lazy and encounter adverse weather, it will not only affect this year's harvest, but also affect next year's harvest. Although "Busy in Summer" is busy harvesting and sowing in summer, there is plenty of sunshine in summer, leaving relatively more time for farmers, and the continuous busy days for farmers are relatively short.
Third, an autumn rain and a cold, ten autumn rains put on cotton.
After the autumnal equinox, the average daily temperature in most parts of China dropped below 22℃ for five consecutive days, which marked the official start of autumn in a strict sense, and the crisp autumn will become the norm.
After the autumnal equinox, the direct point of the sun continues to move southward, and the heat radiated by the sun to the ground is less and less, and the heat lost from the ground is more and more. If it rains, the ground will lose more heat and the temperature will drop sharply. People will feel colder after the autumnal equinox. In addition, the autumn rain also means that the cold air in the north continues to invade. When cold and warm air meet, it will rain. With the continuous autumn rain, people need to wear cotton-padded clothes to keep out the cold.