Characteristics of solar terms in the Millennium

Characteristics of the Millennium solar terms: After entering the Millennium solar terms, the summer monsoon is gradually replaced by the winter wind, and the cold air gradually moves south. In addition, the position where the sun directly touches the ground moves south, so the sunshine time in the northern hemisphere is shortened and the sunshine intensity is weakened. At night, it is often partly cloudy and sunny, and the ground radiation dissipates quickly, so the temperature drop is gradually accelerated. There is a saying called "Autumn night in a thousand years, one night is cold".

After the Millennium, the temperature difference between day and night gradually widened. Although the temperature is high at noon during the day, it is already very cold in the morning and at night. According to the standard of "average weather temperature" proposed by modern scholar Zhang Baokun, the average weather temperature is 10-22℃ in spring or autumn. According to this standard, from the beginning of the Millennium solar term, all localities began to enter autumn one after another. At this time, the temperature difference between day and night in China can reach 8℃- 16℃, so the Millennium is a solar term with a large temperature difference in a year.

Phenological phenomenon

During the Millennium solar term, the summer heat gradually disappears, the autumn air is crisp, the osmanthus fragrance is fragrant, migratory birds such as Hongyan and Swallow begin to fly south to avoid the cold, and various birds begin to store food for the winter.

"Hongyan comes, Xuanniao returns." After the Millennium, migratory birds that are most sensitive to climate migrate collectively. Hongyan began to fly from the north to the south, and mysterious birds from the south also flew back to the north, and various birds began to store food for winter. There is a saying in the folk proverb: "The white dew flies in the south in the autumn night", "When beginning of autumn knows it, it makes people sleep, and the sunflower laughs in summer, and the white dew returns to the wild goose, and the osmanthus fragrance fills the garden in the autumn equinox". Therefore, migratory birds like geese are regarded as a symbol of autumn.