The solar term when the plague receded

Beginning of spring, Rain, Creeping, Vernal Equinox, Qingming, Grain Rain, Changxia, Xiaoman, Mangzhong, Summer Solstice, Xiaoshu, Dashu, beginning of autumn, Chushu, Bailu, Autumnal Equinox, Cold Dew, Chufrost, beginning of winter, Light Snow, Heavy Snow, Winter Solstice, Slight Cold and Severe Cold.

Historical story of the twenty-four solar terms

The Han Dynasty absorbed twenty-four solar terms as a supplementary calendar to guide farming, and in the book Huainanzi, the names of twenty-four solar terms are completely consistent with modern times, which is the earliest record of twenty-four solar terms in existing literature.

It is said that the 24 solar terms are based on the time series changes of astronomical phenomena, temperature, precipitation and phenology in the middle and lower reaches of the Yellow River. For other parts of China, the situation described by the same solar term may be quite different. In fact, although "Li Si" can reflect the climate characteristics of the four distinct seasons in the middle and lower reaches of the Yellow River, its specific climate significance is not significant.

In climatology, beginning of spring is usually defined as a day when the daily average temperature is stable above 10℃ every five days, which is inconsistent with the meaning of beginning of spring in the middle and lower reaches of the Yellow River. Only the Lingnan area really enters the spring.

"The dividing line between beginning of spring and China in winter and spring (when the average daily temperature reaches 10 degrees Celsius for five consecutive days, it is counted as spring), from Guilin, Guangxi to Ganzhou, Jiangxi. In the area south of this line, the beginning of spring sometimes smells like spring, but 93% of the land in China is still winter. When it comes to Heilongjiang, it is often long summer and spring, and Grain Rain. The so-called beginning of spring is just a' conception'. "

Each of the 24 solar terms is separated by about half a month, divided into twelve months, and each month has two solar terms. Among the 24 solar terms, "festival" refers to a period of a year, which is a representation of a period of time; And "qi" refers to climate, which is an overview of weather changes.

China has been a country with a very developed agriculture since ancient times. Due to the close relationship between agriculture and meteorology, the ancient working people in China have accumulated rich experience in the relationship between agricultural time and seasonal changes in the long-term agricultural labor practice. For the convenience of memory, the words are connected into a formula: "Spring rain shocks the clear valley in spring, summer is full and summer is hot, autumn is cold and frost falls, and winter snow is raining."

Extended data

The 24 solar terms are divided according to the position of the earth on the ecliptic. Depending on the sun starting from the vernal equinox (longitude zero, at this moment the sun shines vertically on the equator), every advance of 15 degrees is a solar term; After a week's operation, I returned to the vernal equinox, which is a tropical year with 360 degrees, so it is divided into 24 solar terms.

The twenty-four solar terms reflect the annual apparent motion of the sun, so their dates are relatively fixed in the Gregorian calendar. The solar term in the first half of the year is on the 6th, the solar term in the second half is on the 8th and the solar term is on the 23rd, with a difference of 1 ~ 2 days. The earth revolves around the sun once every 365 days at 6: 09 and 10 second (exactly) and rotates once every 24 hours.

Because the orbital plane of the earth's rotation is not the same as the equatorial plane, but maintains a certain inclination angle, the position of direct sunlight on the earth is different all year round. In the northern hemisphere, the sun shines directly on the Tropic of Cancer (23 26' north latitude), which is called summer solstice in astronomy. When the sun shines directly on the tropic of Capricorn (23 26' south latitude), it is called the winter solstice; The solstice in summer and the solstice in winter mean that it is halfway between summer and winter.

Twice a year, when the sun shines directly on the equator, it is the vernal equinox and the autumnal equinox, in the middle of spring and autumn. The day is as long as the night.

The activity law of the direct solar point is as follows: at the vernal equinox (about March 2 1), the direct solar point is at equator 0, and then moves northward. During the summer solstice (around June 22nd), the direct point of the sun is on the Tropic of Cancer (23 26' N), and then moves south. At the autumnal equinox (around September 23), the direct point of the sun is 0 on the equator, and then it continues to move south. During the winter solstice (around 65438+February 22nd), the direct point of the sun is on the tropic of Capricorn (23 26), and then moves northward.

Baidu encyclopedia-24 solar terms in lunar calendar