What is the origin of the vernal equinox solar terms?

When the sun shines directly at the equator, it is designated as "the longitude of the Yellow River is zero", that is, the vernal equinox. What we generally know now is that the sun and the earth have been constantly revolving and rotating. The earth's orbit around the sun is usually called the ecliptic, and the 24 solar terms are divided according to the position of the sun on the ecliptic.

The vernal equinox, autumnal equinox, summer solstice and winter solstice are divided from an astronomical point of view, reflecting the turning point of solar height change. Beginning of spring, Changchun, beginning of autumn and beginning of winter reflect the beginning of the four seasons.

According to Yuan Wucheng's book "Twenty-four Solar Terms", "In mid-February, it is divided into 90 days and a half, so it is called division." Another "Spring and Autumn Story" said: "The vernal equinox, Yin and Yang are also half-phase, so day and night are cold and summer." Lunar Book: "The bucket refers to the vernal equinox, which is about Sunday, and the northern and southern hemispheres are equally divided day and night (except the poles), which is also half of spring, so it is called the vernal equinox." Lunar Book: "The bucket refers to the vernal equinox, which is about Sunday, and the northern and southern hemispheres are equally divided day and night (except the poles), which is also half of spring, hence the name vernal equinox.

The "vernal equinox" means half, that is, it is divided into two parts, day and night are equally divided, and the cold and summer are balanced. In addition, the vernal equinox also means sharing spring equally. Traditionally, it is spring from beginning of spring to long summer, and the vernal equinox is in the middle of three months in spring. Therefore, the vernal equinox was also called "Japan-China", "Day and Night Equinox" and "Midspring Moon" in ancient times. At the vernal equinox, the sun shines directly at the equator of the earth, and the length of day and night is equal.

Meteorological changes of solar terms in vernal equinox

During the spring equinox and solar terms, the East Asian trough is obviously weakened, and the trough ridge activity in the westerly belt is obviously enhanced. From Mongolia to the northeast, there are often low-pressure activities and cyclone development. Low-pressure movement causes cold air to go south, and it is windy and windy in the north. When the long wave trough moves eastward, there will be continuous rainy and cold weather due to the intersection of cold and warm air masses.

After the vernal equinox, the south began to enter a period of frequent strong convective weather. As the weather gets warmer and the soil thaws, the dusty weather in the northern region also increases.

Refer to the above? Baidu encyclopedia-vernal equinox

The Origin and Naming of Twenty-four Solar Terms