What do the arrival of beginning of spring and the vernal equinox represent respectively?

Beginning of spring represents the beginning of spring, and Channel 4 represents the beginning of spring, summer, autumn and winter. )

The vernal equinox, when the sun moves from south to north on the celestial sphere and reaches the intersection of the celestial equator and the ecliptic, is called the vernal equinox, which is the midpoint of spring in the northern hemisphere. The vernal equinox occurs on March 2 1 day, which is as long as day and night, so it is called the vernal equinox.

The twenty-four solar terms are divided according to the position of the sun on the ecliptic (that is, the orbit of the earth around the sun). 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 dates of solar terms are relatively fixed in the solar calendar. For example, beginning of spring in the solar calendar always falls between February 3rd and 5th. However, in the lunar calendar, the date of solar terms is not easy to determine. Take beginning of spring as an example. It can be the first day of the lunar calendar in the previous year, 65438+February 15, and the latest is the first month, 15.

It can be seen from the naming of the twenty-four solar terms that the division of solar terms fully considers the changes of natural phenomena such as seasons, climate and phenology. Among them, beginning of spring, Changxia, beginning of autumn, beginning of winter, vernal equinox, autumnal equinox, summer solstice and winter solstice are used to reflect the seasons, and a year is divided into four seasons: spring, summer, autumn and winter. 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. Because China is a vast country with a very obvious monsoon and continental climate, the weather and climate vary greatly from place to place, so the four seasons in different regions are also very different.

The five solar terms of slight summer heat, great summer heat, slight cold and severe cold reflect the change of temperature and are used to express the degree of heat and cold in different periods of the year; Rain, Grain Rain, light snow and heavy snow reflect the phenomenon of precipitation, indicating the time and intensity of rainfall and snowfall; The three solar terms, White Dew, Cold Dew and First Frost, on the surface reflect the phenomenon of condensation and condensation of water vapor, but in essence reflect the process and degree of gradual temperature drop: when the temperature drops to a certain extent, water vapor condenses; The continuous drop in temperature not only increases condensation, but also gets colder and colder; When the temperature drops below zero degrees Celsius, water vapor condenses into frost.

Xiaoman and awn seeds reflect the maturity and harvest of related crops; Frightening and Qingming reflect natural phenological phenomena, especially stinging, which indicates that spring will return with the recovery of early thunder in the sky and underground stinging insects.

Beginning of spring, Changchun, beginning of autumn and beginning of winter-also known as "Li Si"-respectively represent the beginning of the four seasons. "Stand" means to start. The Gregorian calendar is generally around February 4th, May 5th, August 7th and165438+1October 7th every year. "Li Si" indicates the beginning of the astronomical season. As far as climate is concerned, it is still in the last season. For example, the Yellow River Basin in early spring is still in the middle of winter.