What are the main contents of the ancient Chinese New Year and the Tropic of Cancer in China?

In ancient China, the so-called new moon was based on the full moon in January, and the so-called tropic year was based on the earth's annual revolution around the sun. However, the tropic year, the moon and the day are not multiples of integers, and the twelve moons are about 1 1 day less than one regression, so there should be coordinates of the month, the month and the leap. Although the new moon is convenient for timing, it is difficult to reflect climate change. So people try to divide a solar year into several smaller periods, one is to reflect climate change in detail, and the other is to meet the needs of leap. The result of the exploration was finally determined as 24 solar terms. The twenty-four solar terms were gradually formed on the basis of the sundial measured by the soil. These eight basic points are separation, arrival, opening and closing, which appeared at the latest in the Spring and Autumn Period. Every two points are divided into three sections on average, named after the corresponding meteorological and phenological phenomena. The systematic record of the twenty-four solar terms began with Zhoupian and Huainanzi.