The four seasons in Europe and America, the traditional seasons in China, the climate and the general method of division?

The four seasons are divided according to the changes in the length of day and night and the altitude of the sun. In the division of the four seasons, the apparent position of the sun on the ecliptic is used as the basis, and the bisector, the second solstice, or the four risers are used as the boundaries. However, the boundary points used in the division of the four seasons are not exactly the same in Eastern and Western countries. China's traditional method of dividing the four seasons emphasizes the astronomical significance of the four seasons, using the four risings of the 24 solar terms as the beginning of the four seasons, and the two minutes and two solstices as the midpoints. For example, in spring, the first day of spring is the starting point, the sun's ecliptic is 315°, the spring equinox is the midpoint, and the first day of summer is the end point, the sun's ecliptic becomes 45°, and the sun runs 90° on the ecliptic.

The western four seasons division more emphasis on the climatic significance of the four seasons, is to bisect the two solstices as the starting point of the four seasons, such as spring to spring into the starting point, to the summer solstice as the termination point. This four seasons than our division of the four seasons respectively one and a half months late.

From the astronomical sense, our country's to four for the division of the four seasons boundaries more scientific.

Spring and autumn equinoxes, the length of day and night and the height of the sun around the globe are equal to the average value of the year, with the typical characteristics of the transition from the extreme value (or the very small value) to the very small value (or the very large value). Therefore, the vernal equinox as the midpoint of spring, and the autumnal equinox as the midpoint of autumn is very reasonable; in summer, the day is the longest, the night is the shortest, the sun's altitude is the largest summer solstice day, the surface of the earth to obtain the sun's energy is the most. Therefore, the summer solstice as the midpoint of summer is very reasonable; similarly, the winter solstice as the midpoint of winter is also very scientific.

But, from the actual climate, the summer solstice is not the hottest time, the winter solstice is not the coldest time, the extremes of high and low temperatures are delayed for 1 to 2 months. Our country has "hot in three volts", cold in three nine "said. Therefore, the summer solstice and winter solstice are arranged as the beginning date of summer and winter respectively, which can better correspond to the actual climate. Therefore, the Western division of the four seasons better reflects the actual climate significance.

Both the astronomical division of the seasons in China and the climatic division of the seasons in the West are astronomical divisions. This is because the two divisions, the two solstices and the four risings all have exact astronomical meanings, and all divide the year into four roughly equal seasons of three months each, with the sun orbiting 90° on the ecliptic. None of them reflect the actual conditions of the climate of each place. The seasons divided by this method are the astronomical seasons.

The astronomical seasons are hemispherically uniform. Within the hemispheric sphere, each season has a uniform beginning and ending moment, and all four of these seasons, each of equal length, exist at every location within the hemisphere.

In order to accurately reflect the actual climatic conditions of each location, the four seasons are often divided by climatic methods, for example, the use of the average temperature to divide the four seasons. And the provisions: the average temperature is greater than or equal to 22 ℃ for the period of summer, less than or equal to 10 ℃ for the period of winter, between 10 ℃ ~ 22 ℃ for the spring or fall. By dividing the seasons according to this standard, the seasons and climate in the mid-latitude region are consistent, and the temperature changes in spring, summer, fall and winter in the low-latitude region and near the poles are very inconspicuous. At the same time, in the mid-latitudes, the length of the seasons is not the same. These are the climatic seasons. For example, Beijing has 55 days in spring, 103 days in summer, 50 days in fall and 157 days in winter.

The astronomical seasons have theoretical significance and the climatic seasons have practical value. The astronomical seasons are the basis for the division of climatic seasons. The astronomical seasons are hemispherically uniform. The northern hemisphere is summer, the southern hemisphere is winter; climatic seasons are localized region (mid-latitude) unified. The division of astronomical seasons depends on changes in astronomical phenomena, and the division of climatic seasons depends on changes in temperature. The astronomical seasons are of equal length regardless of the location in either hemisphere, while the climatic seasons are not necessarily of equal length in the same location. This is the main difference between astronomical and climatic seasons.