What are the characteristics of the vernal equinox solar terms?

After the "vernal equinox" solar terms, the air is not as wet and cold as the first three solar terms. On the contrary, the spring breeze is beautiful, and the swallows return to the south to play with the willows. So do you know what are the characteristics of the vernal equinox solar terms? Next, let's take a look at the characteristics of the vernal equinox and solar terms with the old calendar!

Solar term analysis

The vernal equinox was also called "Japan-China", "Day and Night Equinox" and "Midspring Moon" in ancient times. "Twenty-four solar terms" records: "In the middle of February, it is divided into half, which is half of ninety days, so it is called minutes." This means that the length of day and night on the vernal equinox is average, just half of the 90th day of spring, so it is called vernal equinox. People regard beginning of spring, Changxia, beginning of autumn and beginning of winter as the beginning of the four seasons, while the vernal equinox, summer solstice, autumn equinox and winter solstice are in the middle of the four seasons, which all reflect the changes of the four seasons.

Solar term characteristics

On the vernal equinox, the sun shines directly at the equator, and day and night are almost equal. Then the direct sunlight position gradually moved northward, and the days were long and the nights were short. The farther the earth is from the equator, the smaller the noonday angle of the sun, and the less sunlight and heat it gets. Generally, March, April and May are spring in the northern hemisphere and autumn in the southern hemisphere.

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.

The vernal equinox has two meanings; One is that the day and night of the vernal equinox are equal, and the other is that the vernal equinox is half of the 90 days in spring (from beginning of spring to Grain Rain). Dong Zhongshu of the Han Dynasty wrote "The Story of the Spring and Autumn Period, Yin and Yang in and out". The first part is muscular: "The vernal equinox, Yin and Yang are half-phase. Therefore, it is hot and cold all day long. " On this day, the sun shines directly on the equator, and day and night are almost equal. Later, the sun moved further north, and the days in the northern hemisphere were long and the nights were short. The agricultural proverb says that "the vernal equinox and the autumnal equinox are even day and night", and "after eating the vernal equinox, the line will grow by one day."

In ancient times, the vernal equinox was divided into three stages: "wait for the mysterious bird to arrive, wait for the thunder to sound, and wait for the electricity to start." In other words, after the vernal equinox, swallows will fly from the south. Second, when it rains, the sky will thunder. Third, lightning will start to appear.

During the spring equinox, China has entered a bright spring except the Qinghai-Tibet Plateau, Northeast China, Northwest China and North China.