Vernal equinox solar terms phenomenon

The vernal equinox refers to the average time of night and day in a day. What are the phenomena of vernal equinox and solar terms? Come and have a look with me!

Vernal equinox and solar terms:

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.

Formula of solar term phenomenon in vernal equinox:

At the vernal equinox, the direct point of the sun is on the equator, and then the direct point of the sun continues to move northward, so the vernal equinox is also called the ascending equinox.

At the vernal equinox, theoretically, the world is as long as day and night (see the dawn). After the vernal equinox, the days in the northern hemisphere are getting longer and shorter, and the nights in the southern hemisphere are getting shorter and shorter.

At the vernal equinox, there are no extreme days and nights in the world. After the vernal equinox, it began to be extremely daytime near the North Pole, and its scope gradually expanded. Near the Antarctic, the extreme day ends and the extreme night begins, and the scope gradually expands.

Vernal equinox calculation [Y*D+C]-L

Interpretation of the formula: the last two digits of the year are multiplied by 0.2422 plus 20.646, and the leap year is subtracted from the integer, and the c value of 2 1 century vernal equinox is 20.646.

For example, the date of 1992 vernal equinox = [92× 0.2422+20.646]-[92/4] = 42-23 = 19, and March19 is the vernal equinox.

Exception: calculation result in 2084 plus 1 day.

Vernal equinox and solar terms:

1. Vertical egg: Every year on the vernal equinox, tens of millions of people all over the world are doing "vertical egg" experiments. Choose a smooth and symmetrical' fresh egg' that has just been born for four or five days, gently stand up and put it on the table. The vernal equinox has become the best time for vertical egg games, so there is a saying that when the vernal equinox arrives, the eggs will be beautiful. The eggs that stand up are very beautiful. What are the customs of the vernal equinox?

2. Eat Spring Vegetables: In the past, there was an unbroken custom in Siyi called "Eating Spring Vegetables at the Equinox". "Spring vegetable" is a kind of wild amaranth, which villagers call "Artemisia chun". On the vernal equinox, the whole village went to pick spring vegetables. When searching in the wild, it is often green and thin, about the length of a palm. Picked spring vegetables are usually boiled with fish fillets at home, which is called "spring soup". There is a jingle that says, "Spring soup is dirty, but it washes the liver and intestines. The whole family is safe and healthy. " Slowly, it became a custom. Since the spring of the year, people still pray for peace and health at home.

3. Spring Festival: At the vernal equinox in February, people began to sweep graves to worship their ancestors, also known as the Spring Festival. At the beginning of the spring equinox, the graves of ancestors and distant ancestors are swept first, and the whole family and the whole village have to be dispatched on a large scale, and the team often reaches hundreds or even thousands. After the ancestral graves of Kaiji and Yuanzu were swept, they were divided into rooms to sweep the graves of ancestors in each room, and finally each family swept the graves privately. In most Hakka areas, ancestor worship and grave sweeping in spring begin at the vernal equinox or earlier, and must end in Tomb-Sweeping Day at the latest. There is a saying everywhere that after the Qingming Festival, the tomb door is closed, and the ancestors' spirits are not needed.

Introduction of vernal equinox solar terms:

The vernal equinox of 202 1 is 06:45:07 on March 2 1 and 202 1 on the second day of the second lunar month.

The vernal equinox is one of the 24 solar terms, and the vernal equinox is the midpoint of 90 days in spring, which is generally around 2 1 every year. The direct point of the sun is on the equator, and the world is divided equally day and night. In the time period, it refers to the position where the sun is located between 0 degrees and 15 degrees, which is from March 20th to April 5th. But in fact, it usually refers to the day when the sun is really at 0 degrees of the yellow meridian: March 20 or March 2 1.

After the vernal equinox, the overwintering crops in most parts of southern China entered the spring growth stage. The temperature in most parts of the south continues to rise, but generally it doesn't rain as fast as the vernal equinox. In late March, the average temperature in northern South China is mostly 13℃ to 15℃, and in southern South China it is mostly 15℃ to 16℃. Most of the plateau has been melted by snow, and the ten-day average temperature is about 5℃ to 10℃. Most areas in South China, such as river valleys, have the highest temperature, with an average of 18℃ to 20℃. In the south, except for the marginal mountainous areas, the average daily temperature rose steadily to above 12℃ in 1978, which is beneficial to planting crops such as rice and corn, and is also very suitable for afforestation. However, before and after the vernal equinox, there is often a strong cold air intrusion in South China, and the temperature drops obviously, as low as 5℃. Sometimes a small stream of cold air comes one after another, forming a low temperature and rainy weather that lasts for several days, which is not good for agricultural production. According to this feature, we should make full use of the weather forecast, grasp the cold tail and warm head, and sow in time.

;