What is the winter solstice review?

Interpretation of the winter solstice is an important solar term among the 24 solar terms, and it is also a traditional ancestor worship festival in China.

The winter solstice is the 22nd of the 24 solar terms. The solar calendar reaches 270 degrees, and it intersects on the 23rd day of the Gregorian calendar (65438+February, 2 1) every year. The solstice in winter is the southernmost point of direct sunlight. On the day of winter solstice, the sun shines directly on the tropic of Capricorn, which is the most biased in the northern hemisphere, and the solar altitude angle is the smallest, which is the shortest day in all parts of the northern hemisphere.

The solstice in winter is also a turning point for the sun to return directly to the north. After this day, the direct point of the sun will go back. The direct point of the sun will move northward from the Tropic of Capricorn (23 26' s), and the daylight in the northern hemisphere (China is located in the northern hemisphere) will increase day by day.

On the day of winter solstice, although the sun is low and the days are short, the temperature of winter solstice is not the lowest in meteorology. In fact, due to the "accumulated heat" on the surface, it is usually not very cold before the winter solstice, and the real cold is after the winter solstice. Due to the great difference of climate in China, for most parts of China, this climate is obviously late in winter.

Phenological phenomenon

Some ancient Chinese literary works divided the winter solstice into three stages: "First, earthworms knot;": Second, wait for the elk horn to solve; Waiting for the spring to gush out. " It shows that the earthworms in the soil are still curled up, and the elk feel that the yin is gradually receding. Because the direct point of the sun returns to the north from winter to the future, the sun moves back and forth into a new cycle, the height of the sun rises from now on, and the days get longer day by day, so the spring water in the mountain can flow and be as warm as spring.

Winter is a good time to build water conservancy, carry out farmland capital construction and accumulate fertilizer. At the same time, wax fertilizer should be applied to prevent freezing. We should strengthen the management of winter crops, clear ditches and drain water, raise soil and bacon, and plough the uncultivated winter soil to loosen the soil, enhance the ability of water storage and moisture conservation, and eliminate overwintering pests. In the southern coastal areas where spring sowing has begun, it is necessary to do a good job in cold prevention of rice seedlings.