What is the phenological phenomenon of winter solstice? What are the characteristics?

The solar term from winter to solstice has two characteristics, one is the shortest sunshine time, the other is the low temperature and cold climate. This is because, after the winter solstice, although the altitude angle of the sun becomes higher, it is a slow recovery process, and the heat lost every day is still greater than the heat received, showing a situation of "making ends meet". On the day of "March 9 and April 9", the accumulated heat is the least, the temperature is the lowest, and the weather is getting colder and colder.

1, with the shortest sunshine time in winter solstice:

The winter solstice marks the beginning of winter, which means it will be the shortest day in a year. On the solstice of winter, the northern hemisphere receives less sunlight than on any other day of the year.

The direct point of the sun from winter solstice is S23 degrees, which is characterized by the shortest sunshine time in all seasons. Geographically, the sun is the farthest day from us from winter to sunrise, in other words, the shortest day and the longest night from winter to sunrise. After the solstice in winter, the sun is getting closer and closer to us, and the days will gradually get longer.

2. The reason for the sudden drop in temperature at the end of winter solstice:

China has a vast territory, and the climate and landforms vary greatly from place to place. Although the days from winter solstice are short, the temperature from winter solstice is not the lowest; It won't be very cold before the winter solstice, because there is still accumulated heat on the surface. The real cold winter is after the winter solstice.

Because of the great climate difference in different parts of China, the astronomical climate characteristics are obviously late for most parts of China. In fact, the reason is very simple. The earth is not only affected by the sun's illumination, but also by geographical location and other factors, which will lose more heat.

Phenomena of Solstice Winter

Some ancient Chinese literary works divided the winter solstice into three stages: "First, earthworm knot;": Second, wait for the elk horn to solve; Waiting for the spring to gush out. " It means that the earthworm is still curled up in the soil, and the elk feels the yin gradually retreating and falling off its horns.

Since 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 warm at this time.

Baidu encyclopedia-winter solstice