What is the phenomenon of solar aperture?

The aperture around the sun is called solar halo, also known as round rainbow, which is an atmospheric optical phenomenon. When sunlight passes through cirrostratus, it is formed by refraction or reflection of ice crystals.

Solar and lunar halos often appear on the cirrostratus, and the high-rise clouds behind cirrostratus and nimbostratus are signs of heavy rain. So there is a saying that the sun is dizzy in the middle of the night and the moon is dizzy at noon. It means that when cirrostratus appears, with dizziness, the weather will get worse.

I. Introduction

The altitude of cirrostratus is between 5500 and 8000 meters. These clouds are caused by the expansion and cooling of wet air in a wide range of slow oblique movements, so they are related to flowing cyclones and warm fronts and are located at the top of the thunderstorm layer; Sometimes, they are also related to tropical cyclones, because the wind above tropical cyclones blows from the inside to the outside, blowing the cirrostratus away from where they formed. Cirrostratus covers a large area, ranging from several hundred kilometers to several thousand kilometers, with a fairly wide continuous cloud curtain. All of them are composed of ice crystals, and there is a silk thread structure at the bottom of the cloud, which can penetrate the light of the sun and the moon and make the ground objects have shadows. Halos often appear in clouds. If the thickening of cirrostratus decreases and the system develops, it shows that the weather system will affect the stations. Therefore, there is a folk saying that "the sun is dizzy in the middle of the night, the rain is dizzy in the middle of the night, and the moon is dizzy in the afternoon". But if there is no obvious development, even if the cloud cover decreases, the weather will not change obviously in the future.

Cirrostratus is a symbol of high-altitude humid areas and large-scale air rising movement. These two conditions are closely related to the formation of precipitation. During the cold period, especially when it is transformed into cumulus clouds and rain clouds, it represents the arrival of cyclones and long-term stable precipitation. In summer, they represent the arrival of storms and tropical cyclones.

Second, shape.

When cirrostratus appeared, sometimes beautiful colored apertures appeared, the inner layer was red and the outer layer was purple. This aperture is called halo. Solar and lunar halos often appear on the cirrostratus, and the high-rise clouds behind cirrostratus and nimbostratus are signs of heavy rain. When cirrostratus is accompanied by dizziness, the weather will get worse. There is also a colored halo smaller than the halo, called "Hua". The arrangement of colors is purple and red, just the opposite of halo. Rihua and Yuehua are mostly produced at the edge of cumulus clouds. From small to large in central China, the weather tends to be fine. The central region of China is getting smaller from big to small, and the weather may turn rainy. In summer, after the rain clears, a colorful arc is often hung on the cloud curtain opposite the sun. This is a rainbow. People often say: "The east rainbow thunders and the west rainbow rains." If the rainbow is in the east, it will thunder and not rain; The rainbow is in the west and there will be heavy rain. There is also a cloud color, which often appears in the early morning or evening. The sun shone all over the sky and dyed the clouds red. This cloud is called Xia Xia. The morning glow is in the west, indicating that rainy weather is attacking us; The sunset glow in the east means that the weather has been fine in recent days. Therefore, there is a proverb "Don't go out at sunrise, but go to Wan Li Road at sunset".

Solar halos mostly appear in spring and summer. There is a folk proverb that "it rains in the middle of the night when the sun is dizzy, and it is windy at noon when the moon is dizzy", which means that if there is a solar halo, it will rain in the middle of the night, and if there is a lunar halo, it will be windy at noon the next day. To some extent, solar halo can be a precursor of weather change, and it may turn cloudy or rainy, but it is not scientific to say that this phenomenon can predict drought and flood in the climate.

Don't watch with the naked eye for a long time when the solar halo appears, so as not to burn your eyes. When it's going to rain, cirrus clouds like bird feathers often appear in the sky, and then a rainy cirrostratus appears in the air about 6 kilometers below the cirrus clouds. Due to the low temperature, the water droplets in the cloud become small ice crystals in the shape of hexagonal prisms.