What exactly is "Colorful Xiangyun"?

Colorful auspicious clouds often appear in all kinds of fairy tales, which makes people think that colorful auspicious clouds are fictional things in mythology and do not exist in real life, but in fact, colorful auspicious clouds are an objective astronomical phenomenon, but this astronomical phenomenon was called "the sun carries" or "the sun rides" in ancient times, and now we call this astronomical phenomenon "the arc around the earth".

On the morning of May 1 1, "Colorful Xiangyun" appeared over Beijing. Many netizens who saw this scene shouted: The right person is coming. What an amazing astronomical phenomenon this is. In reality, colorful auspicious clouds have seven colors: red, orange, yellow, green, cyan, blue and purple, and the color light is extremely obvious. The whole is cloud-like or flaky, so beautiful that it is almost incomparable to any natural phenomenon.

As we all know, rainbow is a typical atmospheric optical phenomenon, which usually appears in rainy days or after rain, and is formed by twice refraction and once reflection of sunlight.

Similar to the rainbow, the "flat arc around the ground" is also a "colorful auspicious cloud", which is also an atmospheric optical phenomenon, except that the sunlight of the "colorful auspicious cloud" is not water droplets, but ice crystals.

"Colorful Xiangyun" is an optical phenomenon produced by the reflection or refraction of solar rays through the ice crystal structure in the cloud. In mild weather conditions, the sun just forms an appropriate angle with the clouds. Sunlight passes through clouds, and the spectrum of the sun is separated by the refraction and reflection of ice crystals, thus scattering seven colors of light. The emergence of "colorful auspicious clouds" must meet at least three conditions. The angle between the cloud and the sunlight is appropriate, which is generally kept at10 to 40; Thin clouds containing uniform ice crystals, such as: cumulus clouds, cirrocumulus; The weather is fine and the visibility is good.

When sunlight enters the ice crystals from above the ice crystals in the atmosphere, different colors of light will be separated by refraction, thus "colorful auspicious clouds" will appear. If sunlight enters the ice crystals from below the atmospheric ice crystals, it will form another astronomical phenomenon, namely "circumzenithal arc", which is what we see as "inverted rainbow". Compared with "colorful auspicious clouds", the incidence of inverted rainbow is very high, and many people have witnessed it.

There is also a phenomenon called "super rainbow", which is mainly influenced by cold air. The clouds above are thinner and the sunlight is more penetrating. At the same time, under the dual influence of cold air and rainfall, the air quality has improved and there are more water droplets suspended in the air. The visibility of rainbow depends on the size of water droplets in the air. The bigger the water drop, the brighter the rainbow. The smaller the water drops, the less obvious the rainbow is.

Although rainbows, super rainbows and "colorful auspicious clouds" have nothing to do with people's expectation of good luck, meteorologists explained that such weather phenomena mean that the local meteorological environment conditions are good and the air quality is good.