When a dark cloud appears in the sky, what will meteorologists, farmers, poets, and pedestrians think of? what does this mean

A dark cloud appeared in the sky. Meteorologists, farmers, poets, and pedestrians reminded me of the Mid-Autumn Festival, when many strange weather phenomena and wonders will appear.

The moonlight and weather of the Mid-Autumn Festival are most often mentioned in ancient Mid-Autumn poems.

For example, Su Shi said in "Niannujiao·Mid-Autumn Festival":

Looking from a high distance, you can see the sky, and there are no traces of clouds thousands of miles away.

Zhao Changqing mainly talks about the weather of Mid-Autumn Festival. The sky is high and the atmosphere is solemn, and the breeze is even more refreshing, and there are no clouds for thousands of miles.

Su Shunqin’s description is even more surprising: the vast expanse of river is pure blue, and the upper and lower parts are clear and floating. Looking straight at yourself, I want to see the muscles and veins, and there is no way to escape the worries of fish, dragon and fish. I don't doubt that I am born on the ground, but I am afraid of touching a bullfight.

It means that the sky and the atmosphere are spotless, the river is clear and the waves are blue, the moon is bright in the sky, the moon is bright on the water, and the double walls complement each other. The moonlight is so clear that you can almost see through the veins on your body. Even the fish and dragons in the water are afraid of being seen clearly and have nowhere to hide. This situation made the poet forget everything, as if he had boarded a floating raft and soared up, fearing that he would collide with the Dou and Ox stars!

Dongyue Taishan Mountain has an altitude of more than 1,500 meters. Sheng Fusheng of the Qing Dynasty climbed to the top of the mountain during the Mid-Autumn Festival one year, and left behind the "Mid-Autumn Daiding Event":

Into the Clouds Drooping, the wind and thunder are going south and the sun is rushing west. Outside the intermittently setting sun, the blue sea is clear and fresh at midnight. The pillar of heaven is alone and sunny, and the sky is in the upper realm, and the ice wheel is full of mid-autumn. Looking down at the vast sky, there is dust and mist, and a clear sky faces the jade pond.

To put it simply, Mount Taishan is too high, protruding above the sea of ??clouds and dependent on the sky. In the afternoon, the thunderclouds gradually moved southward, and rainbows appeared in the sky. At night, the bright moon shines in the sky, and the earth is "earthly" when you look down. He started admiring the moon from the afternoon to midnight on the top of Mount Tai, and saw many strange Mid-Autumn weather phenomena that could not be seen on the ground.

Why is the moonlight "cold"?

There are many descriptions of "cold moonlight" in ancient poems about the Mid-Autumn Moon. For example, in Su Shi's "Niannujiao·Mid-Autumn Festival" there are "Gui Po (moon) flies over, and where the light shines, the autumn green is soaked in cold for a day" and "the dusk clouds have gathered and overflowed with clear cold"; Su Shunqin's "the breeze gradually rises with a stream of cold light" and so on.

In addition, the moon is often called "Ice Wheel" and "Guanghan Palace" in ancient poems; there is also the line "I want to ride the wind back home, but I am afraid of the beautiful buildings and jade buildings" in Su Shi's "Shui Tiao Ge Tou". "It's cold at high places" and so on, also have the meaning of "the moonlight is cold".

However, from a meteorological point of view, moonlight will not cause cold. The cold is due to the low temperature. There are two reasons for the low temperature on Mid-Autumn Night.

First, the cold air from the north frequently moves southward, directly lowering the temperature (and the Mid-Autumn Festival nights will only be clear under the control of high-pressure cold air).

The second reason is that the ground loses heat by radiation to space on a clear night, and the low temperature on the ground aggravates the low temperature in the atmosphere.

Of course, Su Shi must not have known at the time that even though the temperature on the sunny moon surface (Mid-Autumn Night) can be as high as 180 degrees Celsius above zero, there is no atmosphere on the moon, and once you leave the moon, it will be a universe of minus 273 degrees Celsius. The low temperature of space is "the two heavens of ice and fire". There was no way he could "go back" even if he wanted to.