Composition: I am careless, urgent, urgent, urgent, urgent! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !

The weather under an anticyclone is clear, windless and cloudless. The ground dissipates heat smoothly at night and the temperature drops quickly. However, it is warmer at high altitude. The air is warm at the top and cold at the bottom. The airflow is stable on the ground and all the fog droplets and dust are also Stay calm on the ground and cannot spread upward. At sunrise, the temperature on the ground is the coldest, and the fog droplets and dust are the most concentrated. The sun is covered by this layer of fog and dust. Therefore, when the sun just rises above the ground, we cannot see the sun. We have to wait until the sun rises, the ground is heated, and it condenses in the low altitude. The fog droplets and dust have dissipated before we can see the sun, so the sun will come out later on a sunny day; on the contrary, before the arrival of severe weather such as cyclones, the wind is strong and the water vapor and dust will not accumulate in the low altitude. As soon as the sun rises above the horizon, we will can be seen. Therefore, if the sun appears early, it is not a sign of sunny weather.

* The sun rises early, and the weather is hard to rely on; the sun sets over the mountains, ready to wash clothes. (Hunan)

"The sun rises early and the weather is hard to rely on." The explanation is the same as above. When the sun sets in the west, if the west is clear and cloudless, it means there is no storm coming from the west, so the weather is good.

* The sunrise and sunset are rouge red, and either it rains or the wind comes. (Hubei)

* The moon brings fire, but there is no rain to find me. (Hubei)

* When the sun goes dark, there is no rouge, and when there is no rain, there is wind. (Suzhou, Jiangsu)

* The sunset is a little red in the northwest, and I get up to put up an awning in the middle of the night. (Southern Jiangsu)

* The moon is carmine red, and it is either rain or wind. (Suzhou, Jiangsu)

* The water will be red in the evening, with heavy rain or strong wind. (Yiwu, Zhejiang)

White sunlight (moonlight is similar) passes through the triangular glass block and turns into seven colors of light: red, orange, yellow, green, cyan, blue and purple. Among the solar light waves, the red light wave is the longest, with 1.3 million can be arranged in one meter, and the purple light wave is the shortest, with 25.6 million can be arranged in -1 meter. When the light waves of the sun or moon encounter particles of the same size as the wavelength in the atmosphere, the white light is dispersed into light of different colors and radiates in different directions. This phenomenon is called light scattering. The red light wave is the longest and least likely to scatter, and the path it takes is almost straight; the purple light wave is the shortest, and its ability to scatter is sixteen times greater than the red light wave, so the path it takes is far away from its original path. scattered in a straight line direction.

When the sun is at the zenith, the distance in the air circle that the white sunlight passes through is extremely short, and it encounters the fewest particles, so the shortwave light that is scattered and scattered along the way is the least. . In other words, almost all the original components of sunlight can be sent to our eyes in their original proportions, so when we look directly at the sun, the sun is white. If you look at other parts of the sky, it appears cyan. This is because what we see is not the original component of sunlight, but only the most easily scattered purple and cyan light, while the longer wavelength red light propagates in a straight line. But purple light has the weakest sensitivity to the eyes, and only cyan light can be seen, so the sky appears cyan. When the sun is about to set, the sun is slanting, and the distance that the sun's rays have to travel through the atmosphere is too long, dozens of times longer than when it is at the zenith. Then, the particles encountered by the sun's rays on the way are dozens of times more. Almost all the short wavelengths of sunlight coming from this direction are scattered and go in other directions; what is left is only the red light wave with the longest wavelength and the least scattering. So when the sun is near the horizon, it always looks red.

The red color of the sun when it is near the earth occurs to varying degrees depending on the physical properties of the air. The more intense the disturbance in the air, that is, before the weather changes, the more dust and water droplets will be contained in the air, and the more powerful the white light will be scattered, and the purer the components of the red light wave will become, turning into blood red or carmine. If the sky is very clean, even at the horizon, short-wave light can be transmitted together with red-wave light, and the sunlight at that time will appear white and red. Because the air is clean, the weather will not get bad. There is a similar saying in the West: "The eye sockets of the red sun bring water." "It's like seeing the red sun running fast. The rain will follow."

* The reflection of the sun makes the ghost scream ( Yulin, Sichuan, Guangxi)

When the sun was setting, the zenith was covered by clouds, but there was no storm coming from the west, so the sunshine at that time must have been very strong. Strong sunlight shines from the western horizon to the dense clouds at the zenith, and then reflects to the ground. This is the phenomenon of solar reflection. From this point of view, the necessary condition for solar reflection is that there is no storm in the west, which is also the guarantee that the weather will remain clear tomorrow.

, from the west sky through the zenith, directly to the east sky, this is the proverbial green hill and white hill. I met Qinggang Baigang today. The weather will definitely be good tomorrow. Why?

Atmospheric particles scatter different components of sunlight differently. Sunlight is a complex of red, orange, yellow, green, cyan, indigo and violet light waves. Among them, the red light wave is the longest, the least likely to scatter, and the most likely to go straight; the blue-violet light wave is the shortest, the easiest to scatter, and most likely to go sideways. When the sun sets, only the last bit of the sun's disk is exposed far above the horizon.

Some of the white light emitted from this last point on the solar disk shoots into the vacuum of space, while a very small part of it shoots into our atmosphere from a long distance. However, the long waves that make up white light can only travel in straight lines and will not bend and hit the ground. Only the most easily scattered blue-violet light waves are likely to reach our eyes, so we can only see "green hills" one by one. Purple is not sensitive enough to the human eye, so it is difficult to detect its presence. The part without green hills is relatively white and gray. This is the "white hill". Because this phenomenon only occurs when the atmosphere is very stable and clean, that is, when the sky is clear, so if you see Qinggang today, the weather will be good tomorrow.

* It rains in the morning and clear in the evening. (Hubei)

* The morning glow does not go out, but the sunset glow travels thousands of miles. ("Tian Jia Five Elements" On Xia)

* Don't wash your clothes when it's burning in the morning, it will be sunny tomorrow if it's burning in the evening. (Xining, Qinghai)

* Get up early to burn the clouds and wait for the water to make tea; burn the clouds at night and it will be very hot. (Baoding, Hebei, Chongqing, Sichuan)

* If the sky is burning, there will definitely be no sunny days. (Zhengding, Hebei)

* Burning in the morning with continuous yin, and burning in the eyes in the evening. (Xiangshan, Zhejiang, Hualong, Qinghai)

* When the red clouds are rising, I advise you not to travel far; when the red clouds are setting, the sky is as clear as water. (Hebei)

The sun's rays at sunrise and sunset are red. When this red light hits the clouds, they turn into red clouds, which is called red clouds. In the morning, the sun is in the east. If there are red clouds, they are mostly at the zenith or in the west. This means that there are low clouds at the zenith or in the west. The weather always changes from west to east. This kind of low cloud must be slowly approaching the local area, which shows that rainy days are coming. On the contrary, if the sun is in the west at night, if there are red clouds, mostly at the zenith and the east, then this kind of The low clouds forming clouds will continue to move eastward, getting farther and farther away from the local area. If there is rain, it will not reach the local area, so the weather will be sunny.

* The sun is not red when it rises, and it is windy when there is no rain. (Zhejiang Yiniao)

This sentence means that when the sun comes out and the red light cannot be seen, the weather is going to get bad, and it will be windy even if it doesn't rain. If there is no red light in the morning, it means that there are thick clouds covering the sky, preventing the red light that easily penetrates the atmosphere from penetrating into people's eyes.

* The heat reaches its peak, and the well is filled with rain. (Wei County, Hebei)

* The fire is burning and the dark clouds are covering, and the heavy rain is coming soon. (Hebei)

Both sentences say that if there are red clouds in the sky, it will rain. Such clouds must be cumulonimbus or nimbostratus clouds. Because they all carry thick ice droplets, they are prone to rain. Since it is at the zenith, of course the rain falls locally.

* The sun shines in the east rainbow, the rain in the west; the rainbow in the south sells children in the north. (Zhejiang, Hebei, Kaifeng, Henan, Zhengding, Hebei)

* Donghong radish, Xihonglai, and Nanhong were flooded. (Linfen, Shanxi)

* The east rainbow booms and the west rainbow rains. (Jiangsu)

* Sunny in the east and rain in the west. (Tongliang, Sichuan)

* The rain drops in the early rainbow, and the sun breaks the face in the late rainbow. (Hebei)

* The river is full of rainbows in the morning, but the grass is dry at night. (Guangdong)

* When the rainbow comes in the morning and the rain comes in the evening, the cattle fence posts are rotten by the sun. (Guangdong)

* The rainbow rains in the morning, and the tiles crack in the evening rainbow. (Guangdong)

* There is a rainbow in the east, but the rain falls in vain; there is a rainbow in the west, and people wear raincoats. (Wuxi, Jiangsu, Yiwu, Zhejiang)

Rainbows occur when sunlight enters water droplets floating in the air. Because the speed of light in the air is greater than in water, refraction of light occurs. The reflection inside the water droplet can be more than once or several times in succession. And because the different wavelengths that make up white light - red, orange, yellow, green, cyan, indigo, and violet - have different properties, after these several refractions and reflections, the white light is dispersed and becomes different color waves. It produces various colors, so when viewed from the ground, it looks like a beautiful halo. The rainbow appears in the direction opposite to the sun. Muhong is Donghong, Chaohong is Xihong. If a rainbow is seen in the east, it means that heavy rain is falling in the east; if a rainbow is seen in the west, it means that heavy rain is falling in the west. Because weather changes in the temperate zone always occur in the west and then spread to the east; therefore, the rain in the east rainbow no longer comes to the local area; only the rain in the west rainbow is the precursor of local precipitation.

The size of sky phenomena is often measured in angle. A semicircle from the east through the zenith to the west is 180 degrees. From the horizon to the zenith, it is 90 degrees. The radius of the rainbow is approximately 42 degrees. Its center must be on the extension of the line connecting the sun and the human eye. Obviously, the angle at which the sun is above the horizon must be equal to the angle at which the center of the rainbow arc is below the horizon. Therefore, only when the sun is close to the horizon can the entire semicircular rainbow be seen. The higher the sun is, the lower the rainbow head is. Because the viewing angle of a rainbow is 42 degrees, if the sun is more than 42 degrees above the horizon, under normal circumstances, no rainbow will be visible. Around noon, there is no rainbow because the sun is too high.

The so-called southern rainbow and northern rainbow can only be seen at noon. Near the equator, between the Tropic of Cancer (23.5 north latitude and 23.5 south latitude), the sun is at the zenith almost all year round, so there is no possibility of a southern rainbow or a northern rainbow. But when the latitude is above 40 degrees, in winter, when the sun is at its lowest point in the south, the northern rainbow is easy to see. Because at 40 degrees north latitude, the sun on the winter solstice is only 26.5 degrees above the horizon, which is lower than 42 degrees. Therefore, if there are showers in the north at this time, a rainbow head can be seen on the horizon.

As usual, winter should be dry and drier (as far as our country is concerned). If the Northern Rainbow appears, it is obvious that heavy rains can occur at this time, and this winter must be hot and humid and changeable. Such abnormal weather is unfavorable to human life and crops, so it is a bad omen. In our country, except for places south of Xiamen, the sun will never go north of the zenith, so there will never be a southern rainbow.

Reference materials: /baike.asp?bid=2724