Why are there red clouds at sunrise and sunset?

Clouds often appear on the horizon at sunrise and sunset in the morning and evening. Sunrise and sunset are caused by light scattered by the air. When sunlight enters the atmosphere, it will scatter when it meets atmospheric molecules and particles suspended in the atmosphere. These atmospheric molecules and particles do not emit light, but because of scattering sunlight, each atmospheric molecule forms a scattered light source. According to Rayleigh scattering law, light with shorter wavelength such as purple, blue and cyan is the easiest to scatter, while light with longer wavelength such as red, orange and yellow has stronger transmission ability. So we can see that the bright sky is always blue, while the light above the horizon is only yellow, orange and red with longer wavelengths. After these rays are scattered by air molecules, water vapor and other impurities, the sky there presents gorgeous colors. As the saying goes, the morning glow never dies, and the sunset glow goes to Wan Li Road. In other words, the bright red morning light shows that there are a lot of water droplets in the atmosphere, which indicates that it is going to rain. If there is a fiery red or golden sunset glow, it means that there is no cloud in the west, and the sun can transmit to form a sunset glow, which indicates that the weather will be fine.

The setting sun travels thousands of miles, indicating that there is red light in the sky at night, indicating that it will be sunny the next day. The whole sentence is that the sunrise does not go out, and the sunset is thousands of miles; It means: colorful clouds sometimes appear on the horizon before sunrise and sunset. The glow seen in the eastern sky before and after sunrise is called sunrise, and the glow before and after sunset is called sunset. If there is rosy clouds in the morning, it may rain tomorrow; If there is rosy clouds at night, it may be sunny tomorrow. Weather proverbs, also known as farm proverbs, are popular expressions to express weather changes in the form of idioms or folk songs. Weather proverbs are basically the product of agricultural society. The history of dictation and notes is full of rhymes, anecdotes and proverbs to show whether it will be sunny or stormy tomorrow. These catchy agricultural proverbs, "If the morning sun does not rise, it will travel thousands of miles at dusk" and "When water is used to make tea", were summed up a long time ago. Hard-working farmers, like you, have noticed the colorful phenomena that often appear on the horizon before sunrise and after sunset, that is, morning light and dusk.

The atmosphere itself has no color, but its color comes from sunlight. Just as the clear sky is blue, the formation of rosy clouds at night is also the scattering of sunlight. When the sun rises or sets on the horizon, the light reaches the ground at an oblique angle, that is, the angle with the ground is very small, and then the sun will reach the ground through an atmosphere thicker than at any time of the day. At that time, the blue, purple and even indigo and green light of the "little people" had been scattered in the long process of crossing the atmosphere, and the remaining long-wavelength red, yellow and orange light could pass through all the way and enter our eyes. This is the color of Chardonnay that we usually see.

If there are clouds, they will be dyed orange. This is a beautiful burning cloud. The closer to the horizon, the thicker the atmosphere the sun passes through, the longer the wavelength of the light that can "escape", and the redder the glow; On the contrary, the closer to the sky, the bluer the sky. Similarly, the more dust and water vapor in the atmosphere, the stronger the scattering effect, the redder the smog, the less dust and water vapor, and the closer the smog is to cyan and white, so there is a proverb that "there is no water to burn tea". Dust and water vapor in the air will aggravate the scattering. Generally speaking, there is less dust in the atmosphere in the morning. If there is a gorgeous sunrise, it means there are clouds with a lot of water vapor in the east. The rising sun in Ran Ran heats the lower air and makes it rise into clouds. Once the clouds get longer and thicker, bad weather will come. After being scorched by the sun for a day, there is usually only a little water left in the low-altitude atmosphere, but the dust of that day will float and concentrate in the lower layer. The bright sunset glow is formed by dust and other particles scattering sunlight. They also show that the air in the west is dry. Because the west wind prevails in our country, the air flow has the law from west to east, and the dry air is entrenched overhead, so it must be clear Wan Li.