A rare "mirage" appeared in Shanghai: How did the shadow cast on the object form?

Less than 6: 00 am on August 24th, some netizens claimed that a mirage appeared in Shanghai, and took a video and uploaded it to the network. What is the title? Did you see a mirage in Shanghai today? .

As can be seen from the video, the shadows of Shanghai Center, World Financial Center and Jinmao Tower are clearly visible over Lujiazui.

But then, the Shanghai Meteorological Bureau responded in its official Weibo that this is actually a rare phenomenon of object shadow, but this phenomenon is rare and many people don't understand it. In addition, it is like a mirage, so it is often misunderstood as a mirage.

The phenomenon of shadow casting is rare, but it is not a mirage, and its formation principle is somewhat similar to that of cloud gap light.

What is cloud gap light? This phenomenon often appears around us. Is it actually something that has appeared in our textbooks? Tindal effect? When a beam of light passes through the colloid, there will be an obvious light path inside the colloid. The so-called colloid is a homogeneous mixture.

When sunlight passes through aerosol particles in the air, Michaelis scattering occurs, forming an optical path visible to the naked eye. At sunrise or sunset, the light in the cloud gap often has a golden bonus, like? Holy light? Same.

In theory, gap light can appear at any time of the day. As long as there are gaps in the clouds that block the sun, the phenomenon of gap light can be formed.

Recently, there seems to be a lot of phenomena of cloud gap light, for example, it is rare over the corner building of the Forbidden City in Beijing? Cloud gap light? .

On May 24th, Beijing was sunny and there were many clouds floating in the sky. But around 16, a rare natural wonder suddenly appeared over the Forbidden City. Many obvious lights were transmitted from many gaps in the clouds, reflecting the unique red-walled and red-tiled Forbidden City on the ground, just like? Temple? Just so-so

This rare phenomenon was photographed by Weibo and friends circle, saying that it appeared over the Forbidden City? Wan mang? , is a spectacle that can impact the human visual nerve.

In this regard, there has been controversy for a time, but this is obviously a natural phenomenon, which is caused by? Cloud gap light? Therefore, it is an optical phenomenon that light is projected below through the gap of clouds.

The reason why light is projected in the gap is because there are a lot of substances floating in the air, such as dust and water vapor, which creates a good scattering environment.

Shadows were cast over Shanghai. The Shanghai Meteorological Department explained that because the sun is at a low angle in the morning, strong sunlight shines on the building, and the huge shadow of the building is just projected on the clouds or the air layer with relatively stable stratification.

So the shadow of the building is formed, that is, the shadow we can see with the naked eye is close to the outline of the building. Simply put, it is just the shadow of the building in the sky. Mirage is a natural phenomenon formed by refraction and total reflection of light.

The formation of mirage is closely related to weather situation, meteorological conditions, geographical location and geophysics. To put it bluntly, a mirage is actually an optical phenomenon. When light propagates in a medium with uniform density, it will go straight ahead with the same speed and direction.

However, when the light obliquely enters another medium, its propagation direction will change, so that the light will be deflected at the junction of different media. This is the refraction of light and the root cause of a mirage.

When the sun shines on the ground, the temperature rises, resulting in a temperature gradient. Because of different densities, light will be refracted at the boundary of temperature gradient, that is, a mirage is the result of light refraction along a straight line in gas layers with different densities.

There are many kinds of mirage: according to its position relative to the original, it can be divided into three types: upper, lower and side; According to its symmetrical relationship with the original object, it can be divided into positive, lateral, positive and negative; According to the color, it can be divided into colored mirage and colorless mirage.

Mirages often appear in coastal areas and occasionally in desert areas. People can see houses, people, mountains, forests and other scenery, and they can exercise like real people.

What happened along the coast of Qinhuangdao? The fairy is here? It is reported that on August 15, Qinhuangdao Gold Coast Scenic Area, tourists suddenly saw the endless mountains on the distant sea, as if connected with the sky, as in myth? Fairy mountain? Just so-so

At that time, many tourists were shocked by this, because it looked so spectacular, didn't it? Fairy? Generally speaking, this phenomenon is a mirage.

In a word, a mirage is an optical phenomenon in nature, and its appearance conditions are harsh. Generally, it can only appear in a calm and windless environment, and the temperature of the atmospheric structure above the ground increases abnormally with the increase of height. Therefore, the mirage itself is hard to see.