When and where did a mirage appear

Penglai appeared in Duolian.

Xinhuanet Shandong Channel, April 16, 2009.

On the afternoon of the 14th, a mirage appeared on Changdao Island in Shandong, which lasted for more than 1 hour, and the best observation point was in Penglai, where thousands of people were fortunate enough to witness this spectacle with their own eyes. But Long Island, which is in the middle of it, cannot be seen.

According to meteorologists, the main cause is that the temperature fluctuates greatly in spring, and the air density at high and low altitudes is greatly different due to the influence of the cold air front at the low level, so that the atmosphere becomes a lens, resulting in refraction and the formation of a mirage.

17. A mirage appeared in Shenzhen Bay.

The duration is about 35 minutes.

On July 1, Chengdu's earth-shattering spectacle - mirage appeared, lasting 30 minutes.

Just search for a mirage.

Mirages often occur in seaside and desert areas, as well as in polar ice fields. The reason is that the drastic temperature gradient changes unevenly, which makes the light refraction change significantly under the temperature difference. When the optical fiber is refracted, it will appear in the air or on the ground, also known as a mirage.

It's what we call a mirage.

There are upper and lower mirages. Now is the meaning of manifestation.

Upper mirages are often found in areas such as snowy fields and cold oceans. These areas are cooled near the surface, creating a dramatic temperature gradient of hot at the top and cold at the bottom. Due to the refraction of the atmosphere, the scene of the ground is lifted upwards and displayed in the air, and it seems that the distant scene seems to be at a certain height in the sky, and even the distant horizon can be seen.

The following scenes.

Mirages often occur over waters, land, seashores, and highways that are strongly warmed by the sun. The warming of the earth's surface forms a violent temperature gradient between the upper cold and the lower heat, so that the scene of the physical objects on the ground is refracted under the ground by the family beating. This mirage is often inverted, and the scene has strong shaking.

Mirages appear on the calm sea, rivers, lakes, snowfields, deserts or Gobi deserts, and occasionally appear in the air or "underground" high-rise buildings, rough outlines, trees and other illusions. This kind of illusion often appears on the sea surface of Penglai in Shandong Province of our country, the ancients attributed it to the mirage of the genus of the dragon, exhaled into the outline of the tower, so it was named.

A mirage is an optical phenomenon. The rise of hot air on the sandy or stony surface causes light to refract, resulting in a mirage. There are many types of mirages:

According to the position of its appearance relative to the original object, it can be divided into superior mirage, inferior mirage and lateral mirage; According to its symmetrical relationship with the original, it can be divided into regular mirage, lateral mirage, paramirage and reverse mirage; According to the color, it can be divided into color mirage and non-color stool color mirage and so on.

The earliest description of the phenomenon of mirage in China is Sima Qian's "Historical Records of Tianguan Shulunpai" in the Western Han Dynasty: "The mirage is a meteorological platform, and the vast field is a palace. ”

In other words, there is a gas on the seashore that makes up the shape of a pavilion that hangs in the air, and then expands into the shape of a palace. Later, it was extended to describe unrealistic fantasies, but it also shows that in the Han Dynasty, people had already seen the scene of mirages.

At the end of the Ming Dynasty and the beginning of the Qing Dynasty, there was a man named Fang Yizhi, one of the four sons of the late Ming Dynasty, and he wrote a book called "Physics Knowledge", which recorded a small story about mirages, proving that mirages are not just the refraction of light. But no one went to ** at that time, and they were buried deep in the long river of history.

Manifestations of a mirage

1. Side mirage.

Lateral mirages may occur when the density of the atmosphere in the horizontal direction is very different, so that the refractive index of the atmosphere is very different in the horizontal direction.

2. Mirage.

Any reflection or illusion of an object that appears to be reflected from the ground is called a mirage. Most of the lower mirages occur in the desert during the hot season or at sea with warm currents in the winter. In the sunny and cloudless calm and windless weather, the sun shines on the dry sandy soil, the specific heat of the sand is small, the soil temperature rises very quickly, there is almost no water evaporation here, the heat transfer of soil molecules is extremely slow, and the heat is concentrated in the surface layer, so the air temperature close to the soil layer also rises quickly, but the upper air is still very cold.

When the near-surface layer is a strong cooling layer, the air temperature decreases quickly with altitude, the air density increases with altitude, and the light rays will twist upwards when propagating in the air layer where the air temperature decreases with altitude.

3. Mirage.

Any reflection or illusion of an object that appears to reflect from a layer of air in the sky is called a mirage. Upper mirages are often found at sea, and in the north where there is snow cover. This is because the surface of the sea consumes heat when it evaporates and the temperature of the sea rises slowly, and in areas covered by snow and ice, the ice and snow surface reflects most of the sunlight and consumes a lot of heat when the snow melts, causing the temperature in the lower layers to become very low, so these places are most prone to strong temperature inversion.

If there is a strong temperature inversion near the ground level, the air density decreases rapidly with altitude, and the light rays propagation in the air layer where the air temperature increases with the altitude and the air density decreases sharply with the altitude, and the light from buildings on the distant horizon is refracted into the observer's eye, and a mirage appears.

There is no specific time for the mirage to appear, and the season of appearance is uncertain, and this main Vona depends on the climate of the place. For example, most of the mirages in the Penglai area appear in the months of each year, the mirages near Zimlensk in Russia often appear in spring, and the mirages in Alaska in the United States generally appear in the 20 days after June.

The duration of the mirage of the jujube is not certain, sometimes the lack of rock is not waiting for a few hours, as short as ten minutes, or even fleeting. The appearance of the mirage on March 19, 1957 in Huilai, Guangdong, disappeared from 1 p.m. to 6:45 p.m., which was the longest time in history.

Mirages are often produced in the sea and deserts, and mirages are the result of the refraction of light rays in layers of air with different densities in the direction of a straight line. Mirages are closely related to geographical location, geophysical conditions, and the meteorological characteristics of those places at a given time. The abnormal distribution of air temperature is the meteorological condition for the formation of most mirages.

Mirages often occur in the summer.

The formation of a mirage is closely related to the weather situation, meteorological conditions, geographical location, geophysics, etc., and when the mirage appears, the meteorology will change significantly. According to the data analysis, the day before the "mirage" appeared, there was significant precipitation and cooling weather, and the temperature was generally significantly lower than the previous day.

"Mirages" often occur at sea, because the air humidity and thickness of the space within a certain range of the sea are relatively large, and such a large area of water vapor inadvertently forms a huge lens system under the movement of Lu Qi. When the temperature near the ground changes drastically, it will cause a huge difference in the density of the atmosphere, and the distant scenery will undergo abnormal refraction and total reflection when the light propagation, resulting in a mirage.

Effect of refractive index band on mirage

The occurrence of "mirage" is related to the refractive index of the air layer at different altitudes, and the water vapor content is an important meteorological factor that directly affects the refractive index. At the same time, there is also a certain relationship with the sudden change of temperature and relative humidity. The air near the surface of the sea has a higher refractive index due to the lower sea temperature and moist water vapour, while the air above is warmer due to the influence of sunlight.

The refractive index of the air layer above the sea surface gradually decreases from bottom to top with height, and the refractive index of light in the air also shows discontinuity due to the discontinuity of meteorological changes. When light passes through the top of the air layer with a large refractive index, it is easy to form a total reflection under the meteorological conditions of clear weather, no wind or breeze, thus creating a "mirage" spectacle.

The above content reference: Encyclopedia - Mirage.