Why does the sea market often appear in the spring and summer 30s?

Sunlight falls on the Tropic of Cancer in spring and summer, and the desert and ocean are mostly in the northern hemisphere. It should be, right? Hehe.

Because the illusion of man is very easy to play at this time.

Not necessarily in spring and autumn, as long as the temperature difference between the upper and lower layers of air is large, it can be formed, the main principle is the refraction of light, the object seen is a virtual image, and the real thing is elsewhere.

The sea is generally formed when the temperature is higher in the season, the air temperature on the sea surface is low, and the air blowing from the land to the sea surface has a high temperature and low density, floating in the upper layer, forming a large temperature difference.

Desert mirages are generally mostly in the morning, and the sand temperature is relatively low in the morning, but the air has risen in temperature after being exposed to sunlight, thus forming a temperature difference.

Physical causes. Mirage.

As long as we have general knowledge of physics. It is not difficult to explain the cause of mirages. When we insert the chopsticks into the glass of water, you will happen as if the chopsticks have been broken by water.

This slit tells us that the speed of light travels changes as it passes through a matter of uniform density (medium). And the direction of travel is also deflected. This is the refraction of light in physics.

When light rays move from a less dense substance into a denser substance, that is, when they enter a dense medium from a sphobic medium, they are deflected in the direction of the normal perpendicular to the interface, which is the small angle of refraction and incidence. Conversely, the angle of refraction is greater than the angle of incidence. This is the law of refraction of light.

In nature, the density of each part of the air layer is different, and in special cases, this density difference is very large, so it is very normal for the refraction and reflection of light to occur.

Specific causes. In the Spring Festival or summer, the temperature of the sea water and the temperature of the land are quite different, under the direct influence of the sea breeze and current, the sea surface air often appears cold and warm, and the air density in the lower layer is large, and the air density in the upper layer is small. If sunlight is reflected from an object far away in the ocean and passes through two interfaces with different air densities, light refraction will occur; When this light is obliquely reflected in the person's line of sight from above, an apparition of an object appears in the distance. Mirages are a spectacular natural phenomenon.

Of course, mirages are not unique to the coast, they can be found in deserts, rivers and lakes, mountains and hills.

Mirages are often produced at sea and in the desert. A mirage is the result of the refraction of light rays in layers of air with different densities in 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.

In the summer desert when the scorching sun is headed, the sand is scorched, because the specific heat of the sand is small, the temperature rises very quickly, the temperature of the lower air near the sand rises very high, and the temperature of the upper air is still very low, so that the abnormal distribution of air temperature is formed, due to the thermal expansion and contraction, the density of the lower layer of hot air close to the sand is small and the density of the upper layer of cold air is large, so that the refractive index of the air is small in the lower layer and large in the upper layer. When the light reflected by a distant higher object is constantly refracted from the denser air in the upper layer into the sparse air in the lower layer, the angle of incidence gradually increases, and when it increases to an equal to the critical angle, total reflection occurs, at this time, if people look at the reflected light in the opposite direction, they will see the mirage.

Due to the dark color of the pavement and the strong absorption capacity of the scorching sun in summer, the asphalt road will also form a distribution characteristic of cold and dense air in the upper layer and hot and dense air in the lower layer, so it will also form a mirage.

I just know why it appears in the summer:

The scorching sun in summer, the sand is scorched, because the specific heat of the sand is small, the temperature rises very quickly, the temperature of the lower layer of air near the sand rises very high, and the temperature of the upper layer of air is still very low, so that the abnormal distribution of air temperature is formed, due to thermal expansion and contraction, the density of the lower layer of hot air close to the sand is small and the density of the upper layer of cold air is large, so that the refractive index of the air is small in the lower layer and large in the upper layer. When the light reflected by a distant higher object is constantly refracted when it enters the lower layer of sparse air from the denser air in the upper layer, the angle of incidence gradually increases, and when it increases to an equal to the critical angle, total reflection occurs, at this time, if people look at the reflected light in the opposite direction, they will see the sea market.