MESOSPHERE: CHARACTERISTICS, COMPOSITION, TEMPERATURE AND FUNCTIONS - ENVIRONMENT - 2024

The mesosphere is one of the layers of the Earth's atmosphere, specifically the third, located between the stratosphere and the thermosphere. The transition area between the stratosphere and the mesosphere is called the stratopause, while the area between the mesosphere and the thermosphere is called the mesopause.

The mesosphere is mainly characterized by the very low temperature that occurs there, which is directly related to altitude: the higher the altitude, the lower the temperature. Its importance lies in the fact that this layer acts as a protector of the Earth against the disintegration of rock formations.

The mesosphere is the coldest layer in the atmosphere. Source: This SVG image was created by Medium69.Cette image SVG a été créée par Medium69.Please credit this: William Crochot

The destruction of various formations in the mesosphere (such as meteorites and smaller particles) allows the entry of atmospheric dust, which intervenes in the development of condensation nuclei for polar mesospheric clouds or noctilucent clouds, which occur at a height greater than ordinary clouds.

In addition to the generation of polar mesospheric clouds, the phenomenon of elf rays also occurs, whose origin continues to be considered a mystery.

In the same way, in this layer the so-called shooting stars are produced, which are nothing more than flashes of light product of meteorites or rock formations that were disintegrated thanks to the force of friction.

The mesosphere has been the layer of the atmosphere that has been least explored and studied, because its altitude is very high and does not allow the transit of aircraft such as airplanes or hot air balloons, and at the same time it is too low for artificial satellites to orbit in this.

The little that has been discovered about this layer of the atmosphere has been observed through exploration and study using sounding rockets, but the permanence of these devices must have been very limited.

However, since 2017 NASA has worked on a device that will allow the study of the mesosphere. This artifact is known as sodium Lidar (Light detection and ranging).

characteristics

The main characteristic of the mesosphere is that it is the coldest layer of the Earth's atmosphere, and the temperature decreases more as its altitude increases.

The excessive cooling of this layer due to the low temperature in its upper part - together with other factors that affect the various layers of the atmosphere - represents an indicator of how climate change is evolving.

This layer extends approximately from 50 to 85 kilometers in height, and its approximate thickness is 35 km; However, despite its wide extension, it represents only 0.1% of the total mass of the atmosphere.

In this layer there are zonal winds that are characterized by their east-west component; this element indicates the direction they follow. In addition, atmospheric tides and gravity waves are also present.

The mesosphere is the least dense of the layers of the atmosphere and it would be impossible to breathe in it; Also, the pressure is too low, so if you were without a spacesuit, your blood and body fluids would boil.

The mesosphere is considered mysterious due to the little access that has been had to its study, and also due to the fact that various natural phenomena take place in it that are quite striking.

Natural phenomena that occur in the mesosphere

Noctilucent clouds

Various very particular natural phenomena occur in the mesosphere. An example of this are the noctilucent clouds, which are those that are characterized by their electric blue color and can be viewed from the north and south poles.

These clouds are created when a meteor hits the atmosphere and releases a trail of dust, to which frozen water vapor from the clouds adheres.

Noctilucent clouds or polar mesospheric clouds occur much higher than ordinary clouds, about 80 km in height, while common clouds are observed much lower, in the troposphere.

Shooting Stars

Shooting stars are produced in the mesosphere, sightings of which have always been highly valued by people.

These "stars" are produced thanks to the disintegration of meteorites, which is produced by friction with the air in the atmosphere and causes them to release flashes of light.

Goblin rays

Another phenomenon that occurs in this layer of the atmosphere are the so-called elf rays, whose origin continues to be difficult to understand even though they were discovered in the late 19th century and exposed in 1925 by Charles Wilson.

These rays, generally reddish in color, occur in the mesosphere and can be seen far away from the clouds. It is not yet known what causes them and their diameter can reach tens of kilometers.

MTI

An event known as MTI (mesospheric temperature inversions) also usually occurs in the mesosphere, which displaces the fundamental characteristic of this layer (the decrease in temperature with increasing altitude). In this case, the higher the altitude the higher the temperature.

For a time scientists argued that gravity waves were responsible for this event; However, after studies carried out in the city of Ahmedabad it was discovered that gravity waves do not have such an incidence.

It has been determined that this phenomenon is due to chemical reactions that release heat after solar radiation hits atmospheric elements.

Chemical composition

The chemical composition of gases in the mesosphere is very similar to that of the troposphere in proportion. In the troposphere, the air is mostly made up of nitrogen (78%), 21% oxygen and 1% water vapor and carbon dioxide; this layer is the densest in the atmosphere.

On the contrary, the mesosphere is the least dense layer and its air is very light. The gases in it are not very dense, but it has a higher concentration of ozone and a lower level of water vapor.

As most of the rock formations that impact the atmosphere disintegrate in this layer, residues of these formations remain in the mesosphere and there a relatively high concentration of iron and other metallic atoms is generated.

Temperature

As we mentioned earlier, the mesosphere is the layer with the lowest temperature. Its temperature drops as one advances in this layer; that is, the higher it is, the colder it will be. In fact, the coldest point is reached in the mesopause, the transitional layer between the mesosphere and the thermosphere.

In countries to the north, where the temperature is usually low, noctilucent clouds are very common. This is so because in these areas the temperature of the atmosphere is generally lower, so the mesosphere has even colder temperatures.

The drop in temperature that occurs in this layer is due to the fact that there are very few gas molecules that can absorb the sun's rays and allow the air to remain warm. The lowest temperature reached in this layer is approximately - 110 ° C.

Likewise, the decrease in temperature is due to the emission of carbon dioxide, which has a cooling effect; in the mesosphere, carbon dioxide is responsible for cooling, although it also radiates heat into space.

The least cold part of the mesosphere is the transitional layer between it and the stratosphere: the stratopause. This is so because the little heat that can be found in the mesosphere comes from the stratosphere, so its temperature drops according to altitude and the coldest point is where this layer ends.

Features

Protection against meteorites

The main function of the mesosphere is that it protects the Earth from rock formations (such as meteorites) that invade the atmosphere. Any meteorite that passes through it will be disintegrated by the friction force produced by the air in this layer before it passes through the remaining layers and impacts the Earth.

If the disintegrated meteorite is considerably large, after its disintegration, the flashes of light generated by this reaction can be observed. This is what is known as a shooting star.

The disintegration in the mesosphere of large meteorites and smaller formations generates the entry of tons of atmospheric dust. This affects the chemistry of this layer and contributes to the development of the condensation nuclei of the polar mesospheric clouds.

UV protection

On the other hand, the mesosphere also protects from ultraviolet solar radiation. It is worth noting that this function is attributed to a greater extent to the stratosphere, since this layer protects with more intensity.

Spaceship brake

The mesosphere functions as an aerodynamic brake for spacecraft that are returning to Earth.

In this layer, strong turbulences are usually generated thanks to the low density of its air compared to that of the different layers that make up the Earth's atmosphere.

References

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5. (2017). NASA will create a special instrument to study the Earth's mesosphere. Retrieved on April 21 from La Prensa: laprensa.peru.com
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