The thermosphere consists of. Vertical structure of the atmosphere

Everyone who has flown on an airplane is accustomed to this kind of message: “our flight takes place at an altitude of 10,000 m, the temperature outside is 50 ° C.” It seems nothing special. The farther from the surface of the Earth heated by the Sun, the colder it is. Many people think that the temperature decreases continuously with altitude and that the temperature gradually drops, approaching the temperature of space. By the way, scientists thought so until the end of the 19th century.

Let's take a closer look at the distribution of air temperature over the Earth. The atmosphere is divided into several layers, which primarily reflect the nature of temperature changes.

The lower layer of the atmosphere is called troposphere, which means “sphere of rotation.” All changes in weather and climate are the result of physical processes occurring precisely in this layer. The upper boundary of this layer is located where the decrease in temperature with height is replaced by its increase - approximately at an altitude of 15-16 km above the equator and 7-8 km above the poles. Like the Earth itself, the atmosphere, under the influence of the rotation of our planet, is also somewhat flattened above the poles and swells above the equator. However, this effect is expressed in the atmosphere much more strongly than in the solid shell of the Earth. In the direction from the Earth's surface to At the upper boundary of the troposphere, the air temperature decreases. Above the equator, the minimum air temperature is about -62 ° C, and above the poles - about -45 ° C. At moderate latitudes, more than 75% of the mass of the atmosphere is in the troposphere. In the tropics, about 90% is within the troposphere mass of the atmosphere.

In 1899, a minimum was found in the vertical temperature profile at a certain altitude, and then the temperature increased slightly. The beginning of this increase means the transition to the next layer of the atmosphere - to stratosphere, which means “layer sphere.” The term stratosphere means and reflects the previous idea of ​​​​the uniqueness of the layer lying above the troposphere. The stratosphere extends to an altitude of about 50 km above the earth’s surface. Its peculiarity is, in particular, a sharp increase in air temperature. This increase in temperature is explained ozone formation reaction is one of the main chemical reactions occurring in the atmosphere.

The bulk of ozone is concentrated at altitudes of approximately 25 km, but in general the ozone layer is a highly extended shell, covering almost the entire stratosphere. The interaction of oxygen with ultraviolet rays is one of the beneficial processes in the earth’s atmosphere that contributes to the maintenance of life on Earth. The absorption of this energy by ozone prevents its excessive flow to the earth's surface, where exactly the level of energy that is suitable for the existence of terrestrial life forms is created. The ozonosphere absorbs some of the radiant energy passing through the atmosphere. As a result, a vertical air temperature gradient of approximately 0.62°C per 100 m is established in the ozonosphere, i.e., the temperature increases with altitude up to the upper limit of the stratosphere - the stratopause (50 km), reaching, according to some data, 0°C.

At altitudes from 50 to 80 km there is a layer of the atmosphere called mesosphere. The word "mesosphere" means "intermediate sphere", where the air temperature continues to decrease with height. Above the mesosphere, in a layer called thermosphere, the temperature rises again with altitude up to about 1000°C, and then drops very quickly to -96°C. However, it does not drop indefinitely, then the temperature increases again.

Thermosphere is the first layer ionosphere. Unlike the previously mentioned layers, the ionosphere is not distinguished by temperature. The ionosphere is an area of ​​electrical nature that makes many types of radio communications possible. The ionosphere is divided into several layers, designated by the letters D, E, F1 and F2. These layers also have special names. The separation into layers is caused by several reasons, among which the most important is the unequal influence of the layers on the passage of radio waves. The lowest layer, D, mainly absorbs radio waves and thereby prevents their further propagation. The best studied layer E is located at an altitude of approximately 100 km above the earth's surface. It is also called the Kennelly-Heaviside layer after the names of the American and English scientists who simultaneously and independently discovered it. Layer E, like a giant mirror, reflects radio waves. Thanks to this layer, long radio waves travel further distances than would be expected if they propagated only in a straight line, without being reflected from the E layer. The F layer has similar properties. It is also called the Appleton layer. Together with the Kennelly-Heaviside layer, it reflects radio waves to terrestrial radio stations. Such reflection can occur at various angles. The Appleton layer is located at an altitude of about 240 km.

The outermost region of the atmosphere, the second layer of the ionosphere, is often called exosphere. This term refers to the existence of the outskirts of space near the Earth. It is difficult to determine exactly where the atmosphere ends and space begins, since with altitude the density of atmospheric gases gradually decreases and the atmosphere itself gradually turns into almost a vacuum, in which only individual molecules are found. Already at an altitude of approximately 320 km, the density of the atmosphere is so low that molecules can travel more than 1 km without colliding with each other. The outermost part of the atmosphere serves as its upper boundary, which is located at altitudes from 480 to 960 km.

More information about processes in the atmosphere can be found on the website “Earth Climate”

The upper part of the atmosphere, above the mesosphere, is characterized by very high temperatures and is therefore called the thermosphere. However, two parts are distinguished in it: the ionosphere, extending from the mesosphere to altitudes of the order of a thousand kilometers, and the outer part lying above it - the exosphere, which turns into the earth's corona.

The air in the ionosphere is extremely rarefied. We have already indicated that at altitudes of 300-750 km its average density is about 10-8-10-10 g/m3. But even with such a low density, each cubic centimeter of air at an altitude of 300 km still contains about one billion (109) molecules or atoms, and at an altitude of 600 km - over 10 million (107). This is several orders of magnitude greater than the content of gases in interplanetary space.

The ionosphere, as the name itself says, is characterized by a very strong degree of ionization of the air - the ion content here is many times greater than in the underlying layers, despite the strong general rarefaction of the air. These ions are mainly charged oxygen atoms, charged nitric oxide molecules, and free electrons. Their content at altitudes of 100-400 km is about 1015-106 per cubic centimeter.

Several layers, or regions, with maximum ionization are distinguished in the ionosphere, especially at altitudes of 100-120 km (layer E) and 200-400 km (layer F). But even in the spaces between these layers, the degree of ionization of the atmosphere remains very high. The position of the ionospheric layers and the concentration of ions in them change all the time. Sporadic collections of electrons with particularly high concentrations are called electron clouds.

The electrical conductivity of the atmosphere depends on the degree of ionization. Therefore, in the ionosphere, the electrical conductivity of air is generally 1012 times greater than that of the earth’s surface. Radio waves experience absorption, refraction and reflection in the ionosphere. Waves with a length of more than 20 m cannot pass through the ionosphere at all: they are reflected by electron layers of low concentration in the lower part of the ionosphere (at altitudes of 70-80 km). Medium and short waves are reflected by the overlying ionospheric layers.

It is due to reflection from the ionosphere that long-distance communication on short waves is possible. Multiple reflections from the ionosphere and the earth's surface allow short waves to travel in a zigzag manner over long distances, bending around the surface of the globe. Since the position and concentration of ionospheric layers are constantly changing, the conditions for absorption, reflection and propagation of radio waves also change. Therefore, for reliable radio communications, continuous study of the state of the ionosphere is necessary. Observations of the propagation of radio waves are precisely the means for such research.

In the ionosphere, auroras and the glow of the night sky, which is close in nature to them in nature - constant luminescence of atmospheric air, as well as sharp fluctuations in the magnetic field - ionospheric magnetic storms, are observed.

Ionization in the ionosphere owes its existence to the action of ultraviolet radiation from the Sun. Its absorption by molecules of atmospheric gases leads to the formation of charged atoms and free electrons, as discussed above. Magnetic field fluctuations in the ionosphere and auroras depend on fluctuations in solar activity. Changes in solar activity are associated with changes in the flow of corpuscular radiation coming from the Sun into the earth's atmosphere. Namely, corpuscular radiation is of primary importance for these ionospheric phenomena.

The temperature in the ionosphere increases with altitude to very high values. At altitudes of about 800 km it reaches 1000°.

When we talk about high temperatures in the ionosphere, we mean that particles of atmospheric gases move there at very high speeds. However, the air density in the ionosphere is so low that a body located in the ionosphere, for example a flying satellite, will not be heated by heat exchange with the air. The temperature regime of the satellite will depend on its direct absorption of solar radiation and on the release of its own radiation into the surrounding space. The thermosphere is located above the mesosphere at an altitude of 90 to 500 km above the Earth's surface. Gas molecules here are highly scattered and absorb X-rays and short-wavelength ultraviolet radiation. Because of this, temperatures can reach 1000 degrees Celsius.

The thermosphere basically corresponds to the ionosphere, where ionized gas reflects radio waves back to Earth, a phenomenon that makes radio communications possible.

The Earth's atmosphere is the gaseous shell of the planet. The lower boundary of the atmosphere passes near the surface of the earth (hydrosphere and earth's crust), and the upper boundary is the area in contact with outer space (122 km). The atmosphere contains many different elements. The main ones are: 78% nitrogen, 20% oxygen, 1% argon, carbon dioxide, neon gallium, hydrogen, etc. Interesting facts can be found at the end of the article or by clicking on.

The atmosphere has clearly defined layers of air. The layers of air differ from each other in temperature, difference in gases and their density and. It should be noted that the layers of the stratosphere and troposphere protect the Earth from solar radiation. In the higher layers, a living organism can receive a lethal dose of ultraviolet solar spectrum. To quickly jump to the desired atmosphere layer, click on the corresponding layer:

Troposphere and tropopause

Troposphere - temperature, pressure, altitude

The upper limit is approximately 8 - 10 km. In temperate latitudes it is 16 - 18 km, and in polar latitudes it is 10 - 12 km. Troposphere- This is the lower main layer of the atmosphere. This layer contains more than 80% of the total mass of atmospheric air and close to 90% of all water vapor. It is in the troposphere that convection and turbulence arise, cyclones form and occur. Temperature decreases with increasing altitude. Gradient: 0.65°/100 m. Heated earth and water heat the surrounding air. The heated air rises, cools and forms clouds. The temperature in the upper boundaries of the layer can reach – 50/70 °C.

It is in this layer that changes in climatic weather conditions occur. The lower boundary of the troposphere is called ground level, since it has a lot of volatile microorganisms and dust. Wind speed increases with increasing height in this layer.

Tropopause

This is the transition layer of the troposphere to the stratosphere. Here the dependence of temperature decrease with increasing altitude stops. Tropopause is the minimum altitude where the vertical temperature gradient drops to 0.2°C/100 m. The height of the tropopause depends on strong climatic events such as cyclones. The height of the tropopause decreases above cyclones, and increases above anticyclones.

Stratosphere and Stratopause

The height of the stratosphere layer is approximately 11 to 50 km. There is a slight change in temperature at an altitude of 11 - 25 km. At an altitude of 25 - 40 km it is observed inversion temperatures, from 56.5 rises to 0.8°C. From 40 km to 55 km the temperature stays at 0°C. This area is called - Stratopause.

In the Stratosphere, the effect of solar radiation on gas molecules is observed; they dissociate into atoms. There is almost no water vapor in this layer. Modern supersonic commercial aircraft fly at altitudes of up to 20 km due to stable flight conditions. High-altitude weather balloons rise to a height of 40 km. There are stable air currents here, their speed reaches 300 km/h. Also concentrated in this layer ozone, a layer that absorbs ultraviolet rays.

Mesosphere and Mesopause - composition, reactions, temperature

The mesosphere layer begins at approximately 50 km altitude and ends at 80 - 90 km. Temperatures decrease with increasing altitude by approximately 0.25-0.3°C/100 m. The main energetic effect here is radiant heat exchange. Complex photochemical processes involving free radicals (has 1 or 2 unpaired electrons) because they implement glow atmosphere.

Almost all meteors burn up in the mesosphere. Scientists named this zone - Ignorosphere. This zone is difficult to explore, since aerodynamic aviation here is very poor due to the air density, which is 1000 times less than on Earth. And for launching artificial satellites, the density is still very high. Research is carried out using weather rockets, but this is a perversion. Mesopause transition layer between the mesosphere and thermosphere. Has a temperature of at least -90°C.

Karman Line

Pocket line called the boundary between the Earth's atmosphere and space. According to the International Aviation Federation (FAI), the height of this border is 100 km. This definition was given in honor of the American scientist Theodore Von Karman. He determined that at approximately this altitude the density of the atmosphere is so low that aerodynamic aviation becomes impossible here, since the speed of the aircraft must be greater escape velocity. At such a height, the concept of a sound barrier loses its meaning. Here, the aircraft can be controlled only using reactive forces.

Thermosphere and Thermopause

The upper boundary of this layer is approximately 800 km. The temperature rises to approximately an altitude of 300 km where it reaches about 1500 K. Above the temperature remains unchanged. In this layer occurs Polar Lights- Occurs as a result of the effect of solar radiation on the air. This process is also called the ionization of atmospheric oxygen.

Due to low air rarefaction, flights above the Karman line are only possible along ballistic trajectories. All manned orbital flights (except flights to the Moon) take place in this layer of the atmosphere.

Exosphere - density, temperature, height

The height of the exosphere is above 700 km. Here the gas is very rarefied, and the process takes place dissipation— leakage of particles into interplanetary space. The speed of such particles can reach 11.2 km/sec. An increase in solar activity leads to an expansion of the thickness of this layer.

• The gas shell does not fly into space due to gravity. Air consists of particles that have their own mass. From the law of gravity we can conclude that every object with mass is attracted to the Earth.
• Buys-Ballot's law states that if you are in the Northern Hemisphere and stand with your back to the wind, then there will be an area of ​​high pressure on the right and low pressure on the left. In the Southern Hemisphere, everything will be the other way around.

Every literate person should know not only that the planet is surrounded by an atmosphere made of a mixture of all kinds of gases, but also that there are different layers of the atmosphere that are located at unequal distances from the Earth’s surface.

Observing the sky, we do not see at all its complex structure, its heterogeneous composition, or other things hidden from view. But it is precisely thanks to the complex and multicomponent composition of the air layer that conditions exist around the planet that allowed life to arise here, vegetation to flourish, and everything that has ever been here to appear.

Knowledge about the subject of conversation is given to people already in the 6th grade at school, but some have not yet completed their studies, and some have been there so long ago that they have already forgotten everything. Nevertheless, every educated person should know what the world around him consists of, especially that part of it on which the very possibility of his normal life directly depends.

What is the name of each layer of the atmosphere, at what altitude is it located, and what role does it play? All these issues will be discussed below.

The structure of the Earth's atmosphere

Looking at the sky, especially when it is completely cloudless, it is very difficult to even imagine that it has such a complex and multi-layered structure, that the temperature there at different altitudes is very different, and that it is there, at altitude, that the most important processes take place for all flora and fauna on the ground.

If it were not for such a complex composition of the gas cover of the planet, then there would simply be no life here and even the possibility for its origin.

The first attempts to study this part of the surrounding world were made by the ancient Greeks, but they could not go too far in their conclusions, since they did not have the necessary technical base. They did not see the boundaries of different layers, could not measure their temperature, study their component composition, etc.

Basically, only weather phenomena prompted the most progressive minds to think that the visible sky is not as simple as it seems.

It is believed that the structure of the modern gas shell around the Earth was formed in three stages. First there was a primordial atmosphere of hydrogen and helium captured from outer space.

Then volcanic eruptions filled the air with a mass of other particles, and a secondary atmosphere arose. After passing through all the basic chemical reactions and particle relaxation processes, the current situation arose.

Layers of the atmosphere in order from the surface of the earth and their characteristics

The structure of the gas shell of the planet is quite complex and diverse. Let's look at it in more detail, gradually reaching the highest levels.

Troposphere

Apart from the boundary layer, the troposphere is the lowest layer of the atmosphere. It extends to a height of approximately 8-10 km above the earth's surface in polar regions, 10-12 km in temperate climates, and 16-18 km in tropical parts.

Interesting fact: this distance may vary depending on the time of year - in winter it is slightly less than in summer.

The air of the troposphere contains the main life-giving force for all life on earth. It contains about 80% of all available atmospheric air, more than 90% of water vapor, and it is here that clouds, cyclones and other atmospheric phenomena form.

It is interesting to note the gradual decrease in temperature as you rise from the surface of the planet. Scientists have calculated that for every 100 m of altitude, the temperature decreases by about 0.6-0.7 degrees.

Stratosphere

The next most important layer is the stratosphere. The height of the stratosphere is approximately 45-50 kilometers. It starts at 11 km and negative temperatures already prevail here, reaching as much as -57°C.

Why is this layer important for humans, all animals and plants? It is here, at an altitude of 20-25 kilometers, that the ozone layer is located - it traps ultraviolet rays emanating from the sun and reduces their destructive effect on flora and fauna to an acceptable level.

It is very interesting to note that the stratosphere absorbs many types of radiation that come to the earth from the sun, other stars and outer space. The energy received from these particles is used to ionize the molecules and atoms located here, and various chemical compounds appear.

All this leads to such a famous and colorful phenomenon as the northern lights.

Mesosphere

The mesosphere begins at about 50 and extends to 90 kilometers. The gradient, or temperature difference with changes in altitude, is no longer as large here as in the lower layers. At the upper boundaries of this shell the temperature is about -80°C. The composition of this area includes approximately 80% nitrogen as well as 20% oxygen.

It is important to note that the mesosphere is a kind of dead zone for any flying devices. Airplanes cannot fly here, since the air is too thin, and satellites cannot fly at such a low altitude, since the available air density for them is very high.

Another interesting characteristic of the mesosphere is This is where meteorites that strike the planet burn up. The study of such layers distant from the earth occurs with the help of special rockets, but the efficiency of the process is low, so the knowledge of the region leaves much to be desired.

Thermosphere

Immediately after the considered layer comes the thermosphere, whose altitude in kilometers extends for as much as 800 km. In some ways, this is almost outer space. Here there is an aggressive impact of cosmic radiation, radiation, solar radiation.

All this gives rise to such a wonderful and beautiful phenomenon as the aurora.

The lowest layer of the thermosphere is heated to temperatures of approximately 200 K or more. This happens due to elementary processes between atoms and molecules, their recombination and radiation.

The upper layers are heated due to the magnetic storms occurring here and the electric currents that are generated. The temperature of the layer is uneven and can fluctuate very significantly.

Most artificial satellites, ballistic bodies, manned stations, etc. fly in the thermosphere. Also, launch tests of various types of weapons and missiles are carried out here.

Exosphere

The exosphere, or as it is also called the scattering sphere, is the highest level of our atmosphere, its limit, followed by interplanetary outer space. The exosphere begins at an altitude of approximately 800-1000 kilometers.

The dense layers are left behind and here the air is extremely rarefied; any particles that enter from the outside are simply carried away into space due to the very weak effect of gravity.

This shell ends at an altitude of approximately 3000-3500 km, and there are almost no particles here anymore. This zone is called the near-space vacuum. What predominates here is not individual particles in their normal state, but plasma, most often completely ionized.

The importance of the atmosphere in the life of the Earth

This is what all the main levels of the atmosphere of our planet look like. Its detailed scheme may include other regions, but they are of secondary importance.

It's important to note that The atmosphere plays a decisive role for life on Earth. A lot of ozone in its stratosphere allows flora and fauna to escape from the deadly effects of radiation and radiation from space.

It is also here that the weather is formed, all atmospheric phenomena occur, cyclones and winds arise and die, and this or that pressure is established. All this has a direct impact on the condition of humans, all living organisms and plants.

The nearest layer, the troposphere, gives us the opportunity to breathe, saturates all living things with oxygen and allows them to live. Even small deviations in the structure and component composition of the atmosphere can have the most detrimental effect on all living things.

That is why such a campaign has now been launched against harmful emissions from cars and production, environmentalists are sounding the alarm about the thickness of the ozone layer, the Green Party and others like it are advocating for maximum conservation of nature. This is the only way to prolong normal life on earth and not make it unbearable in terms of climate.

Surprisingly, we have to return to this issue due to the fact that many people have no idea where the International “Space” Station actually flies and where “cosmonauts” go into outer space or into the Earth’s atmosphere.

This is a fundamental question - do you understand? People are drummed into their heads that representatives of humanity, who have been given the proud definition of “astronauts” and “cosmonauts,” freely carry out “outer space” walks and, moreover, there is even a “Space” station flying in this supposed “space.” And all this while all these “achievements” are being realized in the Earth's atmosphere.

All manned orbital flights take place in the thermosphere, mainly at altitudes from 200 to 500 km - below 200 km the braking effect of air is strongly affected, and above 500 km radiation belts extend, which have a harmful effect on people.

Unmanned satellites also mostly fly in the thermosphere - launching a satellite into a higher orbit requires more energy, and for many purposes (for example, for remote sensing of the Earth), low altitude is preferable.

The high air temperature in the thermosphere is not dangerous for aircraft, since due to the strong rarefaction of the air, it practically does not interact with the skin of the aircraft, that is, the air density is not enough to heat the physical body, since the number of molecules is very small and the frequency of their collisions with the hull of the vessel (and, accordingly, the transfer of thermal energy) is small. Thermosphere research is also carried out using suborbital geophysical rockets. Auroras are observed in the thermosphere.

Thermosphere(from the Greek θερμός - “warm” and σφαῖρα - “ball”, “sphere”) - atmospheric layer , next to the mesosphere. It starts at an altitude of 80-90 km and extends up to 800 km. The air temperature in the thermosphere fluctuates at different levels, increases rapidly and discontinuously and can vary from 200 K to 2000 K, depending on the degree of solar activity. The reason is the absorption of ultraviolet radiation from the Sun at altitudes of 150-300 km, due to the ionization of atmospheric oxygen. In the lower part of the thermosphere, the increase in temperature is largely due to the energy released when oxygen atoms combine (recombine) into molecules (in this case, the energy of solar UV radiation, previously absorbed during the dissociation of O2 molecules, is converted into the energy of thermal motion of particles). At high latitudes, an important source of heat in the thermosphere is Joule heat generated by electric currents of magnetospheric origin. This source causes significant but uneven heating of the upper atmosphere in subpolar latitudes, especially during magnetic storms.

Outer space (outer space)- relatively empty areas of the Universe that lie outside the boundaries of the atmospheres of celestial bodies. Contrary to popular belief, space is not completely empty space - it contains a very low density of some particles (mainly hydrogen), as well as electromagnetic radiation and interstellar matter. The word "space" has several different meanings. Sometimes space is understood as all space outside the Earth, including celestial bodies.

400 km - orbital altitude of the International Space Station
500 km is the beginning of the internal proton radiation belt and the end of safe orbits for long-term human flights.
690 km is the boundary between the thermosphere and exosphere.
1000-1100 km is the maximum height of the auroras, the last manifestation of the atmosphere visible from the Earth’s surface (but usually clearly visible auroras occur at altitudes of 90-400 km).
1372 km - the maximum altitude reached by man (Gemini 11 on September 2, 1966).
2000 km - the atmosphere does not affect the satellites and they can exist in orbit for many millennia.
3000 km - the maximum intensity of the proton flux of the internal radiation belt (up to 0.5-1 Gy/hour).
12,756 km - we have moved away to a distance equal to the diameter of planet Earth.
17,000 km - outer electron radiation belt.
35,786 km is the altitude of the geostationary orbit; a satellite at this altitude will always hang above one point of the equator.
90,000 km is the distance to the bow shock wave formed by the collision of the Earth's magnetosphere with the solar wind.
100,000 km is the upper boundary of the Earth’s exosphere (geocorona) observed by satellites. The atmosphere is over, open space and interplanetary space began.

Therefore the news" NASA astronauts repaired the cooling system during a spacewalk ISS ", should sound different - " NASA astronauts repaired the cooling system during entry into the Earth's atmosphere ISS ", and the definitions of “astronauts”, “cosmonauts” and “International Space Station” require adjustments, for the simple reason that the station is not a space station and astronauts with cosmonauts, rather, atmospheric nauts :)