What are the layers of the atmosphere. Atmosphere - the air shell of the Earth

- the air shell of the globe that rotates with the Earth. The upper boundary of the atmosphere is conventionally carried out at altitudes of 150-200 km. The lower boundary is the surface of the Earth.

Atmospheric air is a mixture of gases. Most of its volume in the surface air layer is nitrogen (78%) and oxygen (21%). In addition, the air contains inert gases (argon, helium, neon, etc.), carbon dioxide (0.03), water vapor, and various solid particles (dust, soot, salt crystals).

The air is colorless, and the color of the sky is explained by the peculiarities of the scattering of light waves.

The atmosphere consists of several layers: troposphere, stratosphere, mesosphere and thermosphere.

The bottom layer of air is called troposphere. At different latitudes, its power is not the same. The troposphere repeats the shape of the planet and participates together with the Earth in axial rotation. At the equator, the thickness of the atmosphere varies from 10 to 20 km. At the equator it is greater, and at the poles it is less. The troposphere is characterized by the maximum density of air, 4/5 of the mass of the entire atmosphere is concentrated in it. The troposphere determines weather conditions: various air masses form here, clouds and precipitation form, and intense horizontal and vertical air movement occurs.

Above the troposphere, up to an altitude of 50 km, is located stratosphere. It is characterized by a lower density of air, there is no water vapor in it. In the lower part of the stratosphere at altitudes of about 25 km. there is an "ozone screen" - a layer of the atmosphere with a high concentration of ozone, which absorbs ultraviolet radiation, which is fatal to organisms.

At an altitude of 50 to 80-90 km extends mesosphere. As the altitude increases, the temperature decreases with an average vertical gradient of (0.25-0.3)° / 100 m, and the air density decreases. The main energy process is radiant heat transfer. The glow of the atmosphere is due to complex photochemical processes involving radicals, vibrationally excited molecules.

Thermosphere located at an altitude of 80-90 to 800 km. The air density here is minimal, the degree of air ionization is very high. The temperature changes depending on the activity of the Sun. Due to the large number of charged particles, auroras and magnetic storms are observed here.

The atmosphere is of great importance for the nature of the Earth. Without oxygen, living organisms cannot breathe. Its ozone layer protects all living things from harmful ultraviolet rays. The atmosphere smooths out temperature fluctuations: the Earth's surface does not get supercooled at night and does not overheat during the day. In dense layers of atmospheric air, not reaching the surface of the planet, meteorites burn out from thorns.

The atmosphere interacts with all the shells of the earth. With its help, the exchange of heat and moisture between the ocean and land. Without the atmosphere there would be no clouds, precipitation, winds.

Human activities have a significant adverse effect on the atmosphere. Air pollution occurs, which leads to an increase in the concentration of carbon monoxide (CO 2). And this contributes to global warming and enhances the "greenhouse effect". The ozone layer of the Earth is being destroyed due to industrial waste and transport.

The atmosphere needs to be protected. In developed countries, a set of measures is being taken to protect atmospheric air from pollution.

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Everyone who has flown on an airplane is used to this kind of message: "our flight is at an altitude of 10,000 m, the temperature overboard is 50 ° C." It seems nothing special. The farther from the surface of the Earth heated by the Sun, the colder. Many people think that the decrease in temperature with height goes on continuously and gradually the temperature 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 over the poles and swells over the equator. However, this effect is much stronger in the atmosphere than in the solid shell of the Earth. In the direction from the Earth's surface to the upper boundary of the troposphere, the air temperature drops. Above the equator, the minimum air temperature is about -62 ° C, and above the poles about -45 ° C. In temperate latitudes, more than 75% of the mass of the atmosphere is in the troposphere. In the tropics, about 90% is within the troposphere masses of the atmosphere.

In 1899, a minimum was found in the vertical temperature profile at a certain altitude, and then the temperature slightly increased. 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 former idea of ​​​​the uniqueness of the layer lying above the troposphere. The stratosphere extends to a height of about 50 km above the earth's surface. Its feature is, in particular, a sharp increase in air temperature. This increase in temperature is explained ozone formation reaction - one of the main chemical reactions occurring in the atmosphere.

The bulk of the ozone is concentrated at altitudes of about 25 km, but in general the ozone layer is a shell strongly stretched along the height, covering almost the entire stratosphere. The interaction of oxygen with ultraviolet rays is one of the favorable processes in the earth's atmosphere that contribute 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 such a level of energy is created that is suitable for the existence of terrestrial life forms. 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 rises with height 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", here 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 fall indefinitely, then the temperature rises again.

Thermosphere is the first layer ionosphere. Unlike the previously mentioned layers, the ionosphere is not distinguished by temperature. The ionosphere is a region of an electrical nature that makes many types of radio communications possible. The ionosphere is divided into several layers, designating them with the letters D, E, F1 and F2. These layers also have special names. The division 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 thus prevents their further propagation. The best studied layer E is located at an altitude of about 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 farther distances than would be expected if they propagated only in a straight line, without being reflected from the E layer. The F layer also 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 indicates the existence of the outskirts of space near the Earth. It is difficult to determine exactly where the atmosphere ends and space begins, since the density of atmospheric gases gradually decreases with height and the atmosphere itself gradually turns into an almost vacuum, in which only individual molecules meet. Already at an altitude of about 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 the processes in the atmosphere can be found on the website "Earth climate"

Atmospheric air consists of nitrogen (77.99%), oxygen (21%), inert gases (1%) and carbon dioxide (0.01%). The proportion of carbon dioxide increases over time due to the fact that the products of combustion of fuel are released into the atmosphere, and, in addition, the area of ​​\u200b\u200bforests that absorb carbon dioxide and release oxygen decreases.

The atmosphere also contains a small amount of ozone, which is concentrated at an altitude of about 25-30 km and forms the so-called ozone layer. This layer creates a barrier to solar ultraviolet radiation, which is dangerous for the living organisms of the Earth.

In addition, the atmosphere contains water vapor and various impurities - dust particles, volcanic ash, soot, and so on. The concentration of impurities is higher near the surface of the earth and in certain areas: over large cities, deserts.

Troposphere- lower, it contains most of the air and. The height of this layer is not the same: from 8-10 km near the tropics to 16-18 km near the equator. in the troposphere it decreases with elevation: by 6°C per kilometer. Weather is formed in the troposphere, winds, precipitation, clouds, cyclones and anticyclones are formed.

The next layer of the atmosphere is stratosphere. The air in it is much more rarefied, it has much less water vapor. The temperature in the lower part of the stratosphere is -60 - -80°C and falls with increasing altitude. The ozone layer is in the stratosphere. The stratosphere is characterized by high wind speeds (up to 80-100 m/s).

Mesosphere- the middle layer of the atmosphere lying above the stratosphere at altitudes from 50 to S0-S5 km. The mesosphere is characterized by a decrease in the average temperature with height from 0°C at the lower boundary to -90°C at the upper boundary. Near the upper boundary of the mesosphere, noctilucent clouds are observed, illuminated by the sun at night. The air pressure at the upper boundary of the mesosphere is 200 times less than at the earth's surface.

Thermosphere- located above the mesosphere, at altitudes from SO to 400-500 km, in it the temperature at first slowly, and then quickly begins to rise again. The reason is the absorption of ultraviolet radiation from the Sun at altitudes of 150-300 km. In the thermosphere, the temperature rises continuously up to a height of about 400 km, where it reaches 700-1500°C (depending on solar activity). Under the action of ultraviolet and X-ray and cosmic radiation, air ionization also occurs (“polar lights”). The main regions of the ionosphere lie within the thermosphere.

Exosphere- the outer, most rarefied layer of the atmosphere, it begins at altitudes of 450-000 km, and its upper boundary is located at a distance of several thousand km from the earth's surface, where the concentration of particles becomes the same as in interplanetary space. The exosphere consists of ionized gas (plasma); the lower and middle parts of the exosphere are mainly composed of oxygen and nitrogen; with an increase in altitude, the relative concentration of light gases, especially ionized hydrogen, rapidly increases. The temperature in the exosphere is 1300-3000°C; it grows slowly with height. The exosphere contains the Earth's radiation belts.

The world around us is formed from three very different parts: earth, water and air. Each of them is unique and interesting in its own way. Now we will talk only about the last of them. What is atmosphere? How did it come about? What is it made of and what parts is it divided into? All these questions are extremely interesting.

The very name "atmosphere" is formed from two words of Greek origin, translated into Russian they mean "steam" and "ball". And if you look at the exact definition, you can read the following: "The atmosphere is the air shell of the planet Earth, which rushes along with it in outer space." It developed in parallel with the geological and geochemical processes that took place on the planet. And today all the processes occurring in living organisms depend on it. Without an atmosphere, the planet would become a lifeless desert like the moon.

What does it consist of?

The question of what is the atmosphere and what elements are included in it has interested people for a long time. The main components of this shell were already known in 1774. They were installed by Antoine Lavoisier. He found that the composition of the atmosphere is mostly formed from nitrogen and oxygen. Over time, its components have been refined. And now we know that it contains many more gases, as well as water and dust.

Let us consider in more detail what the Earth's atmosphere near its surface consists of. The most common gas is nitrogen. It contains a little more than 78 percent. But, despite such a large amount, nitrogen in the air is practically not active.

The next largest and most important element is oxygen. This gas contains almost 21%, and it just shows very high activity. Its specific function is to oxidize dead organic matter, which decomposes as a result of this reaction.

Low but important gases

The third gas that is part of the atmosphere is argon. Its slightly less than one percent. It is followed by carbon dioxide with neon, helium with methane, krypton with hydrogen, xenon, ozone and even ammonia. But they are contained so little that the percentage of such components is equal to hundredths, thousandths and millionths. Of these, only carbon dioxide plays a significant role, since it is the building material that plants need for photosynthesis. Its other important function is to keep out radiation and absorb part of the sun's heat.

Another rare but important gas, ozone, exists to trap ultraviolet radiation coming from the sun. Thanks to this property, all life on the planet is reliably protected. On the other hand, ozone affects the temperature of the stratosphere. Due to the fact that it absorbs this radiation, the air is heated.

The constancy of the quantitative composition of the atmosphere is maintained by non-stop mixing. Its layers move both horizontally and vertically. Therefore, anywhere in the world there is enough oxygen and there is no excess of carbon dioxide.

What else is in the air?

It should be noted that steam and dust can be detected in the airspace. The latter consists of pollen and soil particles, in the city they are joined by impurities of particulate emissions from exhaust gases.

But there is a lot of water in the atmosphere. Under certain conditions, it condenses, and clouds and fog appear. In fact, this is the same thing, only the first ones appear high above the surface of the Earth, and the last one spreads along it. Clouds take on a variety of shapes. This process depends on the height above the Earth.

If they formed 2 km above land, then they are called layered. It is from them that rain falls on the ground or snow falls. Cumulus clouds form above them up to a height of 8 km. They are always the most beautiful and picturesque. It is they who are examined and wondered what they look like. If such formations appear in the next 10 km, they will be very light and airy. Their name is cirrus.

What are the layers of the atmosphere?

Although they have very different temperatures from each other, it is very difficult to say at what particular height one layer begins and another ends. This division is very conditional and is approximate. However, the layers of the atmosphere still exist and perform their functions.

The lowest part of the air shell is called the troposphere. Its thickness increases when moving from the poles to the equator from 8 to 18 km. This is the warmest part of the atmosphere, since the air in it is heated from the earth's surface. Most of the water vapor is concentrated in the troposphere, so clouds form in it, precipitation falls, thunderstorms rumble and winds blow.

The next layer is about 40 km thick and is called the stratosphere. If the observer moves to this part of the air, he will find that the sky has become purple. This is due to the low density of the substance, which practically does not scatter the sun's rays. It is in this layer that jet planes fly. For them, all open spaces are open there, since there are practically no clouds. Inside the stratosphere there is a layer consisting of a large amount of ozone.

It is followed by the stratopause and the mesosphere. The latter has a thickness of about 30 km. It is characterized by a sharp decrease in air density and temperature. The sky appears black to the observer. Here you can even watch the stars during the day.

Layers with little to no air

The structure of the atmosphere continues with a layer called the thermosphere - the longest of all the others, its thickness reaches 400 km. This layer is characterized by a huge temperature, which can reach 1700 ° C.

The last two spheres are often combined into one and called it the ionosphere. This is due to the fact that reactions occur in them with the release of ions. It is these layers that allow you to observe such a natural phenomenon as the northern lights.

The next 50 km from the Earth are reserved for the exosphere. This is the outer shell of the atmosphere. In it, air particles are scattered into space. Weather satellites usually move in this layer.

The Earth's atmosphere ends with a magnetosphere. It was she who sheltered most of the artificial satellites of the planet.

After all that has been said, there should be no question about what the atmosphere is. If there are doubts about its necessity, then it is easy to dispel them.

The value of the atmosphere

The main function of the atmosphere is to protect the surface of the planet from overheating during the day and excessive cooling at night. The next importance of this shell, which no one will dispute, is to supply oxygen to all living beings. Without it, they would suffocate.

Most meteorites burn up in the upper layers, never reaching the Earth's surface. And people can admire the flying lights, mistaking them for shooting stars. Without an atmosphere, the entire Earth would be littered with craters. And about protection from solar radiation has already been mentioned above.

How does a person affect the atmosphere?

Very negative. This is due to the growing activity of people. The main share of all the negative aspects falls on industry and transport. By the way, it is cars that emit almost 60% of all pollutants that penetrate the atmosphere. The remaining forty are divided between energy and industry, as well as industries for the destruction of waste.

The list of harmful substances that replenish the composition of the air every day is very long. Because of the transport in the atmosphere are: nitrogen and sulfur, carbon, blue and soot, as well as a strong carcinogen that causes skin cancer - benzopyrene.

The industry accounts for the following chemical elements: sulfur dioxide, hydrocarbons and hydrogen sulfide, ammonia and phenol, chlorine and fluorine. If the process continues, then soon the answers to the questions: “What is the atmosphere? What does it consist of? will be completely different.

The Earth's atmosphere is the gaseous envelope of the planet. The lower boundary of the atmosphere passes near the earth's surface (the hydrosphere and the earth's crust), and the upper boundary is the area of ​​contact 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 viewed at the end of the article or by clicking on.

The atmosphere has distinct layers of air. Air layers differ in temperature, gas difference 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 the ultraviolet solar spectrum. To quickly jump to the desired layer of the atmosphere, click on the corresponding layer:

Troposphere and tropopause

Troposphere - temperature, pressure, altitude

The upper limit is kept at around 8 - 10 km approximately. In temperate latitudes 16 - 18 km, and in polar 10 - 12 km. Troposphere It 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 the total water vapor. It is in the troposphere that convection and turbulence arise, cyclones form, and occur. Temperature decreases with height. Gradient: 0.65°/100 m. The heated earth and water heat up the enclosing 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 limit of the troposphere is called surface since it has a lot of volatile microorganisms and dust. Wind speed increases with height in this layer.

tropopause

This is the transitional layer of the troposphere to the stratosphere. Here, the dependence of the decrease in temperature with an increase in altitude ceases. The tropopause is the minimum height 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 from 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, inversion temperature, from 56.5 rises to 0.8°C. From 40 km to 55 km the temperature stays at around 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 up to 20 km due to stable flight conditions. High-altitude weather balloons rise to a height of 40 km. There are steady air currents here, their speed reaches 300 km/h. Also in this layer is concentrated ozone, a layer that absorbs ultraviolet rays.

Mesosphere and Mesopause - composition, reactions, temperature

The mesosphere layer begins at about 50 km and ends at around 80-90 km. Temperatures decrease with elevation by about 0.25-0.3°C/100 m. Radiant heat exchange is the main energy effect here. Complex photochemical processes involving free radicals (has 1 or 2 unpaired electrons) since they implement glow atmosphere.

Almost all meteors burn up in the mesosphere. Scientists have named this area Ignorosphere. This zone is difficult to explore, as 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 with the help of meteorological rockets, but this is a perversion. mesopause transitional layer between mesosphere and thermosphere. Has a minimum temperature of -90°C.

Karman Line

Pocket line called the boundary between the Earth's atmosphere and outer 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 Theodor von Karman. He determined that at about this height the density of the atmosphere is so low that aerodynamic aviation becomes impossible here, since the speed of the aircraft must be greater first space velocity. At such a height, the concept of a sound barrier loses its meaning. Here you can control the aircraft only due to reactive forces.

Thermosphere and Thermopause

The upper boundary of this layer is about 800 km. The temperature rises up to about 300 km, where it reaches about 1500 K. Above, the temperature remains unchanged. In this layer there is 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 the low rarefaction of the air, flights above the Karman line are possible only 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. The growth of solar activity leads to the expansion of the thickness of this layer.

• The gas shell does not fly away into space due to gravity. Air is made up of particles that have their own mass. From the law of gravitation, it can be concluded 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 a high pressure zone on the right, and low pressure on the left. In the Southern Hemisphere, it will be the other way around.