Layers of the atmosphere. Layers of the atmosphere in order from the surface of the earth Upper boundary of the upper atmosphere

The atmosphere is the gas or air envelope that surrounds our planet. The atmosphere is a mixture of gases, it contains various impurities of condensation (condensation products of water vapor, particles that make up fogs, clouds, precipitation) and non-condensation (solid particles: dust, smoke, fumes, plant spores, etc.) origin . The composition of the atmosphere: nitrogen (78.8%), oxygen (20.95%), argon (0.93%). In addition, the atmosphere contains water vapor and carbon dioxide, which greatly affect the temperature regime of the atmosphere.

The troposphere is the closest earth's surface layer. It extends up to a height of 8..10 km in the polar regions, up to 10...12 km in temperate latitudes and up to 16..18 km in the tropics. In the troposphere, it stands out boundary layer(friction layer), located at a height of up to 100 m from the z.p. In the troposphere, the temperature decreases with height, averaging 0.65 for every 100 m. The decrease is due to the fact that the air in the troposphere is heated and cooled from the earth's surface. Clouds, fogs are observed here, thunderstorms, tornadoes, hurricanes develop. The wind increases with height, its speed reaches its maximum values ​​at a height of 8..10 km (at temperate latitudes), sometimes reaching 100 km/h or more (jet streams). The western direction of the wind prevails. Various air masses are formed, atmospheric fronts are formed, cyclones and anticyclones develop. The dustiest part of the atmosphere

The stratosphere is located from the tropopause (located between the troposphere and the stratosphere) to a height of about 50 km. The air temperature is practically constant, above the temperature increases due to the absorption of the ultraviolet particle of the solar spectrum by atmospheric ozone. There are practically no clouds, only mother-of-pearl clouds at altitudes of 20 ... 30 km, where the air temperature is -55 ... -100. It can be observed only at dusk, after sunset or before sunrise. It is observed mainly over Alaska and Scandinavia. The speed of the western wind decreases with height, reaching a minimum value at a height of 18 ... 21 km, after which the speed begins to increase again, changing directions to the east. The eastern direction is separated from the western layers located below with weak unstable winds. This transitional layer is called the cycle pause. Sometimes sharp stratospheric warmings are observed.

The region of the atmosphere with charged particles is called the ionosphere. The concentration of ions and electrons is not constant. The maximum concentration occurs at an altitude of 70 ... 80 km

2. Standard atmosphere (sa). Tasks are solved with the help of

standard atmosphere- this is a conditional constant atmosphere, independent of the latitude of the place, season and synoptic conditions. It uses long-term meteorological observations based on the results of measurements using radio sounding and meteorological rockets. Aircraft flight performance is affected by the state of the atmosphere. To compare the performance data of different aircraft and helicopters, they are brought to the same atmospheric conditions. For this purpose, a standard atmosphere is used.

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 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 a height 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 decreases. Over the equator, the minimum air temperature is about -62°C, and over 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% of the mass of the atmosphere is within the troposphere.

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"

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

Observing the sky, we absolutely do not see either its complex structure, or its heterogeneous composition, or other things hidden from the eyes. But it is precisely thanks to the complex and multicomponent composition of the air layer that around the planet there are conditions on it that allowed life to arise here, vegetation to flourish, 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 finished their studies, and some have been there so long 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 of the layers of the atmosphere, at what height is it located, what role does it play? All these questions 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 multilayered structure that the temperature there at different altitudes is very different, and that it is there, at altitude, that the most important processes for all flora and fauna take place. 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 the component composition, etc.

Basically only weather conditions 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 gaseous envelope around the Earth was formed in three stages. First there was a primary atmosphere of hydrogen and helium captured from outer space.

Then the eruption of volcanoes filled the air with a mass of other particles, and a secondary atmosphere arose. After going through all the main 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 planet's gaseous envelope is quite complex and diverse. Let's consider 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 the polar regions, 10-12 km in temperate climate, and in the tropical parts - by 16-18 kilometers.

Interesting fact: this distance may vary depending on the time of year - in winter it is somewhat 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, it is here that clouds, cyclones and other atmospheric phenomena.

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 from 11 km and negative temperatures already prevail here, reaching as much as -57 ° С.

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

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

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

Mesosphere

The mesosphere starts at about 50 and extends up to 90 kilometers. The gradient, or temperature drop with a change in altitude, is not as large here as in the lower layers. In the upper boundaries of this shell, the temperature is about -80°C. The composition of this region 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, because the air is extremely rarefied, while satellites cannot fly at such a low altitude, since the available air density is very high for them.

Another one interesting characteristic mesosphere - it is here that meteorites that hit the planet burn up. The study of such layers remote from the earth is carried out 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 thermosphere, the height in km of which extends for as much as 800 km. In a way, this is almost open space. 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 borealis.

The lowest layer of the thermosphere heats up to a temperature of about 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 flows flowing here. magnetic storms, electric currents, which are then generated. The bed temperature is not uniform and can fluctuate very significantly.

In the thermosphere, the flight of most artificial satellites, ballistic bodies, manned stations, etc. It also tests the launches of various weapons and missiles.

Exosphere

The exosphere, or as it is also called the scattering sphere, is the highest level of our atmosphere, its limit, followed by the interplanetary space. The exosphere begins from a height of about 800-1000 kilometers.

The dense layers are left behind and here the air is extremely rarefied, any particles that fall from the side are simply carried away into space due to the very weak action of gravity.

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

The importance of the atmosphere in the life of the Earth

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

It is important to note that The atmosphere plays a crucial 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.

Also, it is here that the weather is formed, all atmospheric phenomena occur, cyclones, winds arise and die, this or that pressure is established. All this has a direct impact on the state of man, all living organisms and plants.

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

That is why such a campaign is now 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 stand up for the maximum conservation of nature. This is the only way to extend normal life on earth and not make it unbearable in terms of 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, which extends from the mesosphere to heights of the order of a thousand kilometers, and the outer part lying above it - the exosphere, passing 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 - more than 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 air ionization - the content of ions here is many times greater than in the underlying layers, despite the strong overall 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.

In the ionosphere, there are several layers, or regions, with maximum ionization, especially at altitudes of 100-120 km (layer E) and 200-400 km (layer F). But even in the intervals 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 accumulations of electrons with a particularly high concentration 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 longer than 20 m cannot pass through the ionosphere at all: they are already 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-range communication at short waves is possible. Multiple reflections from the ionosphere and the earth's surface allows short waves to zigzag to propagate over long distances, bending around the surface globe. Since the position and concentration of the ionospheric layers are continuously changing, the conditions for absorption, reflection and propagation of radio waves also change. Therefore, reliable radio communication requires continuous study of the state of the ionosphere. Observations on the propagation of radio waves are precisely the means for such research.

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

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

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

Speaking of high temperatures ionosphere, mean that the particles of atmospheric gases move there with a very high speeds. However, the air density in the ionosphere is so low that a body located in the ionosphere, such as a flying satellite, will not be heated by heat exchange with air. Temperature regime satellite will depend on its direct absorption solar radiation and from the return 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. The gas molecules here are highly scattered, they absorb x-rays (X rays) and the short-wave part of ultraviolet radiation. Because of this, the temperature can reach 1000 degrees Celsius.

the thermosphere basically corresponds to the ionosphere, where ionized gas reflects radio waves back to the Earth - this phenomenon makes it possible to establish radio communications.

The atmosphere is the gaseous shell of our planet that rotates with the Earth. The gas in the atmosphere is called air. The atmosphere is in contact with the hydrosphere and partially covers the lithosphere. But it is difficult to determine the upper bounds. Conventionally, it is assumed that the atmosphere extends upwards for about three thousand kilometers. There it flows smoothly into the airless space.

The chemical composition of the Earth's atmosphere

Formation chemical composition atmosphere began about four billion years ago. Initially, the atmosphere consisted only of light gases - helium and hydrogen. According to scientists, the initial prerequisites for the creation of a gas shell around the Earth were volcanic eruptions, which, together with lava, emitted a huge amount of gases. Subsequently, gas exchange began with water spaces, with living organisms, with the products of their activity. The composition of the air gradually changed and modern form established several million years ago.

The main components of the atmosphere are nitrogen (about 79%) and oxygen (20%). The remaining percentage (1%) is accounted for by the following gases: argon, neon, helium, methane, carbon dioxide, hydrogen, krypton, xenon, ozone, ammonia, sulfur dioxide and nitrogen, nitrous oxide and carbon monoxide, included in this one percent.

In addition, the air contains water vapor and particulate matter (plant pollen, dust, salt crystals, aerosol impurities).

IN Lately scientists note not qualitative, but quantitative change some air ingredients. And the reason for this is the person and his activity. Only in the last 100 years, the content of carbon dioxide has increased significantly! This is fraught with many problems, the most global of which is climate change.

Formation of weather and climate

The atmosphere is playing essential role in the formation of climate and weather on Earth. A lot depends on the amount of sunlight, on the nature of the underlying surface and atmospheric circulation.

Let's look at the factors in order.

1. The atmosphere transmits the heat of the sun's rays and absorbs harmful radiation. The ancient Greeks knew that the rays of the Sun fall on different parts of the Earth at different angles. The very word "climate" in translation from ancient Greek means "slope". So, at the equator, the sun's rays fall almost vertically, because it is very hot here. The closer to the poles, the greater the angle of inclination. And the temperature is dropping.

2. Due to the uneven heating of the Earth, air currents are formed in the atmosphere. They are classified according to their size. The smallest (tens and hundreds of meters) are local winds. This is followed by monsoons and trade winds, cyclones and anticyclones, planetary frontal zones.

All these air masses are constantly moving. Some of them are quite static. For example, the trade winds that blow from the subtropics towards the equator. The movement of others is largely dependent on atmospheric pressure.

3. Atmospheric pressure is another factor influencing climate formation. This is the air pressure on the earth's surface. As you know, air masses move from an area with high atmospheric pressure towards an area where this pressure is lower.

There are 7 zones in total. Equator - zone low pressure. Further, on both sides of the equator up to the thirtieth latitudes - the region high pressure. From 30° to 60° - again low pressure. And from 60° to the poles - a zone of high pressure. Air masses circulate between these zones. Those that go from the sea to land bring rain and bad weather, and those that blow from the continents bring clear and dry weather. In places where air currents collide, zones are formed atmospheric front, which are characterized by precipitation and inclement, windy weather.

Scientists have proven that even a person's well-being depends on atmospheric pressure. Normal according to international standards Atmosphere pressure- 760 mm Hg column at 0°C. This figure is calculated for those areas of land that are almost flush with sea level. The pressure decreases with altitude. Therefore, for example, for St. Petersburg 760 mm Hg. - is the norm. But for Moscow, which is located higher, normal pressure- 748 mm Hg

The pressure changes not only vertically, but also horizontally. This is especially felt during the passage of cyclones.

The structure of the atmosphere

The atmosphere is like a layer cake. And each layer has its own characteristics.

. Troposphere is the layer closest to the Earth. The "thickness" of this layer changes as you move away from the equator. Above the equator, the layer extends upwards for 16-18 km, in temperate zones- at 10-12 km, at the poles - at 8-10 km.

It is here that 80% of the total mass of air and 90% of water vapor are contained. Clouds form here, cyclones and anticyclones arise. The air temperature depends on the altitude of the area. On average, it drops by 0.65°C for every 100 meters.

. tropopause- transitional layer of the atmosphere. Its height is from several hundred meters to 1-2 km. The air temperature in summer is higher than in winter. So, for example, over the poles in winter -65 ° C. And over the equator at any time of the year it is -70 ° C.

. Stratosphere- this is a layer, the upper boundary of which runs at an altitude of 50-55 kilometers. Turbulence is low here, water vapor content in the air is negligible. But a lot of ozone. Its maximum concentration is at an altitude of 20-25 km. In the stratosphere, the air temperature begins to rise and reaches +0.8 ° C. This is due to the fact that the ozone layer interacts with ultraviolet radiation.

. Stratopause- a low intermediate layer between the stratosphere and the mesosphere following it.

. Mesosphere- the upper boundary of this layer is 80-85 kilometers. Here complex photochemical processes involving free radicals take place. It is they who provide that gentle blue glow of our planet, which is seen from space.

Most comets and meteorites burn up in the mesosphere.

. mesopause- the next intermediate layer, the air temperature in which is at least -90 °.

. Thermosphere- the lower boundary begins at an altitude of 80 - 90 km, and the upper boundary of the layer passes approximately at the mark of 800 km. The air temperature is rising. It can vary from +500° C to +1000° C. During the day, temperature fluctuations amount to hundreds of degrees! But the air here is so rarefied that the understanding of the term "temperature" as we imagine it is not appropriate here.

. Ionosphere- unites mesosphere, mesopause and thermosphere. The air here consists mainly of oxygen and nitrogen molecules, as well as quasi-neutral plasma. The sun's rays, falling into the ionosphere, strongly ionize air molecules. IN bottom layer(up to 90 km) the degree of ionization is low. The higher, the more ionization. So, at an altitude of 100-110 km, electrons are concentrated. This contributes to the reflection of short and medium radio waves.

The most important layer of the ionosphere is the upper one, which is located at an altitude of 150-400 km. Its peculiarity is that it reflects radio waves, and this contributes to the transmission of radio signals over long distances.

It is in the ionosphere that such a phenomenon as aurora occurs.

. Exosphere- consists of oxygen, helium and hydrogen atoms. The gas in this layer is very rarefied, and often hydrogen atoms escape into outer space. Therefore, this layer is called the "scattering zone".

The first scientist who suggested that our atmosphere has weight was the Italian E. Torricelli. Ostap Bender, for example, in the novel "The Golden Calf" lamented that each person was pressed by an air column weighing 14 kg! But grand schemer was a little wrong. An adult person experiences pressure of 13-15 tons! But we do not feel this heaviness, because atmospheric pressure is balanced by the internal pressure of a person. The weight of our atmosphere is 5,300,000,000,000,000 tons. The figure is colossal, although it is only a millionth of the weight of our planet.