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What makes up the atmosphere. Layers of the atmosphere - troposphere, stratosphere, mesosphere, thermosphere and exosphere

Composition of the Earth. Air

Air is a mechanical mixture of various gases that make up the Earth's atmosphere. Air is necessary for the respiration of living organisms and is widely used in industry.

The fact that air is a mixture, and not a homogeneous substance, was proven during the experiments of the Scottish scientist Joseph Black. During one of them, the scientist discovered that when white magnesia (magnesium carbonate) is heated, “bound air” is released, that is, carbon dioxide, and burnt magnesia (magnesium oxide) is formed. When burning limestone, on the contrary, “bound air” is removed. Based on these experiments, the scientist concluded that the difference between carbon dioxide and caustic alkalis is that the former contains carbon dioxide, which is one of the constituents of air. Today we know that in addition to carbon dioxide, the composition of the earth’s air includes:

The ratio of gases in the earth's atmosphere indicated in the table is typical for its lower layers, up to an altitude of 120 km. In these areas lies a well-mixed, homogeneous region called the homosphere. Above the homosphere lies the heterosphere, which is characterized by the decomposition of gas molecules into atoms and ions. The regions are separated from each other by a turbo pause.

The chemical reaction in which molecules are decomposed into atoms under the influence of solar and cosmic radiation is called photodissociation. The decay of molecular oxygen produces atomic oxygen, which is the main gas of the atmosphere at altitudes above 200 km. At altitudes above 1200 km, hydrogen and helium, which are the lightest of the gases, begin to predominate.

Since the bulk of the air is concentrated in the 3 lower atmospheric layers, changes in air composition at altitudes above 100 km do not have a noticeable effect on the overall composition of the atmosphere.

Nitrogen is the most common gas, accounting for more than three-quarters of the Earth's air volume. Modern nitrogen was formed by the oxidation of the early ammonia-hydrogen atmosphere by molecular oxygen, which is formed during photosynthesis. Currently, small amounts of nitrogen enter the atmosphere as a result of denitrification - the process of reducing nitrates to nitrites, followed by the formation of gaseous oxides and molecular nitrogen, which is produced by anaerobic prokaryotes. Some nitrogen enters the atmosphere during volcanic eruptions.

In the upper layers of the atmosphere, when exposed to electrical discharges with the participation of ozone, molecular nitrogen is oxidized to nitrogen monoxide:

N 2 + O 2 → 2NO

Under normal conditions, the monoxide immediately reacts with oxygen to form nitrous oxide:

2NO + O 2 → 2N 2 O

Nitrogen is the most important chemical element in the earth's atmosphere. Nitrogen is part of proteins and provides mineral nutrition to plants. It determines the rate of biochemical reactions and plays the role of an oxygen diluent.

The second most common gas in the Earth's atmosphere is oxygen. The formation of this gas is associated with the photosynthetic activity of plants and bacteria. And the more diverse and numerous photosynthetic organisms became, the more significant the process of oxygen content in the atmosphere became. A small amount of heavy oxygen is released during degassing of the mantle.

In the upper layers of the troposphere and stratosphere, under the influence of ultraviolet solar radiation (we denote it as hν), ozone is formed:

O 2 + hν → 2O

As a result of the same ultraviolet radiation, ozone decomposes:

O 3 + hν → O 2 + O

О 3 + O → 2О 2

As a result of the first reaction, atomic oxygen is formed, and as a result of the second, molecular oxygen is formed. All 4 reactions are called the “Chapman mechanism”, named after the British scientist Sidney Chapman who discovered them in 1930.

Oxygen is used for the respiration of living organisms. With its help, oxidation and combustion processes occur.

Ozone serves to protect living organisms from ultraviolet radiation, which causes irreversible mutations. The highest concentration of ozone is observed in the lower stratosphere within the so-called. ozone layer or ozone screen, lying at altitudes of 22-25 km. The ozone content is small: at normal pressure, all the ozone in the earth's atmosphere would occupy a layer only 2.91 mm thick.

The formation of the third most common gas in the atmosphere, argon, as well as neon, helium, krypton and xenon, is associated with volcanic eruptions and the decay of radioactive elements.

In particular, helium is a product of the radioactive decay of uranium, thorium and radium: 238 U → 234 Th + α, 230 Th → 226 Ra + 4 He, 226 Ra → 222 Rn + α (in these reactions the α-particle is the helium nucleus, which in During the process of energy loss, it captures electrons and becomes 4 He).

Argon is formed during the decay of the radioactive isotope of potassium: 40 K → 40 Ar + γ.

Neon escapes from igneous rocks.

Krypton is formed as the end product of the decay of uranium (235 U and 238 U) and thorium Th.

The bulk of atmospheric krypton was formed in the early stages of the Earth's evolution as a result of the decay of transuranic elements with a phenomenally short half-life or came from space, where the krypton content is ten million times higher than on Earth.

Xenon is the result of the fission of uranium, but the bulk of this gas remains from the early stages of the formation of the Earth, from the primordial atmosphere.

Carbon dioxide enters the atmosphere as a result of volcanic eruptions and during the decomposition of organic matter. Its content in the atmosphere of the Earth's mid-latitudes varies greatly depending on the seasons of the year: in winter the amount of CO 2 increases, and in summer it decreases. This fluctuation is associated with the activity of plants that use carbon dioxide in the process of photosynthesis.

Hydrogen is formed as a result of the decomposition of water by solar radiation. But, being the lightest of the gases that make up the atmosphere, it constantly evaporates into outer space, and therefore its content in the atmosphere is very small.

Water vapor is the result of the evaporation of water from the surface of lakes, rivers, seas and land.

The concentration of the main gases in the lower layers of the atmosphere, with the exception of water vapor and carbon dioxide, is constant. In small quantities the atmosphere contains sulfur oxide SO 2, ammonia NH 3, carbon monoxide CO, ozone O 3, hydrogen chloride HCl, hydrogen fluoride HF, nitrogen monoxide NO, hydrocarbons, mercury vapor Hg, iodine I 2 and many others. In the lower atmospheric layer, the troposphere, there is always a large amount of suspended solid and liquid particles.

Sources of particulate matter in the Earth's atmosphere include volcanic eruptions, pollen, microorganisms, and, more recently, human activities, such as the burning of fossil fuels during production. The smallest particles of dust, which are condensation nuclei, cause the formation of fogs and clouds. Without particulate matter constantly present in the atmosphere, precipitation would not fall on Earth.

Changing the earth's surface. No less important was the activity of the wind, which carried small fractions of rocks over long distances. Temperature fluctuations and other atmospheric factors significantly influenced the destruction of rocks. Along with this, A. protects the Earth's surface from the destructive effects of falling meteorites, most of which burn up when entering the dense layers of the atmosphere.

The activity of living organisms, which has had a strong influence on the development of oxygen, itself depends to a very large extent on atmospheric conditions. A. delays most of the ultraviolet radiation from the Sun, which has a detrimental effect on many organisms. Atmospheric oxygen is used in the process of respiration by animals and plants, atmospheric carbon dioxide is used in the process of plant nutrition. Climatic factors, especially thermal and moisture regimes, affect health and human activity. Agriculture is especially dependent on climatic conditions. In turn, human activity has an ever-increasing influence on the composition of the atmosphere and the climate regime.

The structure of the atmosphere

Vertical distribution of temperature in the atmosphere and related terminology.

Numerous observations show that A. has a clearly defined layered structure (see figure). The main features of the layered structure of aluminum are determined primarily by the characteristics of the vertical temperature distribution. In the lowest part of the atmosphere—the troposphere, where intense turbulent mixing is observed (see Turbulence in the atmosphere and hydrosphere), the temperature decreases with increasing altitude, and the vertical decrease in temperature averages 6° per 1 km. The height of the troposphere varies from 8-10 km at polar latitudes to 16-18 km at the equator. Due to the fact that air density rapidly decreases with height, about 80% of the total mass of air is concentrated in the troposphere. Above the troposphere there is a transition layer - the tropopause with a temperature of 190-220, above which the stratosphere begins. In the lower part of the stratosphere, the decrease in temperature with height stops, and the temperature remains approximately constant up to an altitude of 25 km - the so-called. isothermal region(lower stratosphere); higher the temperature begins to increase - the inversion region (upper stratosphere). Temperatures reach a maximum of ~270 K at the level of the stratopause, located at an altitude of about 55 km. The A layer, located at altitudes from 55 to 80 km, where the temperature again decreases with height, is called the mesosphere. Above it there is a transition layer - mesopause, above which is the thermosphere, where the temperature, increasing with height, reaches very high values ​​(over 1000 K). Even higher (at altitudes of ~ 1000 km or more) is the exosphere, from where atmospheric gases are dispersed into space due to dissipation and where a gradual transition from atmospheric to interplanetary space occurs. Usually, all layers of the atmosphere located above the troposphere are called upper, although sometimes the stratosphere or its lower part is also referred to as the lower layers of the atmosphere.

All structural parameters of Africa (temperature, pressure, density) have significant spatiotemporal variability (latitudinal, annual, seasonal, daily, etc.). Therefore, the data in Fig. reflect only the average state of the atmosphere.

Atmospheric structure diagram:
1 - sea level; 2 - the highest point of the Earth - Mount Chomolungma (Everest), 8848 m; 3 - fair weather cumulus clouds; 4 - powerful cumulus clouds; 5 - shower (thunderstorm) clouds; 6 - nimbostratus clouds; 7 - cirrus clouds; 8 - airplane; 9 - layer of maximum ozone concentration; 10 - pearlescent clouds; 11 - stratospheric balloon; 12 - radiosonde; 1З - meteors; 14 - noctilucent clouds; 15 - auroras; 16 - American X-15 rocket aircraft; 17, 18, 19 - radio waves reflected from ionized layers and returning to Earth; 20 - sound wave reflected from the warm layer and returning to Earth; 21 - the first Soviet artificial Earth satellite; 22 - intercontinental ballistic missile; 23 - geophysical research rockets; 24 - meteorological satellites; 25 - spacecraft Soyuz-4 and Soyuz-5; 26 - space rockets leaving the atmosphere, as well as a radio wave penetrating the ionized layers and leaving the atmosphere; 27, 28 - dissipation (slippage) of H and He atoms; 29 - trajectory of solar protons P; 30 - penetration of ultraviolet rays (wavelength l > 2000 and l< 900).

The layered structure of the atmosphere has many other diverse manifestations. The chemical composition of the atmosphere is heterogeneous over altitude. If at altitudes up to 90 km, where there is intense mixing of the atmosphere, the relative composition of the permanent components of the atmosphere remains practically unchanged (this entire thickness of the atmosphere is called the homosphere), then above 90 km - in heterosphere- under the influence of the dissociation of molecules of atmospheric gases by ultraviolet radiation from the sun, a strong change in the chemical composition of the atmosphere occurs with altitude. Typical features of this part of Africa are layers of ozone and the atmosphere's own glow. A complex layered structure is characteristic of atmospheric aerosol—solid particles of terrestrial and cosmic origin suspended in air. The most common aerosol layers are found below the tropopause and at an altitude of about 20 km. The vertical distribution of electrons and ions in the atmosphere is layered, which is expressed in the existence of D-, E-, and F-layers of the ionosphere.

Atmospheric composition

One of the most optically active components is atmospheric aerosol - particles suspended in the air ranging in size from several nm to several tens of microns, formed during the condensation of water vapor and entering the atmosphere from the earth's surface as a result of industrial pollution, volcanic eruptions, and also from space. Aerosol is observed both in the troposphere and in the upper layers of A. The aerosol concentration quickly decreases with height, but this variation is superimposed by numerous secondary maxima associated with the existence of aerosol layers.

Upper atmosphere

Above 20-30 km, as a result of dissociation, the molecules of atoms disintegrate to one degree or another into atoms, and free atoms and new, more complex molecules appear in the atom. Somewhat higher, ionization processes become significant.

The most unstable region is the heterosphere, where the processes of ionization and dissociation give rise to numerous photochemical reactions that determine changes in the composition of air with height. Gravitational separation of gases also occurs here, which is expressed in the gradual enrichment of Africa with lighter gases as the altitude increases. According to rocket measurements, gravitational separation of neutral gases - argon and nitrogen - is observed above 105-110 km. The main components of oxygen in the 100-210 km layer are molecular nitrogen, molecular oxygen and atomic oxygen (the concentration of the latter at the level of 210 km reaches 77 ± 20% of the concentration of molecular nitrogen).

The upper part of the thermosphere consists mainly of atomic oxygen and nitrogen. At an altitude of 500 km, molecular oxygen is practically absent, but molecular nitrogen, the relative concentration of which greatly decreases, still dominates over atomic nitrogen.

In the thermosphere, tidal movements (see Ebb and flow), gravitational waves, photochemical processes, an increase in the mean free path of particles, and other factors play an important role. The results of observations of satellite braking at altitudes of 200-700 km led to the conclusion that there is a relationship between density, temperature and solar activity, which is associated with the existence of daily, semi-annual and annual variations in structural parameters. It is possible that diurnal variations are largely due to atmospheric tides. During periods of solar flares, temperatures at an altitude of 200 km in low latitudes can reach 1700-1900°C.

Above 600 km, helium becomes the predominant component, and even higher, at altitudes of 2-20 thousand km, the Earth’s hydrogen corona extends. At these altitudes, the Earth is surrounded by a shell of charged particles, the temperature of which reaches several tens of thousands of degrees. The Earth's inner and outer radiation belts are located here. The inner belt, filled mainly with protons with energies of hundreds of MeV, is limited to altitudes of 500-1600 km at latitudes from the equator to 35-40°. The outer belt consists of electrons with energies of the order of hundreds of keV. Beyond the outer belt there is an "outermost belt" in which the concentration and flow of electrons is much higher. The intrusion of solar corpuscular radiation (solar wind) into the upper layers of the sun gives rise to auroras. Under the influence of this bombardment of the upper atmosphere by electrons and protons of the solar corona, the atmosphere’s own glow, which was previously called glow of the night sky. When the solar wind interacts with the Earth's magnetic field, a zone is created, called. Earth's magnetosphere, where solar plasma streams do not penetrate.

The upper layers of Africa are characterized by the existence of strong winds, the speed of which reaches 100-200 m/sec. Wind speed and direction within the troposphere, mesosphere and lower thermosphere have great spatiotemporal variability. Although the mass of the upper layers of the sky is insignificant compared to the mass of the lower layers and the energy of atmospheric processes in the high layers is relatively small, apparently there is some influence of the high layers of the sky on the weather and climate in the troposphere.

Radiation, heat and water balances of the atmosphere

Practically the only source of energy for all physical processes developing in Africa is solar radiation. The main feature of the radiation regime of A. is the so-called. greenhouse effect: A. weakly absorbs short-wave solar radiation (most of it reaches the earth's surface), but retains long-wave (entirely infrared) thermal radiation from the earth's surface, which significantly reduces the heat transfer of the Earth into outer space and increases its temperature.

Solar radiation arriving in Africa is partially absorbed in Africa, mainly by water vapor, carbon dioxide, ozone, and aerosols and is scattered on aerosol particles and on fluctuations in the density of Africa. Due to the dispersion of the radiant energy of the Sun in Africa, not only direct solar radiation is observed, but also scattered radiation, together they make up the total radiation. Reaching the earth's surface, the total radiation is partially reflected from it. The amount of reflected radiation is determined by the reflectivity of the underlying surface, the so-called. albedo Due to the absorbed radiation, the earth's surface heats up and becomes a source of its own long-wave radiation directed towards the earth. In turn, the earth also emits long-wave radiation directed towards the earth's surface (the so-called anti-radiation of the earth) and into outer space (the so-called outgoing radiation). Rational heat exchange between the earth's surface and the earth is determined by effective radiation - the difference between the intrinsic radiation of the earth's surface and the counter-radiation absorbed by it. The difference between the short-wave radiation absorbed by the earth's surface and the effective radiation is called radiation balance.

The transformation of the energy of solar radiation after its absorption on the earth's surface and in the atmosphere constitutes the heat balance of the earth. The main source of heat for the atmosphere is the earth's surface, which absorbs the bulk of solar radiation. Since the absorption of solar radiation in the Earth is less than the loss of heat from the Earth into the world space by long-wave radiation, the radiation heat consumption is replenished by the influx of heat to the Earth from the earth’s surface in the form of turbulent heat exchange and the arrival of heat as a result of condensation of water vapor in the Earth. Since the total The amount of condensation throughout Africa is equal to the amount of precipitation, as well as the amount of evaporation from the earth's surface; the arrival of condensation heat in Africa is numerically equal to the heat lost for evaporation on the Earth's surface (see also Water balance).

Some of the energy of solar radiation is spent on maintaining the general circulation of the atmosphere and on other atmospheric processes, but this part is insignificant compared to the main components of the heat balance.

Air movement

Due to the high mobility of atmospheric air, winds are observed at all altitudes. Air movements depend on many factors, the main one being the uneven heating of air in different regions of the globe.

Particularly large temperature contrasts at the Earth's surface exist between the equator and the poles due to differences in the arrival of solar energy at different latitudes. Along with this, the distribution of temperature is influenced by the location of continents and oceans. Due to the high heat capacity and thermal conductivity of ocean waters, the oceans significantly attenuate temperature fluctuations that arise as a result of changes in the arrival of solar radiation throughout the year. In this regard, in temperate and high latitudes, the air temperature over the oceans in summer is noticeably lower than over the continents, and higher in winter.

The uneven heating of the atmosphere contributes to the development of a system of large-scale air currents - the so-called. general atmospheric circulation, which creates horizontal heat transfer in the atmosphere, as a result of which differences in the heating of atmospheric air in individual areas are noticeably smoothed out. Along with this, the general circulation carries out moisture circulation in Africa, during which water vapor is transferred from the oceans to land and the continents are moistened. The movement of air in the general circulation system is closely related to the distribution of atmospheric pressure and also depends on the rotation of the Earth (see Coriolis force). At sea level, the pressure distribution is characterized by a decrease near the equator, an increase in the subtropics (high pressure belts) and a decrease in temperate and high latitudes. At the same time, over the continents of extratropical latitudes, the pressure is usually increased in winter and decreased in summer.

Associated with the planetary pressure distribution is a complex system of air currents, some of which are relatively stable, while others are constantly changing in space and time. Stable air currents include trade winds, which are directed from the subtropical latitudes of both hemispheres to the equator. Monsoons are also relatively stable - air currents that arise between the ocean and the mainland and are seasonal. In temperate latitudes, westerly air currents predominate (from west to east). These currents include large eddies - cyclones and anticyclones, usually extending over hundreds and thousands of km. Cyclones are also observed in tropical latitudes, where they are distinguished by their smaller sizes, but especially high wind speeds, often reaching the strength of a hurricane (so-called tropical cyclones). In the upper troposphere and lower stratosphere there are relatively narrow (hundreds of kilometers wide) jet streams that have sharply defined boundaries, within which the wind reaches enormous speeds - up to 100-150 m/sec. Observations show that the features of atmospheric circulation in the lower part of the stratosphere are determined by processes in the troposphere.

In the upper half of the stratosphere, where temperature increases with altitude, wind speed increases with altitude, with eastern winds dominating in summer and westerly winds in winter. The circulation here is determined by a stratospheric heat source, the existence of which is associated with the intense absorption of ultraviolet solar radiation by ozone.

In the lower part of the mesosphere in temperate latitudes, the speed of the winter westerly transport increases to maximum values ​​- about 80 m/sec, and the summer eastern transport - up to 60 m/sec at a level of about 70 km. Research in recent years has clearly shown that the features of the temperature field in the mesosphere cannot be explained only by the influence of radiation factors. Dynamic factors are of primary importance (in particular, heating or cooling when air descends or rises), and heat sources arising from photochemical reactions (for example, recombination of atomic oxygen) are also possible.

Above the cold mesopause layer (in the thermosphere), the air temperature begins to increase rapidly with altitude. In many respects, this region of Africa is similar to the lower half of the stratosphere. It is likely that the circulation in the lower part of the thermosphere is determined by processes in the mesosphere, and the dynamics of the upper layers of the thermosphere is determined by the absorption of solar radiation here. However, it is difficult to study atmospheric motion at these altitudes due to their significant complexity. Tidal movements (mainly solar semidiurnal and diurnal tides) become of great importance in the thermosphere, under the influence of which wind speeds at altitudes of more than 80 km can reach 100-120 m/sec. A characteristic feature of atmospheric tides is their strong variability depending on latitude, time of year, altitude above sea level and time of day. In the thermosphere, significant changes in wind speed with height are also observed (mainly near the 100 km level), attributed to the influence of gravitational waves. Located in the altitude range of 100-110 km so-called. The turbopause sharply separates the region above from the zone of intense turbulent mixing.

Along with large-scale air currents, numerous local air circulations are observed in the lower layers of the atmosphere (breeze, bora, mountain-valley winds, etc.; see Local winds). In all air currents, wind pulsations are usually observed, corresponding to the movement of air vortices of medium and small sizes. Such pulsations are associated with atmospheric turbulence, which significantly affects many atmospheric processes.

Climate and weather

Differences in the amount of solar radiation arriving at different latitudes of the earth's surface and the complexity of its structure, including the distribution of oceans, continents and major mountain systems, determine the diversity of the Earth's climates (see Climate).

Literature

  • Meteorology and hydrology for 50 years of Soviet power, ed. E. K. Fedorova, Leningrad, 1967;
  • Khrgian A. Kh., Atmospheric Physics, 2nd ed., M., 1958;
  • Zverev A.S., Synoptic meteorology and fundamentals of weather prediction, Leningrad, 1968;
  • Khromov S.P., Meteorology and climatology for geographical faculties, Leningrad, 1964;
  • Tverskoy P.N., Course of Meteorology, Leningrad, 1962;
  • Matveev L. T., Fundamentals of general meteorology. Atmospheric Physics, Leningrad, 1965;
  • Budyko M.I., Thermal balance of the earth's surface, Leningrad, 1956;
  • Kondratyev K. Ya., Actinometry, Leningrad, 1965;
  • Khvostikov I. A., High layers of the atmosphere, Leningrad, 1964;
  • Moroz V.I., Physics of Planets, M., 1967;
  • Tverskoy P.N., Atmospheric electricity, Leningrad, 1949;
  • Shishkin N. S., Clouds, precipitation and thunderstorm electricity, M., 1964;
  • Ozone in the Earth's Atmosphere, ed. G. P. Gushchina, Leningrad, 1966;
  • Imyanitov I.M., Chubarina E.V., Electricity of the free atmosphere, Leningrad, 1965.

M. I. Budyko, K. Ya. Kondratiev.

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The Earth's atmosphere is a shell of air.

The presence of a special ball above the earth's surface was proven by the ancient Greeks, who called the atmosphere a steam or gas ball.

This is one of the geospheres of the planet, without which the existence of all living things would not be possible.

Where is the atmosphere

The atmosphere surrounds the planets with a dense layer of air, starting from the earth's surface. It comes into contact with the hydrosphere, covers the lithosphere, extending far into outer space.

What does the atmosphere consist of?

The air layer of the Earth consists mainly of air, the total mass of which reaches 5.3 * 1018 kilograms. Of these, the diseased part is dry air, and much less is water vapor.

Over the sea, the density of the atmosphere is 1.2 kilograms per cubic meter. The temperature in the atmosphere can reach –140.7 degrees, air dissolves in water at zero temperature.

The atmosphere consists of several layers:

  • Troposphere;
  • Tropopause;
  • Stratosphere and stratopause;
  • Mesosphere and mesopause;
  • A special line above sea level called the Karman line;
  • Thermosphere and thermopause;
  • Scattering zone or exosphere.

Each layer has its own characteristics; they are interconnected and ensure the functioning of the planet’s air envelope.

Limits of the atmosphere

The lowest edge of the atmosphere passes through the hydrosphere and the upper layers of the lithosphere. The upper boundary begins in the exosphere, which is located 700 kilometers from the surface of the planet and will reach 1.3 thousand kilometers.

According to some reports, the atmosphere reaches 10 thousand kilometers. Scientists agreed that the upper boundary of the air layer should be the Karman line, since aeronautics is no longer possible here.

Thanks to constant studies in this area, scientists have established that the atmosphere comes into contact with the ionosphere at an altitude of 118 kilometers.

Chemical composition

This layer of the Earth consists of gases and gaseous impurities, which include combustion residues, sea salt, ice, water, and dust. The composition and mass of gases that can be found in the atmosphere almost never changes, only the concentration of water and carbon dioxide changes.

The composition of the water can vary from 0.2 percent to 2.5 percent, depending on latitude. Additional elements are chlorine, nitrogen, sulfur, ammonia, carbon, ozone, hydrocarbons, hydrochloric acid, hydrogen fluoride, hydrogen bromide, hydrogen iodide.

A separate part is occupied by mercury, iodine, bromine, and nitric oxide. In addition, liquid and solid particles called aerosol are found in the troposphere. One of the rarest gases on the planet, radon, is found in the atmosphere.

In terms of chemical composition, nitrogen occupies more than 78% of the atmosphere, oxygen - almost 21%, carbon dioxide - 0.03%, argon - almost 1%, the total amount of the substance is less than 0.01%. This air composition was formed when the planet first emerged and began to develop.

With the advent of man, who gradually moved to production, the chemical composition changed. In particular, the amount of carbon dioxide is constantly increasing.

Functions of the atmosphere

Gases in the air layer perform a variety of functions. Firstly, they absorb rays and radiant energy. Secondly, they influence the formation of temperature in the atmosphere and on Earth. Thirdly, it ensures life and its course on Earth.

In addition, this layer provides thermoregulation, which determines the weather and climate, the mode of heat distribution and atmospheric pressure. The troposphere helps regulate the flow of air masses, determine the movement of water, and heat exchange processes.

The atmosphere constantly interacts with the lithosphere and hydrosphere, providing geological processes. The most important function is that it provides protection from dust of meteorite origin, from the influence of space and the sun.

Data

  • Oxygen is provided on Earth by the decomposition of organic matter in solid rock, which is very important during emissions, decomposition of rocks, and oxidation of organisms.
  • Carbon dioxide helps photosynthesis occur, and also contributes to the transmission of short waves of solar radiation and the absorption of long thermal waves. If this does not happen, then the so-called greenhouse effect is observed.
  • One of the main problems associated with the atmosphere is pollution, which occurs due to the operation of factories and automobile emissions. Therefore, many countries have introduced special environmental control, and at the international level special mechanisms are being undertaken to regulate emissions and the greenhouse effect.

- the air shell of the globe, rotating together with the Earth. The upper boundary of the atmosphere is conventionally drawn at altitudes of 150-200 km. The lower boundary is the Earth's surface.

Atmospheric air is a mixture of gases. Most of its volume in the surface layer of air accounts for 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 characteristics of the scattering of light waves.

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

The lower ground layer of air is called troposphere. At different latitudes its power is not the same. The troposphere follows 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 maximum air density; 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 lower air density and lacks water vapor. 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 it extends mesosphere. With increasing altitude, 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 atmospheric glow is caused by complex photochemical processes involving radicals and vibrationally excited molecules.

Thermosphere located at an altitude of 80-90 to 800 km. The air density here is minimal, and the degree of air ionization is very high. 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 smoothes 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, before reaching the surface of the planet, meteorites burn from thorns.

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

Human economic activities have a significant adverse impact on the atmosphere. Atmospheric air pollution occurs, which leads to an increase in the concentration of carbon monoxide (CO 2). And this contributes to global warming and increases the “greenhouse effect”. The Earth's ozone layer is destroyed due to industrial waste and transport.

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

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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 does it consist of and into what parts is it divided? All these questions are extremely interesting.

The name “atmosphere” itself 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 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 the atmosphere is 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 discovered that the composition of the atmosphere was mostly composed of nitrogen and oxygen. Over time, its components were refined. And now it is known that it contains many other gases, as well as water and dust.

Let's take a closer look at what makes up the Earth's atmosphere near its surface. The most common gas is nitrogen. It contains slightly more than 78 percent. But, despite such a large amount, nitrogen is practically inactive in the air.

The next element in quantity and very important in importance is oxygen. This gas contains almost 21%, and it exhibits 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. It's a little less than one percent. After it come carbon dioxide with neon, helium with methane, krypton with hydrogen, xenon, ozone and even ammonia. But there are so few of them 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 block radiation and absorb some of the sun's heat.

Another small 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 heats up.

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

What else is in the air?

It should be noted that steam and dust can be found in the airspace. The latter consists of pollen and soil particles; in the city they are joined by impurities of solid 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 essence, these are the same thing, only the former appear high above the surface of the Earth, and the latter spreads along it. Clouds take different 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 pours on the ground or snow falls. Above them, cumulus clouds form up to a height of 8 km. They are always the most beautiful and picturesque. They are the ones who look at them and wonder what they look like. If such formations appear in the next 10 km, they will be very light and airy. Their name is feathery.

What layers is the atmosphere divided into?

Although they have very different temperatures from each other, it is very difficult to tell at what specific height one layer begins and the other 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 as it moves from the poles to the equator from 8 to 18 km. This is the warmest part of the atmosphere because the air in it is heated by the earth's surface. Most of the water vapor is concentrated in the troposphere, which is why clouds form, precipitation falls, thunderstorms rumble and winds blow.

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

After it come the stratopause and mesosphere. The latter is about 30 km thick. 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 in which there is practically 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 distinguished by its enormous temperature, which can reach 1700 °C.

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

The next 50 km from the Earth are allocated to the exosphere. This is the outer shell of the atmosphere. It disperses air particles into space. Weather satellites usually move in this layer.

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

After all that has been said, there should be no questions left about what the atmosphere is. If you have any doubts about its necessity, they can be easily dispelled.

The meaning of atmosphere

The main function of the atmosphere is to protect the planet's surface from overheating during the day and excessive cooling at night. The next important purpose of this shell, which no one will dispute, is to supply oxygen to all living beings. Without this 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 protection from solar radiation has already been discussed above.

How does a person influence the atmosphere?

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

The list of harmful substances that daily replenish the air is very long. Due to transport in the atmosphere there 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.