Draw the structure of the atmosphere and give a brief description. Atmosphere and the world of atmospheric phenomena

Composition of the atmosphere. The air envelope of our planet - atmosphere protects the earth's surface from the harmful effects of ultraviolet radiation from the Sun on living organisms. It also protects the Earth from cosmic particles - dust and meteorites.

The atmosphere consists of a mechanical mixture of gases: 78% of its volume is nitrogen, 21% is oxygen and less than 1% is helium, argon, krypton and other inert gases. The amount of oxygen and nitrogen in the air is practically unchanged, because nitrogen almost does not combine with other substances, and oxygen, which, although very active and spent on respiration, oxidation and combustion, is constantly replenished by plants.

Up to an altitude of approximately 100 km, the percentage of these gases remains virtually unchanged. This is due to the fact that the air is constantly mixed.

In addition to the mentioned gases, the atmosphere contains about 0.03% carbon dioxide, which is usually concentrated close to earth's surface and is distributed unevenly: in cities, industrial centers and areas of volcanic activity, its quantity increases.

There is always a certain amount of impurities in the atmosphere - water vapor and dust. The content of water vapor depends on the air temperature: the higher the temperature, the more vapor the air can hold. Due to the presence of vaporous water in the air, atmospheric phenomena such as rainbows, refraction of sunlight, etc. are possible.

Dust enters the atmosphere during volcanic eruptions, sand and dust storms, during incomplete combustion of fuel at thermal power plants, etc.

The structure of the atmosphere. The density of the atmosphere changes with altitude: it is highest at the Earth's surface and decreases as it goes up. Thus, at an altitude of 5.5 km the density of the atmosphere is 2 times, and at an altitude of 11 km it is 4 times less than in the surface layer.

Depending on the density, composition and properties of gases, the atmosphere is divided into five concentric layers (Fig. 34).

Rice. 34. Vertical section of the atmosphere (stratification of the atmosphere)

1. The bottom layer is called troposphere. Its upper boundary passes at an altitude of 8-10 km at the poles and 16-18 km at the equator. The troposphere contains up to 80% of the total mass of the atmosphere and almost all water vapor.

The air temperature in the troposphere decreases with height by 0.6 °C every 100 m and at its upper boundary is -45-55 °C.

The air in the troposphere is constantly mixed and moves in different directions. Only here are fogs, rains, snowfalls, thunderstorms, storms and others observed weather phenomena.

2. Located above stratosphere, which extends to an altitude of 50-55 km. Air density and pressure in the stratosphere are negligible. Thin air consists of the same gases as in the troposphere, but it contains more ozone. The highest concentration of ozone is observed at an altitude of 15-30 km. The temperature in the stratosphere increases with altitude and at its upper boundary reaches 0 °C and above. This is because ozone absorbs short-wave energy from the sun, causing the air to warm up.

3. Lies above the stratosphere mesosphere, extending to an altitude of 80 km. There the temperature drops again and reaches -90 °C. The air density there is 200 times less than at the surface of the Earth.

4. Above the mesosphere is located thermosphere(from 80 to 800 km). The temperature in this layer increases: at an altitude of 150 km to 220 °C; at an altitude of 600 km up to 1500 °C. Atmospheric gases (nitrogen and oxygen) are in an ionized state. Under the influence of short-wave solar radiation, individual electrons are separated from the shells of atoms. As a result, in this layer - ionosphere layers of charged particles appear. Their densest layer is located at an altitude of 300-400 km. Due to the low density sun rays they do not scatter there, so the sky is black, stars and planets shine brightly on it.

In the ionosphere there are polar lights, powerful electric currents are generated that cause disturbances magnetic field Earth.

5. Above 800 km is the outer shell - exosphere. The speed of movement of individual particles in the exosphere is approaching critical - 11.2 mm/s, so individual particles can overcome gravity and escape into outer space.

The meaning of atmosphere. The role of the atmosphere in the life of our planet is extremely great. Without her, the Earth would be dead. The atmosphere protects the Earth's surface from extreme heating and cooling. Its effect can be likened to the role of glass in greenhouses: allowing the sun's rays to pass through and preventing heat loss.

The atmosphere protects living organisms from short-wave and corpuscular radiation from the Sun. The atmosphere is the environment where weather phenomena occur, with which all human activity is associated. The study of this shell is carried out at meteorological stations. Day and night, in any weather, meteorologists monitor the state of the lower layer of the atmosphere. Four times a day, and at many stations hourly they measure temperature, pressure, air humidity, note cloudiness, wind direction and speed, amount of precipitation, electrical and sound phenomena in the atmosphere. Meteorological stations are located everywhere: in Antarctica and in tropical rainforests, on high mountains and in vast expanses of tundra. Observations are also carried out on the oceans from specially built ships.

Since the 30s. XX century observations began in the free atmosphere. They began to launch radiosondes that rise to a height of 25-35 km and, using radio equipment, transmit information about temperature, pressure, air humidity and wind speed to Earth. Nowadays, meteorological rockets and satellites are also widely used. The latter have television installations that transmit images of the earth's surface and clouds.

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5. The air shell of the earth§ 31. Heating of the atmosphere

The Earth's atmosphere is the gaseous envelope of our planet. Its lower boundary passes at the level of the earth's crust and hydrosphere, and the upper boundary passes into the near-Earth region of outer space. The atmosphere contains about 78% nitrogen, 20% oxygen, up to 1% argon, carbon dioxide, hydrogen, helium, neon and some other gases.

This earth's shell is characterized by clearly defined layering. The layers of the atmosphere are determined by the vertical distribution of temperature and the different densities of gases at different levels. There are such layers of the Earth's atmosphere: troposphere, stratosphere, mesosphere, thermosphere, exosphere. The ionosphere is separated separately.

Up to 80% of the total mass of the atmosphere is the troposphere - the lower ground layer of the atmosphere. The troposphere in the polar zones is located at a level of up to 8-10 km above the earth's surface, in the tropical zone - up to a maximum of 16-18 km. Between the troposphere and the overlying layer of the stratosphere there is a tropopause - a transition layer. In the troposphere, the temperature decreases as altitude increases, and similarly, atmospheric pressure decreases with altitude. The average temperature gradient in the troposphere is 0.6°C per 100 m. The temperature at different levels of this shell is determined by the characteristics of the absorption of solar radiation and the efficiency of convection. Almost all human activity takes place in the troposphere. The highest mountains do not go beyond the troposphere; only air transport can cross the upper boundary of this shell at a small height and be in the stratosphere. A large proportion of water vapor is found in the troposphere, which is responsible for the formation of almost all clouds. Also, almost all aerosols (dust, smoke, etc.) formed on the earth’s surface are concentrated in the troposphere. In the boundary lower layer of the troposphere, daily fluctuations in temperature and air humidity are pronounced, and wind speed is usually reduced (it increases with increasing altitude). In the troposphere, there is a variable division of the air thickness into air masses in the horizontal direction, differing in a number of characteristics depending on the zone and area of ​​their formation. At atmospheric fronts - the boundaries between air masses - cyclones and anticyclones form, which determine the weather in a certain area for a specific period of time.

The stratosphere is the layer of atmosphere between the troposphere and mesosphere. The limits of this layer range from 8-16 km to 50-55 km above the Earth's surface. In the stratosphere, the gas composition of the air is approximately the same as in the troposphere. A distinctive feature is a decrease in water vapor concentration and an increase in ozone content. The ozone layer of the atmosphere, which protects the biosphere from the aggressive effects of ultraviolet light, is located at a level of 20 to 30 km. In the stratosphere, temperature increases with altitude, and temperature values ​​are determined by solar radiation, and not by convection (movements of air masses), as in the troposphere. The heating of the air in the stratosphere is due to the absorption of ultraviolet radiation by ozone.

Above the stratosphere the mesosphere extends to a level of 80 km. This layer of the atmosphere is characterized by the fact that the temperature decreases as the altitude increases from 0 ° C to - 90 ° C. This is the coldest region of the atmosphere.

Above the mesosphere is the thermosphere up to a level of 500 km. From the border with the mesosphere to the exosphere, the temperature varies from approximately 200 K to 2000 K. Up to the level of 500 km, the air density decreases several hundred thousand times. The relative composition of the atmospheric components of the thermosphere is similar to the surface layer of the troposphere, but with increasing altitude more oxygen goes into the atomic state. A certain proportion of molecules and atoms of the thermosphere are in an ionized state and are distributed in several layers; they are united by the concept of the ionosphere. Thermosphere characteristics vary widely depending on geographic latitude, solar radiation, time of year and day.

The upper layer of the atmosphere is the exosphere. This is the thinnest layer of the atmosphere. In the exosphere, the mean free path of particles is so enormous that particles can freely escape into interplanetary space. The mass of the exosphere is one ten-millionth of the total mass of the atmosphere. The lower boundary of the exosphere is the level of 450-800 km, and the upper boundary is considered to be the region where the concentration of particles is the same as in outer space - several thousand kilometers from the Earth's surface. The exosphere consists of plasma - ionized gas. Also in the exosphere are the radiation belts of our planet.

Video presentation - layers of the Earth's atmosphere:

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

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

Troposphere and tropopause

Troposphere - temperature, pressure, altitude

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

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

Tropopause

This is the transition layer of the troposphere to the stratosphere. Here the dependence of temperature decrease with increasing altitude stops. Tropopause - 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 11 to 50 km. There is a slight change in temperature at an altitude of 11 - 25 km. At an altitude of 25 - 40 km it is observed inversion temperatures, from 56.5 rises to 0.8°C. From 40 km to 55 km the temperature stays at 0°C. This area is called - Stratopause.

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

Mesosphere and Mesopause - composition, reactions, temperature

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

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

Karman Line

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

Thermosphere and Thermopause

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

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

Exosphere - density, temperature, height

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

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

ATMOSPHERE
gaseous envelope surrounding a celestial body. Its characteristics depend on the size, mass, temperature, rotation speed and chemical composition of a given celestial body, and are also determined by the history of its formation from the moment of its inception. The Earth's atmosphere is made up of a mixture of gases called air. Its main components are nitrogen and oxygen in a ratio of approximately 4:1. A person is affected mainly by the state of the lower 15-25 km of the atmosphere, since it is in this lower layer that the bulk of the air is concentrated. The science that studies the atmosphere is called meteorology, although the subject of this science is also the weather and its effect on humans. The state of the upper layers of the atmosphere, located at altitudes from 60 to 300 and even 1000 km from the Earth's surface, also changes. Strong winds, storms develop here, and amazing electrical phenomena such as auroras occur. Many of the listed phenomena are associated with the flow of solar radiation, cosmic radiation, and the Earth's magnetic field. The high layers of the atmosphere are also a chemical laboratory, since there, under conditions close to vacuum, some atmospheric gases, under the influence of a powerful flow of solar energy, enter into chemical reactions. The science that studies these interrelated phenomena and processes is called high-atmospheric physics.
GENERAL CHARACTERISTICS OF THE EARTH'S ATMOSPHERE
Dimensions. Until sounding rockets and artificial satellites explored the outer layers of the atmosphere at distances several times greater than the radius of the Earth, it was believed that as we move away from the earth's surface, the atmosphere gradually becomes more rarefied and smoothly passes into interplanetary space. It has now been established that energy flows from the deep layers of the Sun penetrate into outer space far beyond the Earth’s orbit, right up to the outer limits of the Solar System. This so-called The solar wind flows around the Earth's magnetic field, forming an elongated "cavity" within which the Earth's atmosphere is concentrated. The Earth's magnetic field is noticeably narrowed on the day side facing the Sun and forms a long tongue, probably extending beyond the Moon's orbit, on the opposite, night side. The boundary of the Earth's magnetic field is called the magnetopause. On the daytime side, this boundary runs at a distance of about seven Earth radii from the surface, but during periods of increased solar activity it turns out to be even closer to the Earth’s surface. The magnetopause is also the boundary earth's atmosphere, the outer shell of which is also called the magnetosphere, since charged particles (ions) are concentrated in it, the movement of which is determined by the Earth’s magnetic field. The total weight of atmospheric gases is approximately 4.5 * 1015 tons. Thus, the “weight” of the atmosphere per unit area, or atmospheric pressure, is approximately 11 tons/m2 at sea level.
Meaning for life. From the above it follows that the Earth is separated from interplanetary space by a powerful protective layer. Outer space is permeated with powerful ultraviolet and x-ray radiation from the Sun and even harder cosmic radiation, and these types of radiation are destructive to all living things. At the outer edge of the atmosphere, the radiation intensity is lethal, but much of it is retained by the atmosphere far from the Earth's surface. The absorption of this radiation explains many of the properties of the high layers of the atmosphere and especially the electrical phenomena occurring there. The lowest, ground-level layer of the atmosphere is especially important for humans, who live at the point of contact between the solid, liquid and gaseous shells of the Earth. The upper shell of the “solid” Earth is called the lithosphere. About 72% of the Earth's surface is covered by ocean waters, which make up most of the hydrosphere. The atmosphere borders both the lithosphere and the hydrosphere. Man lives at the bottom of the ocean of air and near or above the level of the ocean of water. The interaction of these oceans is one of the important factors determining the state of the atmosphere.
Compound. The lower layers of the atmosphere consist of a mixture of gases (see table). In addition to those listed in the table, other gases are present in the form of small impurities in the air: ozone, methane, substances such as carbon monoxide (CO), nitrogen and sulfur oxides, ammonia.

COMPOSITION OF THE ATMOSPHERE

In the high layers of the atmosphere, the composition of the air changes under the influence of hard radiation from the Sun, which leads to the disintegration of oxygen molecules into atoms. Atomic oxygen is the main component of the high layers of the atmosphere. Finally, in the layers of the atmosphere furthest from the Earth's surface, the main components are the lightest gases - hydrogen and helium. Since the bulk of the substance is concentrated in the lower 30 km, changes in the composition of the air at altitudes above 100 km do not have a noticeable effect on the overall composition of the atmosphere.
Energy exchange. The sun is the main source of energy supplied to the Earth. At a distance of approx. 150 million km from the Sun, the Earth receives approximately one two-billionth of the energy it emits, mainly in the visible part of the spectrum, which humans call “light.” Most of this energy is absorbed by the atmosphere and lithosphere. The Earth also emits energy, mostly in the form of long-wave infrared radiation. In this way, a balance is established between the energy received from the Sun, the heating of the Earth and atmosphere, and the reverse flow of thermal energy emitted into space. The mechanism of this equilibrium is extremely complex. Dust and gas molecules scatter light, partially reflecting it into outer space. Even more of the incoming radiation is reflected by clouds. Some of the energy is absorbed directly by gas molecules, but mainly by rocks, vegetation and surface waters. Water vapor and carbon dioxide present in the atmosphere transmit visible radiation but absorb infrared radiation. Thermal energy accumulates mainly in the lower layers of the atmosphere. A similar effect occurs in a greenhouse when glass allows light to enter and the soil heats up. Since glass is relatively opaque to infrared radiation, heat accumulates in the greenhouse. The heating of the lower atmosphere due to the presence of water vapor and carbon dioxide is often called the greenhouse effect. Cloudiness plays a significant role in maintaining heat in the lower layers of the atmosphere. If clouds clear or air becomes more transparent, the temperature inevitably drops as the Earth's surface radiates heat energy freely into the surrounding space. Water on the Earth's surface absorbs solar energy and evaporates, turning into gas - water vapor, which carries a huge amount of energy into the lower layers of the atmosphere. When water vapor condenses and clouds or fog form, this energy is released as heat. About half of the solar energy reaching the earth's surface is spent on the evaporation of water and enters the lower layers of the atmosphere. Thus, due to the greenhouse effect and water evaporation, the atmosphere warms up from below. This partly explains the high activity of its circulation compared to the circulation of the World Ocean, which is heated only from above and is therefore much more stable than the atmosphere.
See also METEOROLOGY AND CLIMATOLOGY. In addition to the general heating of the atmosphere by solar “light,” significant heating of some of its layers occurs due to ultraviolet and X-ray radiation from the Sun. Structure. Compared to liquids and solids, in gaseous substances the force of attraction between molecules is minimal. As the distance between molecules increases, gases are able to expand indefinitely if nothing prevents them. The lower boundary of the atmosphere is the surface of the Earth. Strictly speaking, this barrier is impenetrable, since gas exchange occurs between air and water and even between air and rocks, but in this case these factors can be neglected. Since the atmosphere is a spherical shell, it has no lateral boundaries, but only a lower boundary and an upper (outer) boundary, open from the side of interplanetary space. Some neutral gases leak through the outer boundary, as well as matter enters from the surrounding outer space. Most charged particles, with the exception of high-energy cosmic rays, are either captured by the magnetosphere or repelled by it. The atmosphere is also affected by the force of gravity, which holds the air shell at the surface of the Earth. Atmospheric gases are compressed by own weight. This compression is maximum at the lower boundary of the atmosphere, therefore the air density is greatest here. At any height above the earth's surface, the degree of air compression depends on the mass of the overlying air column, therefore, with height, the density of air decreases. The pressure, equal to the mass of the overlying air column per unit area, is directly dependent on density and, therefore, also decreases with height. If the atmosphere were an “ideal gas” with a constant composition independent of altitude, a constant temperature, and a constant force of gravity acting on it, then the pressure would decrease 10 times for every 20 km of altitude. The actual atmosphere differs slightly from ideal gas up to approximately an altitude of 100 km, and then the pressure decreases more slowly with height, as the composition of the air changes. Minor changes The described model also includes a decrease in gravity with distance from the center of the Earth, which is approx. 3% for every 100 km of altitude. Unlike atmospheric pressure, temperature does not decrease continuously with altitude. As shown in Fig. 1, it decreases to approximately a height of 10 km, and then begins to increase again. This occurs when ultraviolet solar radiation is absorbed by oxygen. This produces ozone gas, whose molecules consist of three oxygen atoms (O3). It also absorbs ultraviolet radiation, and so this layer of the atmosphere, called the ozonosphere, warms up. Higher up, the temperature drops again, since there are much fewer gas molecules there, and energy absorption is correspondingly reduced. In even higher layers, the temperature rises again due to the absorption of the shortest wavelength ultraviolet and X-ray radiation from the Sun by the atmosphere. Under the influence of this powerful radiation, ionization of the atmosphere occurs, i.e. a gas molecule loses an electron and acquires a positive electrical charge. Such molecules become positively charged ions. Due to the presence of free electrons and ions, this layer of the atmosphere acquires the properties of an electrical conductor. It is believed that the temperature continues to rise to heights where the thin atmosphere passes into interplanetary space. At a distance of several thousand kilometers from the Earth's surface, temperatures ranging from 5,000° to 10,000° C are likely to prevail. Although the molecules and atoms have very high speeds of movement, and therefore a high temperature, this rarefied gas is not “hot” in the usual sense . Due to the tiny number of molecules at high altitudes, their total thermal energy very small. Thus, the atmosphere consists of separate layers (i.e., a series of concentric shells, or spheres), the separation of which depends on which property is of greatest interest. Based on the average temperature distribution, meteorologists have developed a diagram of the structure of the ideal “average atmosphere” (see Fig. 1).

The troposphere is the lower layer of the atmosphere, extending to the first thermal minimum (the so-called tropopause). The upper limit of the troposphere depends on geographic latitude (in the tropics - 18-20 km, in temperate latitudes - about 10 km) and time of year. The US National Weather Service conducted soundings near the South Pole and revealed seasonal changes in the height of the tropopause. In March, the tropopause is at an altitude of approx. 7.5 km. From March to August or September there is a steady cooling of the troposphere, and its boundary rises to an altitude of approximately 11.5 km for a short period in August or September. Then from September to December it decreases rapidly and reaches its lowest position - 7.5 km, where it remains until March, fluctuating within just 0.5 km. It is in the troposphere that the weather is mainly formed, which determines the conditions for human existence. Most of the atmospheric water vapor is concentrated in the troposphere, and therefore this is where clouds primarily form, although some, consisting of ice crystals, are found in higher layers. The troposphere is characterized by turbulence and powerful air currents (winds) and storms. In the upper troposphere there are strong air currents in a strictly defined direction. Turbulent vortices, similar to small whirlpools, are formed under the influence of friction and dynamic interaction between slow and fast moving air masses. Because there is usually no cloud cover at these high levels, this turbulence is called "clear-air turbulence."
Stratosphere. The upper layer of the atmosphere is often mistakenly described as a layer with relatively constant temperatures, where winds blow more or less steadily and where meteorological elements change little. The upper layers of the stratosphere heat up when oxygen and ozone absorb ultraviolet radiation from the sun. The upper boundary of the stratosphere (stratopause) is where the temperature rises slightly, reaching an intermediate maximum, which is often comparable to the temperature of the surface layer of air. Based on observations made using airplanes and balloons designed to fly at constant altitudes, turbulent disturbances and strong winds blowing in different directions have been established in the stratosphere. As in the troposphere, there are powerful air vortices, which are especially dangerous for high-speed aircraft. Strong winds, called jet streams, blow in narrow zones along the poleward boundaries of temperate latitudes. However, these zones can shift, disappear and reappear. Jet streams typically penetrate the tropopause and appear in the upper troposphere, but their speed decreases rapidly with decreasing altitude. It is possible that some of the energy entering the stratosphere (mainly spent on ozone formation) affects processes in the troposphere. Particularly active mixing is associated with atmospheric fronts, where extensive stratospheric air flows were recorded well below the tropopause and tropospheric air was drawn into the lower stratosphere. Significant progress has been made in studying the vertical structure of the lower layers of the atmosphere due to the improvement of the technology for launching radiosondes to altitudes of 25-30 km. The mesosphere, located above the stratosphere, is a shell in which, up to a height of 80-85 km, the temperature drops to the minimum values ​​for the atmosphere as a whole. Record low temperatures to -110° C were recorded by meteorological rockets launched from the American-Canadian installation at Fort Churchill (Canada). The upper limit of the mesosphere (mesopause) approximately coincides with the lower limit of the region of active absorption of X-ray and short-wave ultraviolet radiation from the Sun, which is accompanied by heating and ionization of the gas. In the polar regions, cloud systems often appear during the mesopause in the summer, which occupy a large area but have little vertical development. Such night-glowing clouds often reveal large-scale wave-like air movements in the mesosphere. The composition of these clouds, sources of moisture and condensation nuclei, dynamics and connection with meteorological factors have not yet been sufficiently studied. The thermosphere is a layer of the atmosphere in which the temperature continuously rises. Its power can reach 600 km. The pressure and, therefore, the density of the gas constantly decreases with altitude. Near the earth's surface, 1 m3 of air contains approx. 2.5 x 1025 molecules, at a height of approx. 100 km, in the lower layers of the thermosphere - approximately 1019, at an altitude of 200 km, in the ionosphere - 5 * 10 15 and, according to calculations, at an altitude of approx. 850 km - approximately 1012 molecules. In interplanetary space, the concentration of molecules is 10 8-10 9 per 1 m3. At an altitude of approx. 100 km the number of molecules is small, and they rarely collide with each other. The average distance that a chaotically moving molecule travels before colliding with another similar molecule is called its mean free path. The layer in which this value increases so much that the probability of intermolecular or interatomic collisions can be neglected is located on the boundary between the thermosphere and the overlying shell (exosphere) and is called a thermopause. The thermopause is approximately 650 km from the earth's surface. At a certain temperature, the speed of a molecule depends on its mass: lighter molecules move faster than heavier ones. In the lower atmosphere, where the free path is very short, there is no noticeable separation of gases by their molecular weight, but it is expressed above 100 km. In addition, under the influence of ultraviolet and X-ray radiation from the Sun, oxygen molecules disintegrate into atoms whose mass is half the mass of the molecule. Therefore, as it moves away from the Earth’s surface, atomic oxygen acquires more higher value as part of the atmosphere and at an altitude of approx. 200 km becomes its main component. Higher up, at a distance of approximately 1200 km from the Earth's surface, light gases predominate - helium and hydrogen. The outer shell of the atmosphere consists of them. This separation by weight, called diffuse stratification, is similar to the separation of mixtures using a centrifuge. The exosphere is the outer layer of the atmosphere, formed based on changes in temperature and the properties of the neutral gas. Molecules and atoms in the exosphere rotate around the Earth in ballistic orbits under the influence of gravity. Some of these orbits are parabolic and resemble the trajectories of projectiles. Molecules can rotate around the Earth and in elliptical orbits, like satellites. Some molecules, mainly hydrogen and helium, have open trajectories and go into outer space (Fig. 2).

SOLAR-TERRESTRIAL CONNECTIONS AND THEIR INFLUENCE ON THE ATMOSPHERE
Atmospheric tides. The attraction of the Sun and Moon causes tides in the atmosphere, similar to earth and sea tides. But atmospheric tides have a significant difference: the atmosphere reacts most strongly to the attraction of the Sun, while the earth's crust and ocean respond most strongly to the attraction of the Moon. This is explained by the fact that the atmosphere is heated by the Sun and, in addition to the gravitational one, a powerful thermal tide occurs. In general, the mechanisms of formation of atmospheric and sea tides are similar, with the exception that in order to predict the reaction of air to gravitational and thermal influences, it is necessary to take into account its compressibility and temperature distribution. It is not entirely clear why semidiurnal (12-hour) solar tides in the atmosphere prevail over daily solar and semidiurnal lunar tides, although the driving forces of the latter two processes are much more powerful. Previously, it was believed that a resonance arises in the atmosphere, which enhances the oscillations with a 12-hour period. However, observations made using geophysical rockets indicate the absence of temperature reasons for such resonance. When solving this problem, it is probably necessary to take into account all the hydrodynamic and thermal features of the atmosphere. At the earth's surface near the equator, where the influence of tidal fluctuations is maximum, it provides a change in atmospheric pressure of 0.1%. The tidal wind speed is approx. 0.3 km/h. Due to the complex thermal structure of the atmosphere (especially the presence of a minimum temperature in the mesopause), tidal air currents are intensified, and, for example, at an altitude of 70 km their speed is approximately 160 times higher than that of the earth's surface, which has important geophysical consequences. It is believed that in the lower part of the ionosphere (layer E), tidal fluctuations move ionized gas vertically in the Earth's magnetic field, and therefore electric currents arise here. These constantly emerging systems of currents on the Earth's surface are established by disturbances in the magnetic field. Daily variations of the magnetic field are in fairly good agreement with the calculated values, which provides convincing evidence in favor of the theory of tidal mechanisms of the “atmospheric dynamo”. Electrical currents generated in the lower part of the ionosphere (E layer) must travel somewhere, and therefore the circuit must be closed. The analogy with a dynamo becomes complete if we consider the oncoming movement as the work of an engine. It is assumed that the reverse circulation of electric current occurs in a higher layer of the ionosphere (F), and this counter flow may explain some of the peculiar features of this layer. Finally, the tidal effect should also generate horizontal flows in the E layer and therefore in the F layer.
Ionosphere. Trying to explain the mechanism of the occurrence of auroras, scientists of the 19th century. suggested that there is a zone with electrically charged particles in the atmosphere. In the 20th century convincing evidence was obtained experimentally of the existence at altitudes of 85 to 400 km of a layer that reflects radio waves. It is now known that its electrical properties are the result of ionization of atmospheric gas. Therefore, this layer is usually called the ionosphere. The effect on radio waves occurs mainly due to the presence of free electrons in the ionosphere, although the mechanism of radio wave propagation is associated with the presence of large ions. The latter are also of interest when studying the chemical properties of the atmosphere, since they are more active than neutral atoms and molecules. Chemical reactions occurring in the ionosphere play an important role in its energy and electrical balance.
Normal ionosphere. Observations made using geophysical rockets and satellites have provided a wealth of new information indicating that ionization of the atmosphere occurs under the influence of solar radiation wide range. Its main part (more than 90%) is concentrated in the visible part of the spectrum. Ultraviolet radiation, which has a shorter wavelength and higher energy than violet light rays, is emitted by hydrogen in the Sun's inner atmosphere (the chromosphere), and x-rays, which have even higher energy, are emitted by gases in the Sun's outer shell (the corona). The normal (average) state of the ionosphere is due to constant powerful radiation. Regular changes occur in the normal ionosphere due to the daily rotation of the Earth and seasonal differences in the angle of incidence of the sun's rays at noon, but unpredictable and abrupt changes in the state of the ionosphere also occur.
Disturbances in the ionosphere. As is known, powerful cyclically repeating disturbances occur on the Sun, which reach a maximum every 11 years. Observations under the International Geophysical Year (IGY) program coincided with the period of the highest solar activity for the entire period of systematic meteorological observations, i.e. from the beginning of the 18th century. During periods of high activity, the brightness of some areas on the Sun increases several times, and they send out powerful pulses of ultraviolet and X-ray radiation. Such phenomena are called solar flares. They last from several minutes to one to two hours. During the flare, solar gas (mostly protons and electrons) is erupted, and elementary particles rush into outer space. Electromagnetic and corpuscular radiation from the Sun during such flares has a strong impact on the Earth's atmosphere. The initial reaction is observed 8 minutes after the flare, when intense ultraviolet and x-ray radiation reaches the Earth. As a result, ionization increases sharply; X-rays penetrate the atmosphere to the lower boundary of the ionosphere; the number of electrons in these layers increases so much that the radio signals are almost completely absorbed (“extinguished”). The additional absorption of radiation causes the gas to heat up, which contributes to the development of winds. Ionized gas is an electrical conductor, and when it moves in the Earth's magnetic field, a dynamo effect occurs and electric current. Such currents can, in turn, cause noticeable disturbances in the magnetic field and manifest themselves in the form of magnetic storms. This initial phase only takes short time, corresponding to the duration of the solar flare. During powerful solar flares, a stream of accelerated particles rushes into outer space. When it is directed towards the Earth, the second phase begins, which has a great influence on the state of the atmosphere. Many natural phenomena, among which the most famous are aurorae, indicate that a significant number of charged particles reach the Earth (see also AURORAS). Nevertheless, the processes of separation of these particles from the Sun, their trajectories in interplanetary space and the mechanisms of interaction with the Earth’s magnetic field and magnetosphere have not yet been sufficiently studied. The problem became more complicated after the discovery in 1958 by James Van Allen of shells consisting of charged particles held by a geomagnetic field. These particles move from one hemisphere to the other, rotating in spirals around magnetic field lines. Near the Earth, at a height depending on the shape of the field lines and the energy of the particles, there are “reflection points” at which the particles change the direction of movement to the opposite (Fig. 3). Because the magnetic field strength decreases with distance from the Earth, the orbits in which these particles move become somewhat distorted: electrons are deflected to the east, and protons to the west. Therefore, they are distributed in the form of belts around the globe.

Some consequences of heating the atmosphere by the Sun. Solar energy affects the entire atmosphere. Belts formed by charged particles in the Earth’s magnetic field and rotating around it have already been mentioned above. These belts come closest to the earth's surface in the subpolar regions (see Fig. 3), where aurorae are observed. Figure 1 shows that in auroral regions in Canada, thermosphere temperatures are significantly higher than in the Southwestern United States. It is likely that the captured particles release part of their energy into the atmosphere, especially when colliding with gas molecules near the points of reflection, and leave their previous orbits. This is how the high layers of the atmosphere in the auroral zone are heated. One more thing important discovery was done while studying the orbits of artificial satellites. Luigi Iacchia, an astronomer at the Smithsonian Astrophysical Observatory, believes that the slight deviations in these orbits are due to changes in the density of the atmosphere as it is heated by the Sun. He suggested the existence of a maximum electron density at an altitude of more than 200 km in the ionosphere, which does not correspond to solar noon, but under the influence of friction forces is delayed in relation to it by about two hours. At this time, atmospheric density values ​​typical for an altitude of 600 km are observed at a level of approx. 950 km. In addition, the maximum electron density experiences irregular fluctuations due to short-term flashes of ultraviolet and X-ray radiation from the Sun. L. Iacchia also discovered short-term fluctuations in air density, corresponding to solar flares and magnetic field disturbances. These phenomena are explained by the intrusion of particles of solar origin into the Earth's atmosphere and the heating of those layers where satellites orbit.
ATMOSPHERIC ELECTRICITY
In the ground layer of the atmosphere, a small part of the molecules is subject to ionization under the influence of cosmic rays, radiation from radioactive rocks and decay products of radium (mainly radon) in the air itself. During ionization, an atom loses an electron and acquires a positive charge. The free electron quickly combines with another atom to form a negatively charged ion. Such paired positive and negative ions have molecular sizes. Molecules in the atmosphere tend to cluster around these ions. Several molecules combined with an ion form a complex, usually called a “light ion.” The atmosphere also contains complexes of molecules, known in meteorology as condensation nuclei, around which, when the air is saturated with moisture, the condensation process begins. These nuclei are particles of salt and dust, as well as pollutants released into the air from industrial and other sources. Light ions often attach to such nuclei, forming "heavy ions." Under the influence electric field light and heavy ions move from one area of ​​the atmosphere to another, transferring electrical charges. Although the atmosphere is not generally considered to be electrically conductive, it does have some conductivity. Therefore, a charged body left in the air slowly loses its charge. Atmospheric conductivity increases with altitude due to increased cosmic ray intensity, decreased ion loss at lower pressure (and thus longer mean free path), and fewer heavy nuclei. Atmospheric conductivity reaches its maximum value at an altitude of approx. 50 km, so-called "compensation level". It is known that between the Earth’s surface and the “compensation level” there is a constant potential difference of several hundred kilovolts, i.e. constant electric field. It turned out that the potential difference between a certain point located in the air at a height of several meters and the surface of the Earth is very large - more than 100 V. The atmosphere has a positive charge, and the earth's surface is negatively charged. Since the electric field is a region at each point of which there is a certain potential value, we can talk about a potential gradient. In clear weather, within the lower few meters the electric field strength of the atmosphere is almost constant. Due to differences in the electrical conductivity of air in the surface layer, the potential gradient is subject to daily fluctuations, the course of which varies significantly from place to place. In the absence of local sources of air pollution - over the oceans, high in the mountains or in the polar regions - the diurnal variation of the potential gradient is the same in clear weather. The magnitude of the gradient depends on universal, or Greenwich mean, time (UT) and reaches a maximum at 19 hours E. Appleton suggested that this maximum electrical conductivity probably coincides with the greatest thunderstorm activity on a planetary scale. Lightning strikes during thunderstorms carry a negative charge to the Earth's surface, since the bases of the most active cumulonimbus thunderclouds have a significant negative charge. The tops of thunderclouds have a positive charge, which, according to Holzer and Saxon's calculations, drains from their tops during thunderstorms. Without constant replenishment, the charge on the earth's surface would be neutralized by atmospheric conductivity. The assumption that the potential difference between the earth's surface and the "compensation level" is maintained by thunderstorms is supported by statistical data. For example, the maximum number of thunderstorms is observed in the river valley. Amazons. Most often, thunderstorms occur there at the end of the day, i.e. OK. 19:00 Greenwich Mean Time, when the potential gradient is maximum anywhere in the world. Moreover, seasonal variations in the shape of the diurnal variation curves of the potential gradient are also in full agreement with data on the global distribution of thunderstorms. Some researchers argue that the source of the Earth's electric field may have external origin, as electric fields are believed to exist in the ionosphere and magnetosphere. This circumstance probably explains the appearance of very narrow elongated forms of auroras, similar to coulisses and arches
(see also AURORA LIGHTS). Due to the presence of a potential gradient and conductivity of the atmosphere, charged particles begin to move between the “compensation level” and the Earth’s surface: positively charged ions towards the Earth’s surface, and negatively charged ones upward from it. The strength of this current is approx. 1800 A. Although this value seems large, it must be remembered that it is distributed over the entire surface of the Earth. The current strength in a column of air with a base area of ​​1 m2 is only 4 * 10 -12 A. On the other hand, the current strength during a lightning discharge can reach several amperes, although, of course, such a discharge has a short duration - from a fraction of a second to a whole second or a little more with repeated shocks. Lightning is of great interest not only as a peculiar natural phenomenon. It makes it possible to observe an electrical discharge in a gaseous medium at a voltage of several hundred million volts and a distance between electrodes of several kilometers. In 1750, B. Franklin proposed to the Royal Society of London to conduct an experiment with an iron rod mounted on an insulating base and mounted on a high tower. He expected that as a thundercloud approached the tower, a charge of the opposite sign would be concentrated at the upper end of the initially neutral rod, and a charge of the same sign as at the base of the cloud would be concentrated at the lower end. If the electric field strength during a lightning discharge increases sufficiently, the charge from the upper end of the rod will partially flow into the air, and the rod will acquire a charge of the same sign as the base of the cloud. The experiment proposed by Franklin was not carried out in England, but it was carried out in 1752 in Marly near Paris by the French physicist Jean d'Alembert. He used an iron rod 12 m long inserted into a glass bottle (which served as an insulator), but did not place it on the tower. May 10 his assistant reported that when a thundercloud was over the bar, sparks appeared when a grounded wire was brought to it. Franklin himself, not knowing about the successful experiment carried out in France, in June of the same year conducted his famous experiment with a kite and observed electric ones. sparks at the end of a wire tied to it. The following year, by studying the charges collected from the rod, Franklin discovered that the bases of thunderclouds were usually negatively charged. More detailed studies of lightning became possible in the late 19th century thanks to the improvement of photographic methods, especially after the invention of the apparatus. with rotating lenses, which made it possible to record rapidly developing processes. This type of camera was widely used in the study of spark discharges. It has been found that there are several types of lightning, with the most common being line, plane (in-cloud) and ball (air discharges). Linear lightning is a spark discharge between a cloud and the earth's surface, following a channel with downward branches. Flat lightning occurs within a thundercloud and appears as flashes of diffuse light. Air discharges of ball lightning, starting from a thundercloud, are often directed horizontally and do not reach the earth's surface.

A lightning discharge usually consists of three or more repeated discharges - pulses following the same path. The intervals between successive pulses are very short, from 1/100 to 1/10 s (this is what causes lightning to flicker). In general, the flash lasts about a second or less. A typical lightning development process can be described as follows. First, a weakly luminous leader discharge rushes from above to the earth's surface. When he reaches it, a brightly glowing return, or main, discharge passes from the ground up through the channel laid by the leader. The leading discharge, as a rule, moves in a zigzag manner. The speed of its spread ranges from one hundred to several hundred kilometers per second. On its way, it ionizes air molecules, creating a channel with increased conductivity, through which the reverse discharge moves upward at a speed approximately one hundred times greater than that of the leading discharge. The size of the channel is difficult to determine, but the diameter of the leading discharge is estimated at 1-10 m, and the diameter of the reverse discharge is several centimeters. Lightning discharges create radio interference by emitting radio waves in a wide range - from 30 kHz to ultra-low frequencies. The greatest emission of radio waves is probably in the range from 5 to 10 kHz. Such low-frequency radio interference is “concentrated” in the space between the lower boundary of the ionosphere and the earth’s surface and can spread to distances of thousands of kilometers from the source.
CHANGES IN THE ATMOSPHERE
Impact of meteors and meteorites. Although meteor showers sometimes create a dramatic display of light, individual meteors are rarely seen. Much more numerous are invisible meteors, too small to be visible when they are absorbed into the atmosphere. Some of the smallest meteors probably do not heat up at all, but are only captured by the atmosphere. These fine particles with sizes ranging from a few millimeters to ten-thousandths of a millimeter are called micrometeorites. The amount of meteoric matter entering the atmosphere every day ranges from 100 to 10,000 tons, with the majority of this material coming from micrometeorites. Since meteoric matter partially burns in the atmosphere, its gas composition is replenished with traces of various chemical elements. For example, rocky meteors introduce lithium into the atmosphere. The combustion of metal meteors leads to the formation of tiny spherical iron, iron-nickel and other droplets that pass through the atmosphere and settle on the earth's surface. They can be found in Greenland and Antarctica, where ice sheets remain almost unchanged for years. Oceanologists find them in bottom ocean sediments. Most meteor particles entering the atmosphere settle within approximately 30 days. Some scientists believe that this cosmic dust plays an important role in the formation of such atmospheric phenomena, like rain, because they serve as condensation nuclei for water vapor. Therefore, it is assumed that precipitation is statistically related to large meteor showers. However, some experts believe that since the total supply of meteoric material is many tens of times greater than its supply even with the largest meteor shower, the change in total number of this substance resulting from one such rain can be neglected. However, there is no doubt that the largest micrometeorites and, of course, visible meteorites leave long traces of ionization in the high layers of the atmosphere, mainly in the ionosphere. Such traces can be used for long-distance radio communications, as they reflect high-frequency radio waves. The energy of meteors entering the atmosphere is spent mainly, and perhaps completely, on heating it. This is one of the minor components of the thermal balance of the atmosphere.
Carbon dioxide of industrial origin. IN Carboniferous period Woody vegetation was widespread on Earth. Much of the carbon dioxide absorbed by plants at that time accumulated in coal deposits and oil-bearing sediments. Man has learned to use huge reserves of these minerals as an energy source and is now rapidly returning carbon dioxide to the cycle of substances. The fossil state is probably ca. 4*10 13 tons of carbon. Over the last century, humanity has burned so much fossil fuel that approximately 4*10 11 tons of carbon have been re-entered into the atmosphere. Currently there is approx. 2 * 10 12 tons of carbon, and in the next hundred years due to the combustion of fossil fuels this figure may double. However, not all the carbon will remain in the atmosphere: some of it will dissolve in the ocean waters, some will be absorbed by plants, and some will be bound during the weathering of rocks. It is not yet possible to predict how much carbon dioxide will be contained in the atmosphere or exactly what impact it will have on the global climate. However, it is believed that any increase in its content will cause warming, although it is not at all necessary that any warming will significantly affect the climate. The concentration of carbon dioxide in the atmosphere, according to measurement results, is noticeably increasing, although at a slow pace. Climate data for Svalbard and Little America Station on the Ross Ice Shelf in Antarctica show rising averages annual temperatures over approximately a 50-year period by 5° and 2.5° C, respectively.
Exposure to cosmic radiation. When high-energy cosmic rays interact with individual components of the atmosphere, radioactive isotopes are formed. Among them, the 14C carbon isotope stands out, accumulating in plant and animal tissues. By measuring the radioactivity of organic substances that have not exchanged carbon with the environment for a long time, their age can be determined. The radiocarbon method has established itself as the most reliable way of dating fossil organisms and objects of material culture, the age of which does not exceed 50 thousand years. Other radioactive isotopes with long half-lives can be used to date materials hundreds of thousands of years old if the fundamental challenge of measuring extremely low levels of radioactivity can be solved.
(see also RADIOCARBON DATING).
ORIGIN OF THE EARTH'S ATMOSPHERE
The history of the formation of the atmosphere has not yet been completely reliably reconstructed. Nevertheless, some probable changes in its composition have been identified. The formation of the atmosphere began immediately after the formation of the Earth. There are quite good reasons to believe that in the process of the evolution of the Earth and its acquisition of dimensions and mass close to modern ones, it almost completely lost its original atmosphere. It is believed that at an early stage the Earth was in a molten state and ca. 4.5 billion years ago it took shape solid. This milestone is taken as the beginning of the geological chronology. Since that time, there has been a slow evolution of the atmosphere. Some geological processes, such as the outpouring of lava during volcanic eruptions, were accompanied by the release of gases from the bowels of the Earth. They probably included nitrogen, ammonia, methane, water vapor, carbon monoxide and dioxide. Under the influence of solar ultraviolet radiation, water vapor decomposed into hydrogen and oxygen, but the released oxygen reacted with carbon monoxide to form carbon dioxide. Ammonia decomposed into nitrogen and hydrogen. During the process of diffusion, hydrogen rose up and left the atmosphere, and heavier nitrogen could not evaporate and gradually accumulated, becoming its main component, although some of it was bound during chemical reactions. Under the influence ultraviolet rays and electrical discharges, a mixture of gases that were probably present in the original atmosphere of the Earth entered into chemical reactions, which resulted in the formation of organic substances, in particular amino acids. Consequently, life could have originated in an atmosphere fundamentally different from the modern one. With the advent of primitive plants, the process of photosynthesis began (see also PHOTOSYNTHESIS), accompanied by the release of free oxygen. This gas, especially after diffusion into the upper layers of the atmosphere, began to protect its lower layers and the surface of the Earth from life-threatening ultraviolet and X-ray radiation. It is estimated that the presence of only 0.00004 of the modern volume of oxygen could lead to the formation of a layer with half the current concentration of ozone, which nevertheless provided very significant protection from ultraviolet rays. It is also likely that the primary atmosphere contained a lot of carbon dioxide. It was used up during photosynthesis, and its concentration must have decreased as the plant world evolved and also due to absorption during certain geological processes. Because greenhouse effect associated with the presence of carbon dioxide in the atmosphere, some scientists believe that fluctuations in its concentration are one of the important reasons such large-scale climate changes in Earth's history as ice ages. The helium present in the modern atmosphere is probably largely a product of radioactive decay uranium, thorium and radium. These radioactive elements emit alpha particles, which are the nuclei of helium atoms. Since no electrical charge is created or lost during radioactive decay, there are two electrons for every alpha particle. As a result, it combines with them, forming neutral helium atoms. Radioactive elements are contained in minerals dispersed in rocks, so a significant part of the helium formed as a result of radioactive decay is retained in them, escaping very slowly into the atmosphere. A certain amount of helium rises upward into the exosphere due to diffusion, but due to the constant influx from the earth's surface, the volume of this gas in the atmosphere is constant. Based on spectral analysis Starlight and the study of meteorites can estimate the relative abundance of various chemical elements in the Universe. The concentration of neon in space is about ten billion times higher than on Earth, krypton is ten million times higher, and xenon is a million times higher. It follows that the concentration of these inert gases, which were initially present in the Earth’s atmosphere and were not replenished during chemical reactions, decreased greatly, probably even at the stage of the Earth’s loss of its primary atmosphere. An exception is the inert gas argon, since in the form of the 40Ar isotope it is still formed during the radioactive decay of the potassium isotope.
OPTICAL PHENOMENA
The variety of optical phenomena in the atmosphere is due to for various reasons. The most common phenomena include lightning (see above) and the very spectacular northern and southern auroras (see also AURORA). In addition, the rainbow, gal, parhelium (false sun) and arcs, corona, halos and Brocken ghosts, mirages, St. Elmo's fires, luminous clouds, green and crepuscular rays are especially interesting. Rainbow is the most beautiful atmospheric phenomenon. Usually this is a huge arch consisting of multi-colored stripes, observed when the Sun illuminates only part of the sky and the air is saturated with water droplets, for example during rain. The multi-colored arcs are arranged in a spectral sequence (red, orange, yellow, green, blue, indigo, violet), but the colors are almost never pure because the stripes overlap each other. As a rule, the physical characteristics of rainbows vary significantly, and therefore they are very diverse in appearance. Their common feature is that the center of the arc is always located on a straight line drawn from the Sun to the observer. The main rainbow is an arc consisting of the brightest colors - red on the outside and purple on the inside. Sometimes only one arc is visible, but often a side arc appears on the outside of the main rainbow. It has not as bright colors as the first one, and the red and purple stripes in it change places: the red one is located on the inside. The formation of the main rainbow is explained by double refraction (see also OPTICS) and single internal reflection of rays sunlight(see Fig. 5). Penetrating inside a drop of water (A), a ray of light is refracted and decomposed, as if passing through a prism. Then it reaches the opposite surface of the drop (B), is reflected from it and leaves the drop outside (C). In this case, the light ray is refracted a second time before reaching the observer. The original white beam is decomposed into rays different colors with a divergence angle of 2°. When a secondary rainbow is formed, double refraction and double reflection of the sun's rays occur (see Fig. 6). In this case, the light is refracted, penetrating into the drop through its lower part (A), and reflected from the inner surface of the drop, first at point B, then at point C. At point D, the light is refracted, leaving the drop towards the observer.

At sunrise and sunset, the observer sees a rainbow in the form of an arc equal to half a circle, since the axis of the rainbow is parallel to the horizon. If the Sun is higher above the horizon, the arc of the rainbow is less than half the circumference. When the Sun rises above 42° above the horizon, the rainbow disappears. Everywhere, except at high latitudes, a rainbow cannot appear at noon, when the Sun is too high. It is interesting to estimate the distance to the rainbow. Although the multi-colored arc appears to be located in the same plane, this is an illusion. In fact, the rainbow has enormous depth, and it can be imagined as the surface of a hollow cone, at the top of which the observer is located. The axis of the cone connects the Sun, the observer and the center of the rainbow. The observer looks as if along the surface of this cone. No two people can ever see exactly the same rainbow. Of course, you can observe basically the same effect, but the two rainbows occupy different positions and are formed by different water droplets. When rain or spray forms a rainbow, the full optical effect is achieved by the combined effect of all the water droplets crossing the surface of the rainbow cone with the observer at the apex. The role of every drop is fleeting. The surface of the rainbow cone consists of several layers. Quickly crossing them and passing through a series of critical points, each drop instantly decomposes the sun's ray into the entire spectrum in a strictly defined sequence - from red to purple. Many drops intersect the surface of the cone in the same way, so that the rainbow appears to the observer as continuous both along and across its arc. Halos are white or iridescent light arcs and circles around the disk of the Sun or Moon. They arise due to the refraction or reflection of light by ice or snow crystals in the atmosphere. The crystals that form the halo are located on the surface of an imaginary cone with an axis directed from the observer (from the top of the cone) to the Sun. Under certain conditions, the atmosphere can be saturated with small crystals, many of whose faces form a right angle with the plane passing through the Sun, the observer and these crystals. Such faces reflect incoming light rays with a deviation of 22°, forming a halo that is reddish on the inside, but it can also consist of all colors of the spectrum. Less common is a halo with an angular radius of 46°, located concentrically around a 22° halo. Its inner side also has a reddish tint. The reason for this is also the refraction of light, which occurs in this case on the edges of the crystals forming right angles. The ring width of such a halo exceeds 2.5°. Both 46-degree and 22-degree halos tend to be brightest at the top and bottom of the ring. The rare 90-degree halo is a faintly luminous, almost colorless ring that shares a center with two other halos. If it is colored, it will have a red color on the outside of the ring. The mechanism of occurrence of this type of halo is not fully understood (Fig. 7).

Parhelia and arcs. Parhelic circle (or circle of false suns) - white ring centered at the zenith point, passing through the Sun parallel to the horizon. The reason for its formation is the reflection of sunlight from the edges of the surfaces of ice crystals. If the crystals are sufficiently evenly distributed in the air, a complete circle becomes visible. Parhelia, or false suns, are brightly luminous spots reminiscent of the Sun that form at the intersection points of the parhelic circle with halos having angular radii of 22°, 46° and 90°. The most frequently occurring and brightest parhelium forms at the intersection with the 22-degree halo, usually colored in almost every color of the rainbow. False suns at intersections with 46- and 90-degree halos are observed much less frequently. Parhelia that occur at intersections with 90-degree halos are called paranthelia, or false countersuns. Sometimes an antelium (anti-sun) is also visible - a bright spot located on the parhelium ring exactly opposite the Sun. It is assumed that the cause of this phenomenon is the double internal reflection of sunlight. The reflected ray follows the same path as the incident ray, but in the opposite direction. A near-zenith arc, sometimes incorrectly called the upper tangent arc of a 46-degree halo, is an arc of 90° or less centered at the zenith, located approximately 46° above the Sun. It is rarely visible and only for a few minutes, has bright colors, with the red color confined to the outer side of the arc. The near-zenith arc is remarkable for its color, brightness and clear outlines. Another interesting and very rare optical effect of the halo type is the Lowitz arc. They arise as a continuation of the parhelia at the intersection with the 22-degree halo, extend from the outer side of the halo and are slightly concave towards the Sun. Columns of whitish light, like various crosses, are sometimes visible at dawn or dusk, especially in the polar regions, and can accompany both the Sun and the Moon. At times, lunar halos and other effects similar to those described above are observed, with the most common lunar halo (a ring around the Moon) having an angular radius of 22°. Just like false suns, false moons can arise. Coronas, or crowns, are small concentric rings of color around the Sun, Moon or other bright objects that are observed from time to time when the light source is behind translucent clouds. The radius of the corona is less than the radius of the halo and is approx. 1-5°, the blue or violet ring is closest to the Sun. A corona occurs when light is scattered by small water droplets, forming a cloud. Sometimes the corona appears as a luminous spot (or halo) surrounding the Sun (or Moon), which ends in a reddish ring. In other cases, at least two concentric rings of larger diameter, very faintly colored, are visible outside the halo. This phenomenon is accompanied by rainbow clouds. Sometimes the edges of very high clouds have bright colors.
Gloria (halos). Under special conditions, unusual atmospheric phenomena occur. If the Sun is behind the observer, and its shadow is projected onto nearby clouds or a curtain of fog, under a certain state of the atmosphere around the shadow of a person’s head, you can see a colored luminous circle - a halo. Typically, such a halo is formed due to the reflection of light from dew drops on a grassy lawn. Glorias are also quite often found around the shadow cast by the aircraft on the underlying clouds.
Ghosts of Brocken. In some areas of the globe, when the shadow of an observer located on a hill at sunrise or sunset falls behind him on clouds located at a short distance, a striking effect is discovered: the shadow takes on colossal dimensions. This occurs due to the reflection and refraction of light by tiny water droplets in the fog. The described phenomenon is called the "Ghost of Brocken" after the peak in the Harz Mountains in Germany.
Mirages- an optical effect caused by the refraction of light when passing through layers of air of different densities and expressed in the appearance of a virtual image. In this case, distant objects may appear raised or lowered relative to their actual position, and may also be distorted and acquire irregular, fantastic shapes. Mirages are often observed in hot climates, such as over sandy plains. Lower mirages are common, when a distant, almost flat desert surface takes on the appearance of open water, especially when viewed from a slight elevation or simply located above a layer of heated air. This illusion usually occurs on a heated asphalt road, which looks like a water surface far ahead. In reality, this surface is a reflection of the sky. Below eye level, objects may appear in this “water,” usually upside down. An “air layer cake” is formed over the heated land surface, with the layer closest to the ground being the hottest and so rarefied that light waves passing through it are distorted, since the speed of their propagation varies depending on the density of the medium. The upper mirages are less common and more picturesque than the lower ones. Distant objects (often located beyond the sea horizon) appear upside down in the sky, and sometimes an upright image of the same object also appears above. This phenomenon is typical in cold regions, especially when there is a significant temperature inversion, when there is a warmer layer of air above a colder layer. This optical effect manifests itself as a result of complex patterns of propagation of the front of light waves in layers of air with inhomogeneous density. Very unusual mirages occur from time to time, especially in the polar regions. When mirages occur on land, trees and other landscape components are upside down. In all cases, objects are visible more clearly in the upper mirages than in the lower ones. When the boundary of two air masses is a vertical plane, lateral mirages are sometimes observed.
St. Elmo's Fire. Some optical phenomena in the atmosphere (for example, glow and the most common meteorological phenomenon- lightning) are electrical in nature. Much less common are St. Elmo's lights - luminous pale blue or purple brushes from 30 cm to 1 m or more in length, usually on the tops of masts or the ends of yards of ships at sea. Sometimes it seems that the entire rigging of the ship is covered with phosphorus and glows. St. Elmo's Fire sometimes appears on mountain peaks, as well as on the spiers and sharp corners of tall buildings. This phenomenon represents brush electric discharges at the ends of electrical conductors when the electric field strength in the atmosphere around them greatly increases. Will-o'-the-wisps are a faint bluish or greenish glow that is sometimes observed in swamps, cemeteries and crypts. They often look like a candle flame raised about 30 cm above the ground, quietly burning, giving no heat, and hovering for a moment over the object. The light seems completely elusive and, when the observer approaches, seems to move to another place. The reason for this phenomenon is the decomposition of organic residues and the spontaneous combustion of swamp gas methane (CH4) or phosphine (PH3). Will-o'-the-wisps have different shapes, sometimes even spherical. Green ray - a flash of emerald green sunlight at the moment when the last ray of the Sun disappears behind the horizon. The red component of sunlight disappears first, all the others follow in order, and the last one remains is emerald green. This phenomenon occurs only when only the very edge of the solar disk remains above the horizon, otherwise a mixture of colors occurs. Crepuscular rays are diverging beams of sunlight that become visible due to their illumination of dust in the high layers of the atmosphere. The shadows of the clouds form dark stripes, and rays spread between them. This effect occurs when the Sun is low on the horizon before dawn or after sunset.

Atmosphere (from the Greek ατμός - “steam” and σφαῖρα - “sphere”) is the gas shell of a celestial body held around it by gravity. The atmosphere is the gaseous shell of the planet, consisting of a mixture of various gases, water vapor and dust. The atmosphere exchanges matter between the Earth and the Cosmos. The Earth receives cosmic dust and meteorite material, and loses the lightest gases: hydrogen and helium. The Earth's atmosphere is penetrated through and through by powerful radiation from the Sun, which determines the thermal regime of the planet's surface, causing the dissociation of molecules of atmospheric gases and the ionization of atoms.

The Earth's atmosphere contains oxygen, used by most living organisms for respiration, and carbon dioxide, consumed by plants, algae and cyanobacteria during photosynthesis. The atmosphere is also the planet's protective layer, protecting its inhabitants from the sun's ultraviolet radiation.

All massive bodies - planets - have an atmosphere. earth type, gas giants.

Atmospheric composition

The atmosphere is a mixture of gases consisting of nitrogen (78.08%), oxygen (20.95%), carbon dioxide (0.03%), argon (0.93%), a small amount of helium, neon, xenon, krypton (0.01%), 0.038% carbon dioxide, and small quantity hydrogen, helium, other noble gases and pollutants.

The modern composition of the Earth's air was established more than a hundred million years ago, but the sharply increased human production activity nevertheless led to its change. Currently, there is an increase in CO 2 content by approximately 10-12%. The gases included in the atmosphere perform various functional roles. However, the main significance of these gases is determined primarily by the fact that they very strongly absorb radiant energy and thereby have a significant impact on the temperature regime of the Earth's surface and atmosphere.

Initial composition A planet's atmosphere usually depends on the chemical and temperature properties of the sun during the formation of planets and the subsequent release of external gases. Then the composition of the gas shell evolves under the influence of various factors.

The atmospheres of Venus and Mars are primarily composed of carbon dioxide with minor additions of nitrogen, argon, oxygen and other gases. The Earth's atmosphere is largely the product of the organisms that live in it. The low-temperature gas giants - Jupiter, Saturn, Uranus and Neptune - can retain mainly low molecular weight gases - hydrogen and helium. High-temperature gas giants, such as Osiris or 51 Pegasi b, on the contrary, cannot hold it and the molecules of their atmosphere are scattered in space. This process occurs slowly and constantly.

Nitrogen, The most common gas in the atmosphere, it is chemically inactive.

Oxygen, unlike nitrogen, is a chemically very active element. The specific function of oxygen is the oxidation of organic matter of heterotrophic organisms, rocks and under-oxidized gases emitted into the atmosphere by volcanoes. Without oxygen, there would be no decomposition of dead organic matter.

Atmospheric structure

The structure of the atmosphere consists of two parts: the inner one - the troposphere, stratosphere, mesosphere and thermosphere, or ionosphere, and the outer one - the magnetosphere (exosphere).

1) Troposphere– this is the lower part of the atmosphere in which 3/4 i.e. is concentrated. ~ 80% of the entire earth's atmosphere. Its height is determined by the intensity of vertical (ascending or descending) air flows caused by heating of the earth's surface and ocean, therefore the thickness of the troposphere at the equator is 16–18 km, in temperate latitudes 10–11 km, and at the poles – up to 8 km. The air temperature in the troposphere at altitude decreases by 0.6ºС for every 100 m and ranges from +40 to - 50ºС.

2)Stratosphere is located above the troposphere and has a height of up to 50 km from the surface of the planet. The temperature at an altitude of up to 30 km is constant -50ºС. Then it begins to rise and at an altitude of 50 km reaches +10ºС.

The upper boundary of the biosphere is the ozone screen.

The ozone layer is a layer of the atmosphere within the stratosphere located at different heights from the Earth's surface and having a maximum ozone density at an altitude of 20-26 km.

The height of the ozone layer at the poles is estimated at 7-8 km, at the equator at 17-18 km, and maximum height presence of ozone – 45-50 km. Life above the ozone shield is impossible due to the harsh ultraviolet radiation of the Sun. If you compress all the ozone molecules, you will get a ~ 3mm layer around the planet.

3) Mesosphere– the upper boundary of this layer is located up to a height of 80 km. Its main feature is a sharp drop in temperature -90ºС at its upper limit. Noctilucent clouds consisting of ice crystals are recorded here.

4) Ionosphere (thermosphere) - is located up to an altitude of 800 km and is characterized by a significant increase in temperature:

150 km temperature +240ºС,

200 km temperature +500ºС,

600 km temperature +1500ºС.

Under the influence of ultraviolet radiation from the Sun, gases are in an ionized state. Ionization is associated with the glow of gases and the appearance of auroras.

The ionosphere has the ability to repeatedly reflect radio waves, which ensures long-distance radio communications on the planet.

5) Exosphere– is located above 800 km and extends up to 3000 km. Here the temperature is >2000ºС. The speed of gas movement is approaching critical ~ 11.2 km/sec. The dominant atoms are hydrogen and helium, which form a luminous corona around the Earth, extending to an altitude of 20,000 km.

Functions of the atmosphere

1) Thermoregulatory - weather and climate on Earth depend on the distribution of heat and pressure.

2) Life-sustaining.

3) In the troposphere, global vertical and horizontal movements of air masses occur, which determine the water cycle and heat exchange.

4) Almost all surface geological processes are caused by the interaction of the atmosphere, lithosphere and hydrosphere.

5) Protective - the atmosphere protects the earth from space, solar radiation and meteorite dust.

Functions of the atmosphere. Without the atmosphere, life on Earth would be impossible. A person consumes 12-15 kg daily. air, inhaling every minute from 5 to 100 liters, which significantly exceeds the average daily need for food and water. In addition, the atmosphere reliably protects a person from dangers that threaten him from space: it does not allow meteorites to pass through, cosmic radiation. A person can live without food for five weeks, without water for five days, without air for five minutes. Normal human life requires not only air, but also a certain purity of it. The health of people, the state of flora and fauna, the strength and durability of building structures and structures depend on the air quality. Polluted air is destructive to waters, land, seas, and soils. The atmosphere determines the light and regulates the thermal regimes of the earth, promotes the redistribution of heat to globe. The gas shell protects the Earth from excessive cooling and heating. If our planet were not surrounded by an air shell, then within one day the amplitude of temperature fluctuations would reach 200 C. The atmosphere saves everything living on Earth from destructive ultraviolet, x-rays and cosmic rays. The atmosphere plays a great role in the distribution of light. Its air breaks the sun's rays into a million small rays, scatters them and creates uniform illumination. The atmosphere serves as a conductor of sounds.