That the atmosphere is shared. The structure of the atmosphere

Earth's atmosphere

Atmosphere(from. Old Greekἀτμός - steam and σφαῖρα - ball) - gas shell ( geosphere), surrounding the planet Earth. Its inner surface covers hydrosphere and partially bark, the outer one borders on the near-Earth part of outer space.

The set of branches of physics and chemistry that study the atmosphere is usually called atmospheric physics. The atmosphere determines weather on the surface of the Earth, studying weather meteorology, and long-term variations climate - climatology.

The structure of the atmosphere

The structure of the atmosphere

Troposphere

Its upper limit is at an altitude of 8-10 km in polar, 10-12 km in temperate and 16-18 km in tropical latitudes; lower in winter than in summer. The lower, main layer of the atmosphere. Contains more than 80% of the total mass of atmospheric air and about 90% of all water vapor present in the atmosphere. In the troposphere are highly developed turbulence And convection, arise clouds, are developing cyclones And anticyclones. Temperature decreases with increasing altitude with average vertical gradient 0.65°/100 m

The following are accepted as “normal conditions” at the Earth’s surface: density 1.2 kg/m3, barometric pressure 101.35 kPa, temperature plus 20 °C and relative humidity 50%. These conditional indicators have purely engineering significance.

Stratosphere

A layer of the atmosphere located at an altitude of 11 to 50 km. Characterized by a slight change in temperature in the 11-25 km layer (lower layer of the stratosphere) and an increase in the 25-40 km layer from −56.5 to 0.8 ° WITH(upper layer of the stratosphere or region inversions). Having reached a value of about 273 K (almost 0 ° C) at an altitude of about 40 km, the temperature remains constant up to an altitude of about 55 km. This region of constant temperature is called stratopause and is the boundary between the stratosphere and mesosphere.

Stratopause

The boundary layer of the atmosphere between the stratosphere and mesosphere. In the vertical temperature distribution there is a maximum (about 0 °C).

Mesosphere

Earth's atmosphere

Mesosphere begins at an altitude of 50 km and extends to 80-90 km. Temperature decreases with height with an average vertical gradient of (0.25-0.3)°/100 m. The main energy process is radiant heat transfer. Complex photochemical processes involving free radicals, vibrationally excited molecules, etc., cause the glow of the atmosphere.

Mesopause

Transitional layer between the mesosphere and thermosphere. There is a minimum in the vertical temperature distribution (about -90 °C).

Karman Line

The height above sea level, which is conventionally accepted as the boundary between the Earth's atmosphere and space.

Thermosphere

Main article: Thermosphere

The upper limit is about 800 km. The temperature rises to altitudes of 200-300 km, where it reaches values ​​of the order of 1500 K, after which it remains almost constant to high altitudes. Under the influence of ultraviolet and x-ray solar radiation and cosmic radiation, air ionization occurs (“ auroras") - main areas ionosphere lie inside the thermosphere. At altitudes above 300 km, atomic oxygen predominates.

Atmospheric layers up to an altitude of 120 km

Exosphere (scattering sphere)

Exosphere- dispersion zone, the outer part of the thermosphere, located above 700 km. The gas in the exosphere is very rarefied, and from here its particles leak into interplanetary space ( dissipation).

Up to an altitude of 100 km, the atmosphere is a homogeneous, well-mixed mixture of gases. In higher layers, the distribution of gases by height depends on their molecular weights; the concentration of heavier gases decreases faster with distance from the Earth's surface. Due to the decrease in gas density, the temperature drops from 0 °C in the stratosphere to −110 °C in the mesosphere. However, the kinetic energy of individual particles at altitudes of 200-250 km corresponds to a temperature of ~1500 °C. Above 200 km, significant fluctuations in temperature and gas density in time and space are observed.

At an altitude of about 2000-3000 km, the exosphere gradually turns into the so-called near space vacuum, which is filled with highly rarefied particles of interplanetary gas, mainly hydrogen atoms. But this gas represents only part of the interplanetary matter. The other part consists of dust particles of cometary and meteoric origin. In addition to extremely rarefied dust particles, electromagnetic and corpuscular radiation of solar and galactic origin penetrates into this space.

The troposphere accounts for about 80% of the mass of the atmosphere, the stratosphere - about 20%; the mass of the mesosphere is no more than 0.3%, the thermosphere is less than 0.05% of the total mass of the atmosphere. Based on the electrical properties in the atmosphere, the neutronosphere and ionosphere are distinguished. It is currently believed that the atmosphere extends to an altitude of 2000-3000 km.

Depending on the composition of the gas in the atmosphere, they emit homosphere And heterosphere. Heterosphere - This is the area where gravity affects the separation of gases, since their mixing at such an altitude is negligible. This implies a variable composition of the heterosphere. Below it lies a well-mixed, homogeneous part of the atmosphere, called homosphere. The boundary between these layers is called turbo pause, it lies at an altitude of about 120 km.

Physical properties

The thickness of the atmosphere is approximately 2000 - 3000 km from the Earth's surface. Total mass air- (5.1-5.3)×10 18 kg. Molar mass clean dry air is 28.966. Pressure at 0 °C at sea level 101.325 kPa; critical temperature?140.7 °C; critical pressure 3.7 MPa; C p 1.0048×10 3 J/(kg K) (at 0 °C), C v 0.7159×10 3 J/(kg K) (at 0 °C). The solubility of air in water at 0 °C is 0.036%, at 25 °C - 0.22%.

Physiological and other properties of the atmosphere

Already at an altitude of 5 km above sea level, an untrained person develops oxygen starvation and without adaptation, a person’s performance is significantly reduced. The physiological zone of the atmosphere ends here. Human breathing becomes impossible at an altitude of 15 km, although up to approximately 115 km the atmosphere contains oxygen.

The atmosphere supplies us with the oxygen necessary for breathing. However, due to the drop in the total pressure of the atmosphere, as you rise to altitude, the partial pressure of oxygen decreases accordingly.

The human lungs constantly contain about 3 liters of alveolar air. Partial pressure oxygen in alveolar air at normal atmospheric pressure is 110 mm Hg. Art., carbon dioxide pressure - 40 mm Hg. Art., and water vapor - 47 mm Hg. Art. With increasing altitude, oxygen pressure drops, and the total vapor pressure of water and carbon dioxide in the lungs remains almost constant - about 87 mm Hg. Art. The supply of oxygen to the lungs will completely stop when the ambient air pressure becomes equal to this value.

At an altitude of about 19-20 km, the atmospheric pressure drops to 47 mm Hg. Art. Therefore, at this altitude, water and interstitial fluid begin to boil in the human body. Outside the pressurized cabin at these altitudes, death occurs almost instantly. Thus, from the point of view of human physiology, “space” begins already at an altitude of 15-19 km.

Dense layers of air - the troposphere and stratosphere - protect us from the damaging effects of radiation. With sufficient rarefaction of air, at altitudes of more than 36 km, ionizing agents have an intense effect on the body. radiation- primary cosmic rays; At altitudes of more than 40 km, the ultraviolet part of the solar spectrum is dangerous for humans.

As we rise to an ever greater height above the Earth's surface, such familiar phenomena observed in the lower layers of the atmosphere as the propagation of sound, the emergence of aerodynamic lift and resistance, heat transfer convection and etc.

In rarefied layers of air, distribution sound turns out to be impossible. Up to altitudes of 60-90 km, it is still possible to use air resistance and lift for controlled aerodynamic flight. But starting from altitudes of 100-130 km, concepts familiar to every pilot numbers M And sound barrier lose their meaning, there is a conditional Karman Line beyond which begins the sphere of purely ballistic flight, which can only be controlled using reactive forces.

At altitudes above 100 km, the atmosphere is deprived of another remarkable property - the ability to absorb, conduct and transmit thermal energy by convection (i.e. by mixing air). This means that various elements of equipment on the orbital space station will not be able to be cooled from the outside in the same way as is usually done on an airplane - with the help of air jets and air radiators. At such a height, as in space generally, the only way to transfer heat is thermal radiation.

Atmospheric composition

Composition of dry air

The Earth's atmosphere consists mainly of gases and various impurities (dust, water droplets, ice crystals, sea salts, combustion products).

The concentration of gases that make up the atmosphere is almost constant, with the exception of water (H 2 O) and carbon dioxide (CO 2).

Composition of dry air
Nitrogen
Oxygen
Argon
Water
Carbon dioxide
Neon
Helium
Methane
Krypton
Hydrogen
Xenon
Nitrous oxide

In addition to the gases indicated in the table, the atmosphere contains SO 2, NH 3, CO, ozone, hydrocarbons, HCl, HF, couples Hg, I 2 , and also NO and many other gases in small quantities. The troposphere constantly contains a large number of suspended solid and liquid particles ( aerosol).

History of atmospheric formation

According to the most common theory, the Earth's atmosphere has had four different compositions over time. Initially it consisted of light gases ( hydrogen And helium), captured from interplanetary space. This is the so-called primary atmosphere(about four billion years ago). At the next stage, active volcanic activity led to the saturation of the atmosphere with gases other than hydrogen (carbon dioxide, ammonia, water vapor). This is how it was formed secondary atmosphere(about three billion years before the present day). This atmosphere was restorative. Further, the process of atmosphere formation was determined by the following factors:

leakage of light gases (hydrogen and helium) into interplanetary space;

chemical reactions occurring in the atmosphere under the influence of ultraviolet radiation, lightning discharges and some other factors.

Gradually these factors led to the formation tertiary atmosphere, characterized by a much lower content of hydrogen and a much higher content of nitrogen and carbon dioxide (formed as a result of chemical reactions from ammonia and hydrocarbons).

Nitrogen

The formation of a large amount of N 2 is due to the oxidation of the ammonia-hydrogen atmosphere by molecular O 2, which began to come from the surface of the planet as a result of photosynthesis, starting 3 billion years ago. N2 is also released into the atmosphere as a result of denitrification of nitrates and other nitrogen-containing compounds. Nitrogen is oxidized by ozone to NO in the upper atmosphere.

Nitrogen N 2 reacts only under specific conditions (for example, during a lightning discharge). The oxidation of molecular nitrogen by ozone during electrical discharges is used in the industrial production of nitrogen fertilizers. They can oxidize it with low energy consumption and convert it into a biologically active form. cyanobacteria (blue-green algae) and nodule bacteria that form rhizobial symbiosis With legumes plants, so-called green manure.

Oxygen

The composition of the atmosphere began to change radically with the appearance on Earth living organisms, as a result photosynthesis accompanied by the release of oxygen and absorption of carbon dioxide. Initially, oxygen was spent on the oxidation of reduced compounds - ammonia, hydrocarbons, nitrous form gland contained in the oceans, etc. At the end of this stage, the oxygen content in the atmosphere began to increase. Gradually, a modern atmosphere with oxidizing properties formed. Since this caused serious and abrupt changes in many processes occurring in atmosphere, lithosphere And biosphere, this event was called Oxygen disaster.

During Phanerozoic the composition of the atmosphere and oxygen content underwent changes. They correlated primarily with the rate of deposition of organic sediment. Thus, during periods of coal accumulation, the oxygen content in the atmosphere apparently significantly exceeded the modern level.

Carbon dioxide

The content of CO 2 in the atmosphere depends on volcanic activity and chemical processes in the earth's shells, but most of all - on the intensity of biosynthesis and decomposition of organic matter in biosphere Earth. Almost the entire current biomass of the planet (about 2.4 × 10 12 tons ) is formed due to carbon dioxide, nitrogen and water vapor contained in the atmospheric air. Buried in ocean, V swamps and in forests organic matter turns into coal, oil And natural gas. (cm. Geochemical carbon cycle)

Noble gases

Source of inert gases - argon, helium And krypton- volcanic eruptions and decay of radioactive elements. The Earth in general and the atmosphere in particular are depleted of inert gases compared to space. It is believed that the reason for this lies in the continuous leakage of gases into interplanetary space.

Air pollution

Recently, the evolution of the atmosphere has begun to be influenced by Human. The result of his activities was a constant significant increase in the content of carbon dioxide in the atmosphere due to the combustion of hydrocarbon fuels accumulated in previous geological eras. Huge amounts of CO 2 are consumed during photosynthesis and absorbed by the world's oceans. This gas enters the atmosphere due to the decomposition of carbonate rocks and organic substances of plant and animal origin, as well as due to volcanism and human industrial activity. Over the past 100 years, the content of CO 2 in the atmosphere has increased by 10%, with the bulk (360 billion tons) coming from fuel combustion. If the growth rate of fuel combustion continues, then in the next 50 - 60 years the amount of CO 2 in the atmosphere will double and could lead to global climate change.

Fuel combustion is the main source of polluting gases ( CO, NO, SO 2 ). Sulfur dioxide is oxidized by atmospheric oxygen to SO 3 in the upper layers of the atmosphere, which in turn interacts with water and ammonia vapor, and the resulting sulfuric acid (H 2 SO 4 ) And ammonium sulfate ((NH 4 ) 2 SO 4 ) return to the surface of the Earth in the form of the so-called. acid rain. Usage internal combustion engines leads to significant atmospheric pollution with nitrogen oxides, hydrocarbons and lead compounds ( tetraethyl lead Pb(CH 3 CH 2 ) 4 ) ).

Aerosol pollution of the atmosphere is caused by both natural causes (volcanic eruptions, dust storms, entrainment of drops of sea water and plant pollen, etc.) and human economic activities (mining ores and building materials, burning fuel, making cement, etc.). Intense large-scale release of particulate matter into the atmosphere is one of the possible causes of climate change on the planet.

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 pressure. It should be noted that the layers of the stratosphere and troposphere protect the Earth from solar radiation. In the higher layers, a living organism can receive a lethal dose of ultraviolet solar spectrum. To quickly jump to the desired atmosphere layer, click on the corresponding layer:

Troposphere and tropopause

Troposphere - temperature, pressure, altitude

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

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

Tropopause

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

Stratosphere and Stratopause

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

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

Mesosphere and Mesopause - composition, reactions, temperature

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

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

Karman Line

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

Thermosphere and Thermopause

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

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

Exosphere - density, temperature, height

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

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

Atmosphere(from the Greek atmos - steam and spharia - ball) - the air shell of the Earth, rotating with it. The development of the atmosphere was closely related to the geological and geochemical processes occurring on our planet, as well as to the activities of living organisms.

The lower boundary of the atmosphere coincides with the surface of the Earth, since air penetrates into the smallest pores in the soil and is dissolved even in water.

The upper boundary at an altitude of 2000-3000 km gradually passes into outer space.

Thanks to the atmosphere, which contains oxygen, life on Earth is possible. Atmospheric oxygen is used in the breathing process of humans, animals, and plants.

If there were no atmosphere, the Earth would be as quiet as the Moon. After all, sound is the vibration of air particles. The blue color of the sky is explained by the fact that the sun's rays, passing through the atmosphere, like through a lens, are decomposed into their component colors. In this case, the rays of blue and blue colors are scattered the most.

The atmosphere traps most of the sun's ultraviolet radiation, which has a detrimental effect on living organisms. It also retains heat near the Earth's surface, preventing our planet from cooling.

The structure of the atmosphere

In the atmosphere, several layers can be distinguished, differing in density (Fig. 1).

Troposphere

Troposphere- the lowest layer of the atmosphere, the thickness of which above the poles is 8-10 km, in temperate latitudes - 10-12 km, and above the equator - 16-18 km.

Rice. 1. The structure of the Earth's atmosphere

The air in the troposphere is heated by the earth's surface, that is, by land and water. Therefore, the air temperature in this layer decreases with height by an average of 0.6 °C for every 100 m. At the upper boundary of the troposphere it reaches -55 °C. At the same time, in the region of the equator at the upper boundary of the troposphere, the air temperature is -70 °C, and in the region of the North Pole -65 °C.

About 80% of the mass of the atmosphere is concentrated in the troposphere, almost all the water vapor is located, thunderstorms, storms, clouds and precipitation occur, and vertical (convection) and horizontal (wind) movement of air occurs.

We can say that weather is mainly formed in the troposphere.

Stratosphere

Stratosphere- a layer of the atmosphere located above the troposphere at an altitude of 8 to 50 km. The color of the sky in this layer appears purple, which is explained by the thinness of the air, due to which the sun's rays are almost not scattered.

The stratosphere contains 20% of the mass of the atmosphere. The air in this layer is rarefied, there is practically no water vapor, and therefore almost no clouds and precipitation form. However, stable air currents are observed in the stratosphere, the speed of which reaches 300 km/h.

This layer is concentrated ozone(ozone screen, ozonosphere), a layer that absorbs ultraviolet rays, preventing them from reaching the Earth and thereby protecting living organisms on our planet. Thanks to ozone, the air temperature at the upper boundary of the stratosphere ranges from -50 to 4-55 °C.

Between the mesosphere and stratosphere there is a transition zone - the stratopause.

Mesosphere

Mesosphere- a layer of the atmosphere located at an altitude of 50-80 km. The air density here is 200 times less than at the Earth's surface. The color of the sky in the mesosphere appears black, and stars are visible during the day. The air temperature drops to -75 (-90)°C.

At an altitude of 80 km begins thermosphere. The air temperature in this layer rises sharply to a height of 250 m, and then becomes constant: at an altitude of 150 km it reaches 220-240 ° C; at an altitude of 500-600 km exceeds 1500 °C.

In the mesosphere and thermosphere, under the influence of cosmic rays, gas molecules disintegrate into charged (ionized) particles of atoms, so this part of the atmosphere is called ionosphere- a layer of very rarefied air, located at an altitude of 50 to 1000 km, consisting mainly of ionized oxygen atoms, nitrogen oxide molecules and free electrons. This layer is characterized by high electrification, and long and medium radio waves are reflected from it, like from a mirror.

In the ionosphere, aurorae appear - the glow of rarefied gases under the influence of electrically charged particles flying from the Sun - and sharp fluctuations in the magnetic field are observed.

Exosphere

Exosphere- the outer layer of the atmosphere located above 1000 km. This layer is also called the scattering sphere, since gas particles move here at high speed and can be scattered into outer space.

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%), ozone and other gases, but their content is negligible (Table 1). 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 that make up 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.

Table 1. Chemical composition of dry atmospheric air near the earth's surface

	Volume concentration. %	Molecular weight, units
Oxygen
Carbon dioxide
Nitrous oxide
	from 0 to 0.00001
Sulfur dioxide	from 0 to 0.000007 in summer; from 0 to 0.000002 in winter
	From 0 to 0.000002	46,0055/17,03061
Azog dioxide
Carbon monoxide

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.

The role of carbon dioxide in the atmosphere is extremely large. It enters the atmosphere as a result of combustion processes, respiration of living organisms, and decay and is, first of all, the main building material for the creation of organic matter during photosynthesis. In addition, the ability of carbon dioxide to transmit short-wave solar radiation and absorb part of the thermal long-wave radiation is of great importance, which will create the so-called greenhouse effect, which will be discussed below.

Atmospheric processes, especially the thermal regime of the stratosphere, are also influenced by ozone. This gas serves as a natural absorber of ultraviolet radiation from the sun, and the absorption of solar radiation leads to heating of the air. Average monthly values ​​of the total ozone content in the atmosphere vary depending on the latitude and time of year within the range of 0.23-0.52 cm (this is the thickness of the ozone layer at ground pressure and temperature). There is an increase in ozone content from the equator to the poles and an annual cycle with a minimum in autumn and a maximum in spring.

A characteristic property of the atmosphere is that the content of the main gases (nitrogen, oxygen, argon) changes slightly with altitude: at an altitude of 65 km in the atmosphere the content of nitrogen is 86%, oxygen - 19, argon - 0.91, at an altitude of 95 km - nitrogen 77, oxygen - 21.3, argon - 0.82%. The constancy of the composition of atmospheric air vertically and horizontally is maintained by its mixing.

In addition to gases, the air contains water vapor And solid particles. The latter can have both natural and artificial (anthropogenic) origin. These are pollen, tiny salt crystals, road dust, and aerosol impurities. When the sun's rays penetrate the window, they can be seen with the naked eye.

There are especially many particulate particles in the air of cities and large industrial centers, where emissions of harmful gases and their impurities formed during fuel combustion are added to aerosols.

The concentration of aerosols in the atmosphere determines the transparency of the air, which affects solar radiation reaching the Earth's surface. The largest aerosols are condensation nuclei (from lat. condensatio- compaction, thickening) - contribute to the transformation of water vapor into water droplets.

The importance of water vapor is determined primarily by the fact that it delays long-wave thermal radiation from the earth's surface; represents the main link of large and small moisture cycles; increases the air temperature during condensation of water beds.

The amount of water vapor in the atmosphere varies in time and space. Thus, the concentration of water vapor at the earth's surface ranges from 3% in the tropics to 2-10 (15)% in Antarctica.

The average content of water vapor in the vertical column of the atmosphere in temperate latitudes is about 1.6-1.7 cm (this is the thickness of the layer of condensed water vapor). Information regarding water vapor in different layers of the atmosphere is contradictory. It was assumed, for example, that in the altitude range from 20 to 30 km, specific humidity increases strongly with altitude. However, subsequent measurements indicate greater dryness of the stratosphere. Apparently, the specific humidity in the stratosphere depends little on altitude and is 2-4 mg/kg.

The variability of water vapor content in the troposphere is determined by the interaction of the processes of evaporation, condensation and horizontal transport. As a result of condensation of water vapor, clouds form and precipitation falls in the form of rain, hail and snow.

The processes of phase transitions of water occur predominantly in the troposphere, which is why clouds in the stratosphere (at altitudes of 20-30 km) and mesosphere (near the mesopause), called pearlescent and silvery, are observed relatively rarely, while tropospheric clouds often cover about 50% of the entire earth's surface. surfaces.

The amount of water vapor that can be contained in the air depends on the air temperature.

1 m 3 of air at a temperature of -20 ° C can contain no more than 1 g of water; at 0 °C - no more than 5 g; at +10 °C - no more than 9 g; at +30 °C - no more than 30 g of water.

Conclusion: The higher the air temperature, the more water vapor it can contain.

The air may be rich And not saturated water vapor. So, if at a temperature of +30 °C 1 m 3 of air contains 15 g of water vapor, the air is not saturated with water vapor; if 30 g - saturated.

Absolute humidity is the amount of water vapor contained in 1 m3 of air. It is expressed in grams. For example, if they say “absolute humidity is 15,” this means that 1 m L contains 15 g of water vapor.

Relative humidity- this is the ratio (in percentage) of the actual content of water vapor in 1 m 3 of air to the amount of water vapor that can be contained in 1 m L at a given temperature. For example, if the radio broadcast a weather report that the relative humidity is 70%, this means that the air contains 70% of the water vapor it can hold at that temperature.

The higher the relative humidity, i.e. The closer the air is to a state of saturation, the more likely precipitation is.

Always high (up to 90%) relative air humidity is observed in the equatorial zone, since the air temperature remains high there throughout the year and large evaporation occurs from the surface of the oceans. The relative humidity is also high in the polar regions, but because at low temperatures even a small amount of water vapor makes the air saturated or close to saturated. In temperate latitudes, relative humidity varies with the seasons - it is higher in winter, lower in summer.

The relative air humidity in deserts is especially low: 1 m 1 of air there contains two to three times less water vapor than is possible at a given temperature.

To measure relative humidity, a hygrometer is used (from the Greek hygros - wet and metreco - I measure).

When cooled, saturated air cannot retain the same amount of water vapor; it thickens (condenses), turning into droplets of fog. Fog can be observed in summer on a clear, cool night.

Clouds- this is the same fog, only it is formed not at the earth’s surface, but at a certain height. As the air rises, it cools and the water vapor in it condenses. The resulting tiny droplets of water make up clouds.

Cloud formation also involves particulate matter suspended in the troposphere.

Clouds can have different shapes, which depend on the conditions of their formation (Table 14).

The lowest and heaviest clouds are stratus. They are located at an altitude of 2 km from the earth's surface. At an altitude of 2 to 8 km, more picturesque cumulus clouds can be observed. The highest and lightest clouds are cirrus clouds. They are located at an altitude of 8 to 18 km above the earth's surface.

Families	Kinds of clouds	Appearance
A. Upper clouds - above 6 km	I. Cirrus	Thread-like, fibrous, white
	II. Cirrocumulus	Layers and ridges of small flakes and curls, white
	III. Cirrostratus	Transparent whitish veil
B. Mid-level clouds - above 2 km	IV. Altocumulus	Layers and ridges of white and gray color
	V. Altostratified	Smooth veil of milky gray color
B. Low clouds - up to 2 km	VI. Nimbostratus	Solid shapeless gray layer
	VII. Stratocumulus	Non-transparent layers and ridges of gray color
	VIII. Layered	Non-transparent gray veil
D. Clouds of vertical development - from the lower to the upper tier	IX. Cumulus	Clubs and domes are bright white, with torn edges in the wind
	X. Cumulonimbus	Powerful cumulus-shaped masses of dark lead color

Atmospheric protection

The main sources are industrial enterprises and cars. In large cities, the problem of gas pollution on main transport routes is very acute. That is why many large cities around the world, including our country, have introduced environmental control of the toxicity of vehicle exhaust gases. According to experts, smoke and dust in the air can reduce the supply of solar energy to the earth's surface by half, which will lead to a change in natural conditions.

The atmosphere is a mixture of various gases. It extends from the Earth's surface to a height of 900 km, protecting the planet from the harmful spectrum of solar radiation, and contains gases necessary for all life on the planet. The atmosphere traps heat from the sun, warming the earth's surface and creating a favorable climate.

Atmospheric composition

The Earth's atmosphere consists mainly of two gases - nitrogen (78%) and oxygen (21%). In addition, it contains impurities of carbon dioxide and other gases. in the atmosphere it exists in the form of vapor, moisture droplets in clouds and ice crystals.

Layers of the atmosphere

The atmosphere consists of many layers, between which there are no clear boundaries. The temperatures of different layers differ markedly from each other.

• Airless magnetosphere. This is where most of the Earth's satellites fly outside the Earth's atmosphere.
• Exosphere (450-500 km from the surface). Almost no gases. Some weather satellites fly in the exosphere. The thermosphere (80-450 km) is characterized by high temperatures, reaching 1700°C in the upper layer.
• Mesosphere (50-80 km). In this area, the temperature drops as altitude increases. This is where most meteorites (fragments of space rocks) that enter the atmosphere burn up.
• Stratosphere (15-50 km). Contains ozone layer, i.e. a layer of ozone that absorbs ultraviolet radiation from the Sun. This causes temperatures near the Earth's surface to rise. Jet planes usually fly here because Visibility in this layer is very good and there is almost no interference caused by weather conditions.
• Troposphere. The height varies from 8 to 15 km from the earth's surface. It is here that the planet's weather is formed, since in This layer contains the most water vapor, dust and winds. The temperature decreases with distance from the earth's surface.

Atmosphere pressure

Although we don't feel it, layers of the atmosphere exert pressure on the Earth's surface. It is highest near the surface, and as you move away from it it gradually decreases. It depends on the temperature difference between land and ocean, and therefore in areas located at the same altitude above sea level there are often different pressures. Low pressure brings wet weather, while high pressure usually brings clear weather.

Movement of air masses in the atmosphere

And the pressures force the lower layers of the atmosphere to mix. This is how winds arise, blowing from areas of high pressure to areas of low pressure. In many regions, local winds also arise due to differences in temperature between land and sea. Mountains also have a significant influence on the direction of winds.

Greenhouse effect

Carbon dioxide and other gases that make up the earth's atmosphere trap heat from the sun. This process is commonly called the greenhouse effect, since it is in many ways reminiscent of the circulation of heat in greenhouses. The greenhouse effect causes global warming on the planet. In areas of high pressure - anticyclones - clear sunny weather sets in. Areas of low pressure - cyclones - usually experience unstable weather. Heat and light entering the atmosphere. Gases trap heat reflected from the earth's surface, thereby causing an increase in temperature on Earth.

There is a special ozone layer in the stratosphere. Ozone blocks most of the sun's ultraviolet radiation, protecting the Earth and all life on it from it. Scientists have found that the cause of the destruction of the ozone layer is special chlorofluorocarbon dioxide gases contained in some aerosols and refrigeration equipment. Over the Arctic and Antarctica, huge holes have been discovered in the ozone layer, contributing to an increase in the amount of ultraviolet radiation affecting the Earth's surface.

Ozone is formed in the lower atmosphere as a result between solar radiation and various exhaust fumes and gases. Usually it is dispersed throughout the atmosphere, but if a closed layer of cold air forms under a layer of warm air, ozone concentrates and smog occurs. Unfortunately, this cannot replace the ozone lost in ozone holes.

A hole in the ozone layer over Antarctica is clearly visible in this satellite photograph. The size of the hole varies, but scientists believe that it is constantly growing. Efforts are being made to reduce the level of exhaust gases in the atmosphere. Air pollution should be reduced and smokeless fuels used in cities. Smog causes eye irritation and suffocation for many people.

The emergence and evolution of the Earth's atmosphere

The modern atmosphere of the Earth is the result of long evolutionary development. It arose as a result of the combined actions of geological factors and the vital activity of organisms. Throughout geological history, the earth's atmosphere has undergone several profound changes. Based on geological data and theoretical premises, the primordial atmosphere of the young Earth, which existed about 4 billion years ago, could consist of a mixture of inert and noble gases with a small addition of passive nitrogen (N. A. Yasamanov, 1985; A. S. Monin, 1987; O. G. Sorokhtin, S. A. Ushakov, 1991, 1993). Currently, the view on the composition and structure of the early atmosphere has changed somewhat. The primary atmosphere (proto-atmosphere) at the earliest protoplanetary stage., i.e. older than 4.2 billion years, could consist of a mixture of methane, ammonia and carbon dioxide. As a result of degassing of the mantle and active weathering processes occurring on the earth's surface, water vapor, carbon compounds in the form of CO 2 and CO, sulfur and its compounds began to enter the atmosphere , as well as strong halogen acids - HCI, HF, HI and boric acid, which were supplemented by methane, ammonia, hydrogen, argon and some other noble gases in the atmosphere. This primary atmosphere was extremely thin. Therefore, the temperature at the earth's surface was close to the temperature of radiative equilibrium (A. S. Monin, 1977).

Over time, the gas composition of the primary atmosphere began to transform under the influence of weathering processes of rocks protruding on the earth's surface, the activity of cyanobacteria and blue-green algae, volcanic processes and the action of sunlight. This led to the decomposition of methane into carbon dioxide, ammonia into nitrogen and hydrogen; Carbon dioxide, which slowly sank to the earth's surface, and nitrogen began to accumulate in the secondary atmosphere. Thanks to the vital activity of blue-green algae, oxygen began to be produced in the process of photosynthesis, which, however, in the beginning was mainly spent on the “oxidation of atmospheric gases, and then rocks. At the same time, ammonia, oxidized to molecular nitrogen, began to accumulate intensively in the atmosphere. It is assumed that a significant amount of nitrogen in the modern atmosphere is relict. Methane and carbon monoxide were oxidized to carbon dioxide. Sulfur and hydrogen sulfide were oxidized to SO 2 and SO 3, which, due to their high mobility and lightness, were quickly removed from the atmosphere. Thus, the atmosphere from a reducing atmosphere, as it was in the Archean and Early Proterozoic, gradually turned into an oxidizing one.

Carbon dioxide entered the atmosphere both as a result of methane oxidation and as a result of degassing of the mantle and weathering of rocks. In the event that all the carbon dioxide released over the entire history of the Earth was preserved in the atmosphere, its partial pressure at present could become the same as on Venus (O. Sorokhtin, S. A. Ushakov, 1991). But on Earth the reverse process was at work. A significant part of carbon dioxide from the atmosphere was dissolved in the hydrosphere, in which it was used by hydrobionts to build their shells and biogenically converted into carbonates. Subsequently, thick strata of chemogenic and organogenic carbonates were formed from them.

Oxygen entered the atmosphere from three sources. For a long time, starting from the moment the Earth appeared, it was released during the degassing of the mantle and was mainly spent on oxidative processes. Another source of oxygen was the photodissociation of water vapor by hard ultraviolet solar radiation. Appearances; free oxygen in the atmosphere led to the death of most prokaryotes that lived in reducing conditions. Prokaryotic organisms changed their habitats. They left the surface of the Earth into its depths and areas where recovery conditions still remained. They were replaced by eukaryotes, which began to energetically convert carbon dioxide into oxygen.

During the Archean and a significant part of the Proterozoic, almost all the oxygen arising in both abiogenic and biogenic ways was mainly spent on the oxidation of iron and sulfur. By the end of the Proterozoic, all metallic divalent iron located on the earth's surface either oxidized or moved into the earth's core. This caused the partial pressure of oxygen in the early Proterozoic atmosphere to change.

In the middle of the Proterozoic, the oxygen concentration in the atmosphere reached the Jury point and amounted to 0.01% of the modern level. Starting from this time, oxygen began to accumulate in the atmosphere and, probably, already at the end of the Riphean its content reached the Pasteur point (0.1% of the modern level). It is possible that the ozone layer appeared in the Vendian period and that it never disappeared.

The appearance of free oxygen in the earth's atmosphere stimulated the evolution of life and led to the emergence of new forms with more advanced metabolism. If earlier eukaryotic unicellular algae and cyanea, which appeared at the beginning of the Proterozoic, required an oxygen content in water of only 10 -3 of its modern concentration, then with the emergence of non-skeletal Metazoa at the end of the Early Vendian, i.e. about 650 million years ago, the oxygen concentration in the atmosphere should be significantly higher. After all, Metazoa used oxygen respiration and this required that the partial pressure of oxygen reach a critical level - the Pasteur point. In this case, the anaerobic fermentation process was replaced by an energetically more promising and progressive oxygen metabolism.

After this, further accumulation of oxygen in the earth's atmosphere occurred quite quickly. The progressive increase in the volume of blue-green algae contributed to the achievement in the atmosphere of the oxygen level necessary for the life support of the animal world. A certain stabilization of the oxygen content in the atmosphere occurred from the moment when plants reached land - approximately 450 million years ago. The emergence of plants onto land, which occurred in the Silurian period, led to the final stabilization of oxygen levels in the atmosphere. From that time on, its concentration began to fluctuate within rather narrow limits, never exceeding the limits of the existence of life. The oxygen concentration in the atmosphere has completely stabilized since the appearance of flowering plants. This event occurred in the middle of the Cretaceous period, i.e. about 100 million years ago.

The bulk of nitrogen was formed in the early stages of the Earth's development, mainly due to the decomposition of ammonia. With the appearance of organisms, the process of binding atmospheric nitrogen into organic matter and burying it in marine sediments began. After organisms reached land, nitrogen began to be buried in continental sediments. The processes of processing free nitrogen especially intensified with the advent of land plants.

At the turn of the Cryptozoic and Phanerozoic, i.e. about 650 million years ago, the content of carbon dioxide in the atmosphere decreased to tenths of a percent, and it reached a content close to the modern level only recently, approximately 10-20 million years ago.

Thus, the gas composition of the atmosphere not only provided living space for organisms, but also determined the characteristics of their life activity and contributed to settlement and evolution. Emerging disruptions in the distribution of the gas composition of the atmosphere favorable for organisms, both due to cosmic and planetary reasons, led to mass extinctions of the organic world, which repeatedly occurred during the Cryptozoic and at certain boundaries of Phanerozoic history.

Ethnospheric functions of the atmosphere

The Earth's atmosphere provides the necessary substances, energy and determines the direction and speed of metabolic processes. The gas composition of the modern atmosphere is optimal for the existence and development of life. Being the area where weather and climate are formed, the atmosphere must create comfortable conditions for the life of people, animals and vegetation. Deviations in one direction or another in the quality of atmospheric air and weather conditions create extreme conditions for the life of flora and fauna, including humans.

The Earth's atmosphere not only provides the conditions for the existence of humanity, but is the main factor in the evolution of the ethnosphere. At the same time, it turns out to be an energy and raw material resource for production. In general, the atmosphere is a factor that preserves human health, and some areas, due to physical-geographical conditions and atmospheric air quality, serve as recreational areas and are areas intended for sanatorium-resort treatment and recreation of people. Thus, the atmosphere is a factor of aesthetic and emotional impact.

The ethnosphere and technosphere functions of the atmosphere, defined quite recently (E. D. Nikitin, N. A. Yasamanov, 2001), require independent and in-depth study. Thus, the study of atmospheric energy functions is very relevant, both from the point of view of the occurrence and operation of processes that damage the environment, and from the point of view of the impact on the health and well-being of people. In this case, we are talking about the energy of cyclones and anticyclones, atmospheric vortices, atmospheric pressure and other extreme atmospheric phenomena, the effective use of which will contribute to the successful solution of the problem of obtaining alternative energy sources that do not pollute the environment. After all, the air environment, especially that part of it that is located above the World Ocean, is an area where a colossal amount of free energy is released.

For example, it has been established that tropical cyclones of average strength release energy equivalent to the energy of 500 thousand atomic bombs dropped on Hiroshima and Nagasaki in just one day. In 10 days of the existence of such a cyclone, enough energy is released to satisfy all the energy needs of a country like the United States for 600 years.

In recent years, a large number of works by natural scientists have been published, in one way or another dealing with various aspects of activity and the influence of the atmosphere on earthly processes, which indicates the intensification of interdisciplinary interactions in modern natural science. At the same time, the integrating role of certain of its directions is manifested, among which we should note the functional-ecological direction in geoecology.

This direction stimulates analysis and theoretical generalization on the ecological functions and planetary role of various geospheres, and this, in turn, is an important prerequisite for the development of methodology and scientific foundations for the holistic study of our planet, the rational use and protection of its natural resources.

The Earth's atmosphere consists of several layers: the troposphere, stratosphere, mesosphere, thermosphere, ionosphere and exosphere. At the top of the troposphere and the bottom of the stratosphere there is a layer enriched with ozone, called the ozone shield. Certain (daily, seasonal, annual, etc.) patterns in the distribution of ozone have been established. Since its origin, the atmosphere has influenced the course of planetary processes. The primary composition of the atmosphere was completely different than at the present time, but over time the share and role of molecular nitrogen steadily increased, about 650 million years ago free oxygen appeared, the amount of which continuously increased, but the concentration of carbon dioxide decreased accordingly. The high mobility of the atmosphere, its gas composition and the presence of aerosols determine its outstanding role and active participation in a variety of geological and biosphere processes. The atmosphere plays a great role in the redistribution of solar energy and the development of catastrophic natural phenomena and disasters. Atmospheric vortices - tornadoes (tornadoes), hurricanes, typhoons, cyclones and other phenomena have a negative impact on the organic world and natural systems. The main sources of pollution, along with natural factors, are various forms of human economic activity. Anthropogenic impacts on the atmosphere are expressed not only in the appearance of various aerosols and greenhouse gases, but also in an increase in the amount of water vapor, and manifest themselves in the form of smog and acid rain. Greenhouse gases change the temperature regime of the earth's surface; emissions of some gases reduce the volume of the ozone layer and contribute to the formation of ozone holes. The ethnospheric role of the Earth's atmosphere is great.

The role of the atmosphere in natural processes

The surface atmosphere, in its intermediate state between the lithosphere and outer space and its gas composition, creates conditions for the life of organisms. At the same time, the weathering and intensity of destruction of rocks, the transfer and accumulation of clastic material depend on the amount, nature and frequency of precipitation, on the frequency and strength of winds and especially on air temperature. The atmosphere is a central component of the climate system. Air temperature and humidity, cloudiness and precipitation, wind - all this characterizes the weather, i.e. the continuously changing state of the atmosphere. At the same time, these same components characterize the climate, i.e., the average long-term weather regime.

The composition of gases, the presence of clouds and various impurities, which are called aerosol particles (ash, dust, particles of water vapor), determine the characteristics of the passage of solar radiation through the atmosphere and prevent the escape of the Earth's thermal radiation into outer space.

The Earth's atmosphere is very mobile. The processes that arise in it and changes in its gas composition, thickness, cloudiness, transparency and the presence of certain aerosol particles in it affect both the weather and the climate.

The action and direction of natural processes, as well as life and activity on Earth, are determined by solar radiation. It provides 99.98% of the heat supplied to the earth's surface. Every year this amounts to 134 * 10 19 kcal. This amount of heat can be obtained by burning 200 billion tons of coal. The reserves of hydrogen that create this flow of thermonuclear energy in the mass of the Sun will last for at least another 10 billion years, i.e., for a period twice as long as the existence of our planet and itself.

About 1/3 of the total amount of solar energy arriving at the upper boundary of the atmosphere is reflected back into space, 13% is absorbed by the ozone layer (including almost all ultraviolet radiation). 7% - the rest of the atmosphere and only 44% reaches the earth's surface. The total solar radiation reaching the Earth per day is equal to the energy that humanity received as a result of burning all types of fuel over the last millennium.

The amount and nature of the distribution of solar radiation on the earth's surface are closely dependent on cloudiness and transparency of the atmosphere. The amount of scattered radiation is affected by the height of the Sun above the horizon, the transparency of the atmosphere, the content of water vapor, dust, the total amount of carbon dioxide, etc.

The maximum amount of scattered radiation reaches the polar regions. The lower the Sun is above the horizon, the less heat enters a given area of ​​the terrain.

Atmospheric transparency and cloudiness are of great importance. On a cloudy summer day it is usually colder than on a clear one, since daytime cloudiness prevents the heating of the earth's surface.

The dustiness of the atmosphere plays a major role in the distribution of heat. The finely dispersed solid particles of dust and ash found in it, which affect its transparency, negatively affect the distribution of solar radiation, most of which is reflected. Fine particles enter the atmosphere in two ways: either ash emitted during volcanic eruptions, or desert dust carried by winds from arid tropical and subtropical regions. Especially a lot of such dust is formed during droughts, when currents of warm air carry it into the upper layers of the atmosphere and can remain there for a long time. After the eruption of the Krakatoa volcano in 1883, dust thrown tens of kilometers into the atmosphere remained in the stratosphere for about 3 years. As a result of the 1985 eruption of the El Chichon volcano (Mexico), dust reached Europe, and therefore there was a slight decrease in surface temperatures.

The Earth's atmosphere contains variable amounts of water vapor. In absolute terms by weight or volume, its amount ranges from 2 to 5%.

Water vapor, like carbon dioxide, enhances the greenhouse effect. In the clouds and fogs that arise in the atmosphere, peculiar physical and chemical processes occur.

The primary source of water vapor into the atmosphere is the surface of the World Ocean. A layer of water with a thickness of 95 to 110 cm evaporates from it annually. Part of the moisture returns to the ocean after condensation, and the other is directed by air currents towards the continents. In areas of variable humid climate, precipitation moistens the soil, and in humid climates it creates groundwater reserves. Thus, the atmosphere is an accumulator of humidity and a reservoir of precipitation. and fogs that form in the atmosphere provide moisture to the soil cover and thereby play a decisive role in the development of flora and fauna.

Atmospheric moisture is distributed over the earth's surface due to the mobility of the atmosphere. It is characterized by a very complex system of winds and pressure distribution. Due to the fact that the atmosphere is in continuous motion, the nature and scale of the distribution of wind flows and pressure are constantly changing. The scale of circulation varies from micrometeorological, with a size of only a few hundred meters, to a global scale of several tens of thousands of kilometers. Huge atmospheric vortices participate in the creation of systems of large-scale air currents and determine the general circulation of the atmosphere. In addition, they are sources of catastrophic atmospheric phenomena.

The distribution of weather and climatic conditions and the functioning of living matter depend on atmospheric pressure. If atmospheric pressure fluctuates within small limits, it does not play a decisive role in the well-being of people and the behavior of animals and does not affect the physiological functions of plants. Changes in pressure are usually associated with frontal phenomena and weather changes.

Atmospheric pressure is of fundamental importance for the formation of wind, which, being a relief-forming factor, has a strong impact on the animal and plant world.

Wind can suppress plant growth and at the same time promote seed transfer. The role of wind in shaping weather and climate conditions is great. It also acts as a regulator of sea currents. Wind, as one of the exogenous factors, contributes to the erosion and deflation of weathered material over long distances.

Ecological and geological role of atmospheric processes

A decrease in the transparency of the atmosphere due to the appearance of aerosol particles and solid dust in it affects the distribution of solar radiation, increasing the albedo or reflectivity. Various chemical reactions that cause the decomposition of ozone and the generation of “pearl” clouds consisting of water vapor lead to the same result. Global changes in reflectivity, as well as changes in atmospheric gases, mainly greenhouse gases, are responsible for climate change.

Uneven heating, which causes differences in atmospheric pressure over different parts of the earth's surface, leads to atmospheric circulation, which is the hallmark of the troposphere. When a difference in pressure occurs, air rushes from areas of high pressure to areas of low pressure. These movements of air masses, together with humidity and temperature, determine the main ecological and geological features of atmospheric processes.

Depending on the speed, the wind performs various geological work on the earth's surface. At a speed of 10 m/s, it shakes thick tree branches, lifting and transporting dust and fine sand; breaks tree branches at a speed of 20 m/s, carries sand and gravel; at a speed of 30 m/s (storm) tears off the roofs of houses, uproots trees, breaks poles, moves pebbles and carries small rubble, and a hurricane wind at a speed of 40 m/s destroys houses, breaks and demolishes power line poles, uproots large trees.

Squalls and tornadoes (tornadoes) - atmospheric vortices that arise in the warm season on powerful atmospheric fronts, with speeds of up to 100 m/s, have a great negative environmental impact with catastrophic consequences. Squalls are horizontal whirlwinds with hurricane wind speeds (up to 60-80 m/s). They are often accompanied by heavy downpours and thunderstorms lasting from several minutes to half an hour. Squalls cover areas up to 50 km wide and travel a distance of 200-250 km. A squall storm in Moscow and the Moscow region in 1998 damaged the roofs of many houses and toppled trees.

Tornadoes, called tornadoes in North America, are powerful funnel-shaped atmospheric vortices, often associated with thunderclouds. These are columns of air tapering in the middle with a diameter of several tens to hundreds of meters. A tornado has the appearance of a funnel, very similar to the trunk of an elephant, descending from the clouds or rising from the surface of the earth. Possessing strong rarefaction and a high rotation speed, a tornado travels up to several hundred kilometers, drawing in dust, water from reservoirs and various objects. Powerful tornadoes are accompanied by thunderstorms, rain and have great destructive power.

Tornadoes rarely occur in subpolar or equatorial regions, where it is constantly cold or hot. There are few tornadoes in the open ocean. Tornadoes occur in Europe, Japan, Australia, the USA, and in Russia they are especially frequent in the Central Black Earth region, in the Moscow, Yaroslavl, Nizhny Novgorod and Ivanovo regions.

Tornadoes lift and move cars, houses, carriages, and bridges. Particularly destructive tornadoes are observed in the United States. Every year there are from 450 to 1500 tornadoes with an average death toll of about 100 people. Tornadoes are fast-acting catastrophic atmospheric processes. They are formed in just 20-30 minutes, and their lifetime is 30 minutes. Therefore, it is almost impossible to predict the time and place of tornadoes.

Other destructive but long-lasting atmospheric vortices are cyclones. They are formed due to a pressure difference, which under certain conditions contributes to the emergence of a circular movement of air flows. Atmospheric vortices originate around powerful upward flows of moist warm air and rotate at high speed clockwise in the southern hemisphere and counterclockwise in the northern. Cyclones, unlike tornadoes, originate over oceans and produce their destructive effects over continents. The main destructive factors are strong winds, intense precipitation in the form of snowfall, downpours, hail and surge floods. Winds with speeds of 19 - 30 m/s form a storm, 30 - 35 m/s - a storm, and more than 35 m/s - a hurricane.

Tropical cyclones - hurricanes and typhoons - have an average width of several hundred kilometers. The wind speed inside the cyclone reaches hurricane force. Tropical cyclones last from several days to several weeks, moving at speeds from 50 to 200 km/h. Mid-latitude cyclones have a larger diameter. Their transverse dimensions range from a thousand to several thousand kilometers, and the wind speed is stormy. They move in the northern hemisphere from the west and are accompanied by hail and snowfall, which are catastrophic in nature. In terms of the number of victims and damage caused, cyclones and associated hurricanes and typhoons are the largest natural atmospheric phenomena after floods. In densely populated areas of Asia, the death toll from hurricanes is in the thousands. In 1991, during a hurricane in Bangladesh, which caused the formation of sea waves 6 m high, 125 thousand people died. Typhoons cause great damage to the United States. At the same time, tens and hundreds of people die. In Western Europe, hurricanes cause less damage.

Thunderstorms are considered a catastrophic atmospheric phenomenon. They occur when warm, moist air rises very quickly. On the border of the tropical and subtropical zones, thunderstorms occur 90-100 days a year, in the temperate zone 10-30 days. In our country, the largest number of thunderstorms occur in the North Caucasus.

Thunderstorms usually last less than an hour. Particularly dangerous are intense downpours, hail, lightning strikes, gusts of wind, and vertical air currents. The hail hazard is determined by the size of the hailstones. In the North Caucasus, the mass of hailstones once reached 0.5 kg, and in India, hailstones weighing 7 kg were recorded. The most urban-dangerous areas in our country are located in the North Caucasus. In July 1992, hail damaged 18 aircraft at the Mineralnye Vody airport.

Dangerous atmospheric phenomena include lightning. They kill people, livestock, cause fires, and damage the power grid. About 10,000 people die from thunderstorms and their consequences every year around the world. Moreover, in some areas of Africa, France and the USA, the number of victims from lightning is greater than from other natural phenomena. The annual economic damage from thunderstorms in the United States is at least $700 million.

Droughts are typical for desert, steppe and forest-steppe regions. A lack of precipitation causes drying out of the soil, a decrease in the level of groundwater and in reservoirs until they dry out completely. Moisture deficiency leads to the death of vegetation and crops. Droughts are especially severe in Africa, the Near and Middle East, Central Asia and southern North America.

Droughts change human living conditions and have an adverse effect on the natural environment through processes such as soil salinization, dry winds, dust storms, soil erosion and forest fires. Fires are especially severe during drought in taiga regions, tropical and subtropical forests and savannas.

Droughts are short-term processes that last for one season. When droughts last more than two seasons, there is a threat of famine and mass mortality. Typically, drought affects the territory of one or more countries. Prolonged droughts with tragic consequences occur especially often in the Sahel region of Africa.

Atmospheric phenomena such as snowfalls, short-term heavy rains and prolonged lingering rains cause great damage. Snowfalls cause massive avalanches in the mountains, and rapid melting of fallen snow and prolonged rainfall lead to floods. The huge mass of water falling on the earth's surface, especially in treeless areas, causes severe soil erosion. There is an intensive growth of gully-beam systems. Floods occur as a result of large floods during periods of heavy precipitation or high water after sudden warming or spring melting of snow and, therefore, are atmospheric phenomena in origin (they are discussed in the chapter on the ecological role of the hydrosphere).

Anthropogenic atmospheric changes

Currently, there are many different anthropogenic sources that cause air pollution and lead to serious disturbances in the ecological balance. In terms of scale, two sources have the greatest impact on the atmosphere: transport and industry. On average, transport accounts for about 60% of the total amount of atmospheric pollution, industry - 15, thermal energy - 15, technologies for the destruction of household and industrial waste - 10%.

Transport, depending on the fuel used and the types of oxidizers, emits into the atmosphere nitrogen oxides, sulfur, carbon oxides and dioxides, lead and its compounds, soot, benzopyrene (a substance from the group of polycyclic aromatic hydrocarbons, which is a strong carcinogen that causes skin cancer).

Industry emits sulfur dioxide, carbon oxides and dioxides, hydrocarbons, ammonia, hydrogen sulfide, sulfuric acid, phenol, chlorine, fluorine and other chemical compounds into the atmosphere. But the dominant position among emissions (up to 85%) is occupied by dust.

As a result of pollution, the transparency of the atmosphere changes, causing aerosols, smog and acid rain.

Aerosols are dispersed systems consisting of solid particles or liquid droplets suspended in a gaseous environment. The particle size of the dispersed phase is usually 10 -3 -10 -7 cm. Depending on the composition of the dispersed phase, aerosols are divided into two groups. One includes aerosols consisting of solid particles dispersed in a gaseous medium, the second includes aerosols that are a mixture of gaseous and liquid phases. The former are called smokes, and the latter - fogs. In the process of their formation, condensation centers play an important role. Volcanic ash, cosmic dust, industrial emissions products, various bacteria, etc. act as condensation nuclei. The number of possible sources of concentration nuclei is constantly growing. So, for example, when dry grass is destroyed by fire on an area of ​​4000 m 2, an average of 11 * 10 22 aerosol nuclei are formed.

Aerosols began to form from the moment our planet appeared and influenced natural conditions. However, their quantity and actions, balanced with the general cycle of substances in nature, did not cause profound environmental changes. Anthropogenic factors of their formation have shifted this balance towards significant biosphere overloads. This feature has been especially evident since humanity began to use specially created aerosols both in the form of toxic substances and for plant protection.

The most dangerous to vegetation are aerosols of sulfur dioxide, hydrogen fluoride and nitrogen. When they come into contact with a damp leaf surface, they form acids that have a detrimental effect on living things. Acid mists enter the respiratory organs of animals and humans along with inhaled air and have an aggressive effect on the mucous membranes. Some of them decompose living tissue, and radioactive aerosols cause cancer. Among radioactive isotopes, Sg 90 is particularly dangerous not only for its carcinogenicity, but also as an analogue of calcium, replacing it in the bones of organisms, causing their decomposition.

During nuclear explosions, radioactive aerosol clouds are formed in the atmosphere. Small particles with a radius of 1 - 10 microns fall not only into the upper layers of the troposphere, but also into the stratosphere, where they can remain for a long time. Aerosol clouds are also formed during the operation of reactors in industrial installations that produce nuclear fuel, as well as as a result of accidents at nuclear power plants.

Smog is a mixture of aerosols with liquid and solid dispersed phases, which form a foggy curtain over industrial areas and large cities.

There are three types of smog: icy, wet and dry. Ice smog is called Alaskan smog. This is a combination of gaseous pollutants with the addition of dust particles and ice crystals that occur when droplets of fog and steam from heating systems freeze.

Wet smog, or London-type smog, is sometimes called winter smog. It is a mixture of gaseous pollutants (mainly sulfur dioxide), dust particles and fog droplets. The meteorological prerequisite for the appearance of winter smog is windless weather, in which a layer of warm air is located above the ground layer of cold air (below 700 m). In this case, there is not only horizontal, but also vertical exchange. Pollutants, usually dispersed in high layers, in this case accumulate in the surface layer.

Dry smog occurs during the summer and is often called Los Angeles-type smog. It is a mixture of ozone, carbon monoxide, nitrogen oxides and acid vapors. Such smog is formed as a result of the decomposition of pollutants by solar radiation, especially its ultraviolet part. The meteorological prerequisite is atmospheric inversion, expressed in the appearance of a layer of cold air above warm air. Typically, gases and solid particles lifted by warm air currents are then dispersed into the upper cold layers, but in this case they accumulate in the inversion layer. In the process of photolysis, nitrogen dioxides formed during the combustion of fuel in car engines decompose:

NO 2 → NO + O

Then ozone synthesis occurs:

O + O 2 + M → O 3 + M

NO + O → NO 2

Photodissociation processes are accompanied by a yellow-green glow.

In addition, reactions of the type occur: SO 3 + H 2 0 -> H 2 SO 4, i.e. strong sulfuric acid is formed.

With a change in meteorological conditions (the appearance of wind or a change in humidity), the cold air dissipates and the smog disappears.

The presence of carcinogenic substances in smog leads to breathing problems, irritation of mucous membranes, circulatory disorders, asthmatic suffocation and often death. Smog is especially dangerous for young children.

Acid rain is atmospheric precipitation acidified by industrial emissions of sulfur oxides, nitrogen and vapors of perchloric acid and chlorine dissolved in them. In the process of burning coal and gas, most of the sulfur contained in it, both in the form of oxide and in compounds with iron, in particular in pyrite, pyrrhotite, chalcopyrite, etc., is converted into sulfur oxide, which, together with carbon dioxide, is emitted into atmosphere. When atmospheric nitrogen and technical emissions combine with oxygen, various nitrogen oxides are formed, and the volume of nitrogen oxides formed depends on the combustion temperature. The bulk of nitrogen oxides occurs during the operation of vehicles and diesel locomotives, and a smaller portion occurs in the energy sector and industrial enterprises. Sulfur and nitrogen oxides are the main acid formers. When reacting with atmospheric oxygen and water vapor contained in it, sulfuric and nitric acids are formed.

It is known that the alkaline-acid balance of the environment is determined by the pH value. A neutral environment has a pH value of 7, an acidic environment has a pH value of 0, and an alkaline environment has a pH value of 14. In the modern era, the pH value of rainwater is 5.6, although in the recent past it was neutral. A decrease in pH value by one corresponds to a tenfold increase in acidity and, therefore, at present, rain with increased acidity falls almost everywhere. The maximum acidity of rain recorded in Western Europe was 4-3.5 pH. It should be taken into account that a pH value of 4-4.5 is lethal for most fish.

Acid rain has an aggressive effect on the Earth's vegetation, on industrial and residential buildings and contributes to a significant acceleration of the weathering of exposed rocks. Increased acidity prevents the self-regulation of neutralization of soils in which nutrients dissolve. In turn, this leads to a sharp decrease in yield and causes degradation of the vegetation cover. Soil acidity promotes the release of bound heavy soils, which are gradually absorbed by plants, causing serious tissue damage and penetrating the human food chain.

A change in the alkaline-acid potential of sea waters, especially in shallow waters, leads to the cessation of reproduction of many invertebrates, causes the death of fish and disrupts the ecological balance in the oceans.

As a result of acid rain, forests in Western Europe, the Baltic States, Karelia, the Urals, Siberia and Canada are at risk of destruction.

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

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

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

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

The structure of the Earth's atmosphere

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

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

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

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

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

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

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

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

Troposphere

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

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

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

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

Stratosphere

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

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

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

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

Mesosphere

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

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

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

Thermosphere

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

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

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

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

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

Exosphere

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

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

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

The importance of the atmosphere in the life of the Earth

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

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

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

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

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