The earth's atmosphere escapes into space. Atmosphere

ATMOSPHERE

ATMOSPHERE, a shell of gases that surrounds the earth. It protects the planet from the harsh conditions of space, and the gases that make it up are necessary for the existence of life. Approximately 95% by weight of the entire atmosphere is located up to a height of 25 km; the mixture of gases in the lower atmosphere is commonly referred to as air. The composition of the atmosphere as a percentage by weight is as follows: 78.09% nitrogen, 20.9% oxygen, 0.93% argon, 0.03% carbon dioxide, 0.05% hydrogen, other gases and various amounts of water vapor. The atmosphere can be thought of as concentric shells. The inner one is called the TROPOSPHERE, it contains dust and water vapor, and weather conditions are created. The STRATOSPHERE extends to a height of 10 to 55 km; it is clearer, colder, and contains ozone. Above, up to a height of 70 km, lies the MESOSPHERE, in which, under the influence of sunlight, chemical reactions. In the THERMOSPHERE, the temperature gradually rises. Further, at a height of up to 400 km, the exosphere is located, where helium and hydrogen are released into space. The IONOSPHERE extends up to 50 km up to the VAN ALLEN RADIATION BELTS.

Atmosphere A study of the evolution of the Earth's atmosphere shows that oxygen levels began to rise 2,000 million years ago. years ago, oh which is evidenced by the formation of extensive "red-colored" deposits - sands colored by oxidized iron. About 4,500 million years ago, the absorption of carbon dioxide (carbon dioxide) by sedimentary rocks began. Huge deposits of carbon in the form of limestone, coal and oil indicate that at one time the concentration of carbon dioxide was much higher than now, when it is only 0.04%. The first deposits of carbonates appeared 1,700 million years ago, and sulfate deposits - 1,000 million years ago. The decrease in the proportion of carbon dioxide was balanced by an increase in the content of nitrogen in the air. Forms of "respiration" progressed from fermentation 4,000 million years ago to anaerobic photosynthesis (3,000 million years > shad) and to aerobic foyusynthesis (500 million years ago). The modern atmosphere has some curious properties. In the thermosphere, which extends to a height of 80 to 400 km (1), aurorae are formed, clouds glowing at night (2) appear only at the mesopause at the boundary between the thermosphere and the non-zosphere. mesosphere Cosmic rays (1) penetrate the bcipaio sphere. Most of human activity occurs in the troposphere (5), where the weather is created, which directly affects us

Scientific and technical encyclopedic dictionary.

Synonyms:

See what "ATMOSPHERE" is in other dictionaries:

Atmosphere … Spelling Dictionary

atmosphere- uh. atmosphere f., n. lat. atmosphaera gr. 1. physical, meteor. Air shell of the earth, air. Sl. 18. In the atmosphere, or in the air that surrounds us .. and which we breathe. Karamzin 11 111. Scattering of light by the atmosphere. Astr. Lalanda 415.… … Historical dictionary gallicisms of the Russian language

Earth (from the Greek atmos steam and sphaira ball), the gaseous shell of the Earth, connected with it by gravity and taking part in its daily and annual rotation. Atmosphere. Scheme of the structure of the Earth's atmosphere (according to Ryabchikov). Weight A. approx. 5.15 10 8 kg.… … Ecological dictionary

- (Greek atmosphaira, from atmos pairs, and sphaira ball, sphere). 1) A gaseous shell that surrounds the earth or another planet. 2) the mental environment in which one moves. 3) a unit that measures the pressure experienced or produced ... ... Dictionary foreign words Russian language

Air. See circle... Dictionary of Russian synonyms and similar expressions. under. ed. N. Abramova, M .: Russian dictionaries, 1999. atmosphere, air, circle, environment, climate, environment, conditions, microclimate, fifth ocean, background Russian Dictionary ... Synonym dictionary

- (the atmosphere is wrong), atmosphere, women. (from the Greek atmos breath and sphaira ball). 1. only units The air envelope that surrounds the earth (est.). || The gaseous shell surrounding some planets (astro). Atmosphere of Mars. 2. only units Air (colloquial) ... Dictionary Ushakov

Off-system unit of pressure. The normal, or physical, atmosphere (denoted atm.) Is equal to 101,325 Pa 1013.25 hPa 760 mm Hg 10 332 mm water column 1.0332 atm; technical atmosphere (at) is equal to 1 kgf / cm & sup2 735.56 mm of mercury ... ... Big encyclopedic Dictionary

- (inosk.) environment, sphere, wind (own air that surrounds us, which we breathe). Wed Olga Fyodorovna was a good barometer for determining the atmosphere at home: she predicted a thunderstorm as thoroughly as possible ... Lѣkov. Seedy kind… Michelson's Big Explanatory Phraseological Dictionary (original spelling)

The gaseous envelope of the Earth, consisting, excluding water and dust (by volume), of nitrogen (78.08%), oxygen (20.95%), argon (0.93%), carbon dioxide (about 0.09%) and hydrogen , neon, helium, krypton, xenon and a number of other gases (about 0.01% in total). Dry composition... Geological Encyclopedia

Female surrounding the globe of the earth or otherwise heavenly body air, with all its natural impurities: fumes, clouds, etc. The earthly world does not rise from the earth even a hundred versts. From the density of the summer kolozemnitsa haze in ... ... Dahl's Explanatory Dictionary

Books

• Atmosphere. Common Meteorology, Camille Flammarion. P. V. Lukovnikov's bookstore, St. Petersburg, 1900. Owner's binding. The safety is good. The cover has some wear and tear, and some of the spine is missing. This edition…

The atmosphere is one of the most important components of our planet. It is she who "shelters" people from the harsh conditions of outer space, such as solar radiation and space debris.

However, many facts about the atmosphere are unknown to most people.

1. The true color of the sky

Although it's hard to believe, the sky is actually purple. When light enters the atmosphere, air and water particles absorb the light, scattering it. At the same time, the most scattered purple That's why people see blue skies.

2. An exclusive element in the Earth's atmosphere

As many remember from school, the Earth's atmosphere consists of approximately 78% nitrogen, 21% oxygen, and small impurities of argon, carbon dioxide and other gases. But few people know that our atmosphere is the only one on this moment discovered by scientists (in addition to comet 67P), which has free oxygen. Because oxygen is a highly reactive gas, it often reacts with other chemicals in space. Its pure form on Earth makes the planet habitable.

3. White stripe in the sky

Surely, some sometimes wondered why a white stripe remains in the sky behind a jet plane. These white trails, known as contrails, form when hot, moist exhaust gases from an aircraft engine mix with colder outside air. Water vapor from exhaust gases freezes and becomes visible.

4. The main layers of the atmosphere

Earth's atmosphere is made up of five main layers that make possible life on the planet. The first of these, the troposphere, extends from sea level to an altitude of about 17 km to the equator. Most of weather phenomena happens in it.

5. Ozone layer

The next layer of the atmosphere, the stratosphere, reaches a height of about 50 km at the equator. It contains the ozone layer, which protects people from dangerous ultraviolet rays. Even though this layer is above the troposphere, it may actually be warmer due to the energy it absorbs from the sun's rays. Most jet planes and weather balloons fly in the stratosphere. Planes can fly faster in it because they are less affected by gravity and friction. Weather balloons can get a better idea of ​​storms, most of which occur lower in the troposphere.

6. Mesosphere

The mesosphere is the middle layer, extending to a height of 85 km above the surface of the planet. Its temperature fluctuates around -120°C. Most of the meteors that enter the Earth's atmosphere burn up in the mesosphere. The last two layers that pass into space are the thermosphere and the exosphere.

7. The disappearance of the atmosphere

The Earth has most likely lost its atmosphere several times. When the planet was covered in oceans of magma, massive interstellar objects crashed into it. These impacts, which also formed the Moon, may have formed the planet's atmosphere for the first time.

8. If there were no atmospheric gases...

Without various gases in the atmosphere, the Earth would be too cold for human existence. Water vapor, carbon dioxide, and other atmospheric gases absorb heat from the sun and "distribute" it over the planet's surface, helping to create a habitable climate.

9. Formation of the ozone layer

The notorious (and importantly necessary) ozone layer was created when oxygen atoms reacted with ultraviolet light from the sun to form ozone. It is ozone that absorbs most of the harmful radiation from the sun. Despite its importance, the ozone layer was formed relatively recently after enough life arose in the oceans to release into the atmosphere the amount of oxygen needed to create a minimum concentration of ozone.

10. Ionosphere

The ionosphere is so named because high-energy particles from space and from the sun help form ions, creating an "electric layer" around the planet. When there were no satellites, this layer helped reflect radio waves.

11. Acid rain

Acid rain that destroys entire forests and devastates aquatic ecosystems, is formed in the atmosphere when sulfur dioxide or nitrogen oxide particles mix with water vapor and fall to the ground as rain. These chemical compounds are also found in nature: sulfur dioxide is produced during volcanic eruptions, and nitric oxide - during lightning strikes.

12. Lightning Power

Lightning is so powerful that just a single discharge can heat the surrounding air up to 30,000 °C. The rapid heating causes an explosive expansion of the nearby air, which is heard in the form of a sound wave called thunder.

Aurora Borealis and Aurora Australis (Northern and Southern Aurora) are caused by ion reactions taking place in the fourth level of the atmosphere, the thermosphere. When highly charged particles solar wind collide with air molecules over the planet's magnetic poles, they glow and create magnificent light shows.

14. Sunsets

In 2013, scientists discovered that tiny microbes can survive many kilometers above the Earth's surface. At an altitude of 8-15 km above the planet, microbes were found that destroy organic chemicals that float in the atmosphere, "feeding" on them.

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

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

What does it consist of?

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

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

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

Low but important gases

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

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

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

What else is in the air?

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

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

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

What are the layers of the atmosphere?

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

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

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

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

Layers with little to no air

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

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

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

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

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

The value of the atmosphere

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

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

How does a person affect the atmosphere?

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

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

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

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 connected with the geological and geochemical processes taking place on our planet, as well as with 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 limit at an altitude of 2000-3000 km gradually passes into outer space.

Oxygen-rich atmosphere makes life possible on Earth. Atmospheric oxygen is used in the process of breathing by 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, as if through a lens, are decomposed into their component colors. In this case, the rays of blue and blue colors are scattered most of all.

The atmosphere retains most of the ultraviolet radiation from the Sun, which has a detrimental effect on living organisms. It also keeps heat at the surface of the Earth, preventing our planet from cooling.

The structure of the atmosphere

Several layers can be distinguished in the atmosphere, differing in density and density (Fig. 1).

Troposphere

Troposphere- the lowest layer of the atmosphere, whose thickness 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 from the earth's surface, i.e. from 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 °С, and in the region of the North Pole -65 °С.

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

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

Stratosphere

Stratosphere- the 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 rarefaction of the air, due to which the sun's rays almost do not scatter.

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 clouds and precipitation are almost not formed. 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 passing to the Earth and thereby protecting living organisms on our planet. Due to ozone, the air temperature at the upper boundary of the stratosphere is in the range from -50 to 4-55 °C.

Between the mesosphere and the stratosphere there is a transitional 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 surface of the Earth. The color of the sky in the mesosphere appears black, 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 a height of 150 km it reaches 220-240 °C; at an altitude of 500-600 km it exceeds 1500 °C.

In the mesosphere and thermosphere, under the action of cosmic rays, gas molecules break up 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, nitric oxide molecules and free electrons. This layer is characterized by high electrification, and long and medium radio waves are reflected from it, as from a mirror.

In the ionosphere, auroras arise - 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.

Composition of the atmosphere

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). Modern composition The air of the Earth 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 the content of CO 2 by about 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 thus have a significant effect on the temperature regime of the Earth's surface and atmosphere.

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

	Volume concentration. %	Molecular weight, units
Oxygen
Carbon dioxide
Nitrous oxide
	0 to 0.00001
Sulfur dioxide	from 0 to 0.000007 in summer; 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, chemically little active.

Oxygen, unlike nitrogen, is a chemically very active element. The specific function of oxygen is oxidation organic matter heterotrophic organisms, rocks and underoxidized 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 exceptionally great. It enters the atmosphere as a result of the processes of combustion, respiration of living organisms, decay and is, first of all, the main building material for the creation of organic matter during photosynthesis. In addition, the property 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.

The influence on atmospheric processes, especially on the thermal regime of the stratosphere, is also exerted by ozone. This gas serves as a natural absorber of solar ultraviolet radiation, and the absorption of solar radiation leads to air heating. The average monthly values ​​of the total ozone content in the atmosphere vary depending on the latitude of the area and the season within 0.23-0.52 cm (this is the thickness of the ozone layer at ground pressure and temperature). There is an increase in the ozone content from the equator to the poles and an annual variation with a minimum in autumn and a maximum in spring.

A characteristic property of the atmosphere can be called the fact that the content of the main gases (nitrogen, oxygen, argon) changes slightly with height: at an altitude of 65 km in the atmosphere, the nitrogen content 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, air contains water vapor And solid particles. The latter can have both natural and artificial (anthropogenic) origin. These are flower pollen, tiny salt crystals, road dust, aerosol impurities. When the sun's rays penetrate the window, they can be seen with the naked eye.

There are especially many particulate matter 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 the 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 value of water vapor is determined primarily by the fact that it delays the long-wave thermal radiation of the earth's surface; represents the main link of large and small moisture cycles; raises the temperature of the air when the water beds condense.

The amount of water vapor in the atmosphere varies over time and space. Thus, the concentration of water vapor near 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 (the layer of condensed water vapor will have such a thickness). Information about 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, the specific humidity strongly increases with height. However, subsequent measurements indicate a greater dryness of the stratosphere. Apparently, the specific humidity in the stratosphere depends little on height and amounts to 2–4 mg/kg.

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

The processes of phase transitions of water proceed mainly in the troposphere, which is why clouds in the stratosphere (at altitudes of 20-30 km) and mesosphere (near the mesopause), called mother-of-pearl and silver, are observed relatively rarely, while tropospheric clouds often cover about 50% of the entire earth surfaces.

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

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 °С - no more than 9 g; at +30 °С - no more than 30 g of water.

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

Air can be rich And not saturated steam. 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- this is the amount of water vapor contained in 1 m 3 of air. It is expressed in grams. For example, if they say "absolute humidity is 15", then this means that 1 mL contains 15 g of water vapor.

Relative humidity- this is the ratio (in percent) 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 a weather report is broadcast over the radio that the relative humidity is 70%, this means that the air contains 70% of the water vapor that it can hold at a given temperature.

The greater the relative humidity of the air, t. the closer the air is to saturation, the more likely it is to fall.

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

The relative humidity of the air is especially low in deserts: 1 m 1 of air there contains two to three times less than the amount of water vapor 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 in itself, it thickens (condenses), turning into droplets of fog. Fog can be observed in the 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 the clouds.

involved in the formation of clouds particulate matter suspended in the troposphere.

Clouds may have different shape, which depends 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 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. Pinnate	Threadlike, fibrous, white
	II. cirrocumulus	Layers and ridges of small flakes and curls, white
	III. Cirrostratus	Transparent whitish veil
B. Clouds of the middle layer - above 2 km	IV. Altocumulus	Layers and ridges of white and gray
	V. Altostratified	Smooth veil of milky gray color
B. Lower clouds - up to 2 km	VI. Nimbostratus	Solid shapeless gray layer
	VII. Stratocumulus	Opaque layers and ridges of gray
	VIII. layered	Illuminated gray veil
D. Clouds of vertical development - from the lower to the upper tier	IX. Cumulus	Clubs and domes 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 automobiles. In large cities, the problem of gas contamination of the main transport routes is very acute. That is why in many major cities around the world, including in our country, introduced environmental control of the toxicity of car exhaust gases. According to experts, smoke and dust in the air can halve the flow of solar energy to the earth's surface, which will lead to a change in natural conditions.

The gaseous envelope that surrounds our planet Earth, known as the atmosphere, consists of five main layers. These layers originate on the surface of the planet, from sea level (sometimes below) and rise to outer space in the following sequence:

• Troposphere;
• Stratosphere;
• Mesosphere;
• Thermosphere;
• Exosphere.

Diagram of the main layers of the Earth's atmosphere

In between each of these main five layers are transitional zones called "pauses" where changes in air temperature, composition and density occur. Together with pauses, the Earth's atmosphere includes a total of 9 layers.

Troposphere: where the weather happens

Of all the layers of the atmosphere, the troposphere is the one with which we are most familiar (whether you realize it or not), since we live at its bottom - the surface of the planet. It envelops the surface of the Earth and extends upwards for several kilometers. The word troposphere means "change of the ball". A very fitting name, as this layer is where our day to day weather happens.

Starting from the surface of the planet, the troposphere rises to a height of 6 to 20 km. The lower third of the layer closest to us contains 50% of all atmospheric gases. This the only part the entire composition of the atmosphere that breathes. Due to the fact that the air is heated from below by the earth's surface, which absorbs the thermal energy of the Sun, the temperature and pressure of the troposphere decrease with increasing altitude.

At the top is a thin layer called the tropopause, which is just a buffer between the troposphere and stratosphere.

Stratosphere: home of ozone

The stratosphere is the next layer of the atmosphere. It extends from 6-20 km to 50 km above the earth's surface. This is the layer in which most commercial airliners fly and balloons travel.

Here, the air does not flow up and down, but moves parallel to the surface in very fast air currents. Temperatures increase as you ascend, thanks to an abundance of naturally occurring ozone (O3), a by-product of solar radiation, and oxygen, which has the ability to absorb the sun's harmful ultraviolet rays (any rise in temperature with altitude is known in meteorology as an "inversion") .

Because the stratosphere has warmer temperatures at the bottom and cooler temperatures at the top, convection (vertical movements of air masses) is rare in this part of the atmosphere. In fact, you can view a storm raging in the troposphere from the stratosphere, because the layer acts as a "cap" for convection, through which storm clouds do not penetrate.

The stratosphere is again followed by a buffer layer, this time called the stratopause.

Mesosphere: middle atmosphere

The mesosphere is located approximately 50-80 km from the Earth's surface. The upper mesosphere is the coldest natural place on Earth, where temperatures can drop below -143°C.

Thermosphere: upper atmosphere

The mesosphere and mesopause are followed by the thermosphere, located between 80 and 700 km above the surface of the planet, and containing less than 0.01% of the total air in the atmospheric shell. Temperatures here reach up to +2000° C, but due to the strong rarefaction of the air and the lack of gas molecules to transfer heat, these high temperatures are perceived as very cold.

Exosphere: the boundary of the atmosphere and space

At an altitude of about 700-10,000 km above the earth's surface is the exosphere - the outer edge of the atmosphere, bordering space. Here meteorological satellites revolve around the Earth.

How about the ionosphere?

The ionosphere is not a separate layer, and in fact this term is used to refer to the atmosphere at an altitude of 60 to 1000 km. It includes the uppermost parts of the mesosphere, the entire thermosphere and part of the exosphere. The ionosphere gets its name because in this part of the atmosphere, the Sun's radiation is ionized when it passes the Earth's magnetic fields at and . This phenomenon is observed from the earth as the northern lights.