Upper layers of the atmosphere and their characteristics. Atmosphere. Structure and composition of the Earth's 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 atmospheric air and about 90% of all water vapor available in the atmosphere. Turbulence and convection are highly developed in the troposphere, clouds arise, and cyclones and anticyclones develop. Temperature decreases with increasing altitude with an average vertical gradient of 0.65°/100 m

Tropopause

The transition layer from the troposphere to the stratosphere, a layer of the atmosphere in which the decrease in temperature with height stops.

Stratosphere

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

The 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 atmospheric luminescence.

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. The Karman line is located at an altitude of 100 km above sea level.

Boundary of the Earth's atmosphere

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, ionization of the air (“auroras”) occurs - the main regions of the ionosphere lie inside the thermosphere. At altitudes above 300 km, atomic oxygen predominates. The upper limit of the thermosphere is largely determined by the current activity of the Sun. During periods of low activity, a noticeable decrease in the size of this layer occurs.

Thermopause

The region of the atmosphere adjacent to the thermosphere. In this region, the absorption of solar radiation is negligible and the temperature does not actually change with altitude.

Exosphere (scattering sphere)

Atmospheric layers up to an altitude of 120 km

The exosphere is a 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 ~150 °C. Above 200 km, significant fluctuations in temperature and gas density in time and space are observed.

At an altitude of about 2000-3500 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, homosphere and heterosphere are distinguished. The heterosphere is an area where gravity affects the separation of gases, since their mixing at such a height is negligible. This implies a variable composition of the heterosphere. Below it lies a well-mixed, homogeneous part of the atmosphere called the homosphere. The boundary between these layers is called the turbopause; it lies at an altitude of about 120 km.

In the atmosphere - (5.1-5.3)⋅10 18 kg. Of these, the mass of dry air is (5.1352 ± 0.0003)⋅10 18 kg, the total mass of water vapor is on average 1.27⋅10 16 kg.

In addition to the gases indicated in the table, the atmosphere contains N 2 O (\displaystyle ((\ce (N2O)))) and other nitrogen oxides ( NO 2 (\displaystyle (\ce (NO2))), ), propane and other hydrocarbons, O 3 (\displaystyle ((\ce (O3)))) , Cl 2 (\displaystyle (\ce (Cl2))) , SO 2 (\displaystyle (\ce (SO2))) , NH 3 (\displaystyle (\ce (NH3))) , , HCl (\displaystyle (\ce (HCl))) , HF (\displaystyle (\ce (HF))) , HBr (\displaystyle (\ce (HBr))) , HI (\displaystyle ((\ce (HI)))), couples Hg (\displaystyle (\ce (Hg))) , I 2 (\displaystyle (\ce (I2))) , Br 2 (\displaystyle (\ce (Br2))), as well as many other gases in small quantities. The troposphere constantly contains a large amount of suspended solid and liquid particles (aerosol). The rarest gas in the Earth's atmosphere is Rn (\displaystyle (\ce (Rn))) .

The structure of the atmosphere

Atmospheric boundary layer

The lower layer of the troposphere (1-2 km thick), in which the state and properties of the Earth's surface directly affect the dynamics 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 the total water vapor present in the atmosphere. Turbulence and convection are highly developed in the troposphere, clouds appear, and cyclones and anticyclones develop. Temperature decreases with increasing altitude with an average vertical gradient of 0.65°/100 meters.

Tropopause

The transition layer from the troposphere to the stratosphere, a layer of the atmosphere in which the decrease in temperature with height stops.

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 minus 56.5 to +0.8 ° C (upper layer of the stratosphere or inversion region). 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 the stratopause and is the boundary between the stratosphere and mesosphere. In the middle of the 19th century, it was believed that at an altitude of 12 km (6 thousand toises) the Earth’s atmosphere ends (Five weeks in a balloon, 13 chapters). The stratosphere contains the ozone layer, which protects the Earth from ultraviolet radiation.

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

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 solar radiation and cosmic radiation, ionization of the air (“ auroras”) occurs - the main regions of the ionosphere lie inside the thermosphere. At altitudes above 300 km, atomic oxygen predominates. The upper limit of the thermosphere is largely determined by the current activity of the Sun. During periods of low activity - for example, in 2008-2009 - there is a noticeable decrease in the size of this layer.

Thermopause

The region of the atmosphere adjacent above the thermosphere. In this region, the absorption of solar radiation is negligible and the temperature practically does not change with altitude.

Exosphere (scattering sphere)

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 minus 110 °C in the mesosphere. However, the kinetic energy of individual particles at altitudes of 200-250 km corresponds to a temperature of ~ 150 °C. Above 200 km, significant fluctuations in temperature and gas density in time and space are observed.

At an altitude of about 2000-3500 km, the exosphere gradually turns into the so-called near space vacuum, which is filled with rare 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.

Analysis of data from the SWAN instrument on the SOHO spacecraft showed that the outermost part of the Earth's exosphere (geocorona) extends about 100 Earth radii or about 640 thousand km, that is, much further than the orbit of the Moon.

Review

Based on electrical properties in the atmosphere, they distinguish neutrosphere And ionosphere.

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 the homosphere. The boundary between these layers is called the turbopause, it lies at an altitude of about 120 km.

Other properties of the atmosphere and effects on the human body

Already at an altitude of 5 km above sea level, an untrained person begins to experience 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 9 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.

History of atmospheric formation

According to the most common theory, the Earth's atmosphere has had three different compositions throughout its history. Initially, it consisted of light gases (hydrogen and helium) captured from interplanetary space. This is the so-called primary atmosphere. 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. 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 chemical reactions from ammonia and hydrocarbons).

Nitrogen

The formation of a large amount of nitrogen is due to the oxidation of the ammonia-hydrogen atmosphere by molecular oxygen O 2 (\displaystyle (\ce (O2))), which began to come from the surface of the planet as a result of photosynthesis, starting 3 billion years ago. Also nitrogen N 2 (\displaystyle (\ce (N2))) released into the atmosphere as a result of denitrification of nitrates and other nitrogen-containing compounds. Nitrogen is oxidized by ozone to NO (\displaystyle ((\ce (NO)))) V upper layers atmosphere.

Nitrogen N 2 (\displaystyle (\ce (N2))) reacts only under specific conditions (for example, during a lightning discharge). Oxidation of molecular nitrogen with ozone during electrical discharges in small quantities is used in industrial production nitrogen fertilizers. Cyanobacteria (blue-green algae) and nodule bacteria, which form rhizobial symbiosis with leguminous plants, which can be effective green manures - plants that do not deplete, but enrich the soil with natural fertilizers, can oxidize it with low energy consumption and convert it into a biologically active form.

Oxygen

The composition of the atmosphere began to change radically with the appearance of living organisms on Earth, as a result of photosynthesis, accompanied by the release of oxygen and the absorption of carbon dioxide. Initially, oxygen was spent on the oxidation of reduced compounds - ammonia, hydrocarbons, ferrous form of iron contained in the oceans and others. 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 the atmosphere, lithosphere and biosphere, this event was called the Oxygen Catastrophe.

Noble gases

Sources of noble gases are volcanic eruptions and the decay of radioactive elements. The Earth in general, and the atmosphere in particular, are depleted in inert gases compared to space and some other planets. This applies to helium, neon, krypton, xenon and radon. The concentration of argon, on the contrary, is abnormally high and amounts to almost 1% of the gas composition of the atmosphere. A large amount of this gas is due to the intense decay of the radioactive isotope potassium-40 in the bowels of the Earth.

Air pollution

Recently, humans have begun to influence the evolution of the atmosphere. The result of human activity has been a constant increase in the content of carbon dioxide in the atmosphere due to the combustion of hydrocarbon fuels accumulated in previous geological eras. Enormous quantities are consumed during photosynthesis and are 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 last 100 years content CO 2 (\displaystyle (\ce (CO2))) in the atmosphere 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 200-300 years the amount CO 2 (\displaystyle (\ce (CO2))) in the atmosphere will double and may lead to global climate change.

Fuel combustion is the main source of polluting gases ( CO (\displaystyle ((\ce (CO)))) ,

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 due to the fact that Sun rays, passing through the atmosphere, as if through a lens, they are decomposed into 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.

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

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 current composition of the Earth’s air was established more than a hundred million years ago, but the sharply increased production activity man nevertheless led to his 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 temperature regime Earth's surface and atmosphere.

Table 1. Chemical composition 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, decay and is, first of all, the main construction material to create 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.

Influence at atmospheric processes, especially on the thermal regime of the stratosphere, also has 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 value of water vapor is determined primarily by the fact that it delays long-wavelength thermal radiation 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 fall precipitation 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 it stays there throughout the year heat air 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 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. 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
B. Mid-level clouds - above 2 km	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 source is 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 by half solar energy to the earth's surface, which will lead to changes in natural conditions.

> Earth's atmosphere

Description Earth's atmosphere for children of all ages: what air is made of, the presence of gases, layers with photos, climate and weather of the third planet of the solar system.

For the little ones It is already known that the Earth is the only planet in our system that has a viable atmosphere. The gas blanket is not only rich in air, but also protects us from excessive heat and solar radiation. Important explain to the children that the system is designed incredibly well, because it allows the surface to warm up during the day and cool down at night, maintaining an acceptable balance.

Begin explanation for children It is possible from the fact that the globe of the earth's atmosphere extends over 480 km, but most of it is located 16 km from the surface. The higher the altitude, the lower the pressure. If we take sea level, then the pressure there is 1 kg per square centimeter. But at an altitude of 3 km, it will change - 0.7 kg per square centimeter. Of course, in such conditions it is more difficult to breathe ( children you could feel this if you ever went hiking in the mountains).

Composition of the Earth's air - explanation for children

Among the gases there are:

Nitrogen – 78%.
Oxygen – 21%.
Argon – 0.93%.
Carbon dioxide – 0.038%.
IN small quantities there is also water vapor and other gas impurities.

Atmospheric layers of the Earth - explanation for children

Parents or teachers At school We should remind you that the earth's atmosphere is divided into 5 levels: exosphere, thermosphere, mesosphere, stratosphere and troposphere. With each layer, the atmosphere dissolves more and more until the gases finally disperse into space.

The troposphere is closest to the surface. With a thickness of 7-20 km, it makes up half of the earth's atmosphere. The closer to Earth, the more the air warms up. Almost all water vapor and dust are collected here. Children may not be surprised that clouds float at this level.

The stratosphere starts from the troposphere and rises 50 km above the surface. There is a lot of ozone here, which heats the atmosphere and protects from harmful solar radiation. The air is 1000 times thinner than above sea level and unusually dry. That is why airplanes feel great here.

Mesosphere: 50 km to 85 km above the surface. The peak is called the mesopause and is the coolest place in the earth's atmosphere (-90°C). It is very difficult to explore because jet planes cannot get there, and the orbital altitude of the satellites is too high. Scientists only know that this is where meteors burn up.

Thermosphere: 90 km and between 500-1000 km. The temperature reaches 1500°C. It is considered part of the earth's atmosphere, but it is important explain to the children that the air density here is so low that most of it is already perceived as outer space. In fact, this is where the space shuttles and the International Space Station are located. In addition, auroras are formed here. Charged cosmic particles come into contact with atoms and molecules of the thermosphere, transferring them to a higher energy level. Thanks to this, we see these photons of light in the form of the aurora.

The exosphere is the highest layer. An incredibly thin line of merging the atmosphere with space. Consists of widely scattered hydrogen and helium particles.

Earth's climate and weather - explanation for children

For the little ones need to explain that the Earth manages to support many living species thanks to a regional climate that is represented by extreme cold at the poles and tropical warmth at the equator. Children should know that regional climate is the weather that in a particular area remains unchanged for 30 years. Of course, sometimes it can change for a few hours, but for the most part it remains stable.

In addition, the global earth climate is distinguished - the average of the regional one. It has changed throughout human history. Today there is rapid warming. Scientists are sounding the alarm as greenhouse gases caused by human activity are trapping heat in the atmosphere, risking turning our planet into Venus.

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

In the ionosphere there are polar lights, powerful electric currents, which cause disturbances in the Earth's magnetic field.

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

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

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

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

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