The solid air envelope of the earth is called. The main spheres of planet Earth: lithosphere, hydrosphere, biosphere and atmosphere

The air shell of our planet - the atmosphere - protects living organisms on the earth's surface from the damaging effects of ultraviolet radiation from the Sun and other hard cosmic radiation. It protects the Earth from meteorites and cosmic dust. The atmosphere also serves as a "clothing" that does not allow the loss of heat radiated by the Earth into space. Atmospheric air is a source of respiration for humans, animals and vegetation, a raw material for combustion and decomposition processes, and for the synthesis of chemicals. It is a material used for cooling various industrial and transport installations, as well as an environment into which human waste, higher and lower animals and plants, production and consumption waste are thrown.

The interaction of atmospheric air with water and soil entails certain changes in the biosphere as a whole and in its individual components, intensifying and accelerating undesirable changes in the composition and structure of atmospheric air and the Earth's climate.

It is known that a person can live without food for about 5 weeks, without water for about 5 days, and without air he will not live even 5 minutes. A person's need for clean air (“clean” is understood as air suitable for breathing and without negative consequences for the human body) ranges from 5 to 10 l / min or 12-15 kg / day. It is clear from this how important the atmosphere is in solving environmental problems.

Exosphere

Thermosphere

auroras in the lower ionosphere

Mesopause

Noctilucent clouds

Stratosphere

Tropopause ^

• 1,9-10 8
• 3.8-10 ^ 1.4-10 7 2.2-10 "7 3-S" 7
• 1- 10- 6
• 2- 10 ^ 7-10 *
• 4 10 5 0,0004

Sea level

120 -90 -60 -30 0 30 60 90 120 150 180 210 240 270 300 330 360 390 1 °

Temperature, ° С

Figure: 21. Vertical section of the atmosphere

Humanity lives at the bottom of the Great Air Ocean, which is a shell continuously, completely surrounding the globe. The most studied part of the atmosphere extends from sea level to an altitude of 100 km. In general, the atmosphere is divided into several spheres: troposphere, stratosphere, mesosphere, ionosphere (thermosphere), exosphere. The boundaries between the spheres are called pauses (Fig. 21). In terms of chemical composition, the Earth's atmosphere is subdivided into the lower (up to 100 km) - homosphere, which has a composition similar to surface air, and the upper - heterosphere, heterogeneous chemical composition... In addition to gases, the atmosphere contains various aerosols - dusty or water particles suspended in a gaseous medium. They have both natural and technogenic origin.

The troposphere is surface bottom part atmosphere, that is, the zone where most living organisms live, including humans. More than 80% of the mass of the entire atmosphere is concentrated in this area. Its power (height on the earth's surface) is determined by the intensity of the vertical (ascending and descending) air flows caused by the heating of the earth's surface. As a result, at the equator it extends to an altitude of 16-18 km, in middle (temperate) latitudes - up to 10-11 km, and at the poles - up to 8 km. A regular decrease in air temperature with an average height of 0.6 in C for every 100 m was noted.

The troposphere contains most of cosmic and anthropogenic dust, water vapor, nitrogen, oxygen and inert gases. It is practically transparent to shortwave solar radiation passing through it. At the same time, the water vapor, ozone and carbon dioxide contained in it absorb quite strongly the thermal (long-wave) radiation of our planet, as a result of which some heating of the troposphere occurs. This leads to vertical movement of air currents, condensation of water vapor, the formation of clouds and precipitation.

The stratosphere is located above the troposphere up to an altitude of 50-55 km. The temperature at its upper boundary rises due to the presence of ozone.

Mesosphere - the upper boundary of this layer is fixed at heights of about 80 km. Its main feature is a sharp drop in temperature (-75 ° - 90 ° C) at the upper border. There are so-called noctilucent clouds, consisting of ice crystals.

The ionosphere (thermosphere) is located up to an altitude of 800 km, and it is characterized by a significant increase in temperature (over 1000 ° C). Under the influence of ultraviolet radiation from the Sun, atmospheric gases are in an ionized state. This state is associated with the appearance of the aurora, as the glow of gases. The ionosphere has the ability to repeatedly reflect radio waves, which provides long-range radio communications on Earth.

The exosphere extends from an altitude of 800 km to an altitude of 2000-3000 km. In this range of altitudes, temperatures rise to 2000 "C. It is very important that the speed of gas movement is approaching a critical value of 11.2 km / s. The composition is dominated by hydrogen and helium atoms, which form the so-called corona around our planet, stretching up to heights of 20 thousand km.

As can be seen from the above, the temperature in the atmosphere changes in a very complex way (see Fig. 21) and has a maximum or minimum value during pauses. The higher the rise above the earth's surface, the lower the atmospheric pressure. Due to the high compressibility of the atmosphere, its pressure decreases from an average value of 760 mm Hg. Art. (101 325 Pa) at sea level up to 2.3 -K) "mm Hg. (0.305 Pa) at an altitude of 100 km and only up to 1 -10 6 mm Hg. (1.3! 0" 4 Pa ) at an altitude of 200 km.

The living conditions on the Earth's surface in terms of its atmospheric "support" differ sharply at high altitudes, ie, at the heights of the stratosphere, most of the life forms of the Earth cannot exist without means of protection.

The composition of the atmosphere is not constant in height and varies over a fairly wide range. The main reasons for this are: the force of gravity, diffusion mixing, the action of cosmic and solar rays and high-energy particles emitted by them (Table 8).

Sunlight spectrum

Table 8

Under the influence of gravity, heavier atoms and molecules descend into the lower part of the atmosphere, while lighter ones remain in its upper part. Table 9 shows the composition of dry air near sea level, and Fig. 21 shows the change in the average molecular weight of the atmosphere depending on the height above the Earth's surface.

In general, the mechanical mixture of atmospheric gases is represented on average by nitrogen - 78% of its volume; oxygen - 21%; helium, argon, krypton and the above-mentioned other components - 1% or less.

Composition of atmospheric air

Notes: I. Ozone O, sulfur dioxide 50; nitrogen dioxide NO ^ amchiacMH ^ and CO monoxide are present in the form of contaminants and, as a result, their content can vary significantly. 2. The mole fraction is understood as the ratio of the number of moles of a particular component in the considered air sample to the total number of moles of all components in this sample.

The average molecular weight of such air is 28.96 amu. e. m and remains almost unchanged up to an altitude of 90 km. At high altitudes, the molecular weight sharply decreases, and at altitudes of 500 km and above, helium becomes the most important component of the atmosphere, although its content in it at sea level is extremely low. The main components of air (99 % from the entire composition) are diatomic gases (oxygen 0 2 and nitrogen N 2).

Oxygen is the most essential atmospheric element for the functioning of the biosphere. If in the atmosphere it can be up to 23% by weight, then in water - about 89%, and in the human body - almost 65%. In total, in all geospheres - the atmosphere, hydrosphere and in the accessible part of the lithosphere, oxygen accounts for 50% of the total mass of air. But in a free state oxygen is concentrated in the atmosphere, where its amount is estimated at 1.5 10 15 g. In nature, the processes of oxygen consumption and release are constantly occurring. Oxygen consumption occurs during the respiration of humans and animals, during various oxidative processes, such as combustion, corrosion of metals, smoldering of organic residues. As a result, oxygen goes from a free state to a bound one. However, its amount remains practically unchanged due to the vital activity of plants. It is believed that ocean phytoplacton and terrestrial plants play a major role in oxygen recovery. Align-

Oxygen exists in the atmosphere in the form of allotropic modifications - 0 2 and 0 3 (ozone). In all states (gaseous, liquid and solid) 0 2 is paramagnetic and has a very high dissociation energy - 496 kJ / mol. In the gaseous state 0 2 is colorless, in the liquid and solid it has a light blue color. Chemically very active, forms compounds with all elements except helium and neon.

Ozone Oj is a gas formed from 0 2 in a quiet electric discharge at a concentration of up to 10%, is diamagnetic, toxic, has a dark blue (blue) color. Traces of O appear under the action of ultraviolet (UV) radiation from 0 2 in the upper atmosphere. The maximum concentration of 0 3 in the upper atmosphere at altitudes of 25-45 km forms the now known ozone screen (layer).

Another very important and constant component of air is nitrogen, the mass of which is 75.5% (4 -10 15 g). It is part of proteins and nitrogenous compounds, which are the basis of all life on our planet.

Nitrogen N 2 is a colorless, chemically inactive gas. The dissociation energy of N 2 - 2N is almost two times higher than that of O 2 and amounts to 944.7 kJ / mol. The high bond strength N and N determines its low reactivity. However, despite this, nitrogen forms many different compounds, including with oxygen. So, N, 0 - dinitrogen oxide is relatively inert, but when heated, it turns into N 2 and O 2. Nitrogen monoxide -NO instantly reacts with ozone according to the reaction:

2NO + O, \u003d 2N0 3

Molecule NO is paramagnetic. The electron of the n-orbital is easily split off with the formation of the nitrosonium cation NO *, the bond in which is strengthened. Nitrogen dioxide NO, very toxic, forms strong nitric acid on contact with water

2NOj + H, 0 - HN0 3 + HNOj

Under natural conditions, the formation of the considered nitrogen oxides occurs during lightning discharges and as a result of the activity of nitrogen-fixing and protein-decomposing bacteria.

The use of nitrogen fertilizers (nitrates, ammonia) leads to an increase in the amount of nitrogen oxides of bacterial origin in the atmosphere. The share of natural processes in the formation of nitrogen oxides is estimated at 50%.

The composition of the atmosphere, especially in the upper layers (above the troposphere), is greatly influenced by cosmic and solar radiation and emitted high-energy particles.

The sun emits radiant energy - a stream of photons - of a wide variety of wavelengths. Energy E each photon is determined by the ratio

where AND - Planck's constant; V - radiation frequency, V \u003d 1D (X - wavelength).

In other words, the shorter the wavelength, the higher the radiation frequency and, accordingly, the higher the energy. When a photon collides with an atom or a molecule of a substance, various chemical transformations are initiated, such as dissociation, ionization, etc. But for this, certain conditions must be met: first, the photon energy must be no less than that required to break a chemical bond, removal of an electron, etc .; second, molecules (atoms) must absorb these photons.

One of the most important processesoccurring in the upper atmosphere is the photodissociation of oxygen molecules as a result of photon absorption:

Knowing the dissociation energy of the bond in the oxygen molecule (495 kJ / mol), it is possible to calculate the maximum wavelength of the photon causing the formation of O. This length turns out to be equal to 242 nm, which means that all photons with this and shorter wavelength will have an energy that sufficient for the above reaction to proceed.

Oxygen molecules are also capable of absorbing a wide range of high-energy shortwave radiation from the solar spectrum. The oxygen composition of the atmosphere (see Fig. 21) indicates how intensely the photodissociation of oxygen occurs at high altitudes. At an altitude of 400 km, 99% of oxygen is dissociated, while O, respectively, accounts for only 1%. At an altitude of 130 km, the O and O contents are approximately the same; at lower altitudes, the O 2 content significantly exceeds the O content.

Due to the high binding energy of the K molecule, (944 kJ / mol), photons with only a very short wavelength have sufficient energy to cause the dissociation of this molecule. In addition, And, poorly absorbs photons, even if they have sufficient energy. As a result, the photodissociation of N3 in the upper atmosphere is very insignificant and very little atmospheric nitrogen is formed.

Vaporous water is contained near the Earth's surface and already at an altitude of 30 km its content is 3 million, and at even higher altitudes the content of water vapor is even lower. This means that the amount of water moving into the upper atmosphere is very small. Once in the upper atmosphere, water vapor undergoes photodissociation:

H 2 0 + -> H + OH

OH + Ay -\u003e H + O

Submitted by a number of specialists on early stages development of the Earth, when the oxygen atmosphere had not yet been formed, it was photodissociation that largely contributed to its formation.

As a result of the action of solar radiation on the molecules of matter in the atmosphere, free electrons and positive ions are formed. Such processes are called photoionization. For their course, the above conditions must also be met. Table 10 shows some of the most important photoionization processes occurring in the upper atmosphere. As follows from the table, the photons causing photoionization belong to the short-wave (high-frequency) ultraviolet part of the spectrum. Radiation from this part of the spectrum does not reach the Earth's surface, it is absorbed by the upper layers of the atmosphere.

Table 10

Energy and wave parameters of photoionization processes

	Ionization energy, kJ / mop
O) + dy -\u003e O / + e

The resulting molecular ions are very reactive. Without any additional energy, they very quickly enter into reactions when colliding with a variety of charged particles and neutral molecules.

One of the most obvious reactions is the recombination of a molecular ion with an electron - the reverse reaction of photoionization. This releases an amount of energy equal to the ionization energy of a neutral molecule. And if there is no way to give up this excess energy, for example, as a result of a collision with another molecule, then it causes the dissociation of the newly formed molecule. In the upper atmosphere, due to the very low density of matter, the probability of collision between molecules and energy transfer is very small. Therefore, almost all acts of recombination of electrons with molecular ions lead to dissociation:

N5 + e-\u003e N + N1, DN

SG! + c-\u003e o + o, dn

G ^ O "+ c-\u003e N + O, DN

The atomic nitrogen contained in the upper atmosphere is formed mainly as a result of dissociative recombination.

In the case when a molecular ion collides with any neutral molecule, an electron transfer can occur between them, for example

N, + 0, - "Ы 2 + 0 ',

This type of reaction is called charge transfer reaction.

In order for such a reaction to take place, the ionization energy of a molecule that loses an electron must be less than the ionization energy of a molecule formed as a result of charge transfer. As you can see from the table. 10, the ionization energy of O is less than that of N2, the charge transfer reaction is exothermic, excess energy is released in the form of the kinetic energy of the resulting products. According to these data, the reactions indicated below should also be carried out and be exothermic (i.e., DN

SG + 0, -\u003e O + O2

about; + No- "o, - + - oo '

N2 + N0 - "+ N0 *

Since the N2 molecule has the highest ionization energy of all particles in the upper atmosphere, the N2 ion is able to enter into transfer reactions with any molecule that collides with it. The rate of the charge transfer reaction is rather high, therefore, although the photoionization process leads to the intense formation of N3 ions, their concentration in the upper atmosphere is very low.

In addition to the above, reactions occur in the upper layers of the atmosphere, during which the interacting particles exchange atoms:

O + N5 - »NO + N HM; + 0-\u003e N0 + N

These reactions are also exothermic and very easy. Since the ionization energy N0 is lower than that of other particles (see Table 10), the resulting N0 ions cannot be neutralized as a result of the charge transfer reaction, and the only reason for the death of this ion is the dissociative recombination reaction. This is the reason for the widest distribution of the NO "ion in the upper atmosphere.

Although the upper layers of the atmosphere account for a fairly small part of its entire mass, it is this zone of the atmosphere, due to the chemical reactions taking place in it, that plays a significant role in the formation of conditions for the course of life processes on our planet. It is the upper layers of the atmosphere that play the role of an advanced "bastion" that protects the Earth's surface from the destructive impact of cosmic rays and a "hail" of high-energy particles for all living organisms. It should be noted that the molecules N5, 02 and N0 cannot filter out the entire volume of short-wave radiation, the remnants of which are “neutralized” in the atmosphere as they approach the earth's surface.

Ozone as a filter of short-wave radiation. Chemical processes occurring in the atmosphere, in layers that are located below 90 km, in addition to photodissociation of O, differ significantly from those processes that are observed at high altitudes. In the meso- and stratosphere, in contrast to the higher layers, the concentration of 0 2 increases, so the probability of collision of 0 2 with O, which leads to the formation of 0 3, increases sharply.

This process is described by the following equations:

0 3 + AND - "0 + 0

about; + m -\u003e o, + m ln

where M - 0 2, K.

Molecule O, can give up energy when colliding with O, and Y, molecules. However, most of the O, 'molecules decay into O 2 and O before they undergo a stabilizing collision, that is, the equilibrium of the process 0 7 + O ^ 0 3 is strongly shifted to the left.

Penetration of superfluous beams

Figure: 22.

The rate of ozone formation depends on opposing factors. On the one hand, it increases with a decrease in the height of the atmospheric layers, since the concentration of atmospheric matter increases, and, consequently, the frequency of stabilizing collisions. On the other hand, with decreasing altitude, the velocity decreases, since the amount of atmospheric oxygen formed by the reaction About g + Ay -\u003e 20, due to a decrease in the penetration of high-frequency radiation. Therefore, the maximum ozone concentration, about 10 5% by volume, is observed at an altitude of 40 to 25 km (Fig. 22).

The ozone formation process is exothermic. Ultraviolet radiation of the Sun absorbed by oxygen - reaction 0 2 + 20,

converted into heat energy by reaction

about; + M-\u003e 0 3 + M ’, DN

which is most likely associated with an increase in temperature in the stratosphere, which reaches a maximum in the stratopause (see Fig. 22).

The formed ozone molecules are not very durable, ozone itself is able to absorb solar radiation, as a result of which it decomposes:

0 3 + dy - »O, + O

To implement this process, only 105 kJ / mol is required. This energy can be supplied by photons in a wide wavelength range up to 1140 nm. Ozone molecules most often absorb photons with wavelengths from 200 to 310 nm, which is very important for living organisms on Earth. Radiation in the indicated range is absorbed by other particles not as strongly as by ozone. It is the presence of an ozone layer in the stratosphere that prevents high-energy short-wave photons from penetrating through the atmosphere and reaching the earth's surface. As you know, plants and animals cannot exist in the presence of such radiation, therefore the "ozone shield" plays an important role in preserving life on Earth.

Naturally, the "ozone shield" is not an absolutely insurmountable obstacle to ultraviolet radiation; about one hundredth of it reaches the Earth's surface. With an increase in penetrating radiation, disturbances in the genetic mechanisms of some living organisms occur, and in humans, various skin diseases... Ozone is chemically very active and therefore interacts not only with ultraviolet radiation from the Sun. Nitrogen oxides play an important role in the ozone cycle, increasing the rate of ozone decomposition, acting as a catalyst:

0 3 + NO-\u003e N0.4-0,

N02 + O - »N0 + 02 0 3 + 0-\u003e 20 3

High temperatures, which arise, in particular, during the operation of certain types of aircraft, have a great influence on the destruction of ozone. In this case, the reaction proceeds:

О, + N2 PRN\u003e 2N0, DN\u003e О

The question of the effect of chlorofluoromethanes (freons) on ozone is quite controversial, but in any case it is necessary to dwell on possible reactions with the participation of these compounds, ozone, nitrogen, atomic oxygen and ultraviolet radiation in different layers of the atmosphere.

In the upper atmosphere, in the presence of short-wave ultraviolet radiation, a number of reactions with the participation of chlorofluoromethanes occur, in particular, the action of photons with a wavelength of 190 to 225 nm leads to photolysis of chlorofluoromethanes with the formation of several dozen different compounds and radicals, for example:

CFCL + Av- »CFC + C1

In principle, the reaction does not end there, and further photochemical decomposition of CF x Cl 3 x, again with the formation of free chlorine, is possible.

It was found that chlorine with maximum speed stands out at an altitude of about 30 km, and this just falls on the zone of maximum ozone concentrations.

The formed free atomic chlorine very quickly reacts with ozone:

C1 +0, -\u003e CU + o,

C1 + 20C1 + O,

The last two reactions, as well as reactions:

Oh, + NO-\u003e NO, + O,

generally lead to the disappearance of ozone and atomic oxygen and practically lead to a constant content of nitrogen monoxide and atomic chlorine.

Chlorine monoxide is able to interact with nitrogen oxides:

СЮ + N0 -\u003e С1 + N0,

C10 + N0, - "CINO,

Chloronitrate can be decomposed by ultraviolet radiation or by reaction with atomic oxygen:

CINO, - »O -\u003e O, + CIO + N0

Reactions involving chlorine monoxide are of particular importance as they effectively remove nitrogen and chlorine compounds from the ozone depletion cycle. Methane and hydrogen have a similar effect:

Figure: 23.

C1 + CH, -\u003e HC1 + CH,

a + n g -\u003e ns1 + n

Part of the hydrogen chloride reacts with the hydroxide, which returns the chlorine to its atomic state:

НСН-ОН -\u003e Н, 0 + С1

but the main fraction of HC1 is transferred to the troposphere, where it mixes with water vapor or liquid water, turning into hydrochloric acid.

The reactions considered above proceed in the atmosphere due to the entry of reagents into it from natural and man-made sources, and this process with different concentrations of reagents accompanied the entire history of the formation and existence of the earth's atmosphere. The fact is that chlorofluoromethanes can form even under natural conditions, therefore, the main thing is not the question of the presence of interaction reactions similar to those described above, but of the intensity and volume of the resulting and decaying atmospheric components entering into the reactions and mainly those of them that provide optimal conditions for the flow of life processes on our planet.

Thermal regime of the atmosphere and surface zone of the Earth. The main source of thermal energy coming to the earth's surface and simultaneously heating the atmosphere is naturally the Sun. Sources such as the moon, stars and other planets are

put an insignificant amount of heat. The heated bowels of the Earth are quite tangible, but also not too big a source (Fig. 23).

It is known that the Sun emits colossal energy into world space in the form of heat, light, ultraviolet and other rays. The effect of certain types of radiation on chemical reactions in the atmosphere and the formation of various compounds has already been discussed above.

In general, the entire set of radiant energy of the Sun is called solar radiation. The Earth receives a very small part of it - one two-billionth part, but this volume is sufficient for all processes known on Earth, including life.

Solar radiation is subdivided into direct, scattered and total.

The impact on the earth's surface and its heating in clear, cloudless weather is defined as straight radiation. Direct radiation directly through ultraviolet radiation affects, for example, the pigmentation of the skin of humans and animals, and some other phenomena in living organisms.

When the sun's rays pass through the atmosphere, they, meeting various molecules, dust, water drops on their turbidity, deviate from a straight path, as a result of which solar radiation is scattered. Depending on the amount of cloudiness, the degree of air humidity, its dustiness, the degree of dispersion reaches 45%. Value scattered radiation is quite high - it generally determines the degree of illumination of various relief elements, as well as the color of the sky.

Total radiation, respectively, consists of direct and diffuse radiation.

The angle of incidence of sunlight on the ground surface determines the intensity of radiation, which, in turn, affects the air temperature during the day.

The distribution of solar radiation over the surface of the Earth and the heating of atmospheric air depends on the sphericity of the planet and the inclination of the Earth's axis to the orbital plane. In equatorial and tropical latitudes, the Sun is high above the horizon throughout the year, in mid-latitudes its height changes depending on the season, and in the Antarctic and Arctic regions the Sun never rises high above the horizon. This generally affects the degree of dissipation of solar energy in the atmosphere, as a result of which per unit area of \u200b\u200bthe Earth's surface in the tropics there is more sunlight than in middle or high latitudes. For this reason, the amount of radiation depends on the latitude of the place: the farther from the equator, the less it enters the earth's surface.

Solar radiation100%

/// / V /// /// /// /// / V /// /// /// /\u003e / / LH // y / y /

Absorption

soil

Figure: 24. The balance of solar radiation on the earth's surface during the day

(T.K. Goryshina, 1979)

The urgent movement of the Earth also affects the amount of incoming radiant energy. In middle and high latitudes, its amount depends on the season. At the North Pole, as you know, the Sun does not set over the horizon for 6 months (more precisely, 186 days) and the amount of incoming radiant energy is greater than at the equator. However, the sun's rays have a small angle of incidence and therefore a significant part of the solar radiation is scattered in the atmosphere. In this regard, both the Earth's surface and the atmosphere itself are heated slightly. In winter, in the Arctic and Antarctic latitudes, the Sun does not rise above the horizon, and therefore solar radiation does not reach the earth's surface at all.

Significant influence on the amount of solar radiation "perceived" by the earth's surface, including the surface of the oceans, as well as by the atmosphere, is exerted by the features of the relief, its dissection, the absolute and relative heights of the surface, the "exposure" of the slopes (that is, their "orientation" to the Sun) , even the presence or absence of vegetation and its nature, as well as the "color" of the earth's surface. The latter is determined by the value apbedo, which in general means the amount of light reflected from a unit surface, and sometimes albedo is defined as the value

the reflectivity of a body or a system of bodies, usually considered as a fraction (in%) of the energy of the incident light reflected from the given ground surface

The magnitude of the reflectivity of the earth's surface is influenced, for example, by the presence of snow on it, its purity, etc.

The combination of all these factors shows that there are practically no places on the Earth's surface where the magnitude and intensity of solar radiation would be the same and would not change over time (Fig. 24).

The heating of land and water occurs due to differences in the heat capacity of the materials "forming" them very differently. The land is heated and cooled quickly enough. Water masses in oceans and seas heat up slowly, but retain heat longer.

On land, solar radiation heats only the surface layer of soil and underlying rocks, while in transparent water, heat penetrates to considerable depths, and the heating process proceeds more slowly. Evaporation has a significant effect, since a large amount of incoming thermal energy is consumed for its implementation. The cooling of water proceeds slowly due to the fact that the volume of heated water is significantly greater than the volume of the heated land. Water masses, due to temperature changes in the upper and lower layers, are in a state of continuous "mixing". The cooled upper layers, being denser and heavier, sink down, and warmer water rises towards them from below. The waters of the seas and oceans consume the accumulated heat more "economically" and evenly than the land surface. As a result, the sea is always warmer on average than land, and fluctuations in water temperature are never as sharp as fluctuations in land temperature.

Ambient air temperature. Air, like any transparent body, heats up very little when the sun's rays pass through it. Air heating is carried out due to the heat given off by the heated earth or water surface. Air with a higher temperature and a lower mass as a result rises to the higher cold layers of the atmosphere, where it transfers its heat to them.

As the air rises, it cools. The air temperature at an altitude of 10 km is almost always constant and amounts to -45 "C. The natural decrease in air temperature with altitude is sometimes disturbed by the so-called temperature inversion (temperature permutation). Inversions occur with sharp decreases or increases in the temperature of the earth's surface and adjacent air, which sometimes represents a rapid "swelling" of cold air along the mountain slopes into the valleys.

The atmospheric air is characterized by a daily temperature change. During the day, the Earth's surface heats up and transfers heat to the surrounding air, at night the process is reversed.

The lowest temperatures are observed not at night, but before sunrise, when the earth's surface has already given up its heat. In the same way, the highest air temperatures are established in the afternoon with a delay of 2-4 hours.

In different geographic zones of the Earth, the daily variation of temperatures is different, at the equator, on the seas and near the sea coasts, the amplitudes of air temperature fluctuations are very small, and in deserts, for example, during the day, the Earth's surface heats up to a temperature of about 60 ° C, and at night it drops to almost 0 ° C, that is, the daily “course” of temperatures is 60 ° C.

In the middle latitudes, the greatest amount of solar radiation arrives at the Earth on the days of the solstice (June 22 in the northern hemisphere and December 21 in the southern). However, the hottest months are not June (December), but July (January) due to the fact that in June (December) the actual heating of the earth's surface occurs, which consumes a significant part of solar radiation, and in July (December) the loss in the incoming amount of solar radiation occurs. radiation is not only compensated for, but also exceeds it in the form of heat from the heated earth's surface. Similarly, one can explain why the coldest month is not December (June), but January (July). At sea, due to the fact that the water cools and heats up more slowly, the hottest month is in August (February), the coldest - in February (August).

The geographical latitude of a place affects the annual amplitude of air temperatures. In the equatorial parts, the temperature is practically constant throughout the year and averages 23 ° C. The highest annual amplitudes are typical for territories located in mid-latitudes in the depths of the continents.

Each locality has its own absolute and average values \u200b\u200bof air temperatures. Absolute temperatures are established on the basis of long-term observations at meteorological stations. For example, the hottest place on Earth is located in the Libyan Desert (+58 ° C), the coldest one is in Antarctica (-89.2 C). In our country, the lowest temperature -70.2 ° C was recorded in Eastern Siberia (Oymyakon village).

The average temperature for a given area is calculated at first the disc of the day according to thermometric determinations at 1:00, 7:00, 13 and 19:00, that is, four times a day; then, based on daily average data, monthly and annual average temperatures are calculated.

For practical purposes, maps of isotherms are performed, among which the most indicative are the isotherms of January and July, i.e., the warmest and coldest months.

Water in the atmosphere. The gases that form the atmosphere include water vapor, which is formed by the evaporation of water from the surface of oceans and continents. The higher the temperature and the larger the capacity

steam, the stronger the evaporation. Evaporation rate is affected by wind speed and terrain on land, as well as, naturally, temperature fluctuations.

The ability to release a certain amount of water vapor from any surface when exposed to temperature is called volatility. This conditional value of evaporation is influenced by the air temperature and the amount of water vapor in it. The minimum values \u200b\u200bare recorded for the polar countries and for the equator, and the maximum evaporation is noted for tropical deserts.

The air can accept water vapor up to a certain limit when it becomes saturated. With further heating of the air, it becomes capable of receiving water vapor again, i.e., unsaturated. When unsaturated air is cooled, it passes into a saturated state. There is a relationship between the temperature and the content of water vapor that is contained in the air at the moment (in g per 1 m 5), which is called absolute humidity.

The ratio of the amount of water vapor contained in the air at a given moment to the amount that it can accommodate at a given temperature is called relative humidity (%).

The moment of transition of air from an unsaturated state to a saturated state is called dew point. The lower the air temperature, the less it can contain water vapor and the higher the relative humidity. This means that the dew point is faster in cold air.

At the onset of the dew point, i.e. when the air is completely saturated with water vapor, when the relative humidity approaches 100 %, condensation of water vapor occurs, the transition of water from a gaseous state to a liquid.

So, the process of condensation of water vapor occurs either with strong evaporation of moisture and air saturation with water vapor, or with a decrease in air temperature and relative humidity. At negative temperatures, water vapor, bypassing the liquid state, turns into ice and snow crystals, that is, it turns into a solid state. This process is called sublimation of water vapor.

Condensation and sublimation of water vapor are processes that are the source of atmospheric precipitation. One of the most obvious manifestations of water vapor condensation in the atmosphere is the formation of clouds, which are usually located at heights from several tens and hundreds of meters to several kilometers. An ascending stream of warm air with water vapor enters the atmosphere with conditions for the formation of clouds consisting of water droplets or ice and snow crystals, which is associated with the temperature of the cloud itself. Crystals of ice and snow, water droplets have such a low mass that they can be kept suspended even due to very weak ascending air currents.

Clouds have a varied shape, which depends on many factors: height, wind speed, humidity, etc. The most famous are cumulus, cirrus and stratus, as well as their varieties. Clouds oversaturated with water vapor, having a dark purple or almost black hue, are called clouds. The sky is covered with clouds to varying degrees and this degree, expressed in points (from 1 to 10), is called cloudy. Clouds with high scores create conditions for precipitation.

Atmospheric precipitation is water in all types of solid and liquid phases, which the earth's surface receives in the form of rain, snow, fog, hail or dew condensed on the surface of various bodies. In general, precipitation is one of the most important abiotic factors that significantly affect the conditions for the existence of living organisms. In addition, atmospheric precipitation determines the migration and spread of various substances, including pollutants, in the environment. In the general circulation of moisture, it is precipitation that is most mobile, since the volume of moisture in the atmosphere turns around 40 times a year. Rain is formed when the smallest droplets of moisture contained in a cloud merge into larger ones and, overcoming the resistance of ascending warm air currents, fall under the influence of gravity onto the Earth's surface. In the air that contains dust particles, the condensation process is much faster, since these dust particles act as condensation nuclei. In deserts, where the relative humidity is very low, condensation of water vapor is possible only at significant

heights, at low temperatures. However, rain on the desert

1 Temperature below O C

Temperature higher 0 ° C

does not fall out, since the snowflakes do not have time to fall to the surface, but evaporate. This phenomenon is called dry rains. In the case of condensation of water vapor, which occurs at negative temperatures, precipitation is formed in the form of snow. When mixing snowflakes with water droplets, spherical snowballs with a diameter of 2-3 mm are formed, which fall out in the form of a blizzard. For the formation of hail, it is necessary that the cloud is of considerable size and its lower part Fig. 25. The scheme of the formation of hail in the clouds was the VZONE of POSITIVE themes of the vertical development of psratur, and the upper one was negative.

tel. The resulting lumps of blizzard, rising upward, turn into spherical ice floes - hailstones. The size of the hailstones gradually increases and falls on the earth's surface, overcoming the forces of ascending air currents under the influence of gravity. Hailstones are different in size: from a pea to a chicken egg (Fig. 25).

Precipitation such as dew, frost, fog, frost, ice are formed not in the upper atmosphere, but in the surface layer. With a decrease in temperature at the surface of the earth, the air cannot always hold water vapor, which drops out on various objects in the form dew, and if these objects have a negative temperature, then in the form frost. When exposed to warm air on cold objects, frost - bloom of loose ice and snow crystals. At significant concentrations of water vapor in the surface layer of the atmosphere, fog. The formation of an ice crust on the earth's surface from rainfall is called ice, by the way under ice understand falling out and freezing as it falls.

The main conditions for the occurrence different types precipitation are air temperature, atmospheric circulation, sea currents, relief, etc. There is a zoning in the distribution of precipitation over the earth's surface, the following zones are distinguished:

• humid equatorial (approximately between 20 ° N and 20 "S): this includes the basins of the Amazon River, the Congo River, the coast of the Gulf of Guinea, Indo-Malay region; there are more than 2000 mm of precipitation here, the largest amount of precipitation falls on Kauan Island (Hawaiian Islands) - 11 684 mm and in Cherrapunja (southern slopes of the Himalayas) - 11 633 mm, in this zone are located humid equatorial forests - one of the richest types of vegetation on the globe (more than 50 000 species);
• dry zones of tropical zones (between 20'N and 40'S) - anticyclonic conditions with descending air currents dominate here. Typically, the amount of precipitation is less than 200-250 mm. Therefore, the most extensive deserts of the globe are concentrated in these zones (Sahara, Libyan, the deserts of the Arabian Peninsula, Australia, etc.). The lowest average annual rainfall in the world (only 0.8 mm) is noted in the Atacama Desert (South America);
• humid zones of temperate latitudes (between 40 ° N and 60 ° S) - a significant amount of atmospheric precipitation (more than 500 mm) is due to the cyclonic activity of air masses. Thus, in the forest zone of Europe and North America, the annual amount of precipitation varies from 500 to 1000 mm, beyond the Urals it decreases to 500 mm, and then in the Far East, due to monsoon activity, it again increases to 1000 mm;
• the polar regions of both hemispheres are characterized by an insignificant amount of precipitation (on average, up to 200-250 mm); these minimum precipitation are associated with low air temperatures, negligible evaporation and anticyclonic atmospheric circulation. There are arctic deserts with extremely poor vegetation (mainly mosses and lichens). In Russia, the greatest amount of precipitation falls on the southwestern slopes of the Greater Caucasus - about 4000 mm (Mount Achishko - 3682 mm, and the least - in the tundra of the northeast (about 250 mm) and in the deserts of the Caspian region (less than 300 mm).

Atmospheric pressure. The mass of 1 m 3 of air at sea level at a temperature of +4 ° C averages 1.3 kg, which determines the existence of atmospheric pressure. A person, like other living organisms, does not feel the effects of this pressure, since he has a balancing internal pressure. The atmospheric pressure at a latitude of 45 ° at an altitude equal to sea level at a temperature of +4 ° C is considered normal, it corresponds to 1013 hPa or 760 mm Hg. Art. or 1 atm. Naturally, atmospheric pressure decreases with height, and on average it is 1 hPa for every 8 m of height. It should be said that the pressure changes depending on the density of the air, which, in turn, depends on the temperature. For special

Rotation

Lands North Pole

Figure: 26.

in other maps, lines with the same pressure values \u200b\u200bare shown; these are the so-called isobar maps. The following two patterns have been identified:

• pressure changes from the equator to the poles zonal; at the equator it is low, in the tropics (especially over the oceans) - high, in the temperate - variable from season to season; in polar - increased;
• over the continents, an increased pressure is established in winter, and a lower pressure in summer - Fig. 27. Rose winding (Fig. 26).

Wind. The movement of air due to the difference in atmospheric pressure is called by the wind. The wind speed determines its types, for example, when calm the wind speed is zero, and the wind with a speed of more than 29 m / s is called hurricane. The highest wind speed of over 100 m / s was recorded in Antarctica. For practical purposes, when solving various engineering, environmental and other problems, so-called wind roses (fig. 27).

Some general regularities of the directions of the main air flows in the lower layers of the atmosphere are revealed:

• from tropical and subtropical regions high blood pressure the main air flow moves to the equator in the area of \u200b\u200bconstant low pressure; when the Earth rotates, these flows are oriented to the right in the northern hemisphere and to the left in the southern; these currents of constant winds are called trade winds;
• some of the tropical air moves to temperate latitudes; this process is especially active in summer, since the pressure is usually low in temperate latitudes in summer. This flow is also oriented due to the rotation of the Earth, but it is slow and gradual; in general, in the temperate latitudes of both hemispheres, western air transport prevails;
• from the polar regions of high pressure, air moves to temperate latitudes, taking a northeastern direction in the northern hemisphere and southeasterly in the southern.

In addition to the above described so-called planetary winds, monsoons - winds that change their direction according to the seasons: in winter, winds blow from land to sea, and in summer, from sea to dry. These winds are also deflected in their directions due to the rotation of the Earth. Monsoon winds are especially characteristic of the Far East and Eastern China.

In addition to planetary winds and monsoons, there are local or local winds: breezes - coastal winds; hair dryers - warm dry winds of mountain slopes; dry winds - dry and very hot winds of deserts and semi-deserts; bora (sarma, chipuk, mistral) - dense cold winds from mountain barriers.

Wind is an important abiotic factor that significantly shapes the living conditions of organisms, and also affects the formation of weather and climate. In addition, wind is one of the most promising alternative energy sources.

Weather is the state of the lower atmosphere at a given time and place. The most characteristic feature of the weather is its variability, or rather, continuous change. This is most often and most clearly manifested when changing air masses. Air mass is a huge moving volume of air with a certain temperature, density, humidity, transparency, etc.

Depending on the place of formation, arctic, temperate, tropical and equatorial air masses are distinguished. The place of formation and its duration affect the properties of the air masses above them. For example, the humidity and temperature of air masses are influenced by the fact of their formation over a continent or ocean, in winter or summer.

Russia is located in the temperate zone, therefore, in its west, marine temperate air masses prevail, and above for the most part the rest of the territory is continental; beyond the Arctic Circle arctic air masses are formed.

The encounters of various air masses in the troposphere create transition regions - atmospheric fronts - up to 1000 km long and several hundred meters thick. A warm front is formed when warm air advances on a cold one, and a cold front is formed when the air mass moves in the opposite direction (Fig. 28, 29).

Under certain conditions, powerful eddies with diameters of up to 3 thousand km are formed at the fronts. At reduced pressure in the center of such a vortex, it is called cyclone, with increased - anticyclone (fig. 30). Cyclones usually move from west to east at speeds up to 700 km / day. A type of cyclonic eddies are tropical cyclones, which are smaller in size but very stormy in terms of weather. The pressure in their centers drops to 960 hPa, and the accompanying winds are of a hurricane nature (\u003e 50 m / s) with a storm front width of up to 250 km.

Climate is a long-term weather regime typical for a given area. Climate is one of the important long-term abiotic factors; it affects the regime of rivers, the formation of various types of soils, types of plants and animals

Figure: 28.

00 700 800 km Cold

Horizontal front distance

society. In areas of the Earth, where the surface receives an abundance of heat and moisture, moist evergreen forests with huge bioproductivity are widespread. Areas located near the tropics receive enough heat, but much less moisture, which leads to the formation of semi-desert forms of vegetation. The temperate latitudes have their own peculiarities associated with the stable adaptation of vegetation to rather difficult climatic conditions. The formation of the climate is mainly influenced by geographical position terrain, in particular over water

air

6 Warm air

Thunder cloud

* Ice crystals

Warm Cirrus

air Peristo - layered

Icy -d. - - *

crystals . .

Aquatic * ,

drops ^ ^

- ____; at Cold

Figure: 29.

the surface and over the land are formed by different weather conditions. With distance from the ocean, the average temperature of the warmest month rises and the coldest month decreases, i.e., the amplitude of annual temperatures increases. So, in Nerchinsk it reaches 53.2 ° С, and in Ireland on the Atlantic coast - only 8.1 ° С.

Mountains, hills, hollows are very often zones of special climate, and mountain ranges are climatic divisions.

The sea currents influence the climate, it is enough to mention the influence of the Gulf Stream on the climate of Europe. According to B.P. Alisov, the following zones are distinguished according to the prevailing climate.

1. Equatorial belt, covering the basins of the Congo and Amazon rivers, the coast of the Gulf of Guinea, the Sunda Islands; the average annual temperature is in the range from 25 to 28 ° С, the maximum temperature does not exceed +30 ° С, but the relative humidity is 70-90%. The amount of precipitation exceeds 2000 mm, and in some areas up to 5000 mm. The distribution of precipitation throughout the year is uniform.

High

pressure

Low pressure

Low

pressure

High

pressure

Figure: 30. Scheme of air movement in a cyclone (and) and anticyclone (b)

• 2. Subequatorial belt, occupying the Brazilian Highlands, Central America, most of Hindustan and Indochina, northern Australia. The most characteristic feature is the seasonal change in air masses: the wet (summer) and dry (winter) seasons are distinguished. It is in this belt in the northeast of Hindustan and the Hawaiian Islands that the wettest places on Earth are located, where the most precipitation falls.
• 3. The tropical belt, located on both sides of the tropics, both on the oceans and on the continents. The average temperature significantly exceeds +30 * С (even +55 ° С was noted). Little precipitation falls (less than 200 mm). The largest deserts in the world are located here - the Sahara, Western Australian, Arabian, but at the same time a lot of precipitation falls in the trade wind zones - the Greater Antilles, the eastern coasts of Brazil and Africa.
• 4. Subtropical belt, occupying large spaces between the 25th and 40th parallels north and south latitude. This belt is characterized by a seasonal change in air masses: in summer, the entire region is occupied by tropical air, in winter - by air of temperate latitudes. There are three climatic regions - western, central and eastern. The western climatic region includes the Mediterranean coast, California, the central Andes, southwestern Australia - the climate here is called Mediterranean (the weather is dry and sunny in summer, and warm and humid in winter). In East Asia and in the southeast of North America, the climate is established under the influence of monsoons, the temperature of the coldest month is always more than 0 C. In Eastern Turkey, Iran, Afghanistan, the Great Basin of North America, dry air prevails all year round: tropical in summer, winter - continental. The amount of precipitation does not exceed 400 mm. In winter, the temperature is below 0 ° C, but without snow cover, daily amplitudes of values \u200b\u200bup to 30 "C, a large difference in temperatures throughout the year. Here in the central regions of the continents are deserts.
• 5. Temperate belt, located north and south of the subtropics approximately to the polar circles. In the southern hemisphere, an oceanic climate prevails, and in the northern one there are three climatic regions: western, central and eastern. In the west of Europe and Canada, in the south of the Andes, humid sea air of temperate latitudes prevails (500-1000 mm of precipitation per year). Precipitation falls evenly, annual temperature fluctuations are small. Summer is long and warm; winters are mild, sometimes with heavy snowfalls. In the east (the Far East, northeastern China), the climate is monsoon: in summer, humidity and precipitation are significant due to the oceanic monsoon; in winter, due to the influence of continental masses of cold air, temperatures drop to more than -30 ° С. In the center (middle

Figure: 31.

a strip of Russia, Ukraine, north of Kazakhstan, south of Canada) a temperate climate is formed, although this name is rather arbitrary, since often in winter arctic air comes here with very low temperatures. Winter is long and frosty; snow cover lasts more than three months, rainy, warm summers; the amount of precipitation decreases as it moves inland (from 700 to 200 mm). The most characteristic feature the climate of this region - sharp temperature changes throughout the year, uneven distribution of precipitation, which sometimes causes droughts (Fig. 31, 32).

• 6. Subarctic (subantarctic) belt; these transitional zones are located north of the temperate zone in the northern hemisphere and south of it in the southern hemisphere. They are characterized by a change in air masses according to the seasons: in the summer - the air of temperate latitudes, in the winter - the Arctic (Antarctic). Summers are short, cool, with an average temperature of the warmest month from 12 to 0 ° C with little precipitation (an average of 200 mm). Winter is long, frosty with a lot of snow. In the northern hemisphere at these latitudes there is a tundra zone.
• 7. The Arctic (Antarctic) belt is the source of the formation of cold air masses under conditions of increased pressure. This belt is characterized by long polar nights and polar

Arctic fronts in summer

Polar fronts in summer

in winter

Figure: 32. Atmospheric fronts over the territory of Russia

in winter

days; their duration at the poles reaches six months. The lowered background temperature maintains a permanent ice cover, which lies in the form of a thick layer in Antarctica and Greenland, and ice mountains - icebergs and ice fields float in the polar seas. The absolute minimum temperatures and the most strong winds (fig. 33).

The richest variety of landforms, rivers, seas and lakes create conditions for education microclimate terrain, which is also important for the formation of the living environment.

The atmosphere of the Earth, its air shell as a life environment has features arising from the general characteristics described above and directing the main paths of evolution of the inhabitants of this environment. Thus, a sufficiently high oxygen content (up to 21% in the atmospheric air and somewhat less in the respiratory system of animals) determines the possibility of forming a high level of energy metabolism. It was in these basic conditions of the atmospheric environment that homoiothermal animals arose, characterized by a high level of energy of the organism, a high degree of autonomy from external influences, and high biological activity in ecosystems. On the other hand, atmospheric air is characterized by low and variable humidity. This circumstance in

Wrong Tropic

KEhny tropic

Westerly winds

East winds

Figure: 33. Polar vortex b Northern Hemisphere

in many ways limited the possibilities of mastering the air environment, and in its inhabitants it was guided by the evolution of the fundamental properties of the system of water-salt metabolism and the structure of respiratory organs.

One of the most important (IA Shilov, 2000) features of the atmosphere as an arena of life is the low density of the air environment. Speaking about its inhabitants, we mean terrestrial forms of plants and animals. The fact is that the low density of the habitat closes the possibility of the existence of organisms that carry out their vital functions without connection with the substrate. That is why life in the air is realized near the earth's surface, rising into the atmosphere by no more than 50-70 m (tree crowns in tropical forests). Following the features of the relief, living organisms can be found at high altitudes (up to 5-6 km above sea level, although there is a fact of the presence of birds naked. Everest, and lichens, bacteria and insects are regularly recorded at altitudes of about 7 km). Highland conditions limit physiological processes that are associated with the partial pressure of atmospheric

gases, for example, in the Himalayas, at an altitude of more than 6.2 km, the border of green vegetation passes, since the reduced partial pressure of carbon dioxide does not allow photosynthetic plants to develop; animals, as possessing the ability to move, also rise to great heights. Thus, the temporary stay of living organisms in the atmosphere is recorded at altitudes up to 10-11 km, the record holder is a griffon vulture that collided with an aircraft at an altitude of 12.5 km (I.A. Shilov, 2000); flying insects were found at the same altitudes, and bacteria, spores, protozoa were found at an altitude of 15 km, even the presence of bacteria at an altitude of 77 km was described, and in a viable state.

Life in the atmosphere does not differ in any vertical structure in accordance with the flows of matter and energy moving in the biological cycle. The variety of life forms in the terrestrial environment is more associated with zonal climatic and landscape factors. The sphericity of the Earth, its rotation and movement in its orbit create seasonal and latitudinal dynamics of the intensity of solar energy input to various parts of the earth's surface, where geographic spaces similar in terms of life are formed, within which the features of climate, relief, waters, soil and vegetation cover form the so-called landscape and climatic zones: polar deserts, tundras, temperate forests (coniferous, deciduous), steppes, savannas, deserts, tropical forests.

The complex of physical, geographical and climatic factors forms the most fundamental living conditions in each of the zones and acts as a powerful factor in the evolutionary formation of morphophysiological adaptations of plants and animals to life in these conditions.

Landscape and climatic zones play an essential role in the course of the biogenic cycle. In particular, the leading role of green plants is clearly expressed in the terrestrial environment. The transparency of the atmosphere determines the circumstance of reaching the surface of the planet by the flow of solar radiation. Almost half of it is photosynthetically active radiation with a wavelength of 380-710 nm.

It is this part of the light flux that makes up the energy basis of photosynthesis - a process in which, on the one hand, organic matter is created from inorganic components, and on the other hand, it becomes possible to use the released oxygen for the respiration of both plants themselves and heterotrophic aerobic organisms. In this, the very existence of the biological circulation of substances on the Earth is realized.

An asterisk (2) in the formulas means that this molecule contains excess energy, which it needs to get rid of as quickly as possible, otherwise a reverse reaction will occur.

The atmosphere is the gaseous envelope of our planet, which rotates with the Earth. The gas in the atmosphere is called air. The atmosphere is in contact with the hydrosphere and partially covers the lithosphere. But the upper bounds are difficult to define. It is conventionally assumed that the atmosphere extends upward for about three thousand kilometers. There, it smoothly flows into an airless space.

The chemical composition of the Earth's atmosphere

The formation of the chemical composition of the atmosphere began about four billion years ago. Initially, the atmosphere consisted only of light gases - helium and hydrogen. According to scientists, the initial prerequisites for the creation of a gas shell around the Earth were volcanic eruptions, which, together with lava, emitted a huge amount of gases. Later, gas exchange began with water spaces, with living organisms, with the products of their activity. The composition of the air gradually changed and in modern form was recorded several million years ago.

The main constituents of the atmosphere are nitrogen (about 79%) and oxygen (20%). The remaining percentage (1%) falls on the following gases: argon, neon, helium, methane, carbon dioxide, hydrogen, krypton, xenon, ozone, ammonia, sulfur and nitrogen dioxide, nitrous oxide and carbon monoxide included in this one percent.

In addition, the air contains water vapor and solid particles (plant pollen, dust, salt crystals, aerosol impurities).

Recently, scientists have noted not a qualitative, but a quantitative change in some air ingredients. And the reason for this is the person and his activities. In the last 100 years alone, the carbon dioxide content has increased significantly! This is fraught with many problems, the most global of which is climate change.

Formation of weather and climate

The atmosphere plays a critical role in shaping the climate and weather on Earth. Much depends on the amount of sunlight, on the nature of the underlying surface and atmospheric circulation.

Let's consider the factors in order.

1. The atmosphere allows the heat of sunlight to pass through and absorbs harmful radiation. The ancient Greeks knew that the rays of the Sun fall on different parts of the Earth at different angles. The very word "climate" in translation from ancient Greek means "slope". So, at the equator, the sun's rays fall almost vertically, because it is very hot here. The closer to the poles, the greater the angle of inclination. And the temperature goes down.

2. Due to the uneven heating of the Earth, air currents are formed in the atmosphere. They are classified according to their size. The smallest (tens and hundreds of meters) are local winds. This is followed by monsoons and trade winds, cyclones and anticyclones, planetary frontal zones.

All these air masses are constantly moving. Some of them are pretty static. For example, the trade winds that blow from the subtropics towards the equator. The movement of others is largely dependent on atmospheric pressure.

3. Atmospheric pressure is another factor influencing the formation of the climate. This is the air pressure on the surface of the earth. As is known, air masses move from an area with an increased atmospheric pressure towards an area where this pressure is lower.

There are 7 zones in total. The equator is a low pressure zone. Further, on both sides of the equator up to the thirties latitudes - a high pressure area. From 30 ° to 60 ° - low pressure again. And from 60 ° to the poles - a high pressure zone. Air masses circulate between these zones. Those that go from the sea to the land bring rain and bad weather, and those that blow from the continents - clear and dry weather. In places where air currents collide, zones of an atmospheric front are formed, which are characterized by precipitation and inclement, windy weather.

Scientists have proven that even a person's well-being depends on atmospheric pressure. According to international standards, normal atmospheric pressure is 760 mm Hg. column at a temperature of 0 ° C. This indicator is designed for those land areas that are almost level with sea level. The pressure decreases with height. Therefore, for example, for St. Petersburg 760 mm Hg. is the norm. But for Moscow, which is located higher, normal pressure - 748 mm Hg

The pressure changes not only vertically, but also horizontally. This is especially felt when passing through cyclones.

The structure of the atmosphere

The atmosphere is reminiscent of a puff pastry. And each layer has its own characteristics.

. Troposphere- the layer closest to the Earth. The "thickness" of this layer changes with distance from the equator. Above the equator, the layer extends upward for 16-18 km, in temperate zones - for 10-12 km, at the poles - for 8-10 km.

It is here that 80% of the total mass of air and 90% of water vapor are contained. Here clouds form, cyclones and anticyclones appear. The air temperature depends on the height of the terrain. On average, it drops by 0.65 ° C for every 100 meters.

. Tropopause- the transitional layer of the atmosphere. Its height ranges from several hundred meters to 1-2 km. The air temperature is higher in summer than in winter. So, for example, above the poles in winter -65 ° C. And above the equator at any time of the year it keeps -70 ° C.

. Stratosphere- This is a layer, the upper boundary of which runs at an altitude of 50-55 kilometers. Turbulence is low here, the content of water vapor in the air is negligible. But there is a lot of ozone. Its maximum concentration is at an altitude of 20-25 km. In the stratosphere, the air temperature begins to rise and reaches + 0.8 ° C. This is due to the fact that the ozone layer interacts with ultraviolet radiation.

. Stratopause- a low intermediate layer between the stratosphere and the mesosphere following it.

. Mesosphere- the upper boundary of this layer is 80-85 kilometers. Complex photochemical processes involving free radicals take place here. They provide that gentle blue glow of our planet, which is seen from space.

Most comets and meteorites burn up in the mesosphere.

. Mesopause- the next intermediate layer, the air temperature in which is at least -90 °.

. Thermosphere- the lower boundary begins at an altitude of 80 - 90 km, and the upper boundary of the layer runs at approximately 800 km. The air temperature rises. It can vary from + 500 ° C to + 1000 ° C. Temperature fluctuations are hundreds of degrees during the day! But the air here is so rarefied that understanding the term "temperature" as we imagine it is not appropriate here.

. Ionosphere- combines the mesosphere, mesopause and thermosphere. The air here consists mainly of oxygen and nitrogen molecules, as well as quasi-neutral plasma. The sun's rays entering the ionosphere strongly ionize air molecules. In the lower layer (up to 90 km), the degree of ionization is low. The higher, the more ionization. So, at an altitude of 100-110 km, electrons are concentrated. This contributes to the reflection of short to medium radio waves.

The most important layer of the ionosphere is the upper one, which is located at an altitude of 150-400 km. Its peculiarity is that it reflects radio waves, and this contributes to the transmission of radio signals over long distances.

It is in the ionosphere that such a phenomenon as the aurora occurs.

. Exosphere- consists of oxygen, helium and hydrogen atoms. The gas in this layer is very rarefied and hydrogen atoms often escape into outer space. Therefore, this layer is called the "scattering zone".

The first scientist who suggested that our atmosphere has weight was the Italian E. Torricelli. Ostap Bender, for example, in his novel "The Golden Calf" lamented that an air column weighing 14 kg presses on each person! But the great combinator was a little wrong. An adult is under pressure of 13-15 tons! But we do not feel this heaviness, because atmospheric pressure is balanced by the internal pressure of a person. The weight of our atmosphere is 5,300,000,000,000,000 tons. The figure is colossal, although it is only a millionth of the weight of our planet.

I love the air in the mountains very much. Of course, I am not a climber, my maximum altitude was 2300 m. But if you climb 5 km above sea level, the state of health can deteriorate sharply, as oxygen will decrease. I will now talk about these and other features of the air envelope.

The air shell of the Earth and its composition

The shell around our planet, made of gases, is called the atmosphere. It is thanks to her that you and I can breathe. It includes:

• nitrogen;
• oxygen;
• inert gases;
• carbon dioxide.

78% of the air is nitrogen, but oxygen, without which we could not exist, is 21%. The amount of carbon dioxide in the atmosphere is regularly increasing. The reason for this is human activity. Industrial plants and cars emit huge amounts of combustion products into the atmosphere, and the area of \u200b\u200bforests that could improve the situation is rapidly decreasing.

There is also ozone in the atmosphere, from which a protective layer was formed around the planet. It is located at an altitude of about 30 km and protects our planet from the dangerous effects of the Sun.

At different heights, the air envelope has its own characteristics. In total, 5 layers are distinguished in the atmosphere: troposphere, stratosphere, mesosphere, thermosphere and exosphere. The troposphere is closest to the earth's surface. Rain, snow, fog are formed precisely within this layer.

What functions does the atmosphere perform?

If the Earth did not have a shell, then it is unlikely that living beings could be on its territory. First, it protects all life on the planet from solar radiation. In addition, the atmosphere allows you to maintain a comfortable temperature for life. We are used to seeing blue skies overhead, perhaps due to various particles in the air.

The air envelope distributes sunlight and also allows sound to diffuse. It is thanks to the air that we can hear each other, birdsong, falling raindrops and wind. Of course, without the atmosphere, moisture could not be redistributed. The air creates a favorable habitat for humans, animals and plants.

Atmospheric air consists of nitrogen (77.99%), oxygen (21%), inert gases (1%) and carbon dioxide (0.01%). The share of carbon dioxide increases over time due to the release of fuel combustion products into the atmosphere, and, in addition, the area of \u200b\u200bforests that absorb carbon dioxide and emit oxygen decreases.

There is also a small amount of ozone in the atmosphere, which is concentrated at an altitude of about 25-30 km and forms the so-called ozone layer. This layer creates a barrier to solar ultraviolet radiation, which is dangerous for living organisms on Earth.

In addition, the atmosphere contains water vapor and various impurities - dust particles, volcanic ash, soot and so on. The concentration of impurities is higher at the surface of the earth and in certain areas: over large cities, deserts.

Troposphere - bottom, it contains most of the air and. The height of this layer is not the same: from 8-10 km in the tropics to 16-18 km at the equator. in the troposphere, it decreases with an increase: by 6 ° С per kilometer. Weather forms in the troposphere, winds, precipitation, clouds, cyclones and anticyclones are formed.

The next layer of the atmosphere is stratosphere... The air in it is much more rarefied, there is much less water vapor in it. The temperature in the lower part of the stratosphere is -60 - -80 ° С and decreases with increasing altitude. It is in the stratosphere that the ozone layer is located. The stratosphere is characterized by high wind speeds (up to 80-100 m / s).

Mesosphere - the middle layer of the atmosphere, lying above the stratosphere at heights from 50 to S0-S5 km. The mesosphere is characterized by a decrease in average temperature with an altitude of 0 ° С at the lower border to -90 ° С at the upper border. Near the upper boundary of the mesosphere, noctilucent clouds are observed, illuminated by the sun at night. The air pressure at the upper boundary of the mesosphere is 200 times less than at the earth's surface.

Thermosphere - is located above the mesosphere, at altitudes from SO to 400-500 km, in it the temperature at first slowly, and then quickly begins to rise again. The reason is the absorption of ultraviolet radiation from the Sun at altitudes of 150-300 km. In the thermosphere, the temperature rises continuously to an altitude of about 400 km, where it reaches 700 - 1500 ° C (depending on solar activity). Under the influence of ultraviolet and X-ray and cosmic radiation, air ionization also occurs ("polar lights"). The main areas of the ionosphere lie within the thermosphere.

Exosphere - the outer, most rarefied layer of the atmosphere, it begins at altitudes of 450,000 km, and its upper boundary is at a distance of several thousand km from the earth's surface, where the concentration of particles becomes the same as in interplanetary space. The exosphere is composed of ionized gas (plasma); the lower and middle parts of the exosphere are mainly composed of oxygen and nitrogen; with increasing altitude, the relative concentration of light gases, especially ionized hydrogen, grows rapidly. Temperature in the exosphere 1300-3000 ° С; it grows weakly with height. In the exosphere, the Earth's radiation belts are mainly located.

Earth is the 3rd planet from the Sun, located between Venus and Mars. It is the densest planet in the solar system, the largest of the four, and the only astronomical object known to contain life. According to radiometric dating and other research methods, our planet was formed about 4.54 billion years ago. The Earth interacts gravitationally with other objects in space, especially the Sun and Moon.

The earth consists of four main spheres or shells, which depend on each other and are the biological and physical components of our planet. They are scientifically called biophysical elements, namely the hydrosphere ("hydro" for water), the biosphere ("bio" for living things), the lithosphere ("litho" for land or the earth's surface), and the atmosphere ("atmosphere" for air). These major spheres of our planet are further divided into various sub-spheres.

Let's consider all four shells of the Earth in more detail in order to understand their functions and significance.

The lithosphere is the solid shell of the Earth

Scientists estimate that there are more than 1386 million km³ of water on our planet.

The oceans contain more than 97% of the Earth's water reserves. The rest is fresh water, two-thirds of which is frozen in the polar regions of the planet and on the snow-capped mountains. It is interesting to note that although water covers most of the planet's surface, it only accounts for 0.023% of the total mass of the Earth.

Biosphere - the living shell of the Earth

The biosphere is sometimes considered one big - a complex community of living and nonliving components that function as a whole. However, most often the biosphere is described as a collection of many ecological systems.

Atmosphere - Earth's air shell

The atmosphere is a collection of gases that surround our planet, held in place by Earth's gravity. Most of our atmosphere is near the earth's surface, where it is most dense. The air of the Earth is 79% nitrogen and just under 21% oxygen, as well as argon, carbon dioxide and other gases. Water vapor and dust are also part of the Earth's atmosphere. Other planets and the Moon have very different atmospheres, and some do not have one at all. There is no atmosphere in space.

The atmosphere is so widespread that it is almost invisible, but its weight is equal to a layer of water more than 10 meters deep that covers our entire planet. The lower 30 kilometers of the atmosphere contains about 98% of its total mass.

Scientists claim that many of the gases in our atmosphere were thrown into the air by early volcanoes. At that time, there was little or no free oxygen around the Earth. Free oxygen consists of oxygen molecules that are not bound to another element, such as carbon (to form carbon dioxide) or hydrogen (to form water).

Free oxygen may have been added to the atmosphere by primitive organisms, probably bacteria, at the time. Later, more complex forms added more oxygen to the atmosphere. Oxygen in today's atmosphere has probably taken millions of years to build up.

The atmosphere acts like a giant filter, absorbing most of the ultraviolet radiation and allowing the sun's rays to penetrate. Ultraviolet radiation is harmful to living things and can cause burns. Nevertheless, solar energy is essential for all life on earth.

Earth's atmosphere has. The following layers go from the planet's surface to the sky: troposphere, stratosphere, mesosphere, thermosphere and exosphere. Another layer, called the ionosphere, extends from the mesosphere to the exosphere. Outside the exosphere is space. The boundaries between the atmospheric layers are not clearly defined and vary with latitude and season.

Interrelation of the Earth's shells

All four spheres can be present in one place. For example, a piece of soil will contain minerals from the lithosphere. In addition, there will be elements of the hydrosphere, which is moisture in the soil, the biosphere like insects and plants, and even the atmosphere in the form of soil air.

All spheres are interconnected and depend on each other, as a single organism. Changes in one area will lead to changes in another. Therefore, everything that we do on our planet affects other processes within it (even if we cannot see it with our own eyes).

For people dealing with problems, it is very important to understand the interconnection of all the shells of the Earth.