ATMOSPHERE OF THE EARTH(Greek atmos steam + sphaira ball) - gas shell, surrounding earth... The mass of the atmosphere is about 5.15 · 10 15 The biological significance of the atmosphere is enormous. In the atmosphere, there is a mass-energy exchange between living and inanimate nature, between flora and fauna. Nitrogen of the atmosphere is assimilated by microorganisms; Plants synthesize organic matter from carbon dioxide and water due to the energy of the Sun and release oxygen. The presence of the atmosphere ensures the preservation of water on Earth, which is also important condition the existence of living organisms.

Research carried out using high-altitude geophysical rockets, artificial satellites Earth and interplanetary automatic stations, found that earthly atmosphere stretches for thousands of kilometers. The boundaries of the atmosphere are not constant, they are influenced by the gravitational field of the Moon and the pressure of the stream sun rays... Above the equator, in the region of the earth's shadow, the atmosphere reaches heights of about 10,000 km, and above the poles, its boundaries are 3,000 km away from the earth's surface. The bulk of the atmosphere (80-90%) is within heights of up to 12-16 km, which is explained by the exponential (nonlinear) nature of the decrease in the density (rarefaction) of its gaseous medium as the altitude increases.

The existence of most living organisms in natural conditions is possible in even narrower boundaries of the atmosphere, up to 7-8 km, where there is a combination of such atmospheric factors as gas composition, temperature, pressure, humidity necessary for the active course of biological processes. The movement and ionization of air are also of hygienic importance, precipitation, the electrical state of the atmosphere.

Gas composition

The atmosphere is a physical mixture of gases (Table 1), mainly nitrogen and oxygen (78.08 and 20.95 vol.%). The ratio of atmospheric gases is practically the same up to heights of 80-100 km. The constancy of the main part of the gas composition of the atmosphere is due to the relative balancing of the processes of gas exchange between living and inanimate nature and the continuous mixing of air masses in the horizontal and vertical directions.

Table 1. CHARACTERISTIC OF THE CHEMICAL COMPOSITION OF DRY ATMOSPHERIC AIR AT THE EARTH'S SURFACE

Gas composition	Volume concentration,%
Oxygen
Carbon dioxide
Nitrous oxide
Sulfur dioxide	0 to 0.0001
	0 to 0.000007 in summer, 0 to 0.000002 in winter
Nitrogen dioxide	0 to 0.000002
Carbon monoxide

At altitudes over 100 km, there is a change in the percentage of individual gases associated with their diffuse stratification under the influence of gravity and temperature. In addition, under the influence of the short-wavelength part of ultraviolet and x-rays at an altitude of 100 km or more, oxygen, nitrogen and carbon dioxide molecules are dissociated into atoms. At high altitudes, these gases are in the form of highly ionized atoms.

The content of carbon dioxide in the atmosphere of various regions of the Earth is less constant, which is partly due to the uneven dispersion of large industrial enterprises polluting the air, as well as uneven distribution of vegetation on the Earth, water basins that absorb carbon dioxide. Also changeable in the atmosphere and the content of aerosols (see) - suspended in the air particles ranging in size from several millimicrons to several tens of microns - formed as a result of volcanic eruptions, powerful artificial explosions, industrial pollution. The aerosol concentration decreases rapidly with height.

The most volatile and important of the variable components of the atmosphere is water vapor, the concentration of which in earth surface can range from 3% (in the tropics) to 2 × 10 -10% (in Antarctica). The higher the air temperature, the more moisture, other things being equal, can be in the atmosphere and vice versa. The bulk of water vapor is concentrated in the atmosphere up to heights of 8-10 km. The content of water vapor in the atmosphere depends on the combined influence of the processes of evaporation, condensation and horizontal transfer. At high altitudes, due to a decrease in temperature and condensation of vapors, the air is practically dry.

The atmosphere of the Earth, in addition to molecular and atomic oxygen, contains a small amount of ozone (see), the concentration of which is very variable and varies depending on the altitude and season. Most of the ozone is contained in the region of the poles by the end of the polar night at an altitude of 15-30 km with a sharp decrease up and down. Ozone occurs as a result of the photochemical action of ultraviolet solar radiation on oxygen, predominantly at altitudes of 20-50 km. Diatomic oxygen molecules partially disintegrate into atoms and, joining undecomposed molecules, form triatomic ozone molecules (polymeric, allotropic form of oxygen).

The presence in the atmosphere of a group of so-called inert gases (helium, neon, argon, krypton, xenon) is associated with the continuous course of natural radioactive decay processes.

Biological significance of gases the atmosphere is very great. For most multicellular organisms, a certain content of molecular oxygen in gas or aquatic environment is an indispensable factor of their existence, which determines the release of energy from organic substances during respiration, created initially in the course of photosynthesis. It is no coincidence that the upper boundaries of the biosphere (part of the earth's surface and the lower part of the atmosphere where life exists) are determined by the presence of a sufficient amount of oxygen. In the process of evolution, organisms have adapted to a certain level of oxygen in the atmosphere; a change in oxygen content in the direction of decreasing or increasing has an adverse effect (see Altitude sickness, Hyperoxia, Hypoxia).

The ozone-allotropic form of oxygen also has a pronounced biological effect. At concentrations not exceeding 0.0001 mg / l, which is typical for resort areas and sea coasts, ozone has a healing effect - it stimulates respiration and cardiovascular activity, improves sleep. With an increase in the concentration of ozone, its toxic effect: eye irritation, necrotic inflammation of the mucous membranes of the respiratory tract, exacerbation of pulmonary diseases, autonomic neuroses. Joining with hemoglobin, ozone forms methemoglobin, which leads to impairment of the respiratory function of the blood; it becomes difficult to transfer oxygen from the lungs to the tissues, and suffocation phenomena develop. Atomic oxygen has a similar adverse effect on the body. Ozone plays a significant role in the creation of thermal regimes in various layers of the atmosphere due to the extremely strong absorption of solar radiation and terrestrial radiation. The most intense ozone absorbs ultraviolet and infrared rays. Sun rays with wavelengths less than 300 nm are almost completely absorbed by atmospheric ozone. Thus, the Earth is surrounded by a kind of "ozone screen" that protects many organisms from the harmful effects of ultraviolet radiation from the Sun. Nitrogen of atmospheric air has an important biological significance primarily as a source of the so-called. fixed nitrogen - a resource of plant (and ultimately animal) food. The physiological significance of nitrogen is determined by its participation in creating the level of atmospheric pressure necessary for life processes. Under certain conditions, changes in pressure, nitrogen plays a major role in the development of a number of disorders in the body (see Decompression sickness). Assumptions that nitrogen weakens the toxic effect of oxygen on the body and is absorbed from the atmosphere not only by microorganisms, but also by higher animals are controversial.

Inert gases of the atmosphere (xenon, krypton, argon, neon, helium) at the partial pressure they create under normal conditions can be classified as biologically indifferent gases. With a significant increase in the partial pressure, these gases have a narcotic effect.

The presence of carbon dioxide in the atmosphere ensures the accumulation solar energy in the biosphere due to photosynthesis of complex carbon compounds, which continuously arise, change and decompose in the course of life. This dynamic system supported by the activity of algae and terrestrial plants that capture the energy of sunlight and use it to convert carbon dioxide (see) and water into various organic compounds with the release of oxygen. The length of the biosphere upward is limited in part by the fact that chlorophyll-containing plants cannot live at heights of more than 6-7 km due to the low partial pressure of carbon dioxide. Carbon dioxide is very active in physiological terms, as it plays an important role in the regulation of metabolic processes, the activity of the central nervous system, respiration, blood circulation, oxygen regime of the body. However, this regulation is mediated by the influence of carbon dioxide, formed by the body itself, and not coming from the atmosphere. In the tissues and blood of animals and humans, the partial pressure of carbon dioxide is approximately 200 times higher than the value of its pressure in the atmosphere. And only with a significant increase in the content of carbon dioxide in the atmosphere (more than 0.6-1%), there are disturbances in the body, denoted by the term hypercapnia (see). The complete elimination of carbon dioxide from the inhaled air cannot directly have an adverse effect on humans and animals.

Carbon dioxide plays a role in absorbing long-wavelength radiation and maintaining the "greenhouse effect" that raises the temperature at the Earth's surface. The problem of influence on thermal and other regimes of the atmosphere of carbon dioxide, which enters the air in huge quantities as industrial waste, is also being studied.

Water vapor in the atmosphere (air humidity) also affects the human body, in particular on heat exchange with the environment.

As a result of condensation of water vapor in the atmosphere, clouds are formed and precipitation (rain, hail, snow) falls. Water vapor, scattering solar radiation, is involved in the creation thermal conditions Land and lower layers atmosphere, in the formation of meteorological conditions.

Atmosphere pressure

Atmospheric pressure (barometric) is the pressure exerted by the atmosphere under the influence of gravity on the Earth's surface. The magnitude of this pressure at each point in the atmosphere is equal to the weight of the overlying column of air with a unit base extending over the measurement site to the boundaries of the atmosphere. Measure atmospheric pressure with a barometer (see) and expressed in millibars, in newtons per square meter or the height of the column of mercury in the barometer in millimeters, reduced to 0 ° and the normal value of the acceleration of gravity. Table 2 shows the most common units of measurement of atmospheric pressure.

The change in pressure occurs due to uneven heating of air masses located above land and water in different geographic latitudes. As the temperature rises, the density of the air and the pressure generated by it decrease. A huge accumulation of fast-moving air with reduced pressure (with a decrease in pressure from the periphery to the center of the vortex) is called a cyclone, with increased pressure (with an increase in pressure to the center of the vortex) - an anticyclone. For weather forecasting, non-periodic changes in atmospheric pressure occurring in moving vast masses and associated with the emergence, development and destruction of anticyclones and cyclones are important. Particularly large changes in atmospheric pressure are associated with the rapid movement of tropical cyclones. In this case, atmospheric pressure can change by 30-40 mbar per day.

The drop in atmospheric pressure in millibars over a distance of 100 km is called the horizontal barometric gradient. Typically, the horizontal barometric gradient is 1-3 mbar, but in tropical cyclones sometimes increase to tens of millibars per 100 km.

With the rise to altitude, atmospheric pressure decreases in a logarithmic relationship: at first very sharply, and then less and less noticeably (Fig. 1). Therefore, the barometric pressure curve is exponential.

The decrease in pressure per unit of vertical distance is called the vertical barometric gradient. Often they use its inverse value - the barometric step.

Since the barometric pressure is the sum of the partial pressures of the gases that form the air, it is obvious that with the rise to altitude, along with a decrease in the total pressure of the atmosphere, the partial pressure of the gases that make up the air also decreases. The value of the partial pressure of any gas in the atmosphere is calculated by the formula

where P x ​​is the partial pressure of the gas, Ρ z is the atmospheric pressure at an altitude of Ζ, X% is the percentage of the gas, the partial pressure of which should be determined.

Rice. 1. Change in barometric pressure with altitude above sea level.

Rice. 2. Change in the partial pressure of oxygen in the alveolar air and the saturation of arterial blood with oxygen, depending on the change in altitude when breathing air and oxygen. Oxygen breathing begins at an altitude of 8.5 km (experiment in a pressure chamber).

Rice. 3. Comparative curves of the average values ​​of active consciousness in a person in minutes per different heights after a rapid ascent while breathing air (I) and oxygen (II). At altitudes of more than 15 km, active consciousness is disturbed in the same way when breathing oxygen and air. At altitudes up to 15 km, breathing oxygen significantly prolongs the period of active consciousness (experiment in a pressure chamber).

Since the percentage of gases in the atmosphere is relatively constant, then to determine the partial pressure of any gas, you only need to know the total barometric pressure at a given altitude (Fig. 1 and Table 3).

Table 3. TABLE OF STANDARD ATMOSPHERE (GOST 4401-64) 1

Geometric height (m)	Temperature		Barometric pressure			Oxygen partial pressure (mmHg)
				mmHg Art.

1 Given in an abbreviated form and supplemented by the column "Partial pressure of oxygen".

When determining the partial pressure of a gas in humid air, the pressure (elasticity) must be subtracted from the value of the barometric pressure saturated vapors.

The formula for determining the partial pressure of a gas in humid air will be somewhat different than for dry air:

where рH 2 O - water vapor pressure. At t ° 37 ° the elasticity of saturated water vapor is 47 mm Hg. Art. This value is used to calculate the partial pressures of alveolar air gases in ground and altitude conditions.

The effect on the body of high and low blood pressure. Changes in barometric pressure upward or downward have a variety of effects on the body of animals and humans. The influence of increased pressure is associated with the mechanical and penetrating physicochemical action of the gas medium (the so-called compression and penetrating effects).

The compression effect is manifested by: general volumetric compression, due to a uniform increase in the forces of mechanical pressure on organs and tissues; mechanonarcosis due to uniform volumetric compression at very high barometric pressure; local uneven pressure on the tissues that limit gas-containing cavities when the connection between the outside air and the air in the cavity, for example, the middle ear, and the paranasal cavities, is broken (see Barotrauma); an increase in the density of gas in the external respiration system, which causes an increase in resistance respiratory movements, especially with forced breathing (exercise, hypercapnia).

The penetrating effect can lead to the toxic effect of oxygen and indifferent gases, the increase in the content of which in the blood and tissues causes a narcotic reaction, the first signs of a cut when using a nitrogen-oxygen mixture in a person appear at a pressure of 4-8 ata. An increase in the partial pressure of oxygen initially reduces the level of functioning of the cardiovascular and respiratory systems due to turning off the regulatory influence of physiological hypoxemia. With an increase in the partial pressure of oxygen in the lungs more than 0.8-1 ata, its toxic effect is manifested (damage to the lung tissue, convulsions, collapse).

The penetrating and compressive effects of the increased pressure of the gas environment are used in clinical medicine in the treatment of various diseases with general and local impairment of oxygen supply (see Barotherapy, Oxygen therapy).

Lowering the pressure has an even more pronounced effect on the body. In an extremely rarefied atmosphere, the main pathogenetic factor leading to loss of consciousness in a few seconds, and to death in 4-5 minutes is a decrease in the partial pressure of oxygen in the inhaled air, and then in the alveolar air, blood and tissues (Fig. 2 and 3). Moderate hypoxia causes the development of adaptive reactions of the respiratory system and hemodynamics, aimed at maintaining oxygen supply, primarily to vital organs (brain, heart). With a pronounced lack of oxygen, oxidative processes are inhibited (due to respiratory enzymes), aerobic processes of energy production in mitochondria are disrupted. This leads first to a breakdown in the functions of vital organs, and then to irreversible structural damage and death of the body. The development of adaptive and pathological reactions, a change in the functional state of the body and a person's performance with a decrease in atmospheric pressure is determined by the degree and rate of decrease in the partial pressure of oxygen in the inhaled air, the duration of stay at altitude, the intensity of the work performed, and the initial state of the body (see Altitude sickness).

A decrease in pressure at altitudes (even if the lack of oxygen is excluded) causes serious disorders in the body, united by the concept of "decompression disorders", which include: high-altitude flatulence, barotitis and barosinusitis, high-altitude decompression sickness and high-altitude tissue emphysema.

High-altitude flatulence develops due to the expansion of gases in the gastrointestinal tract with a decrease in barometric pressure on the abdominal wall when climbing to heights of 7-12 km or more. The release of gases dissolved in the intestinal contents is also of some importance.

Expansion of gases leads to stretching of the stomach and intestines, raising the diaphragm, changing the position of the heart, irritation of the receptor apparatus of these organs and the appearance of pathological reflexes that disrupt breathing and blood circulation. Often there are sharp pains in the abdomen. Divers sometimes experience similar phenomena when they ascend from depth to the surface.

The mechanism of development of barotitis and barosinusitis, manifested by a feeling of stuffiness and pain in the middle ear or paranasal cavities, respectively, is similar to the development of high-altitude flatulence.

A decrease in pressure, in addition to the expansion of gases contained in the body cavities, also causes the release of gases from liquids and tissues in which they were dissolved under pressure at sea level or at depth, and the formation of gas bubbles in the body.

This process of release of dissolved gases (primarily nitrogen) causes the development of decompression sickness (see).

Rice. 4. Dependence of the boiling point of water on the altitude and barometric pressure. Pressure numbers are located below the corresponding altitude numbers.

With a decrease in atmospheric pressure, the boiling point of liquids decreases (Fig. 4). At an altitude of more than 19 km, where the barometric pressure is equal to (or less) the elasticity of saturated vapors at body temperature (37 °), the interstitial and intercellular fluid of the body may "boil", as a result of which in large veins, in the cavity of the pleura, stomach, pericardium , in loose adipose tissue, that is, in areas with low hydrostatic and interstitial pressure, water vapor bubbles form, high-altitude tissue emphysema develops. High-altitude "boiling" does not affect cellular structures, localizing only in the intercellular fluid and blood.

Massive bubbles of steam can block the heart and blood circulation and disrupt vital systems and organs. This is a serious complication of acute oxygen starvation, which develops at high altitudes. Prevention of high-altitude tissue emphysema can be ensured by the creation of external counterpressure on the body with high-altitude equipment.

The very process of lowering the barometric pressure (decompression) under certain parameters can become a damaging factor. Depending on the speed, decompression is divided into smooth (slow) and explosive. The latter takes place in less than 1 second and is accompanied by a strong pop (as in a shot), the formation of fog (condensation of water vapor due to cooling of the expanding air). Usually, explosive decompression occurs at altitudes when the glazing of a sealed cabin or an overpressure spacesuit is destroyed.

Explosive decompression primarily affects the lungs. A rapid increase in intrapulmonary excess pressure (more than 80 mm Hg) leads to a significant stretching of the lung tissue, which can cause lung rupture (when they expand by 2.3 times). Explosive decompression can damage the gastrointestinal tract as well. The magnitude of the resulting excess pressure in the lungs will largely depend on the rate of air outflow from them during decompression and the volume of air in the lungs. It is especially dangerous if the upper airways are closed at the time of decompression (when swallowing, holding the breath) or decompression coincides with the deep inspiration phase, when the lungs are filled large quantity air.

Atmosphere temperature

The atmospheric temperature initially decreases with increasing altitude (on average, from 15 ° at the ground to -56.5 ° at an altitude of 11-18 km). The vertical temperature gradient in this zone of the atmosphere is about 0.6 ° for every 100 m; it changes during the day and year (Table 4).

Table 4. CHANGES IN THE VERTICAL TEMPERATURE GRADIENT ABOVE THE MIDDLE STRIP OF THE USSR

Rice. 5. Change in atmospheric temperature at different heights. The boundaries of the spheres are indicated by a dotted line.

At altitudes of 11-25 km, the temperature becomes constant and amounts to -56.5 °; then the temperature begins to rise, reaching 30-40 ° at an altitude of 40 km, and 70 ° at an altitude of 50-60 km (Fig. 5), which is associated with the intense absorption of solar radiation by ozone. From an altitude of 60-80 km, the air temperature again slightly decreases (up to 60 °), and then progressively rises and is 270 ° at an altitude of 120 km, 800 ° at 220 km, 1500 ° at an altitude of 300 km, and

on the border with outer space - more than 3000 °. It should be noted that due to the high rarefaction and low density of gases at these altitudes, their heat capacity and the ability to heat colder bodies are very insignificant. Under these conditions, the transfer of heat from one body to another occurs only through radiation. All considered changes in temperature in the atmosphere are associated with the absorption of thermal energy of the Sun by air masses - direct and reflected.

In the lower part of the atmosphere near the Earth's surface, the temperature distribution depends on the influx of solar radiation and therefore has a mainly latitudinal character, that is, lines of equal temperature - isotherms - are parallel to latitudes. Since the atmosphere in the lower layers is heated from the earth's surface, the horizontal temperature change is strongly influenced by the distribution of continents and oceans, the thermal properties of which are different. Typically, reference books indicate the temperature measured at network meteorological observations thermometer installed at a height of 2 m above the soil surface. The highest temperatures (up to 58 ° C) are observed in the deserts of Iran, and in the USSR - in the south of Turkmenistan (up to 50 °), the lowest (up to -87 °) in Antarctica, and in the USSR - in the regions of Verkhoyansk and Oymyakon (up to -68 ° ). In winter, the vertical temperature gradient in some cases, instead of 0.6 °, can exceed 1 ° per 100 m or even take a negative value. During the day, in the warm season, it can be equal to many tens of degrees per 100 m. There is also a horizontal temperature gradient, which is usually referred to a distance of 100 km along the normal to the isotherm. The value of the horizontal temperature gradient is tenths of a degree per 100 km, and during frontal zones it can exceed 10 ° at 100 m.

The human body is able to maintain thermal homeostasis (see) in a fairly narrow range of fluctuations in the outside air temperature - from 15 to 45 °. Significant differences Atmospheric temperatures near the Earth and at altitudes require the use of special protective technical means to ensure a thermal balance between the human body and the external environment in high-altitude and space flights.

Typical changes in atmospheric parameters (temperature, pressure, chemical composition, electrical state) allow you to conditionally divide the atmosphere into zones or layers. Troposphere- the closest layer to the Earth, the upper boundary of which extends at the equator up to 17-18 km, at the poles - up to 7-8 km, in middle latitudes - up to 12-16 km. The troposphere is characterized by an exponential drop in pressure, the presence of a constant vertical temperature gradient, horizontal and vertical movements of air masses, and significant changes in air humidity. The troposphere contains the bulk of the atmosphere, as well as a significant part of the biosphere; all major types of clouds arise here, form air masses and fronts, cyclones and anticyclones develop. In the troposphere, due to the reflection of the sun's rays by the snow cover of the Earth and the cooling of the surface layers of the air, the so-called inversion takes place, that is, an increase in temperature in the atmosphere from the bottom up instead of the usual decrease.

In the warm season, constant turbulent (random, chaotic) mixing of air masses and heat transfer by air flows (convection) occur in the troposphere. Convection destroys fog and reduces dust in the lower atmosphere.

The second layer of the atmosphere is stratosphere.

It starts from the troposphere in a narrow zone (1-3 km) with a constant temperature (tropopause) and extends to heights of about 80 km. A feature of the stratosphere is the progressive thinness of the air, extremely high intensity of ultraviolet radiation, the absence of water vapor, the presence of a large amount of ozone and a gradual rise in temperature. The high ozone content causes a number of optical phenomena (mirages), causes the reflection of sounds and has a significant effect on the intensity and spectral composition of electromagnetic radiation. Constant mixing of air occurs in the stratosphere, so its composition is similar to that of the troposphere, although its density at the upper boundaries of the stratosphere is extremely low. The prevailing winds in the stratosphere are westerly, and in the upper zone there is a transition to easterly winds.

The third layer of the atmosphere is ionosphere, which starts from the stratosphere and extends to heights of 600-800 km.

The distinctive features of the ionosphere are the extreme rarefaction of the gaseous medium, a high concentration of molecular and atomic ions and free electrons, as well as a high temperature. The ionosphere influences the propagation of radio waves, causing their refraction, reflection and absorption.

The main source of ionization of the high layers of the atmosphere is the ultraviolet radiation of the Sun. In this case, electrons are knocked out of gas atoms, the atoms turn into positive ions, and the knocked out electrons remain free or are captured by neutral molecules with the formation of negative ions. The ionization of the ionosphere is influenced by meteors, corpuscular, X-ray and gamma radiation from the Sun, as well as the seismic processes of the Earth (earthquakes, volcanic eruptions, powerful explosions) that generate acoustic waves in the ionosphere, increasing the amplitude and speed of oscillations of atmospheric particles and contributing to the ionization of gas molecules and atoms (see. Aeroionization).

The electrical conductivity in the ionosphere, associated with a high concentration of ions and electrons, is very high. The increased electrical conductivity of the ionosphere plays an important role in the reflection of radio waves and the appearance of auroras.

The ionosphere is the field of flights of artificial earth satellites and intercontinental ballistic missiles. Currently, space medicine is studying the possible effects of flight conditions in this part of the atmosphere on the human body.

The fourth, outer layer of the atmosphere - exosphere... From here, atmospheric gases are scattered into world space due to dissipation (molecules overcome the forces of gravity). Then there is a gradual transition from the atmosphere to interplanetary space. The exosphere differs from the latter by the presence of a large number of free electrons that form the 2nd and 3rd radiation belts of the Earth.

The division of the atmosphere into 4 layers is very arbitrary. So, according to electrical parameters, the entire thickness of the atmosphere is divided into 2 layers: the neutrosphere, in which neutral particles predominate, and the ionosphere. The troposphere, stratosphere, mesosphere and thermosphere are distinguished by temperature, separated by tropo-, strato- and mesopause, respectively. The layer of the atmosphere located between 15 and 70 km and characterized by a high ozone content is called the ozonosphere.

For practical purposes, it is convenient to use the International Standard Atmosphere (MCA), for a cut they accept following conditions: pressure at sea level at t ° 15 ° is 1013 mbar (1.013 X 10 5 nm 2, or 760 mm Hg); the temperature decreases by 6.5 ° per 1 km to the level of 11 km (conditional stratosphere), and then remains constant. In the USSR, the standard atmosphere is GOST 4401 - 64 (Table 3).

Precipitation. Since the bulk of atmospheric water vapor is concentrated in the troposphere, the processes phase transitions precipitation waters flow mainly in the troposphere. Tropospheric clouds usually cover about 50% of the entire earth's surface, while clouds in the stratosphere (at altitudes of 20-30 km) and near the mesopause, called nacreous and silvery, respectively, are relatively rare. As a result of condensation of water vapor in the troposphere, clouds are formed and precipitation falls.

By the nature of precipitation, precipitation is divided into 3 types: overburden, heavy rainfall, drizzling. The amount of precipitation is determined by the thickness of the layer of precipitated water in millimeters; precipitation is measured by rain gauges and rain gauges. Precipitation intensity is expressed in millimeters per minute.

The distribution of precipitation in individual seasons and days, as well as throughout the territory, is extremely uneven, due to the circulation of the atmosphere and the influence of the Earth's surface. So, on the Hawaiian Islands, an average of 12,000 mm falls per year, and in the driest regions of Peru and the Sahara, precipitation does not exceed 250 mm, and sometimes it does not fall for several years. In the annual dynamics of precipitation, the following types are distinguished: equatorial - with a maximum precipitation after the spring and autumn equinox; tropical - with maximum precipitation in summer; monsoon - with a very pronounced peak in summer and dry winter; subtropical - with maximum precipitation in winter and dry summer; continental temperate latitudes- with a maximum precipitation in summer; marine temperate latitudes - with a maximum precipitation in winter.

The entire atmospheric-physical complex of climatic and meteorological factors that make up the weather is widely used to promote health, hardening and medicinal purposes(see Climatotherapy). Along with this, it was established that sharp fluctuations of these atmospheric factors can negatively affect the physiological processes in the body, causing the development of various pathological conditions and exacerbation of diseases called meteotropic reactions (see Climatopathology). Special meaning in this respect, there are frequent long-term disturbances of the atmosphere and sharp abrupt fluctuations of meteorological factors.

Meteotropic reactions are observed more often in people suffering from diseases of the cardiovascular system, polyarthritis, bronchial asthma, peptic ulcer, skin diseases.

Bibliography: Belinsky VA and Pobyakho VA Aerology, L., 1962, bibliogr .; Biosphere and Its Resources, ed. V.A.Kovdy, M., 1971; Danilov A. D. Chemistry of the ionosphere, L., 1967; Kolobkov N. V. Atmosphere and her life, M., 1968; Kalitin H.H. Fundamentals of atmospheric physics as applied to medicine, L., 1935; Matveev LT Fundamentals of general meteorology, Physics of the atmosphere, L., 1965, bibliogr .; Minkh A.A.Air ionization and its hygienic value, M., 1963, bibliogr .; he, Methods of hygienic research, M., 1971, bibliogr .; Tverskoy P. N. Course of meteorology, L., 1962; Umansky S. P. Man in space, M., 1970; Khvostikov I. A. High layers of the atmosphere, L., 1964; X p and and A. X. Physics of the atmosphere, L., 1969, bibliogr .; Khromov S.P. Meteorology and climatology for geographical faculties, L., 1968.

The effect on the body of high and low blood pressure- Armstrong G. Aviation Medicine, trans. from English, M., 1954, bibliogr .; Zaltsman G.L. Physiological foundations of a person's stay in conditions of increased pressure of gases of the environment, L., 1961, bibliogr .; Ivanov DI and Khromushkin AI Human life support systems for high-altitude and space flights, M., 1968, bibliogr .; Isakov P.K., etc. Theory and practice of aviation medicine, M., 1971, bibliogr .; Kovalenko EA and Chernyakov IN. Tissue oxygen at extreme flight factors, M., 1972, bibliogr .; Miles S. Underwater medicine, trans. from English, M., 1971, bibliogr .; Busby D.E. Space clinical medicine, Dordrecht, 1968.

I. H. Chernyakov, M. T. Dmitriev, S. I. Nepomnyashchy.

The stratosphere (from the Latin stratum - flooring, layer) is the layer of the atmosphere with a height from 11 to 50 km located above the troposphere. The transition from the troposphere to the stratosphere occurs smoothly, since between them there is a thin intermediate layer called the tropopause, in which the temperature does not decrease with height. The main feature of the stratosphere is the increase in temperature with height. In the lower part of this layer (up to an altitude of 25 km), the temperature is stable or grows slowly with height, but from a level of 34 - 36 km, the temperature rise begins to increase. The rise in temperature continues until the stratopause - the upper boundary of the stratosphere, which is as warm as the air masses at the Earth's surface.

Compound

The high stability of the stratosphere is due to an increase in temperature with height. Unlike the troposphere, in this layer there is no ordered vertical movement of air and its mixing, but there are small vertical movements in the form of slow subsidence or rise, covering the layers of the stratosphere over vast spaces. Heating of air in the stratosphere occurs due to the absorption of ultraviolet radiation by ozone, and cooling - due to the long-wave radiation of H2O and CO2 molecules. Therefore, in low latitudes ah, where the content of H2O and CO2 is increased, and O3 is less, it is colder than over high latitudes of the stratosphere. In the stratosphere at an altitude of 20 - 25 km in summer, the wind direction changes from west to east, and in winter, westerly winds constantly blow. At the upper boundary of the stratosphere, the highest wind speeds are observed, as well as jet currents.

At the bottom of the stratosphere at an altitude of 20 - 25 km there is an increased content of aerosol particles, especially sulfate ones, which are brought here during volcanic eruptions. Here they persist longer than in the troposphere, due to low turbulent exchange and the absence of precipitation washout.

There is very little water vapor in the stratosphere, but sometimes nacreous clouds are observed at high latitudes. at an altitude of 22 - 24 km ... They are especially clearly visible at night, illuminated by the Sun below the horizon. These clouds are thought to form from supercooled droplets or ice crystals.

In the stratosphere, the gas composition of the air practically does not differ from that in the troposphere, but it has a difference, namely, an increased content of ozone (O3). The stratosphere can be called the ozonosphere due to the presence of an ozone layer in it. The ozone layer was formed and is preserved due to the interaction of the sun's ultraviolet rays with oxygen molecules, and serves as a reliable barrier to ultraviolet radiation, which is harmful to all living organisms. When solar energy is absorbed by the ozone layer, the temperature of the atmosphere rises, and therefore, the ozone layer is a kind of heat reservoir in the atmosphere. Up to an altitude of 10 km and more than 60 km, the atmosphere is almost completely devoid of ozone, and its maximum concentration is concentrated at an altitude of 20-30 km. In the stratosphere, the thermal regime is mainly determined by radiant heat transfer. Ozone is destroyed when interacting with NO, with free radicals, halogen-containing compounds.

In the stratosphere, the main part of the short-wave part of ultraviolet radiation (180-200 nm) remains and the energy of short waves is transformed. Under the influence of ultraviolet rays, magnetic fields change, molecules decay, ionization, new gases and others are formed chemical compounds... In nature, these processes are observed as aurora borealis, lightning and other glow.

Related materials:

Layers of the atmosphere in order from the surface of the Earth

The role of the atmosphere in the life of the Earth

The atmosphere is the source of oxygen that humans breathe. However, when climbing to altitude, the total atmospheric pressure drops, which leads to a decrease in the partial oxygen pressure.

Human lungs contain approximately three liters of alveolar air. If atmospheric pressure is normal, then the partial oxygen pressure in the alveolar air will be 11 mm Hg. Art., the pressure of carbon dioxide is 40 mm Hg. Art., and water vapor - 47 mm Hg. Art. With increasing altitude, oxygen pressure decreases, and the pressure of water vapor and carbon dioxide in the lungs in total will remain constant - approximately 87 mm Hg. Art. When the air pressure equals this value, oxygen will stop flowing to the lungs.

Due to the decrease in atmospheric pressure at an altitude of 20 km, water and interstitial body fluid will boil here in human body... If you do not use a pressurized cabin, a person will die almost instantly at this height. Therefore, from the point of view of the physiological characteristics of the human body, "space" originates from an altitude of 20 km above sea level.

The role of the atmosphere in the life of the Earth is very great. So, for example, thanks to the dense air layers - the troposphere and stratosphere, people are protected from radiation exposure. In space, in thin air, at an altitude of over 36 km, ionizing radiation acts. At an altitude of over 40 km - ultraviolet.

When rising above the Earth's surface to an altitude of more than 90-100 km, a gradual weakening, and then a complete disappearance of the phenomena familiar to humans, observed in the lower atmospheric layer, will be observed:

Sound does not propagate.

There is no aerodynamic force or drag.

Heat is not transferred by convection, etc.

The atmospheric layer protects the Earth and all living organisms from space radiation, from meteorites, is responsible for regulating seasonal temperature fluctuations, balancing and leveling diurnal. With no atmosphere on Earth daily temperature would fluctuate within +/- 200C˚. The atmospheric layer is a life-giving "buffer" between the earth's surface and space, a carrier of moisture and heat, the processes of photosynthesis and energy exchange, the most important biospheric processes, take place in the atmosphere.

Layers of the atmosphere in order from the surface of the Earth

The atmosphere is a layered structure representing the following layers of the atmosphere in order from the surface of the Earth:

Troposphere.

Stratosphere.

Mesosphere.

Thermosphere.

Exosphere

Each layer has no sharp boundaries between each other, and their height is influenced by latitude and seasons. Such a layered structure was formed as a result temperature changes at various heights. It is thanks to the atmosphere that we see the twinkling stars.

The structure of the Earth's atmosphere by layers:

What is the Earth's atmosphere made of?

Each atmospheric layer differs in temperature, density and composition. The total thickness of the atmosphere is 1.5-2.0 thousand km. What is the Earth's atmosphere made of? Currently, it is a mixture of gases with various impurities.

Troposphere

The structure of the Earth's atmosphere begins with the troposphere, which is the lower part of the atmosphere approximately 10-15 km high. The main part of the atmospheric air is concentrated here. Characteristic troposphere - temperature drop by 0.6 ˚C as it rises upward for every 100 meters. The troposphere has concentrated almost all atmospheric water vapor, and clouds form here.

The height of the troposphere changes daily. In addition, its average value changes depending on the latitude and season of the year. The average height of the troposphere above the poles is 9 km, above the equator - about 17 km. Average indicators annual temperature air above the equator is close to +26 ˚C, and above the North Pole -23 ˚C. The upper line of the tropospheric boundary above the equator is average annual temperature about -70 ˚C, and over the North Pole in summer -45 ˚C and in winter -65 ˚C. Thus, the higher the altitude, the lower the temperature. The sun's rays pass unhindered through the troposphere, heating the Earth's surface. The heat radiated from the sun is trapped by carbon dioxide, methane and water vapor.

Stratosphere

Above the tropospheric layer is the stratosphere, which is 50-55 km high. The peculiarity of this layer is the rise in temperature with height. Between the troposphere and the stratosphere there is a transitional layer called the tropopause.

From an altitude of about 25 kilometers, the temperature of the stratospheric layer begins to increase and, upon reaching maximum height 50 km takes on values ​​from +10 to +30 ˚C.

There is very little water vapor in the stratosphere. Sometimes, at an altitude of about 25 km, you can find rather thin clouds, which are called "nacreous". In the daytime they are not noticeable, and at night they glow due to the illumination of the sun, which is below the horizon. The composition of nacreous clouds is supercooled water droplets. The stratosphere is composed primarily of ozone.

Mesosphere

The height of the mesosphere is approximately 80 km. Here, as it rises upward, the temperature decreases and at the uppermost boundary reaches values ​​of several tens of C˚ below zero. Clouds can also be observed in the mesosphere, presumably formed from ice crystals. These clouds are called "silvery". The mesosphere is characterized by the most cold temperature in the atmosphere: -2 to -138 ˚C.

Thermosphere

This atmospheric layer got its name thanks to high temperatures... The thermosphere consists of:

Ionosphere.

Exospheres.

The ionosphere is characterized by rarefied air, each centimeter of which at an altitude of 300 km consists of 1 billion atoms and molecules, and at an altitude of 600 km - of more than 100 million.

Also, the ionosphere is characterized by high air ionization. These ions are made up of charged oxygen atoms, charged molecules of nitrogen atoms, and free electrons.

Exosphere

The exospheric layer begins at an altitude of 800-1000 km. Particles of gas, especially light ones, move here with great speed, overcoming the force of gravity. Such particles, due to their rapid movement, fly out of the atmosphere into space and scatter. Therefore, the exosphere is called the sphere of dispersion. Mostly hydrogen atoms, which make up the highest layers of the exosphere, fly out into space. Particles in the upper atmosphere and particles solar wind we can observe the northern lights.

Satellites and geophysical rockets made it possible to establish the presence in the upper atmosphere of the planet's radiation belt, consisting of electrically charged particles - electrons and protons.

Blue planet ...

This topic should have appeared on the site one of the first. After all, helicopters are atmospheric aircraft. Atmosphere of earth- their, so to speak, habitat :-). A physical properties of air just determine the quality of this habitat :-). That is, this is one of the foundations. And they always write about the base first. But I realized this only now. However, it is better, as you know, late than never ... Let's touch on this issue, but without getting into the jungle and unnecessary difficulties :-).

So… Atmosphere of earth... This is the gas envelope of our blue planet. Everyone knows this name. Why blue? Simply because the "blue" (as well as blue and violet) component of sunlight (spectrum) is best scattered in the atmosphere, thus coloring it bluish-bluish, sometimes with a tinge of purple tones (on a sunny day, of course :-)) ...

Composition of the Earth's atmosphere.

The composition of the atmosphere is wide enough. I will not list all the components in the text, for this there is a good illustration. The composition of all these gases is practically constant, with the exception of carbon dioxide (CO 2). In addition, the atmosphere necessarily contains water in the form of vapors, suspension of droplets or ice crystals. The amount of water is variable and depends on temperature and, to a lesser extent, on air pressure. In addition, the Earth's atmosphere (especially the current one) contains a certain amount, I would say "all sorts of nasty things" :-). These are SO 2, NH 3, CO, HCl, NO, in addition, there are Hg mercury vapors. True, all this is there in small quantities, thank God :-).

Atmosphere of earth it is customary to divide into several zones following each other in height above the surface.

The first, closest to the earth, is the troposphere. This is the lowest and, so to speak, the main layer for life. different kind... It contains 80% of the mass of all atmospheric air (although by volume it makes up only about 1% of the entire atmosphere) and about 90% of all atmospheric water. The bulk of all winds, clouds, rains and snows 🙂 come from there. The troposphere extends to heights of about 18 km in tropical latitudes and up to 10 km in the polar ones. The air temperature in it drops with a rise to a height of about 0.65º for every 100 m.

Atmospheric zones.

Zone two is the stratosphere. It must be said that another narrow zone is distinguished between the troposphere and stratosphere - the tropopause. The temperature drop with height stops in it. The tropopause has an average thickness of 1.5-2 km, but its boundaries are indistinct and the troposphere often overlaps the stratosphere.

So the stratosphere has an average height of 12 km to 50 km. The temperature in it remains unchanged up to 25 km (about -57 ° C), then somewhere up to 40 km it rises to about 0 ° C and then remains unchanged up to 50 km. The stratosphere is a relatively calm part of the earth's atmosphere. There are practically no unfavorable weather conditions in it. It is in the stratosphere that the famous ozone layer is located at altitudes from 15-20 km to 55-60 km.

This is followed by a small boundary layer stratopause, in which the temperature remains at about 0 ° C, and then the next zone is the mesosphere. It extends to heights of 80-90 km, and the temperature in it drops to about 80 ° C. In the mesosphere, small meteors usually become visible, which begin to glow in it and burn out there.

The next narrow gap is the mesopause followed by the thermosphere zone. Its height is up to 700-800 km. Here the temperature starts to rise again and at altitudes of the order of 300 km can reach values ​​of the order of 1200 ° C. Further, it remains constant. The ionosphere is located inside the thermosphere up to an altitude of about 400 km. Here the air is highly ionized due to exposure to solar radiation and has a high electrical conductivity.

The next and, in general, the last zone is the exosphere. This is the so-called scattering zone. There is mainly very rarefied hydrogen and helium (with a predominance of hydrogen). At altitudes of about 3000 km, the exosphere transforms into a near-space vacuum.

That's something like this. Why approximately? Because these layers are rather conventional. Various changes in altitude, composition of gases, water, temperature, ionization, and so on are possible. In addition, there are many more terms that define the structure and state of the earth's atmosphere.

For example the homosphere and heterosphere. In the first, atmospheric gases are well mixed, and their composition is fairly uniform. The second is located above the first and there is practically no such mixing there. Gases in it are separated by gravity. The boundary between these layers is located at an altitude of 120 km, and it is called the turbopause.

I'll probably end the terms, but I will definitely add that it is conventionally assumed that the boundary of the atmosphere is located at an altitude of 100 km above sea level. This border is called the Pocket Line.

I will add two more pictures to illustrate the structure of the atmosphere. The first, however, is in German, but complete and quite easy to understand :-). It can be enlarged and well seen. The second shows the change in the temperature of the atmosphere with height.

The structure of the Earth's atmosphere.

Change in air temperature with altitude.

Modern manned orbital spacecraft fly at altitudes of about 300-400 km. However, this is no longer aviation, although the region is, of course, closely related in a certain sense, and we will certainly talk about it again :-).

The aviation zone is the troposphere. Modern atmospheric aircraft can fly in the lower layers of the stratosphere. For example, the practical ceiling of the MIG-25RB is 23,000 m.

Flight in the stratosphere.

And exactly physical properties of air the troposphere determine how the flight will be, how effective the aircraft control system will be, how turbulence in the atmosphere will affect it, how the engines will work.

The first main property is air temperature... In gas dynamics, it can be determined on the Celsius scale or on the Kelvin scale.

Temperature t 1 at a given height N on the Celsius scale is defined:

t 1 = t - 6.5H, where t- air temperature near the ground.

The temperature on the Kelvin scale is called absolute temperature , zero on this scale is absolute zero. At absolute zero, the thermal motion of the molecules stops. Absolute zero on the Kelvin scale corresponds to -273º on the Celsius scale.

Accordingly, the temperature T on high N on the Kelvin scale is determined:

T = 273K + t - 6.5H

Air pressure... Atmospheric pressure is measured in Pascals (N / m 2), in the old system of measurement in atmospheres (atm.). There is also such a thing as barometric pressure. This is the pressure measured in millimeters. mercury column using a mercury barometer. Barometric pressure (pressure at sea level) equal to 760 mm Hg. Art. called standard. In physics, 1 atm. is exactly equal to 760 mm Hg.

Air density... In aerodynamics, the most commonly used concept is the mass density of air. This is a mass of air in 1 m 3 volume. The density of the air changes with height, the air becomes more rarefied.

Air humidity... Shows the amount of water in the air. There is a concept “ relative humidity". This is the ratio of the mass of water vapor to the maximum possible at a given temperature. The concept of 0%, that is, when the air is completely dry, it can only exist in the laboratory. On the other hand, 100% humidity is real. This means that the air has absorbed all the water that it could absorb. Something like an absolutely "full sponge". High relative humidity lowers the air density, while low relative humidity increases it accordingly.

Due to the fact that aircraft flights take place under different atmospheric conditions, their flight and aerodynamic parameters in the same flight mode may be different. Therefore for correct assessment of these parameters introduced International Standard Atmosphere (ISA)... It shows the change in the state of the air as it rises to altitude.

The main parameters of the state of air at zero humidity are taken:

pressure P = 760 mm Hg. Art. (101.3 kPa);

temperature t = + 15 ° C (288 K);

mass density ρ = 1.225 kg / m 3;

For ISA it is accepted (as it was said above :-)) that the temperature drops in the troposphere by 0.65º for every 100 meters of height.

Standard atmosphere (example up to 10,000 m).

ISA tables are used for instrument calibration, as well as for navigational and engineering calculations.

Physical properties of air also includes concepts such as inertness, viscosity and compressibility.

Inertia is a property of air that characterizes its ability to resist a change in the state of rest or uniform rectilinear movement . The measure of inertness is the mass density of the air. The higher it is, the higher the inertness and resistance force of the medium when the aircraft moves in it.

Viscosity. Determines the air frictional resistance when the aircraft is moving.

Compressibility measures the change in air density as pressure changes. At low speeds aircraft(up to 450 km / h) pressure changes when flowing around it air flow does not occur, but at high speeds the effect of compressibility begins to manifest itself. Its influence on supersound is especially affected. This is a separate area of ​​aerodynamics and a topic for a separate article :-).

Well, that seems to be all for now ... It's time to finish this slightly boring enumeration, which, however, cannot be done without :-). Atmosphere of earth, its parameters, physical properties of air as important for the aircraft as the parameters of the aircraft itself, and it was impossible not to mention them.

Bye, until next meetings and more interesting topics 🙂 ...

P.S. For sweets, I suggest watching a video shot from the cockpit of the MIG-25PU twin during its flight into the stratosphere. It was apparently a tourist who had money for such flights :-). Filmed basically all through the windshield. Pay attention to the color of the sky ...

Stratosphere

Above the tropopause, up to an altitude of 50-60 km, there is a layer of the atmosphere called stratosphere, the main feature of which is the rise in temperature with height. In the lower part of the stratosphere, up to an altitude of about 25 km, the temperature is constant or slowly increases with height. It should be noted that in winter months at high latitudes, it may even fall slightly. But from an altitude of 34 - 36 km, the temperature begins to rise faster. This increase continues to the upper boundary of the stratosphere, called stratopause... Here, the stratosphere is almost as warm as the air at the Earth's surface.

An increase in temperature with height leads to a high stability of the stratosphere: there are no ordered (convective) vertical air movements and its active mixing, which is characteristic of the troposphere. However, very small in magnitude vertical movements such as slow subsidence or rise sometimes cover the stratospheric layers, which occupy huge spaces.

Water vapor in the stratosphere is negligible. However, at heights of 22 - 24 km in high latitudes are sometimes observed. During the day they are not visible, but at night they seem to be luminous, since they are illuminated by the Sun below the horizon. These clouds are believed to be composed of supercooled droplets.

The composition of the air in the stratosphere is practically the same as in the troposphere, but there is a difference. In the stratosphere, there is an increased content of ozone, an unstable gas, the molecule of which consists of three oxygen atoms. Ozone layer formed and supported by the interaction of ultraviolet radiation from the Sun with ordinary oxygen molecules and serves as a reliable shield on the path of this destructive for all living radiation. Due to the presence of an ozone layer in the stratosphere, it can also be called ozonosphere.

... Once discovered in the troposphere, the drop in temperature with height was mistakenly considered a property of the entire atmosphere, which was explained by the distance from the Earth's surface heated by the Sun. But the very first ascents of balloons with instruments on board gave unexpected data. It turned out that the temperature drops to about an altitude of 10 km, after which it practically does not change, and then even starts to rise slightly. These data went against the established ideas about the vertical change in temperature in the atmosphere. Before launching the balloons, the devices began to be checked more thoroughly, and night launches were also practiced, excluding the heating of devices by the Sun. However, more and more launches brought the same data that the temperature drop with altitude stops. As a result, we had to accept the fact that the laws in force in the lower part of the atmosphere cease to work above a certain height. Thus, for the first time, the atmosphere was divided into layers. The layer in which the temperature decreases with height was called the troposphere, and the layer of the atmosphere in which the temperature stopped decreasing with height - the stratosphere. Considering that the balloons had significant restrictions on the height of their ascent, they could not reach the next layer of the atmosphere - mesosphere, in which the temperature starts to drop again as it rises. As a result, the entire upper atmosphere began to be considered the stratosphere.

It should be noted that the transition from the troposphere to the stratosphere does not occur abruptly. Between them lies an intermediate layer, up to several kilometers thick, in which the temperature drop with height stops and the isothermal layer begins. This layer is called tropopause.

The reason for the rise in temperature in the stratosphere was not immediately discovered. It turned out to be a gas discovered back in 1785, which received the name in 1840 - ozone... As a result of absorption of solar energy, which occurs already in the upper part of the ozone layer, the temperature of the atmosphere at these altitudes rises, and the ozone layer is a kind of heat reservoir in the atmosphere. The ozone content in the lower atmosphere (up to an altitude of 10 km) is negligible. And its greatest content is at altitudes of 20 - 25 km. Ozone molecules are not found at altitudes over 60 km. Data on the ozone content at altitudes were obtained very in an interesting way: a spectrograph was installed on a balloon or meteorological rocket, recording the spectrum of the sun. It is known that when observing from the Earth's surface, the spectrum of the Sun is cut off in the ultraviolet part. When it became clear that this was due to the absorption of solar ultraviolet radiation by ozone, the launching of probes and rockets with spectrographs on board became a logical method for assessing the ozone content at altitudes.

The rise in temperature in the stratosphere starts from about 30 km and continues up to 40-50 km, where the upper part of the ozone layer is located. Despite the fact that there is less ozone here than at lower levels, it is this part of the layer that faces the sun and is heated more strongly by the ultraviolet rays absorbed by it.

The increase in temperature at an altitude of about 40-50 km, as determined by the results of sounding, was confirmed in 1920, when on May 9, a strong explosion of artillery depots took place in Moscow. The sound from the explosion was clearly audible near Moscow - at a distance of up to 60 km, and then again at a great distance in points located in a ring around the city. Between these two zones of audibility there was a “zone of silence” 100 km wide, where the explosion was not heard at all. Professor V.I. Witkiewicz investigated this phenomenon and came to the conclusion that such a distribution of the audibility of sound can be observed if it is reflected from the layers of the atmosphere located at an altitude of 40-50 km. But at the same time, the temperature of the reflective layers should be about plus 40 - 50 degrees.

We have already mentioned the important role of the ozone layer in preserving life on Earth. But in 1985, scientists made public the sensational news: over Antarctica discovered the ozone hole diameter over 1000 km! Every year it appeared here in August, and by December - January it ceased to exist. A smaller ozone hole has also been found over the Arctic. It should be noted that changes in the ozone layer, its decrease, are caused not only by the influence anthropogenic factors... The existing natural changes in wave activity and dynamics of the stratosphere significantly affect the variations in ozone over time. Global interannual variations in total ozone (TO) are indicators of climate change. For example, a noticeable decrease in ozone content in the period between 1979 - 1994. above Western Europe, Eastern Siberia and the eastern United States are associated with a warming climate in these areas, an increase in ozone content in the Labrador region - with a cooling in Greenland and the Western Atlantic.

There are also connections between TO variations in some geographic regions and surface temperature anomalies in others. For example, analysis of interannual TO variations in January and surface temperature in February 1979 - 1994. showed that in order to predict what kind of weather (cold or warm) will be in February in Western Siberia, you need to look at the ozone content at a point west of England (50 ° N, 10 ° W).

The first ascents of the balloon-probes to the maximum height they reached showed that the total temperature variation above the tropopause was quite constant. Hence, it was concluded that at these heights there is no (or almost no) vertical mixing of air. Later high radiosonde ascents made it possible to detect significant seasonal (monsoon) changes in the equator-pole temperature gradient and associated changes in the pressure and wind regime. Another important discovery is related to the significant intraseasonal changes in temperature, wind and ozone content found in the stratosphere, primarily in the winter stratosphere. These intraseasonal changes are especially pronounced in the so-called explosive warmings in the stratosphere of high latitudes.

The first important data on winds in the lower stratosphere in its equatorial part was provided by the eruption of the Krakatao volcano on August 27, 1883, as a result of which great amount volcanic dust. This circumstance made it possible to obtain initial information about some features of the stratosphere at low latitudes.

The movement of volcanic dust showed that in the equatorial zone, not only at sea level, but also in the lower stratosphere, the zonal component of the wind is directed from east to west, and the speed of these eastern flows in the lower stratosphere reaches significant values ​​(25 - 50 m / s). These stratospheric easterly winds got the name winds of Krakatao... The winds of Krakatao go around the entire globe in equatorial (15 ° N - 15 ° S) latitudes at altitudes of 25 - 40 km.

In 1909, the Van Berson expedition to Central Africa first discovered westerly winds in the tropical stratosphere. Subsequent observations showed both the presence of eastern winds of Krakatao in the tropical stratosphere, and the appearance under them of western Berson winds... Berson's westerly winds were also discovered in a series of atomic tests in the Marshall Islands. Subsequent studies have shown that winds in the lower tropical stratosphere change direction between east and west with a period of about 26 - 27 months. So it was established quasi-two-year cyclicity, when in the layer of the tropical stratosphere from 18 - 20 km to 35 km for about one year the winds of the eastern directions dominate, and during the next year - the western ones. The quasi-biennial cyclicity is especially pronounced in the 8 - 10 ° zone on both sides of the equator and has the greatest amplitude at a level of about 23 km, where average duration the cycle is about 26 months. Each of the zonal transfers appears first of all in the upper layers, at a level of about 35 km, and gradually spreads downward at a speed of 1 - 1.5 km per month.

In the upper tropical stratosphere, a six-month cycle was later discovered, which is in some connection with a two-year cycle.

The latest studies of the stratosphere, as noted above, reveal a significant relationship between it and the troposphere. For example, some works have shown that the propagation of the climatic signal from the troposphere to the stratosphere occurs rather quickly - within 3 - 10 days. After that, the anomalous signal exists in the stratosphere much longer (15 - 40 days), which gives grounds for a long-term weather forecast based on the parameters of the stratosphere.

Literature:
P.N. Tverskoy. Meteorology course. Hydrometeoizdat, 1962.
Earth's atmosphere. Collection. Moscow, 1953.
A.L. Katz. Circulation in the stratosphere and mesosphere. Hydrometeoizdat, 1968.
The materials of the journals "Meteorology and Hydrology" and "Science and Life" were also used.