The existence of an atmosphere near the earth is determined by the following factors. Layers of the atmosphere - troposphere, stratosphere, mesosphere, thermosphere and exosphere
Everyone who has flown on an airplane is used to this kind of message: "our flight is at an altitude of 10,000 m, the temperature overboard is 50 ° C." It seems nothing special. The farther from the surface of the Earth heated by the Sun, the colder. Many people think that the decrease in temperature with height goes on continuously and gradually the temperature drops, approaching the temperature of space. By the way, scientists thought so until the end of the 19th century.
Let's take a closer look at the distribution of air temperature over the Earth. The atmosphere is divided into several layers, which primarily reflect the nature of temperature changes.
The lower layer of the atmosphere is called troposphere, which means "sphere of rotation". All changes in weather and climate are the result of physical processes occurring in this layer. The upper boundary of this layer is located where the decrease in temperature with height is replaced by its increase - approximately at an altitude of 15-16 km above the equator and 7-8 km above the poles. Like the Earth itself, the atmosphere under the influence of the rotation of our planet is also somewhat flattened over the poles and swells over the equator. However, this effect is much stronger in the atmosphere than in the solid shell of the Earth. In the direction from the Earth's surface to the upper boundary of the troposphere, the air temperature decreases. Above the equator, the minimum air temperature is about -62 ° C, and above the poles about -45 ° C. In temperate latitudes, more than 75% of the mass of the atmosphere is in the troposphere. In the tropics, about 90% is within the troposphere masses of the atmosphere.
In 1899, a minimum was found in the vertical temperature profile at a certain altitude, and then the temperature slightly increased. The beginning of this increase means the transition to the next layer of the atmosphere - to stratosphere, which means "layer sphere". The term stratosphere means and reflects the former idea of the uniqueness of the layer lying above the troposphere. The stratosphere extends to a height of about 50 km above the earth's surface. Its feature is, in particular, a sharp increase in air temperature. This increase in temperature is explained ozone formation reaction - one of the main chemical reactions occurring in the atmosphere.
The bulk of the ozone is concentrated at altitudes of about 25 km, but in general the ozone layer is a shell strongly stretched along the height, covering almost the entire stratosphere. The interaction of oxygen with ultraviolet rays is one of the favorable processes in the earth's atmosphere that contribute to the maintenance of life on earth. The absorption of this energy by ozone prevents its excessive flow to the earth's surface, where exactly such an energy level is created that is suitable for existence. earthly forms life. The ozonosphere absorbs some radiant energy passing through the atmosphere. As a result, a vertical air temperature gradient of approximately 0.62 ° C per 100 m is established in the ozonosphere, i.e., the temperature rises with height up to the upper limit of the stratosphere - the stratopause (50 km), reaching, according to some data, 0 ° C.
At altitudes from 50 to 80 km there is a layer of the atmosphere called mesosphere. The word "mesosphere" means "intermediate sphere", here the air temperature continues to decrease with height. Above the mesosphere, in a layer called thermosphere, the temperature rises again with altitude up to about 1000°C, and then drops very quickly to -96°C. However, it does not fall indefinitely, then the temperature rises again.
Thermosphere is the first layer ionosphere. Unlike the previously mentioned layers, the ionosphere is not distinguished by temperature. The ionosphere is a region of an electrical nature that makes many types of radio communications possible. The ionosphere is divided into several layers, designating them with the letters D, E, F1 and F2. These layers also have special names. The division into layers is caused by several reasons, among which the most important is the unequal influence of the layers on the passage of radio waves. The lowest layer, D, mainly absorbs radio waves and thus prevents their further propagation. The best studied layer E is located at an altitude of about 100 km above the earth's surface. It is also called the Kennelly-Heaviside layer after the names of the American and English scientists who simultaneously and independently discovered it. Layer E, like a giant mirror, reflects radio waves. Thanks to this layer, long radio waves travel farther distances than would be expected if they propagated only in a straight line, without being reflected from the E layer. The F layer also has similar properties. It is also called the Appleton layer. Together with the Kennelly-Heaviside layer, it reflects radio waves to terrestrial radio stations. Such reflection can occur at various angles. The Appleton layer is located at an altitude of about 240 km.
The outermost region of the atmosphere, the second layer of the ionosphere, is often called exosphere. This term indicates the existence of the outskirts of space near the Earth. It is difficult to determine exactly where the atmosphere ends and space begins, since the density of atmospheric gases gradually decreases with height and the atmosphere itself gradually turns into an almost vacuum, in which only individual molecules meet. Already at an altitude of about 320 km, the density of the atmosphere is so low that molecules can travel more than 1 km without colliding with each other. The outermost part of the atmosphere serves as its upper boundary, which is located at altitudes from 480 to 960 km.
More information about the processes in the atmosphere can be found on the website "Earth climate"
The atmosphere is the air envelope of the Earth. Extending up to 3000 km from the earth's surface. Its traces can be traced to a height of up to 10,000 km. A. has an uneven density of 50 5; its masses are concentrated up to 5 km, 75% - up to 10 km, 90% - up to 16 km.
The atmosphere consists of air - a mechanical mixture of several gases.
Nitrogen(78%) in the atmosphere plays the role of an oxygen diluent, regulating the rate of oxidation, and, consequently, the rate and intensity of biological processes. Nitrogen is the main element earth's atmosphere, which is continuously exchanged with the living matter of the biosphere, and the components of the latter are nitrogen compounds (amino acids, purines, etc.). Extraction of nitrogen from the atmosphere occurs inorganic and biochemical ways, although they are closely interrelated. Inorganic extraction is associated with the formation of its compounds N 2 O, N 2 O 5 , NO 2 , NH 3 . They are in precipitation and are formed in the atmosphere under the action of electrical discharges during thunderstorms or photochemical reactions under the influence of solar radiation.
Biological nitrogen fixation is carried out by some bacteria in symbiosis with higher plants in soils. Nitrogen is also fixed by some plankton microorganisms and algae in marine environment. In quantitative terms, the biological binding of nitrogen exceeds its inorganic fixation. The exchange of all the nitrogen in the atmosphere takes approximately 10 million years. Nitrogen is found in gases of volcanic origin and in igneous rocks. When various samples of crystalline rocks and meteorites are heated, nitrogen is released in the form of N 2 and NH 3 molecules. However, the main form of nitrogen presence, both on Earth and on the terrestrial planets, is molecular. Ammonia, getting into the upper atmosphere, is rapidly oxidized, releasing nitrogen. In sedimentary rocks, it is buried together with organic matter and is found in an increased amount in bituminous deposits. In the process of regional metamorphism of these rocks, nitrogen in different form released into the earth's atmosphere.
Geochemical nitrogen cycle (
Oxygen(21%) is used by living organisms for respiration, is part of organic matter(proteins fats carbohydrates). Ozone O 3 . blocking life-threatening ultraviolet radiation from the Sun.
Oxygen is the second most abundant gas in the atmosphere, playing an extremely important role in many processes in the biosphere. The dominant form of its existence is O 2 . In the upper layers of the atmosphere, under the influence of ultraviolet radiation, the dissociation of oxygen molecules occurs, and at an altitude of about 200 km, the ratio of atomic oxygen to molecular (O: O 2) becomes equal to 10. When these forms of oxygen interact in the atmosphere (at an altitude of 20-30 km), ozone belt (ozone shield). Ozone (O 3) is necessary for living organisms, delaying most of the solar ultraviolet radiation that is harmful to them.
In the early stages of the Earth's development, free oxygen arose in very small quantities as a result of the photodissociation of carbon dioxide and water molecules in the upper atmosphere. However, these small amounts were quickly consumed in the oxidation of other gases. With the advent of autotrophic photosynthetic organisms in the ocean, the situation has changed significantly. The amount of free oxygen in the atmosphere began to progressively increase, actively oxidizing many components of the biosphere. Thus, the first portions of free oxygen contributed primarily to the transition of ferrous forms of iron into oxide, and sulfides into sulfates.
In the end, the amount of free oxygen in the Earth's atmosphere reached a certain mass and turned out to be balanced in such a way that the amount produced became equal to the amount absorbed. A relative constancy of the content of free oxygen was established in the atmosphere.
Geochemical oxygen cycle (V.A. Vronsky, G.V. Voitkevich)
Carbon dioxide, goes to the formation of living matter, and together with water vapor creates the so-called "greenhouse (greenhouse) effect."
Carbon (carbon dioxide) - most of it in the atmosphere is in the form of CO 2 and much less in the form of CH 4. The significance of the geochemical history of carbon in the biosphere is exceptionally great, since it is part of all living organisms. Within living organisms, reduced forms of carbon occur, and in environment biospheres are oxidized. Thus, the chemical exchange of the life cycle is established: CO 2 ↔ living matter.
The primary source of carbon dioxide in the biosphere is volcanic activity associated with secular degassing of the mantle and lower horizons of the earth's crust. Part of this carbon dioxide arises from the thermal decomposition of ancient limestones in various metamorphic zones. Migration of CO 2 in the biosphere proceeds in two ways.
The first method is expressed in the absorption of CO 2 during photosynthesis with the formation of organic substances and subsequent burial in favorable reducing conditions in the lithosphere in the form of peat, coal, oil, oil shale. According to the second method, carbon migration leads to the creation of a carbonate system in the hydrosphere, where CO 2 turns into H 2 CO 3, HCO 3 -1, CO 3 -2. Then, with the participation of calcium (less often magnesium and iron), the precipitation of carbonates occurs in a biogenic and abiogenic way. Thick strata of limestones and dolomites appear. According to A.B. Ronov, the ratio of organic carbon (Corg) to carbonate carbon (Ccarb) in the history of the biosphere was 1:4.
Along with the global cycle of carbon, there are a number of its small cycles. So, on land, green plants absorb CO 2 for the process of photosynthesis during the daytime, and at night they release it into the atmosphere. With the death of living organisms on the earth's surface, organic matter is oxidized (with the participation of microorganisms) with the release of CO 2 into the atmosphere. In recent decades, a special place in the carbon cycle has been occupied by the massive combustion of fossil fuels and the increase in its content in the modern atmosphere.
The carbon cycle in geographical envelope(according to F. Ramad, 1981)
Argon- the third most common atmospheric gas, which sharply distinguishes it from the extremely scarcely common other inert gases. However, argon in its geological history shares the fate of these gases, which are characterized by two features:
- the irreversibility of their accumulation in the atmosphere;
- close association with the radioactive decay of certain unstable isotopes.
Inert gases are outside the circulation of most cyclic elements in the Earth's biosphere.
All inert gases can be divided into primary and radiogenic. The primary ones are those that were captured by the Earth during its formation. They are extremely rare. The primary part of argon is represented mainly by 36 Ar and 38 Ar isotopes, while atmospheric argon consists entirely of the 40 Ar isotope (99.6%), which is undoubtedly radiogenic. In potassium-containing rocks, radiogenic argon accumulated due to the decay of potassium-40 by electron capture: 40 K + e → 40 Ar.
Therefore, the content of argon in rocks is determined by their age and the amount of potassium. To this extent, the concentration of helium in rocks is a function of their age and the content of thorium and uranium. Argon and helium are released into the atmosphere from the earth's interior during volcanic eruptions, through cracks in the earth's crust in the form of gas jets, and also during the weathering of rocks. According to calculations made by P. Dimon and J. Culp, helium and argon accumulate in the earth's crust in the modern era and enter the atmosphere in relatively small quantities. The rate of entry of these radiogenic gases is so low that during the geological history of the Earth it could not provide the observed content of them in the modern atmosphere. Therefore, it remains to be assumed that most of the argon of the atmosphere came from the bowels of the Earth at the earliest stages of its development, and a much smaller part was added later in the process of volcanism and during the weathering of potassium-containing rocks.
Thus, during geological time, helium and argon had different migration processes. There is very little helium in the atmosphere (about 5 * 10 -4%), and the "helium breath" of the Earth was lighter, since it, as the lightest gas, escaped into outer space. And "argon breath" - heavy and argon remained within our planet. Most of the primary inert gases, like neon and xenon, were associated with the primary neon captured by the Earth during its formation, as well as with the release into the atmosphere during degassing of the mantle. The totality of data on the geochemistry of noble gases indicates that the primary atmosphere of the Earth arose at the earliest stages of its development.
The atmosphere contains water vapor And water in liquid and solid state. Water in the atmosphere is an important heat accumulator.
The lower layers of the atmosphere contain a large number of mineral and technogenic dust and aerosols, combustion products, salts, spores and plant pollen, etc.
Up to a height of 100-120 km, due to the complete mixing of air, the composition of the atmosphere is homogeneous. The ratio between nitrogen and oxygen is constant. Above, inert gases, hydrogen, etc. predominate. In the lower layers of the atmosphere there is water vapor. With distance from the earth, its content decreases. Above, the ratio of gases changes, for example, at an altitude of 200-800 km, oxygen prevails over nitrogen by 10-100 times.
The atmosphere has distinct layers of air. Air layers differ in temperature, difference in gases and their density and pressure. It should be noted that the layers of the stratosphere and troposphere protect the Earth from solar radiation. In the higher layers, a living organism can receive a lethal dose of the ultraviolet solar spectrum. To quickly jump to the desired layer of the atmosphere, click on the corresponding layer:
Troposphere and tropopause
Troposphere - temperature, pressure, altitude
The upper limit is kept at around 8 - 10 km approximately. In temperate latitudes 16 - 18 km, and in polar 10 - 12 km. Troposphere It is the lower main layer of the atmosphere. This layer contains more than 80% of the total mass atmospheric air and close to 90% of all water vapor. It is in the troposphere that convection and turbulence arise, clouds form, cyclones occur. Temperature decreases with height. Gradient: 0.65°/100 m. The heated earth and water heat up the enclosing air. The heated air rises, cools and forms clouds. The temperature in the upper boundaries of the layer can reach -50/70 °C.
It is in this layer that changes in climatic weather conditions occur. The lower limit of the troposphere is called surface since it has a lot of volatile microorganisms and dust. Wind speed increases with height in this layer.
tropopause
This is the transitional layer of the troposphere to the stratosphere. Here, the dependence of the decrease in temperature with an increase in altitude ceases. The tropopause is the minimum height where the vertical temperature gradient drops to 0.2°C/100 m. The height of the tropopause depends on strong climatic events such as cyclones. The height of the tropopause decreases above cyclones and increases above anticyclones.
Stratosphere and Stratopause
The height of the stratosphere layer is approximately from 11 to 50 km. There is a slight change in temperature at an altitude of 11-25 km. At an altitude of 25–40 km, inversion temperature, from 56.5 rises to 0.8°C. From 40 km to 55 km the temperature stays at around 0°C. This area is called - stratopause.
In the Stratosphere, the effect of solar radiation on gas molecules is observed, they dissociate into atoms. There is almost no water vapor in this layer. Modern supersonic commercial aircraft fly at altitudes up to 20 km due to stable flight conditions. High-altitude weather balloons rise to a height of 40 km. There are steady air currents here, their speed reaches 300 km/h. Also in this layer is concentrated ozone, a layer that absorbs ultraviolet rays.
Mesosphere and Mesopause - composition, reactions, temperature
The mesosphere layer begins at about 50 km and ends at around 80-90 km. Temperatures decrease with elevation by about 0.25-0.3°C/100 m. Radiant heat exchange is the main energy effect here. Complex photochemical processes involving free radicals (has 1 or 2 unpaired electrons) since they implement glow atmosphere.
Almost all meteors burn up in the mesosphere. Scientists have named this area Ignorosphere. This zone is difficult to explore, as aerodynamic aviation here is very poor due to the air density, which is 1000 times less than on Earth. And to run artificial satellites the density is still very high. Research is carried out with the help of meteorological rockets, but this is a perversion. mesopause transitional layer between mesosphere and thermosphere. Has a minimum temperature of -90°C.
Karman Line
Pocket line called the boundary between the Earth's atmosphere and outer space. According to the International Aviation Federation (FAI), the height of this border is 100 km. This definition was given in honor of the American scientist Theodor von Karman. He determined that at about this height the density of the atmosphere is so low that aerodynamic aviation becomes impossible here, since the speed of the aircraft must be greater first space velocity. At such a height, the concept of a sound barrier loses its meaning. Here you can control the aircraft only due to reactive forces.
Thermosphere and Thermopause
The upper boundary of this layer is about 800 km. The temperature rises up to about 300 km, where it reaches about 1500 K. Above, the temperature remains unchanged. In this layer there is Polar Lights- occurs as a result of the effect of solar radiation on the air. This process is also called the ionization of atmospheric oxygen.
Due to the low rarefaction of the air, flights above the Karman line are possible only along ballistic trajectories. All manned orbital flights (except flights to the Moon) take place in this layer of the atmosphere.
Exosphere - Density, Temperature, Height
The height of the exosphere is above 700 km. Here the gas is very rarefied, and the process takes place dissipation— leakage of particles into interplanetary space. The speed of such particles can reach 11.2 km/sec. Height solar activity leads to the expansion of the thickness of this layer.
- The gas shell does not fly away into space due to gravity. Air is made up of particles that have their own mass. From the law of gravitation, it can be concluded that every object with mass is attracted to the Earth.
- Buys-Ballot's law states that if you are in the Northern Hemisphere and stand with your back to the wind, then the zone will be located on the right high pressure, and on the left - low. In the Southern Hemisphere, it will be the other way around.
Sometimes the atmosphere that surrounds our planet in a thick layer is called the fifth ocean. No wonder the second name of the aircraft is an aircraft. The atmosphere is a mixture of various gases, among which nitrogen and oxygen predominate. It is thanks to the latter that life on the planet is possible in the form to which we are all accustomed. In addition to them, there is another 1% of other components. These are inert (not entering into chemical interactions) gases, sulfur oxide. The fifth ocean also contains mechanical impurities: dust, ash, etc. All layers of the atmosphere in total extend almost 480 km from the surface (data are different, we will dwell on this point in more detail Further). Such an impressive thickness forms a kind of impenetrable shield that protects the planet from destructive cosmic radiation and large objects.
The following layers of the atmosphere are distinguished: the troposphere, followed by the stratosphere, then the mesosphere, and finally the thermosphere. The above order begins at the surface of the planet. The dense layers of the atmosphere are represented by the first two. They filter out a significant part of the destructive
The lowest layer of the atmosphere, the troposphere, extends only 12 km above sea level (18 km in the tropics). Up to 90% of water vapor is concentrated here, so clouds form in it. Most of the air is also concentrated here. All subsequent layers of the atmosphere are colder, since proximity to the surface allows reflected sunlight to heat the air.
The stratosphere extends up to almost 50 km from the surface. Most weather balloons "float" in this layer. Some types of aircraft can also fly here. One of the amazing features is the temperature regime: in the interval from 25 to 40 km, an increase in air temperature begins. From -60 it rises to almost 1. Then there is a slight decrease to zero, which persists up to an altitude of 55 km. The upper bound is the infamous
Further, the mesosphere extends almost up to 90 km. The air temperature drops sharply here. For every 100 meters of elevation, there is a decrease of 0.3 degrees. Sometimes it is called the coldest part of the atmosphere. The air density is low, but it is quite enough to create resistance to falling meteors.
The layers of the atmosphere in the usual sense end at an altitude of about 118 km. The famous auroras are formed here. The region of the thermosphere begins above. Due to X-rays, the ionization of those few air molecules contained in this area occurs. These processes create the so-called ionosphere (it is often included in the thermosphere, so it is not considered separately).
Anything above 700 km is called the exosphere. air is extremely small, so they move freely without experiencing resistance due to collisions. This allows some of them to accumulate energy corresponding to 160 degrees Celsius, while the ambient temperature is low. Gas molecules are distributed throughout the volume of the exosphere in accordance with their mass, so the heaviest of them can only be found in the lower part of the layer. The attraction of the planet, which decreases with height, is no longer able to hold molecules, so cosmic high-energy particles and radiation give gas molecules an impulse sufficient to leave the atmosphere. This region is one of the longest: it is believed that the atmosphere completely passes into the vacuum of space at altitudes greater than 2000 km (sometimes even the number 10000 appears). Artificial orbits still in the thermosphere.
All these numbers are approximate, since the boundaries of the atmospheric layers depend on a number of factors, for example, on the activity of the Sun.
The composition of the earth. Air
Air is a mechanical mixture of various gases that make up the Earth's atmosphere. Air is essential for the respiration of living organisms and is widely used in industry.
The fact that air is a mixture, and not a homogeneous substance, was proved during the experiments of the Scottish scientist Joseph Black. During one of them, the scientist discovered that when white magnesia (magnesium carbonate) is heated, “bound air”, that is, carbon dioxide, is released, and burnt magnesia (magnesium oxide) is formed. In contrast, when limestone is fired, “bound air” is removed. Based on these experiments, the scientist concluded that the difference between carbonic and caustic alkalis is that the former includes carbon dioxide, which is one of the components of air. Today we know that in addition to carbon dioxide, the composition of the earth's air includes:
The ratio of gases in the earth's atmosphere indicated in the table is typical for its lower layers, up to a height of 120 km. In these areas lies a well-mixed, homogeneous region, called the homosphere. Above the homosphere lies the heterosphere, which is characterized by the decomposition of gas molecules into atoms and ions. The regions are separated from each other by a turbopause.
The chemical reaction in which, under the influence of solar and cosmic radiation, molecules decompose into atoms, is called photodissociation. During the decay of molecular oxygen, atomic oxygen is formed, which is the main gas of the atmosphere at altitudes above 200 km. At altitudes above 1200 km, hydrogen and helium, which are the lightest of the gases, begin to predominate.
Since the bulk of the air is concentrated in the 3 lower atmospheric layers, changes in the air composition at altitudes above 100 km do not have a noticeable effect on the overall composition of the atmosphere.
Nitrogen is the most common gas, accounting for more than three-quarters of the earth's air volume. Modern nitrogen was formed by the oxidation of the early ammonia-hydrogen atmosphere with molecular oxygen, which is formed during photosynthesis. Currently, a small amount of nitrogen enters the atmosphere as a result of denitrification - the process of reduction of nitrates to nitrites, followed by the formation of gaseous oxides and molecular nitrogen, which is produced by anaerobic prokaryotes. Some nitrogen enters the atmosphere during volcanic eruptions.
In the upper atmosphere, when exposed to electrical discharges with the participation of ozone, molecular nitrogen is oxidized to nitrogen monoxide:
N 2 + O 2 → 2NO
Under normal conditions, the monoxide immediately reacts with oxygen to form nitrous oxide:
2NO + O 2 → 2N 2 O
Nitrogen is the most important chemical element earth's atmosphere. Nitrogen is part of proteins, provides mineral nutrition to plants. It determines the rate of biochemical reactions, plays the role of an oxygen diluent.
Oxygen is the second most abundant gas in the Earth's atmosphere. The formation of this gas is associated with the photosynthetic activity of plants and bacteria. And the more diverse and numerous photosynthetic organisms became, the more significant the process of oxygen content in the atmosphere became. A small amount of heavy oxygen is released during degassing of the mantle.
In the upper layers of the troposphere and stratosphere, under the influence of ultraviolet solar radiation (we denote it as hν), ozone is formed:
O 2 + hν → 2O
As a result of the action of the same ultraviolet radiation, ozone decays:
O 3 + hν → O 2 + O
O 3 + O → 2O 2
As a result of the first reaction, atomic oxygen is formed, as a result of the second - molecular oxygen. All 4 reactions are called the Chapman mechanism, after the British scientist Sidney Chapman who discovered them in 1930.
Oxygen is used for the respiration of living organisms. With its help, the processes of oxidation and combustion occur.
Ozone serves to protect living organisms from ultraviolet radiation, which causes irreversible mutations. The highest concentration of ozone is observed in the lower stratosphere within the so-called. ozone layer or ozone screen lying at altitudes of 22-25 km. The ozone content is low: at normal pressure all the ozone in the earth's atmosphere would occupy a layer only 2.91 mm thick.
The formation of the third most common gas in the atmosphere, argon, as well as neon, helium, krypton and xenon, is associated with volcanic eruptions and the decay of radioactive elements.
In particular, helium is a product of the radioactive decay of uranium, thorium and radium: 238 U → 234 Th + α, 230 Th → 226 Ra + 4 He, 226 Ra → 222 Rn + α (in these reactions, the α-particle is a helium nucleus, which in in the process of energy loss captures electrons and becomes 4 He).
Argon is formed during the decay of the radioactive isotope of potassium: 40 K → 40 Ar + γ.
Neon escapes from igneous rocks.
Krypton is formed as the end product of the decay of uranium (235 U and 238 U) and thorium Th.
The bulk of atmospheric krypton was formed in the early stages of the Earth's evolution as a result of the decay of transuranium elements with a phenomenally short half-life or came from space, the content of krypton in which is ten million times higher than on Earth.
Xenon is the result of the fission of uranium, but most of this gas is left over from the early stages of the Earth's formation, from the primary atmosphere.
Carbon dioxide enters the atmosphere as a result of volcanic eruptions and in the process of decomposition of organic matter. Its content in the atmosphere of the middle latitudes of the Earth varies greatly depending on the seasons of the year: in winter, the amount of CO 2 increases, and in summer it decreases. This fluctuation is connected with the activity of plants that use carbon dioxide in the process of photosynthesis.
Hydrogen is formed as a result of the decomposition of water by solar radiation. But, being the lightest of the gases that make up the atmosphere, it constantly escapes into outer space, and therefore its content in the atmosphere is very small.
Water vapor is the result of the evaporation of water from the surface of lakes, rivers, seas and land.
The concentration of the main gases in the lower layers of the atmosphere, with the exception of water vapor and carbon dioxide, is constant. In small quantities, the atmosphere contains sulfur oxide SO 2, ammonia NH 3, carbon monoxide CO, ozone O 3, hydrogen chloride HCl, hydrogen fluoride HF, nitrogen monoxide NO, hydrocarbons, mercury vapor Hg, iodine I 2 and many others. In the lower atmospheric layer of the troposphere, there is constantly a large amount of suspended solid and liquid particles.
Sources of particulate matter in the Earth's atmosphere are volcanic eruptions, plant pollen, microorganisms, and more recently human activities such as the burning of fossil fuels in manufacturing processes. The smallest particles of dust, which are the nuclei of condensation, are the causes of the formation of fogs and clouds. Without solid particles constantly present in the atmosphere, precipitation would not fall on the Earth.
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