The atmosphere is the gaseous shell of our planet that rotates with the Earth. The gas in the atmosphere is called air. The atmosphere is in contact with the hydrosphere and partially covers the lithosphere. But it is difficult to determine the upper bounds. Conventionally, it is assumed that the atmosphere extends upwards for about three thousand kilometers. There it flows smoothly into the airless space.
The formation of the chemical composition of the atmosphere began about four billion years ago. Initially, the atmosphere consisted only of light gases - helium and hydrogen. According to scientists, the initial prerequisites for the creation of a gas shell around the Earth were volcanic eruptions, which, together with lava, emitted a huge amount of gases. Subsequently, gas exchange began with water spaces, with living organisms, with the products of their activity. The composition of the air gradually changed and modern form established several million years ago.
The main components of the atmosphere are nitrogen (about 79%) and oxygen (20%). The remaining percentage (1%) is accounted for by the following gases: argon, neon, helium, methane, carbon dioxide, hydrogen, krypton, xenon, ozone, ammonia, sulfur dioxide and nitrogen, nitrous oxide and carbon monoxide, included in this one percent.
In addition, the air contains water vapor and particulate matter (plant pollen, dust, salt crystals, aerosol impurities).
Recently, scientists have noted not a qualitative, but a quantitative change in some air ingredients. And the reason for this is the person and his activity. Only in the last 100 years carbon dioxide has increased significantly! This is fraught with many problems, the most global of which is climate change.
The atmosphere plays a vital role in shaping the climate and weather on Earth. A lot depends on the amount of sunlight, on the nature of the underlying surface and atmospheric circulation.
Let's look at the factors in order.
1. The atmosphere transmits the heat of the sun's rays and absorbs harmful radiation. The ancient Greeks knew that the rays of the Sun fall on different parts of the Earth at different angles. The very word "climate" in translation from ancient Greek means "slope". Yes, at the equator Sun rays they fall almost vertically, because it is very hot here. The closer to the poles, the greater the angle of inclination. And the temperature is dropping.
2. Due to the uneven heating of the Earth, air currents are formed in the atmosphere. They are classified according to their size. The smallest (tens and hundreds of meters) are local winds. This is followed by monsoons and trade winds, cyclones and anticyclones, planetary frontal zones.
All these air masses are constantly moving. Some of them are quite static. For example, the trade winds that blow from the subtropics towards the equator. The movement of others is largely dependent on atmospheric pressure.
3. Atmospheric pressure is another factor influencing climate formation. This is the air pressure on the earth's surface. As you know, air masses move from an area with high atmospheric pressure towards an area where this pressure is lower.
There are 7 zones in total. Equator - zone low pressure. Further, on both sides of the equator up to the thirtieth latitudes - the region high pressure. From 30° to 60° - again low pressure. And from 60° to the poles - a zone of high pressure. Air masses circulate between these zones. Those that go from the sea to land bring rain and bad weather, and those that blow from the continents bring clear and dry weather. In places where air currents collide, zones are formed atmospheric front, which are characterized by precipitation and inclement, windy weather.
Scientists have proven that even a person's well-being depends on atmospheric pressure. According to international standards, normal atmospheric pressure is 760 mm Hg. column at 0°C. This figure is calculated for those areas of land that are almost flush with sea level. The pressure decreases with altitude. Therefore, for example, for St. Petersburg 760 mm Hg. - is the norm. But for Moscow, which is located higher, the normal pressure is 748 mm Hg.
The pressure changes not only vertically, but also horizontally. This is especially felt during the passage of cyclones.
The atmosphere is like a layer cake. And each layer has its own characteristics.
. Troposphere is the layer closest to the Earth. The "thickness" of this layer changes as you move away from the equator. Above the equator, the layer extends upwards for 16-18 km, in temperate zones- at 10-12 km, at the poles - at 8-10 km.
It is here that 80% of the total mass of air and 90% of water vapor are contained. Clouds form here, cyclones and anticyclones arise. The air temperature depends on the altitude of the area. On average, it drops by 0.65°C for every 100 meters.
. tropopause- transitional layer of the atmosphere. Its height is from several hundred meters to 1-2 km. The air temperature in summer is higher than in winter. So, for example, over the poles in winter -65 ° C. And over the equator at any time of the year it is -70 ° C.
. Stratosphere- this is a layer, the upper boundary of which runs at an altitude of 50-55 kilometers. Turbulence is low here, water vapor content in the air is negligible. But a lot of ozone. Its maximum concentration is at an altitude of 20-25 km. In the stratosphere, the air temperature begins to rise and reaches +0.8 ° C. This is due to the fact that the ozone layer interacts with ultraviolet radiation.
. Stratopause- low intermediate layer between the stratosphere and the next mesosphere.
. Mesosphere- the upper boundary of this layer is 80-85 kilometers. Here complex photochemical processes involving free radicals take place. It is they who provide that gentle blue glow of our planet, which is seen from space.
Most comets and meteorites burn up in the mesosphere.
. mesopause- the next intermediate layer, the air temperature in which is at least -90 °.
. Thermosphere- the lower boundary begins at an altitude of 80 - 90 km, and the upper boundary of the layer passes approximately at the mark of 800 km. The air temperature is rising. It can vary from +500° C to +1000° C. During the day, temperature fluctuations amount to hundreds of degrees! But the air here is so rarefied that the understanding of the term "temperature" as we imagine it is not appropriate here.
. Ionosphere- unites mesosphere, mesopause and thermosphere. The air here consists mainly of oxygen and nitrogen molecules, as well as quasi-neutral plasma. The sun's rays, falling into the ionosphere, strongly ionize air molecules. In the lower layer (up to 90 km), the degree of ionization is low. The higher, the more ionization. So, at an altitude of 100-110 km, electrons are concentrated. This contributes to the reflection of short and medium radio waves.
The most important layer of the ionosphere is the upper one, which is located at an altitude of 150-400 km. Its peculiarity is that it reflects radio waves, and this contributes to the transmission of radio signals over long distances.
It is in the ionosphere that such a phenomenon as aurora occurs.
. Exosphere- consists of oxygen, helium and hydrogen atoms. The gas in this layer is very rarefied and hydrogen atoms often escape into space. Therefore, this layer is called the "scattering zone".
The first scientist who suggested that our atmosphere has weight was the Italian E. Torricelli. Ostap Bender, for example, in the novel "The Golden Calf" lamented that each person was pressed by an air column weighing 14 kg! But the great strategist was a little mistaken. An adult person experiences pressure of 13-15 tons! But we do not feel this heaviness, because atmospheric pressure is balanced by the internal pressure of a person. The weight of our atmosphere is 5,300,000,000,000,000 tons. The figure is colossal, although it is only a millionth of the weight of our planet.
Its upper limit is at an altitude of 8-10 km in polar, 10-12 km in temperate and 16-18 km in tropical latitudes; lower in winter than in summer. The lower, main layer of the atmosphere contains more than 80% of the total mass atmospheric air and about 90% of all water vapor in the atmosphere. In the troposphere, turbulence and convection are highly developed, clouds appear, cyclones and anticyclones develop. Temperature decreases with altitude with an average vertical gradient of 0.65°/100 m
The transitional layer from the troposphere to the stratosphere, the layer of the atmosphere in which the decrease in temperature with height stops.
The layer of the atmosphere located at an altitude of 11 to 50 km. A slight change in temperature in the 11-25 km layer (the lower layer of the stratosphere) and its increase in the 25-40 km layer from -56.5 to 0.8 °C (the upper stratosphere layer or inversion region) are typical. Having reached a value of about 273 K (almost 0 °C) at an altitude of about 40 km, the temperature remains constant up to an altitude of about 55 km. This region of constant temperature is called the stratopause and is the boundary between the stratosphere and the mesosphere.
The boundary layer of the atmosphere between the stratosphere and the mesosphere. There is a maximum in the vertical temperature distribution (about 0 °C).
The mesosphere begins at an altitude of 50 km and extends up to 80-90 km. The temperature decreases with height with an average vertical gradient of (0.25-0.3)°/100 m. The main energy process is radiant heat transfer. Complex photochemical processes involving free radicals, vibrationally excited molecules, etc., cause atmospheric luminescence.
Transitional layer between mesosphere and thermosphere. There is a minimum in the vertical temperature distribution (about -90 °C).
Altitude above sea level, which is conventionally accepted as the boundary between the Earth's atmosphere and space. The Karmana line is located at an altitude of 100 km above sea level.
The upper limit is about 800 km. The temperature rises to altitudes of 200-300 km, where it reaches values of the order of 1500 K, after which it remains almost constant up to high altitudes. Under the influence of ultraviolet and X-ray solar radiation and cosmic radiation, air is ionized (“polar lights”) - the main regions of the ionosphere lie inside the thermosphere. At altitudes above 300 km, atomic oxygen predominates. The upper limit of the thermosphere is largely determined by the current activity of the Sun. During periods of low activity, there is a noticeable decrease in the size of this layer.
The region of the atmosphere above the thermosphere. In this region, the absorption of solar radiation is insignificant and the temperature does not actually change with height.
Atmospheric layers up to a height of 120 km
Exosphere - scattering zone, outer part thermosphere located above 700 km. The gas in the exosphere is very rarefied, and hence its particles leak into interplanetary space (dissipation).
Up to a height of 100 km, the atmosphere is a homogeneous, well-mixed mixture of gases. In higher layers, the distribution of gases in height depends on their molecular masses, the concentration of heavier gases decreases faster with distance from the Earth's surface. Due to the decrease in gas density, the temperature drops from 0 °C in the stratosphere to −110 °C in the mesosphere. However, the kinetic energy of individual particles at altitudes of 200–250 km corresponds to a temperature of ~150 °C. Above 200 km, significant fluctuations in temperature and gas density are observed in time and space.
At an altitude of about 2000-3500 km, the exosphere gradually passes into the so-called near space vacuum, which is filled with highly rarefied particles of interplanetary gas, mainly hydrogen atoms. But this gas is only part of the interplanetary matter. The other part is composed of dust-like particles of cometary and meteoric origin. In addition to extremely rarefied dust-like particles, electromagnetic and corpuscular radiation of solar and galactic origin penetrates into this space.
The troposphere accounts for about 80% of the mass of the atmosphere, the stratosphere accounts for about 20%; the mass of the mesosphere is no more than 0.3%, the thermosphere is less than 0.05% of the total mass of the atmosphere. Based on the electrical properties in the atmosphere, the neutrosphere and ionosphere are distinguished. It is currently believed that the atmosphere extends to an altitude of 2000-3000 km.
Depending on the composition of the gas in the atmosphere, homosphere and heterosphere are distinguished. The heterosphere is an area where gravity has an effect on the separation of gases, since their mixing at such a height is negligible. Hence follows the variable composition of the heterosphere. Below it lies a well-mixed, homogeneous part of the atmosphere, called the homosphere. The boundary between these layers is called the turbopause and lies at an altitude of about 120 km.
Atmosphere(from the Greek atmos - steam and spharia - ball) - the air shell of the Earth, rotating with it. The development of the atmosphere was closely connected with the geological and geochemical processes taking place on our planet, as well as with the activities of living organisms.
The lower boundary of the atmosphere coincides with the surface of the Earth, since air penetrates into the smallest pores in the soil and is dissolved even in water.
The upper limit at an altitude of 2000-3000 km gradually passes into outer space.
Oxygen-rich atmosphere makes life possible on Earth. Atmospheric oxygen is used in the process of breathing by humans, animals, and plants.
If there were no atmosphere, the Earth would be as quiet as the moon. After all, sound is the vibration of air particles. The blue color of the sky is explained by the fact that the sun's rays, passing through the atmosphere, as if through a lens, are decomposed into their component colors. In this case, the rays of blue and blue colors are scattered most of all.
The atmosphere retains most of the ultraviolet radiation from the Sun, which has a detrimental effect on living organisms. It also keeps heat at the surface of the Earth, preventing our planet from cooling.
Several layers can be distinguished in the atmosphere, differing in density and density (Fig. 1).
Troposphere- the lowest layer of the atmosphere, whose thickness above the poles is 8-10 km, in temperate latitudes - 10-12 km, and above the equator - 16-18 km.
Rice. 1. The structure of the Earth's atmosphere
The air in the troposphere is heated by earth's surface, i.e. from land and water. Therefore, the air temperature in this layer decreases with height by an average of 0.6 °C for every 100 m. At the upper boundary of the troposphere, it reaches -55 °C. At the same time, in the region of the equator at the upper boundary of the troposphere, the air temperature is -70 ° C, and in the region North Pole-65 °С.
About 80% of the mass of the atmosphere is concentrated in the troposphere, almost all water vapor is located, thunderstorms, storms, clouds and precipitation occur, and vertical (convection) and horizontal (wind) air movement occurs.
We can say that the weather is mainly formed in the troposphere.
Stratosphere- the layer of the atmosphere located above the troposphere at an altitude of 8 to 50 km. The color of the sky in this layer appears purple, which is explained by the rarefaction of the air, due to which the sun's rays almost do not scatter.
The stratosphere contains 20% of the mass of the atmosphere. The air in this layer is rarefied, there is practically no water vapor, and therefore clouds and precipitation are almost not formed. However, stable air currents are observed in the stratosphere, the speed of which reaches 300 km / h.
This layer is concentrated ozone(ozone screen, ozonosphere), a layer that absorbs ultraviolet rays, preventing them from passing to the Earth and thereby protecting living organisms on our planet. Due to ozone, the air temperature at the upper boundary of the stratosphere is in the range from -50 to 4-55 °C.
Between the mesosphere and the stratosphere there is a transitional zone - the stratopause.
Mesosphere- a layer of the atmosphere located at an altitude of 50-80 km. The air density here is 200 times less than at the surface of the Earth. The color of the sky in the mesosphere appears black, stars are visible during the day. The air temperature drops to -75 (-90)°С.
At an altitude of 80 km begins thermosphere. The air temperature in this layer rises sharply to a height of 250 m, and then becomes constant: at a height of 150 km it reaches 220-240 °C; at an altitude of 500-600 km it exceeds 1500 °C.
In the mesosphere and thermosphere, under the action of cosmic rays, gas molecules break up into charged (ionized) particles of atoms, so this part of the atmosphere is called ionosphere- a layer of very rarefied air, located at an altitude of 50 to 1000 km, consisting mainly of ionized oxygen atoms, nitric oxide molecules and free electrons. This layer is characterized by high electrification, and long and medium radio waves are reflected from it, as from a mirror.
In the ionosphere, auroras arise - the glow of rarefied gases under the influence of electrically charged particles flying from the Sun - and sharp fluctuations in the magnetic field are observed.
Exosphere- the outer layer of the atmosphere, located above 1000 km. This layer is also called the scattering sphere, since gas particles move here at high speed and can be scattered into outer space.
The atmosphere is a mixture of gases consisting of nitrogen (78.08%), oxygen (20.95%), carbon dioxide (0.03%), argon (0.93%), a small amount of helium, neon, xenon, krypton (0.01%), ozone and other gases, but their content is negligible (Table 1). The modern composition of the Earth's air was established more than a hundred million years ago, but the sharply increased human production activity nevertheless led to its change. Currently, there is an increase in the content of CO 2 by about 10-12%.
The gases that make up the atmosphere perform various functional roles. However, the main significance of these gases is determined primarily by the fact that they very strongly absorb radiant energy and thus have a significant effect on temperature regime Earth's surface and atmosphere.
Table 1. Chemical composition dry atmospheric air near the earth's surface
|
Volume concentration. % |
Molecular weight, units |
|
|
Oxygen |
||
|
Carbon dioxide |
||
|
Nitrous oxide |
||
|
0 to 0.00001 |
||
|
Sulfur dioxide |
from 0 to 0.000007 in summer; 0 to 0.000002 in winter |
|
|
From 0 to 0.000002 |
46,0055/17,03061 |
|
|
Azog dioxide |
||
|
Carbon monoxide |
Nitrogen, the most common gas in the atmosphere, chemically little active.
Oxygen, unlike nitrogen, is a chemically very active element. The specific function of oxygen is oxidation organic matter heterotrophic organisms, rocks and under-oxidized gases emitted into the atmosphere by volcanoes. Without oxygen, there would be no decomposition of dead organic matter.
The role of carbon dioxide in the atmosphere is exceptionally great. It enters the atmosphere as a result of the processes of combustion, respiration of living organisms, decay and is, first of all, the main building material for the creation of organic matter during photosynthesis. In addition, the property of carbon dioxide to transmit short-wave solar radiation and absorb part of the thermal long-wave radiation is of great importance, which will create the so-called Greenhouse effect, which will be discussed below.
The influence on atmospheric processes, especially on the thermal regime of the stratosphere, is also exerted by ozone. This gas serves as a natural absorber of solar ultraviolet radiation, and the absorption of solar radiation leads to air heating. The average monthly values of the total ozone content in the atmosphere vary depending on the latitude of the area and the season within 0.23-0.52 cm (this is the thickness of the ozone layer at ground pressure and temperature). There is an increase in the ozone content from the equator to the poles and annual course with a minimum in autumn and a maximum in spring.
A characteristic property of the atmosphere can be called the fact that the content of the main gases (nitrogen, oxygen, argon) changes slightly with height: at an altitude of 65 km in the atmosphere, the nitrogen content is 86%, oxygen - 19, argon - 0.91, at an altitude of 95 km - nitrogen 77, oxygen - 21.3, argon - 0.82%. The constancy of the composition of atmospheric air vertically and horizontally is maintained by its mixing.
In addition to gases, air contains water vapor and solid particles. The latter can have both natural and artificial (anthropogenic) origin. These are flower pollen, tiny salt crystals, road dust, aerosol impurities. When the sun's rays penetrate the window, they can be seen with the naked eye.
There are especially many particulate matter in the air of cities and large industrial centers, where emissions of harmful gases and their impurities formed during fuel combustion are added to aerosols.
The concentration of aerosols in the atmosphere determines the transparency of the air, which affects the solar radiation reaching the Earth's surface. The largest aerosols are condensation nuclei (from lat. condensatio- compaction, thickening) - contribute to the transformation of water vapor into water droplets.
The value of water vapor is determined primarily by the fact that it delays the long-wave thermal radiation of the earth's surface; represents the main link of large and small moisture cycles; raises the temperature of the air when the water beds condense.
The amount of water vapor in the atmosphere varies over time and space. Thus, the concentration of water vapor near the earth's surface ranges from 3% in the tropics to 2-10 (15)% in Antarctica.
The average content of water vapor in the vertical column of the atmosphere in temperate latitudes is about 1.6-1.7 cm (the layer of condensed water vapor will have such a thickness). Information about water vapor in different layers of the atmosphere is contradictory. It was assumed, for example, that in the altitude range from 20 to 30 km, the specific humidity strongly increases with height. However, subsequent measurements indicate a greater dryness of the stratosphere. Apparently, the specific humidity in the stratosphere depends little on height and amounts to 2–4 mg/kg.
The variability of water vapor content in the troposphere is determined by the interaction of evaporation, condensation, and horizontal transport. As a result of the condensation of water vapor, clouds form and fall out. precipitation in the form of rain, hail and snow.
The processes of phase transitions of water proceed mainly in the troposphere, which is why clouds in the stratosphere (at altitudes of 20-30 km) and mesosphere (near the mesopause), called mother-of-pearl and silver, are observed relatively rarely, while tropospheric clouds often cover about 50% of the entire earth surfaces.
The amount of water vapor that can be contained in the air depends on the temperature of the air.
1 m 3 of air at a temperature of -20 ° C can contain no more than 1 g of water; at 0 °C - no more than 5 g; at +10 °С - no more than 9 g; at +30 °С - no more than 30 g of water.
Conclusion: The higher the air temperature, the more water vapor it can contain.
Air can be rich and not saturated steam. So, if at a temperature of +30 ° C 1 m 3 of air contains 15 g of water vapor, the air is not saturated with water vapor; if 30 g - saturated.
Absolute humidity- this is the amount of water vapor contained in 1 m 3 of air. It is expressed in grams. For example, if they say " absolute humidity equal to 15", this means that 1 m L contains 15 g of water vapor.
Relative humidity- this is the ratio (in percent) of the actual content of water vapor in 1 m 3 of air to the amount of water vapor that can be contained in 1 m L at a given temperature. For example, if a weather report is broadcast over the radio that the relative humidity is 70%, this means that the air contains 70% of the water vapor that it can hold at a given temperature.
The greater the relative humidity of the air, t. the closer the air is to saturation, the more likely it is to fall.
Always high (up to 90%) relative humidity is observed in equatorial zone, because it stays there throughout the year heat air and there is a large evaporation from the surface of the oceans. The same high relative humidity is in the polar regions, but only because at low temperatures even a small amount of water vapor makes the air saturated or close to saturation. In temperate latitudes, relative humidity varies seasonally - it is higher in winter and lower in summer.
The relative humidity of the air is especially low in deserts: 1 m 1 of air there contains two to three times less than the amount of water vapor possible at a given temperature.
For measuring relative humidity use a hygrometer (from the Greek hygros - wet and metreco - I measure).
When cooled, saturated air cannot retain the same amount of water vapor in itself, it thickens (condenses), turning into droplets of fog. Fog can be observed in the summer on a clear cool night.
Clouds- this is the same fog, only it is formed not at the earth's surface, but at a certain height. As the air rises, it cools and the water vapor in it condenses. The resulting tiny droplets of water make up the clouds.
involved in the formation of clouds particulate matter suspended in the troposphere.
Clouds may have different shape, which depends on the conditions of their formation (Table 14).
The lowest and heaviest clouds are stratus. They are located at an altitude of 2 km from the earth's surface. At an altitude of 2 to 8 km, one can observe more picturesque Cumulus clouds. The highest and lightest are cirrus clouds. They are located at an altitude of 8 to 18 km above the earth's surface.
|
families |
Kinds of clouds |
Appearance |
|
A. Upper clouds - above 6 km |
I. Pinnate |
Threadlike, fibrous, white |
|
II. cirrocumulus |
Layers and ridges of small flakes and curls, white |
|
|
III. Cirrostratus |
Transparent whitish veil |
|
|
B. Clouds of the middle layer - above 2 km |
IV. Altocumulus |
Layers and ridges of white and gray |
|
V. Altostratified |
Smooth veil of milky gray color |
|
|
B. Lower clouds - up to 2 km |
VI. Nimbostratus |
Solid shapeless gray layer |
|
VII. Stratocumulus |
Opaque layers and ridges of gray |
|
|
VIII. layered |
Illuminated gray veil |
|
|
D. Clouds of vertical development - from the lower to the upper tier |
IX. Cumulus |
Clubs and domes bright white, with torn edges in the wind |
|
X. Cumulonimbus |
Powerful cumulus-shaped masses of dark lead color |
The main source are industrial enterprises and cars. In large cities, the problem of gas contamination of the main highways is very sharp. That is why in many major cities around the world, including in our country, introduced environmental control of the toxicity of car exhaust gases. According to experts, smoke and dust in the air can halve the flow of solar energy to the earth's surface, which will lead to a change in natural conditions.
Space is filled with energy. Energy fills space unevenly. There are places of its concentration and discharge. This way you can estimate the density. The planet is an ordered system, with the maximum density of matter in the center and with a gradual decrease in concentration towards the periphery. Interaction forces determine the state of matter, the form in which it exists. Physics describes the aggregate state of substances: solid, liquid, gas and so on.
The atmosphere is the gaseous medium that surrounds the planet. The Earth's atmosphere allows free movement and allows light to pass through, creating a space in which life thrives.
The area from the earth's surface to a height of approximately 16 kilometers (less from the equator to the poles, also depends on the season) is called the troposphere. The troposphere is the layer that contains about 80% of the air in the atmosphere and almost all of the water vapor. It is here that the processes that shape the weather take place. Pressure and temperature decrease with height. The reason for the decrease in air temperature is an adiabatic process, when the gas expands, it cools. At the upper boundary of the troposphere, values can reach -50, -60 degrees Celsius.
Next comes the Stratosphere. It extends up to 50 kilometers. In this layer of the atmosphere, the temperature increases with height, acquiring a value at the top point of about 0 C. The temperature increase is caused by the process of absorption ozone layer ultraviolet rays. Radiation causes a chemical reaction. Oxygen molecules break down into single atoms that can combine with normal oxygen molecules to form ozone.
Radiation from the sun with wavelengths between 10 and 400 nanometers is classified as ultraviolet. The shorter the wavelength of UV radiation, the greater the danger it poses to living organisms. Only a small fraction of the radiation reaches the Earth's surface, moreover, the less active part of its spectrum. This feature of nature allows a person to get a healthy sun tan.
The next layer of the atmosphere is called the Mesosphere. Limits from approximately 50 km to 85 km. In the mesosphere, the concentration of ozone, which could trap UV energy, is low, so the temperature begins to fall again with height. At the peak point, the temperature drops to -90 C, some sources indicate a value of -130 C. Most meteoroids burn up in this layer of the atmosphere.
The layer of the atmosphere that stretches from a height of 85 km to a distance of 600 km from the Earth is called the Thermosphere. The thermosphere is the first to encounter solar radiation, including the so-called vacuum ultraviolet.
Vacuum UV is delayed by the air, thereby heating this layer of the atmosphere to enormous temperatures. However, since the pressure here is extremely low, this seemingly incandescent gas does not have the same effect on objects as it does under conditions on the earth's surface. On the contrary, objects placed in such an environment will cool down.
At an altitude of 100 km, the conditional line "Karman line" passes, which is considered to be the beginning of space.
Auroras occur in the thermosphere. In this layer of the atmosphere, the solar wind interacts with the planet's magnetic field.
The last layer of the atmosphere is the Exosphere, an outer shell that stretches for thousands of kilometers. The exosphere is practically an empty place, however, the number of atoms wandering here is an order of magnitude greater than in interplanetary space.
The person breathes air. Normal pressure - 760 millimeters mercury column. At an altitude of 10,000 m, the pressure is about 200 mm. rt. Art. At this altitude, a person can probably breathe, at least not for a long time, but this requires preparation. The state will obviously be inoperable.
The gas composition of the atmosphere: 78% nitrogen, 21% oxygen, about a percent argon, everything else is a mixture of gases representing the smallest fraction of the total.
STRUCTURE OF THE ATMOSPHERE
Atmosphere(from other Greek ἀτμός - steam and σφαῖρα - ball) - a gaseous shell (geosphere) surrounding the planet Earth. Its inner surface covers the hydrosphere and partially the earth's crust, while its outer surface borders on the near-Earth part of outer space.
Physical Properties
The thickness of the atmosphere is about 120 km from the Earth's surface. The total mass of air in the atmosphere is (5.1-5.3) 10 18 kg. Of these, the mass of dry air is (5.1352 ± 0.0003) 10 18 kg, the total mass of water vapor is on average 1.27 10 16 kg.
The molar mass of clean dry air is 28.966 g/mol, the air density at the sea surface is approximately 1.2 kg/m 3 . The pressure at 0 °C at sea level is 101.325 kPa; critical temperature - -140.7 ° C; critical pressure - 3.7 MPa; C p at 0 °C - 1.0048 10 3 J/(kg K), C v - 0.7159 10 3 J/(kg K) (at 0 °C). The solubility of air in water (by mass) at 0 ° C - 0.0036%, at 25 ° C - 0.0023%.
For "normal conditions" at the Earth's surface are taken: density 1.2 kg / m 3, barometric pressure 101.35 kPa, temperature plus 20 ° C and relative humidity 50%. These conditional indicators have a purely engineering value.
The atmosphere has a layered structure. The layers of the atmosphere differ from each other in air temperature, its density, the amount of water vapor in the air and other properties.
Troposphere(ancient Greek τρόπος - "turn", "change" and σφαῖρα - "ball") - the lower, most studied layer of the atmosphere, 8-10 km high in the polar regions, up to 10-12 km in temperate latitudes, at the equator - 16-18 km.
When rising in the troposphere, the temperature drops by an average of 0.65 K every 100 m and reaches 180-220 K in the upper part. This upper layer of the troposphere, in which the decrease in temperature with height stops, is called the tropopause. The next layer of the atmosphere above the troposphere is called the stratosphere.
More than 80% of the total mass of atmospheric air is concentrated in the troposphere, turbulence and convection are highly developed, the predominant part of water vapor is concentrated, clouds arise, atmospheric fronts also form, cyclones and anticyclones develop, as well as other processes that determine weather and climate. The processes occurring in the troposphere are primarily due to convection.
The part of the troposphere within which glaciers can form on the earth's surface is called the chionosphere.
tropopause(from the Greek τροπος - turn, change and παῦσις - stop, cessation) - the layer of the atmosphere in which the decrease in temperature with height stops; transition layer from troposphere to stratosphere. In the earth's atmosphere, the tropopause is located at altitudes from 8-12 km (above sea level) in the polar regions and up to 16-18 km above the equator. The height of the tropopause also depends on the time of year (the tropopause is higher in summer than in winter) and cyclonic activity (it is lower in cyclones and higher in anticyclones)
The thickness of the tropopause ranges from several hundred meters to 2-3 kilometers. In the subtropics, tropopause ruptures are observed due to powerful jet streams. The tropopause over certain areas is often destroyed and re-formed.
Stratosphere(from Latin stratum - flooring, layer) - a layer of the atmosphere, located at an altitude of 11 to 50 km. A slight change in temperature in the 11-25 km layer (the lower layer of the stratosphere) and its increase in the 25-40 km layer from -56.5 to 0.8 °C (the upper stratosphere layer or inversion region) are typical. Having reached a value of about 273 K (almost 0 °C) at an altitude of about 40 km, the temperature remains constant up to an altitude of about 55 km. This region of constant temperature is called the stratopause and is the boundary between the stratosphere and the mesosphere. The density of air in the stratosphere is tens and hundreds of times less than at sea level.
It is in the stratosphere that the ozonosphere layer ("ozone layer") is located (at an altitude of 15-20 to 55-60 km), which determines the upper limit of life in the biosphere. Ozone (O 3 ) is formed as a result of photochemical reactions most intensively at an altitude of ~30 km. The total mass of O 3 would be at normal pressure a layer with a thickness of 1.7-4.0 mm, but even this is enough to absorb the ultraviolet radiation of the sun that is harmful to life. The destruction of O 3 occurs when it interacts with free radicals, NO, halogen-containing compounds (including "freons").
Most of the short-wavelength part of ultraviolet radiation (180-200 nm) is retained in the stratosphere and the energy of short waves is transformed. Under the influence of these rays, magnetic fields, molecules break up, ionization occurs, new formation of gases and other chemical compounds. These processes can be observed in the form of northern lights, lightning and other glows.
In the stratosphere and higher layers, under the influence of solar radiation, gas molecules dissociate - into atoms (above 80 km, CO 2 and H 2 dissociate, above 150 km - O 2, above 300 km - N 2). At an altitude of 200-500 km, ionization of gases also occurs in the ionosphere; at an altitude of 320 km, the concentration of charged particles (O + 2, O - 2, N + 2) is ~ 1/300 of the concentration of neutral particles. In the upper layers of the atmosphere there are free radicals - OH, HO 2, etc.
There is almost no water vapor in the stratosphere.
Flights into the stratosphere began in the 1930s. The flight on the first stratospheric balloon (FNRS-1), which Auguste Picard and Paul Kipfer made on May 27, 1931 to a height of 16.2 km, is widely known. Modern combat and supersonic commercial aircraft fly in the stratosphere at altitudes generally up to 20 km (although the dynamic ceiling can be much higher). High-altitude weather balloons rise up to 40 km; the record for an unmanned balloon is 51.8 km.
Recently, in the military circles of the United States, much attention has been paid to the development of layers of the stratosphere above 20 km, often called the "prespace" (Eng. « near space» ). It is assumed that unmanned airships and solar-powered aircraft (like the NASA Pathfinder) will be able to long time be located at an altitude of about 30 km and provide surveillance and communications for very large areas, while remaining low-vulnerability to air defense systems; such devices will be many times cheaper than satellites.
Stratopause- the layer of the atmosphere, which is the boundary between two layers, the stratosphere and the mesosphere. In the stratosphere, temperature rises with altitude, and the stratopause is the layer where the temperature reaches its maximum. The temperature of the stratopause is about 0 °C.
This phenomenon is observed not only on Earth, but also on other planets with an atmosphere.
On Earth, the stratopause is located at an altitude of 50 - 55 km above sea level. Atmospheric pressure is about 1/1000 of the pressure at sea level.
Mesosphere(from the Greek μεσο- - “middle” and σφαῖρα - “ball”, “sphere”) - the layer of the atmosphere at altitudes from 40-50 to 80-90 km. It is characterized by an increase in temperature with height; the maximum (about +50°C) temperature is located at an altitude of about 60 km, after which the temperature begins to decrease to −70° or −80°C. Such a decrease in temperature is associated with the energetic absorption of solar radiation (radiation) by ozone. The term was adopted by the Geographical and Geophysical Union in 1951.
The gas composition of the mesosphere, as well as those of the lower atmospheric layers, is constant and contains about 80% nitrogen and 20% oxygen.
The mesosphere is separated from the underlying stratosphere by the stratopause, and from the overlying thermosphere by the mesopause. The mesopause basically coincides with the turbopause.
Meteors begin to glow and, as a rule, burn up completely in the mesosphere.
Noctilucent clouds may appear in the mesosphere.
For flights, the mesosphere is a kind of "dead zone" - the air here is too rarefied to support airplanes or balloons (at an altitude of 50 km, the air density is 1000 times less than at sea level), and at the same time too dense for artificial flights. satellites in such a low orbit. Direct studies of the mesosphere are carried out mainly with the help of suborbital meteorological rockets; in general, the mesosphere has been studied worse than other layers of the atmosphere, in connection with which scientists called it the “ignorosphere”.
mesopause
mesopause The layer of the atmosphere that separates the mesosphere and thermosphere. On Earth, it is located at an altitude of 80-90 km above sea level. In the mesopause, there is a temperature minimum, which is about -100 ° C. Below (starting from a height of about 50 km) the temperature drops with height, above (up to a height of about 400 km) it rises again. The mesopause coincides with the lower boundary of the region of active absorption of the X-ray and the shortest wavelength ultraviolet radiation of the Sun. Silvery clouds are observed at this altitude.
The mesopause exists not only on Earth, but also on other planets with an atmosphere.
Karman Line- height above sea level, which is conventionally accepted as the boundary between the Earth's atmosphere and space.
As defined by the Fédération Aéronautique Internationale (FAI), the Karman Line is at an altitude of 100 km above sea level.
The height was named after Theodor von Karman, an American scientist of Hungarian origin. He was the first to determine that at about this altitude the atmosphere becomes so rarefied that aeronautics becomes impossible, since the speed of the aircraft, necessary to create sufficient lift, becomes greater than the first cosmic speed, and therefore, in order to achieve higher altitudes, it is necessary to use the means of astronautics.
The Earth's atmosphere continues beyond the Karman line. outer part earth's atmosphere, the exosphere, extends to a height of 10 thousand km or more, at such an altitude the atmosphere consists mainly of hydrogen atoms that can leave the atmosphere.
Reaching the Karman Line was the first condition for the Ansari X Prize, as this is the basis for recognizing the flight as a space flight.
