Atmospheric layer over 80 km. The size of the earth's atmosphere

The structure of the Earth's atmosphere

The atmosphere is the gaseous shell of the Earth with aerosol particles contained in it, moving together with the Earth in world space as a whole and at the same time taking part in the rotation of the Earth. At the bottom of the atmosphere, most of our lives take place.

Almost all of our planets have their own atmospheres. solar system, but only the Earth's atmosphere is capable of supporting life.

When our planet formed 4.5 billion years ago, it was apparently devoid of an atmosphere. The atmosphere was formed as a result of volcanic emissions of water vapor with impurities of carbon dioxide, nitrogen and other chemical substances from the depths of a young planet. But the atmosphere can only contain a limited amount of moisture, so the excess moisture through condensation gave rise to the oceans. But then the atmosphere was devoid of oxygen. The first living organisms that originated and developed in the ocean, as a result of the photosynthesis reaction (H 2 O + CO 2 = CH 2 O + O 2), began to release small portions of oxygen, which began to enter the atmosphere.

The formation of oxygen in the Earth's atmosphere led to the formation of the ozone layer at altitudes of about 8 - 30 km. And, thus, our planet has acquired protection from the harmful effects of ultraviolet study. This circumstance served as an impetus for the further evolution of life forms on Earth, since. as a result of increased photosynthesis, the amount of oxygen in the atmosphere began to grow rapidly, which contributed to the formation and maintenance of life forms, including on land.

Today our atmosphere is 78.1% nitrogen, 21% oxygen, 0.9% argon, 0.04% carbon dioxide. Very small fractions compared to the main gases are neon, helium, methane, krypton.

The particles of gas contained in the atmosphere are affected by the force of gravity of the Earth. And, given that air is compressible, its density gradually decreases with height, passing into outer space without a clear boundary. Half of the mass earth's atmosphere concentrated in the lower 5 km, three-quarters in the lower 10 km, nine-tenths in the lower 20 km. 99% of the mass of the Earth's atmosphere is concentrated below a height of 30 km, and this is only 0.5% of the equatorial radius of our planet.

At sea level, the number of atoms and molecules per cubic centimeter of air is about 2 * 10 19 , at an altitude of 600 km it is only 2 * 10 7 . At sea level, an atom or molecule travels about 7 * 10 -6 cm before colliding with another particle. At an altitude of 600 km, this distance is about 10 km. And at sea level, about 7 * 10 9 such collisions occur every second, at an altitude of 600 km - only about one per minute!

But not only pressure changes with altitude. The temperature also changes. So, for example, at the foot of a high mountain it can be quite hot, while the top of the mountain is covered with snow and the temperature there is at the same time below zero. And it is worth climbing by plane to a height of about 10-11 km, as you can hear a message that it is -50 degrees overboard, while at the surface of the earth it is 60-70 degrees warmer ...

Initially, scientists assumed that the temperature decreases with height until it reaches absolute zero (-273.16 ° C). But it's not.

The Earth's atmosphere consists of four layers: troposphere, stratosphere, mesosphere, ionosphere (thermosphere). Such a division into layers is taken on the basis of data on temperature changes with height. The lowest layer, where air temperature drops with height, is called the troposphere. The layer above the troposphere, where the temperature drop stops, is replaced by isotherm and, finally, the temperature begins to rise, is called the stratosphere. The layer above the stratosphere where the temperature drops rapidly again is the mesosphere. And, finally, the layer where the temperature rise again begins, called the ionosphere or thermosphere.

The troposphere extends on average in the lower 12 km. This is where our weather is formed. The highest clouds (cirrus) form in the uppermost layers of the troposphere. The temperature in the troposphere decreases adiabatically with height, i.e. The change in temperature is due to the decrease in pressure with height. The temperature profile of the troposphere is largely determined by the solar radiation reaching the Earth's surface. As a result of the heating of the Earth's surface by the Sun, upward convective and turbulent flows are formed, which form the weather. It is worth noting that the influence of the underlying surface on the lower layers of the troposphere extends to a height of approximately 1.5 km. Of course, excluding mountainous areas.

The upper boundary of the troposphere is the tropopause, the isothermal layer. Remember characteristic appearance thunderclouds, the top of which is an "ejection" of cirrus clouds, called the "anvil". This "anvil" just "spreads" under the tropopause, because due to isotherm, the ascending air currents are significantly weakened, and the cloud ceases to develop vertically. But in special, rare cases, the tops of cumulonimbus clouds can invade the lower layers of the stratosphere, overcoming the tropopause.

The height of the tropopause depends on geographical latitude. So, at the equator, it is at an altitude of about 16 km, and its temperature is about -80 ° C. At the poles, the tropopause is located lower - approximately at an altitude of 8 km. Its temperature here is -40°C in summer and -60°C in winter. Thus, despite more high temperatures near the Earth's surface, the tropical tropopause is much colder than at the poles.

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 chemical composition of the Earth's atmosphere

Formation chemical composition 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, threw out great amount 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).

AT recent times scientists note 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, the content of carbon dioxide has increased significantly! This is fraught with many problems, the most global of which is climate change.

Formation of weather and climate

The atmosphere plays a 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". So, at the equator, the sun's rays fall almost vertically, because it is very hot here. The closer to the poles, the greater the angle of inclination. And the temperature 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. By international standards normal Atmosphere pressure- 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, normal pressure- 748 mm Hg

The pressure changes not only vertically, but also horizontally. This is especially felt during the passage of cyclones.

The structure of the atmosphere

The atmosphere is reminiscent layered 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- a low intermediate layer between the stratosphere and the mesosphere following it.

. 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 often hydrogen atoms escape into outer space. Therefore, this layer is called the "scattering zone".

The first scientist who suggested that our atmosphere has weight was the Italian E. Torricelli. Ostap Bender, for example, in 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.

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

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

Up to a height of about 100 km, the percentage of these gases remains practically unchanged. This is due to the fact that the air is constantly mixed.

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

There is always a certain amount of impurities in the atmosphere - water vapor and dust. The content of water vapor depends on the temperature of the air: the higher the temperature, the more vapor the air holds. Due to the presence of vaporous water in the air, such atmospheric phenomena like rainbow, sun rays refraction, etc.

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

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

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

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

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

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

The air in the troposphere is constantly mixed, moving in different directions. Only here fogs, rains, snowfalls, thunderstorms, storms and others are observed. weather conditions.

2. Above is located stratosphere, which extends to a height of 50-55 km. Air density and pressure in the stratosphere are negligible. The rarefied air consists of the same gases as in the troposphere, but it contains more ozone. The highest concentration of ozone is observed at an altitude of 15-30 km. The temperature in the stratosphere rises with height and reaches 0 °C or more at its upper boundary. This is because ozone absorbs the short wavelength. solar energy, causing the air to heat up.

3. Above the stratosphere lies mesosphere, extending to a height of 80 km. In it, the temperature drops again and reaches -90 ° C. The air density there is 200 times less than at the surface of the Earth.

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

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

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

The value of the atmosphere. The role of the atmosphere in the life of our planet is exceptionally great. Without it, the Earth would be dead. The atmosphere protects the Earth's surface from intense heating and cooling. Its influence can be likened to the role of glass in greenhouses: to let in the sun's rays and prevent heat from escaping.

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

From the 30s. 20th century observations began in the free atmosphere. They began to launch radiosondes, which rise to a height of 25-35 km, and with the help of radio equipment transmit to Earth information about temperature, pressure, air humidity and wind speed. Nowadays, meteorological rockets and satellites are also widely used. The latter have television installations that transmit images of the earth's surface and clouds.

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5. Air shell of the earth§ 31. Heating of the atmosphere

> > Earth's atmosphere

Description Earth's atmosphere for children of all ages: what air consists of, the presence of gases, photo layers, climate and weather of the third planet in the solar system.

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

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

The composition of the Earth's air - an explanation for children

Gases include:

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

Atmospheric layers of the Earth - an explanation for children

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

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

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

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

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

The exosphere is the highest layer. Incredibly thin line of the merger of the atmosphere with space. Consists of widely dispersed hydrogen and helium particles.

Climate and weather of the Earth - an explanation for children

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

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

- air shell the globe rotating with the earth. The upper boundary of the atmosphere is conventionally carried out at altitudes of 150-200 km. The lower boundary is the surface of the Earth.

Atmospheric air is a mixture of gases. Most of its volume in the surface layer of air falls on nitrogen (78%) and oxygen (21%). In addition, the air contains inert gases (argon, helium, neon, etc.), carbon dioxide (0.03), water vapor, and various solid particles (dust, soot, salt crystals).

The air is colorless, and the color of the sky is explained by the peculiarities of the scattering of light waves.

The atmosphere consists of several layers: troposphere, stratosphere, mesosphere and thermosphere.

The bottom layer of air is called troposphere. At different latitudes, its power is not the same. The troposphere repeats the shape of the planet and participates together with the Earth in axial rotation. At the equator, the thickness of the atmosphere varies from 10 to 20 km. At the equator it is greater, and at the poles it is less. The troposphere is characterized by the maximum density of air, 4/5 of the mass of the entire atmosphere is concentrated in it. The troposphere determines weather: various air masses are formed here, clouds and precipitation are formed, there is an intensive horizontal and vertical movement of air.

Above the troposphere, up to an altitude of 50 km, is located stratosphere. It is characterized by a lower density of air, there is no water vapor in it. In the lower part of the stratosphere at altitudes of about 25 km. there is an "ozone screen" - a layer of the atmosphere with a high concentration of ozone, which absorbs ultraviolet radiation fatal to organisms.

At an altitude of 50 to 80-90 km extends mesosphere. As the altitude increases, the temperature decreases with an average vertical gradient of (0.25-0.3)° / 100 m, and the air density decreases. Main energy process is radiant heat transfer. The glow of the atmosphere is due to complex photochemical processes involving radicals, vibrationally excited molecules.

Thermosphere located at an altitude of 80-90 to 800 km. The air density here is minimal, the degree of air ionization is very high. The temperature changes depending on the activity of the Sun. Due to the large number of charged particles, auroras and magnetic storms are observed here.

The atmosphere is of great importance for the nature of the Earth. Without oxygen, living organisms cannot breathe. Its ozone layer protects all living things from destructive ultraviolet rays. The atmosphere smooths out temperature fluctuations: the Earth's surface does not get supercooled at night and does not overheat during the day. In dense layers atmospheric air before reaching the surface of the planet, meteorites burn from thorns.

The atmosphere interacts with all the shells of the earth. With its help, the exchange of heat and moisture between the ocean and land. Without the atmosphere there would be no clouds, precipitation, winds.

Significant adverse effect on the atmosphere economic activity person. Air pollution occurs, which leads to an increase in the concentration of carbon monoxide (CO 2). And this contributes global warming climate and enhances Greenhouse effect». Ozone layer The land is being destroyed due to industrial waste and transport.

The atmosphere needs to be protected. AT developed countries a set of measures is being taken to protect atmospheric air from pollution.

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