Air temperature at different heights above the ground. Change in air temperature with height. Why does the temperature in the mountains decrease with altitude?

inversion

increase in air temperature with height instead of the usual decrease

Alternative descriptions

An excited state of matter in which the number of particles at a higher energy. level exceeds the number of particles at a lower level (physics)

The reversal of the direction of the Earth's magnetic field is observed at time intervals from 500 thousand years to 50 million years

Changing the normal position of elements, placing them in reverse order

Linguistic term for changing the usual word order in a sentence

Reverse order, reverse order

Logical operation "not"

Chromosomal rearrangement associated with the rotation of individual sections of the chromosome by 180

Conformal transformation of the Euclidean plane or space

Permutation in mathematics

A dramatic device that demonstrates the outcome of the conflict at the beginning of the play

In metrology, an abnormal change in some parameter

A state of matter in which the higher energy levels of its constituent particles are more "populated" by particles than the lower ones

In organic chemistry, the process of breaking down a saccharide

Changing the order of words in a sentence

Changing word order for emphasis

white trail behind the plane

Changing word order

Reverse order of elements

Changing the normal order of words in a sentence in order to enhance the expressiveness of speech

In the first sections, we got acquainted in general terms with the structure of the atmosphere along the vertical and with changes in temperature with height.

Here we consider some interesting features of the temperature regime in the troposphere and in the overlying spheres.

Temperature and humidity in the troposphere. The troposphere is the most interesting area, since rock-forming processes are formed here. In the troposphere, as already mentioned in Chapter I, the air temperature decreases with height by an average of 6° per kilometer of elevation, or by 0.6° per 100 m. This value of the vertical temperature gradient is observed most often and is defined as the average of many measurements. In fact, the vertical temperature gradient in the temperate latitudes of the Earth is variable. It depends on the seasons of the year, the time of day, the nature of atmospheric processes, and in the lower layers of the troposphere - mainly on the temperature of the underlying surface.

In the warm season, when the layer of air adjacent to the surface of the earth is sufficiently heated, a decrease in temperature with height is characteristic. With a strong heating of the surface layer of air, the value of the vertical temperature gradient exceeds even 1 ° for every 100 m uplift.

In winter, with a strong cooling of the surface of the earth and the surface layer of air, instead of lowering, an increase in temperature is observed with height, i.e., a temperature inversion occurs. The strongest and most powerful inversions are observed in Siberia, especially in Yakutia in winter, where clear and calm weather prevails, contributing to the radiation and subsequent cooling of the surface air layer. Very often, the temperature inversion here extends to a height of 2-3 km, and the difference between the air temperature at the earth's surface and the upper boundary of the inversion is often 20-25°. Inversions are also characteristic of the central regions of Antarctica. In winter, they are in Europe, especially in its eastern part, Canada and other areas. The magnitude of the change in temperature with height (vertical temperature gradient) largely determines the weather conditions and types of air movement in the vertical direction.

Stable and unstable atmosphere. The air in the troposphere is heated by the underlying surface. Air temperature changes with altitude and with atmospheric pressure. When this happens without heat exchange with the environment, then such a process is called adiabatic. Rising air does work at the expense of internal energy, which is spent on overcoming external resistance. Therefore, when it rises, the air cools, and when it descends, it heats up.

Adiabatic temperature changes occur according to dry adiabatic and wet adiabatic laws.

Accordingly, vertical gradients of temperature change with height are also distinguished. Dry adiabatic gradient is the change in temperature of dry or moist unsaturated air for every 100 m raise and lower it by 1 °, a wet adiabatic gradient is the decrease in temperature of moist saturated air for every 100 m elevation less than 1°.

When dry, or unsaturated, air rises or falls, its temperature changes according to the dry adiabatic law, i.e., respectively, falls or rises by 1 ° every 100 m. This value does not change until the air, when rising, reaches a state of saturation, i.e. condensation level water vapor. Above this level, due to condensation, the latent heat of vaporization begins to be released, which is used to heat the air. This additional heat reduces the amount of air cooling as it rises. A further rise in saturated air occurs already according to the humid adiabatic law, and its temperature does not decrease by 1 ° per 100 m, but less. Since the moisture content of air depends on its temperature, the higher the air temperature, the more heat is released during condensation, and the lower the temperature, the less heat. Therefore, the humid adiabatic gradient in warm air is smaller than in cold air. For example, at a temperature of rising saturated air near the earth's surface of +20°, the humid adiabatic gradient in the lower troposphere is 0.33-0.43° per 100 m, and at a temperature of minus 20° its values ​​range from 0.78° to 0.87° per 100 m.

The wet adiabatic gradient also depends on the air pressure: the lower the air pressure, the smaller the wet adiabatic gradient at the same initial temperature. This is due to the fact that at low pressure, the air density is also less, therefore, the released heat of condensation is used to heat a smaller mass of air.

Table 15 shows the average values ​​of the wet adiabatic gradient at various temperatures and values

pressure 1000, 750 and 500 mb, which approximately corresponds to the surface of the earth and heights of 2.5-5.5 km.

In the warm season, the vertical temperature gradient averages 0.6-0.7° per 100 m uplift.

Knowing the temperature at the surface of the earth, it is possible to calculate the approximate values ​​of the temperature at various heights. If, for example, the air temperature at the earth's surface is 28°, then, assuming that the vertical temperature gradient is on average 0.7° per 100 m or 7° per kilometer, we get that at a height of 4 km the temperature is 0°. The temperature gradient in winter in the middle latitudes over land rarely exceeds 0.4-0.5 ° per 100 m: There are frequent cases when in separate layers of air the temperature almost does not change with height, i.e., isothermia takes place.

By the magnitude of the vertical air temperature gradient, one can judge the nature of the equilibrium of the atmosphere - stable or unstable.

At stable equilibrium atmospheric masses of air do not tend to move vertically. In this case, if a certain volume of air is shifted upwards, it will return to its original position.

Stable equilibrium occurs when the vertical temperature gradient of unsaturated air is less than the dry adiabatic gradient, and the vertical temperature gradient of saturated air is less than the wet adiabatic one. If, under this condition, a small volume of unsaturated air is raised by an external action to a certain height, then as soon as the action of the external force ceases, this volume of air will return to its previous position. This happens because the raised volume of air, having spent internal energy on its expansion, was cooled by 1 ° for every 100 m(according to the dry adiabatic law). But since the vertical temperature gradient of the ambient air was less than the dry adiabatic one, it turned out that the volume of air raised at a given height had a lower temperature than the ambient air. Having a greater density than the surrounding air, it must sink until it reaches its original state. Let's show this with an example.

Suppose that the air temperature near the earth's surface is 20°, and the vertical temperature gradient in the layer under consideration is 0.7° per 100 m. With this value of the gradient, the air temperature at a height of 2 km will be equal to 6° (Fig. 19, a). Under the influence of an external force, a volume of unsaturated or dry air raised from the earth's surface to this height, cooling according to the dry adiabatic law, i.e., by 1 ° per 100 m, will cool by 20 ° and take a temperature equal to 0 °. This volume of air will be 6° colder than the surrounding air, and therefore heavier due to its greater density. So he starts

descend, trying to reach the initial level, i.e., the surface of the earth.

A similar result will be obtained in the case of rising saturated air, if the vertical gradient of the ambient temperature is less than the humid adiabatic one. Therefore, under a stable state of the atmosphere in a homogeneous mass of air, there is no rapid formation of cumulus and cumulonimbus clouds.

The most stable state of the atmosphere is observed at small values ​​of the vertical temperature gradient, and especially during inversions, since in this case, warmer and lighter air is located above the lower cold, and therefore heavy, air.

At unstable equilibrium of the atmosphere the volume of air raised from the earth's surface does not return to its original position, but retains its upward movement to a level at which the temperatures of the rising and surrounding air are equalized. The unstable state of the atmosphere is characterized by large vertical temperature gradients, which is caused by heating of the lower layers of air. At the same time, the air masses warmed up below, as lighter ones, rush upwards.

Suppose, for example, that unsaturated air in the lower layers up to a height of 2 km stratified unstable, i.e. its temperature

decreases with altitude by 1.2° for every 100 m, and above, the air, having become saturated, has a stable stratification, i.e., its temperature drops already by 0.6 ° for every 100 m uplifts (Fig. 19, b). Once in such an environment, the volume of dry unsaturated air will begin to rise according to the dry adiabatic law, i.e., it will cool by 1 ° per 100 m. Then, if its temperature near the earth's surface is 20°, then at a height of 1 km it will become 10°, while the ambient temperature is 8°. Being 2° warmer and therefore lighter, this volume will rush higher. At height 2 km it will be already 4° warmer than the environment, since its temperature will reach 0°, and the ambient temperature is -4°. Being lighter again, the considered volume of air will continue its rise to a height of 3 km, where its temperature becomes equal to the ambient temperature (-10 °). After that, the free rise of the allocated air volume will stop.

To determine the state of the atmosphere are used aerological charts. These are diagrams with rectangular coordinate axes, along which the characteristics of the state of the air are plotted.

Families are plotted on upper-air diagrams dry and wet adiabats, i.e., curves graphically representing the change in the state of air during dry adiabatic and wet adiabatic processes.

Figure 20 shows such a diagram. Here, isobars are shown vertically, isotherms (lines of equal air pressure) horizontally, inclined solid lines are dry adiabats, inclined broken lines are wet adiabats, dotted lines are specific humidity.The above diagram shows curves of air temperature changes with a height of two points for the same observation period - 15:00 on May 3, 1965. On the left - the temperature curve according to the data of a radiosonde launched in Leningrad, on the right - in Tashkent. It follows from the shape of the left curve of temperature change with height that the air in Leningrad is stable. In this case, up to the isobaric surface of 500 mb the vertical temperature gradient averages 0.55° per 100 m. In two small layers (on surfaces 900 and 700 mb) isotherm was recorded. This indicates that over Leningrad at heights of 1.5-4.5 km there is an atmospheric front that separates the cold air masses in the lower one and a half kilometers from the thermal air located above. The height of the condensation level, determined by the position of the temperature curve with respect to the wet adiabat, is about 1 km(900 mb).

In Tashkent, the air had an unstable stratification. Up to height 4 km vertical temperature gradient was close to adiabatic, i.e., for every 100 m rise, the temperature decreased by 1 °, and higher, up to 12 km- more adiabatic. Due to the dryness of the air, cloud formation did not occur.

Over Leningrad, the transition to the stratosphere took place at an altitude of 9 km(300 mb), and over Tashkent it is much higher - about 12 km(200 mb).

With a stable state of the atmosphere and sufficient humidity, stratus clouds and fogs can form, and with an unstable state and a high moisture content of the atmosphere, thermal convection, leading to the formation of cumulus and cumulonimbus clouds. The state of instability is associated with the formation of showers, thunderstorms, hail, small whirlwinds, squalls, etc.

The so-called "chatter" of the aircraft, i.e., the throws of the aircraft during flight, is also caused by the unstable state of the atmosphere.

In summer, the instability of the atmosphere is common in the afternoon, when the layers of air close to the earth's surface are heated. Therefore, heavy rains, squalls and similar dangerous weather phenomena are more often observed in the afternoon, when strong vertical currents arise due to breaking instability - ascending and descending air movement. For this reason, aircraft flying during the day at an altitude of 2-5 km above the earth's surface, they are more subject to "chatter" than during night flight, when, due to the cooling of the surface layer of air, its stability increases.

Humidity also decreases with altitude. Almost half of all humidity is concentrated in the first one and a half kilometers of the atmosphere, and the first five kilometers contain almost 9/10 of all water vapor.

To illustrate the daily observed nature of the change in temperature with height in the troposphere and lower stratosphere in various regions of the Earth, Figure 21 shows three stratification curves up to a height of 22-25 km. These curves were built based on radiosonde observations at 3 pm: two in January - Olekminsk (Yakutia) and Leningrad, and the third in July - Takhta-Bazar (Central Asia). The first curve (Olekminsk) is characterized by the presence of a surface inversion, characterized by an increase in temperature from -48° at the earth's surface to -25° at a height of about 1 km. During this period, the tropopause over Olekminsk was at a height of 9 km(temperature -62°). In the stratosphere, an increase in temperature with height was observed, the value of which is at the level of 22 km approached -50°. The second curve, representing the change in temperature with height in Leningrad, indicates the presence of a small surface inversion, then an isotherm in a large layer and a decrease in temperature in the stratosphere. At level 25 km the temperature is -75°. The third curve (Takhta-Bazar) is very different from the northern point - Olekminsk. The temperature at the earth's surface is above 30°. The tropopause is at 16 km, and above 18 km there is an increase in temperature with altitude, which is usual for a southern summer.

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The sun's rays falling on the surface of the earth heat it up. The air is heated from the bottom up, i.e. from the earth's surface.

The transfer of heat from the lower layers of air to the upper ones occurs mainly due to the rise of warm, heated air up and the lowering of cold air down. This process of heating air is called convection.

In other cases, the upward heat transfer occurs due to dynamic turbulence. This is the name of chaotic whirlwinds that arise in the air as a result of its friction against the earth's surface during horizontal movement or during the friction of different layers of air with each other.

Convection is sometimes called thermal turbulence. Convection and turbulence are sometimes combined by a common name - exchange.

The cooling of the lower layers of the atmosphere occurs differently than heating. The earth's surface continuously loses heat to its surrounding atmosphere by emitting heat rays that are not visible to the eye. Cooling becomes especially strong after sunset (at night). Due to thermal conductivity, the air masses adjacent to the ground also gradually cool, transferring this cooling to the overlying layers of air; at the same time, the lowest layers are most intensively cooled.

Depending on solar heating, the temperature of the lower layers of air changes during the year and day, reaching a maximum at about 13-14 hours. The daily course of air temperature on different days for the same place is not constant; its value depends mainly on the state of the weather. Thus, changes in the temperature of the lower layers of air are associated with changes in the temperature of the earth's (underlying) surface.

Changes in air temperature also occur from its vertical movements.

It is known that when air expands, it cools, and when compressed, it heats up. In the atmosphere, during the upward movement, the air, falling into areas of lower pressure, expands and cools, and, conversely, during the downward movement, the air, compressing, heats up. Changes in air temperature during its vertical movements largely determine the formation and destruction of clouds.

Air temperature usually decreases with altitude. The change in average temperature with height over Europe in summer and winter is given in the table "Average air temperatures over Europe".

The decrease in temperature with height is characterized by a vertical temperature gradient. This is the change in temperature for every 100 m of altitude. For technical and aeronautical calculations, the vertical temperature gradient is assumed to be 0.6. It must be borne in mind that this value is not constant. It may happen that in any layer of air the temperature will not change with height.

Such layers are called layers of isotherm.

Quite often, a phenomenon is observed in the atmosphere when, in a certain layer, the temperature even increases with height. These layers of the atmosphere are called inversion layers. Inversions arise from various reasons. One of them is the cooling of the underlying surface by radiation at night or in winter with a clear sky. Sometimes, in the case of calm or light winds, the surface layers of air also cool and become colder than the overlying layers. As a result, the air at altitude is warmer than at the bottom. Such inversions are called radiation. Strong radiative inversions are usually observed over the snow cover and especially in mountain basins, and also during calm. The inversion layers extend up to a height of several tens or hundreds of meters.

Inversions also arise due to the movement (advection) of warm air onto the cold underlying surface. These are the so-called advective inversions. The height of these inversions is several hundred meters.

In addition to these inversions, frontal inversions and compression inversions are observed. Frontal inversions occur when warm air masses flow onto colder air masses. Compression inversions occur when air descends from the upper atmosphere. At the same time, the descending air is sometimes heated so much that its underlying layers turn out to be colder.

Temperature inversions are observed at various heights of the troposphere, most often at altitudes of about 1 km. The thickness of the inversion layer can vary from several tens to several hundreds of meters. The temperature difference during inversion can reach 15-20°.

Inversion layers play a big role in the weather. Because the air in the inversion layer is warmer than the underlying layer, the air from the lower layers cannot rise. Consequently, layers of inversions retard vertical movements in the underlying air layer. When flying under a layer of inversion, a rheme ("bumpiness") is usually observed. Above the inversion layer, the flight of the aircraft usually proceeds normally. So-called wavy clouds develop under the layers of inversions.

The air temperature affects the piloting technique and the operation of the materiel. At temperatures near the ground below -20 °, the oil freezes, so it has to be filled in in a heated state. In flight, at low temperatures, the water in the engine cooling system is intensively cooled. At elevated temperatures (above + 30 °), the motor may overheat. Air temperature also affects the performance of the aircraft crew. At low temperatures, reaching up to -56 ° in the stratosphere, special uniforms are required for the crew.

Air temperature is very important for weather forecasting.

Measurement of air temperature during the flight on an aircraft is carried out using electric thermometers attached to the aircraft. When measuring air temperature, it must be borne in mind that due to the high speeds of modern aircraft, thermometers give errors. The high speeds of the aircraft cause an increase in the temperature of the thermometer itself, due to the friction of its reservoir against the air and the effect of heating due to air compression. Friction heating increases with an increase in aircraft flight speed and is expressed by the following quantities:

Speed ​​in km/h …………. 100 200 Z00 400 500 600

Friction heating ……. 0°.34 1°.37 3°.1 5°.5 8°.6 12°,b

Heating from compression is expressed by the following quantities:

Speed ​​in km/h …………. 100 200 300 400 500 600

Heating by compression ……. 0°.39 1°.55 3°.5 5°.2 9°.7 14°.0

Distortions in the readings of a thermometer installed on an airplane, when flying in clouds, are 30% less than the above values, due to the fact that part of the heat that occurs during friction and compression is spent on the evaporation of water condensed in the air in the form of droplets.

Air temperature. Units of measure, change in temperature with altitude. Inversion, isothermy, Types of inversions, Adiabatic process.

Air temperature is a value that characterizes its thermal state. It is expressed either in degrees Celsius (ºС on a centigrade scale or in Kelvin (K) on an absolute scale. The transition from temperature in Kelvin to temperature in degrees Celsius is performed by the formula

t=T-273º

The lower layer of the atmosphere (troposphere) is characterized by a decrease in temperature with height, amounting to 0.65ºС per 100 m.

This change in temperature with height per 100m is called the vertical temperature gradient. Knowing the temperature near the earth's surface and using the value of the vertical gradient, it is possible to calculate the approximate temperature at any height (for example, at a temperature near the earth's surface of +20ºС at a height of 5000m, the temperature will be equal to:

20º- (0.65 * 50) \u003d - 12..5.

The vertical gradient γ is not a constant value and depends on the type of air mass, time of day and season, nature of the underlying surface, and other factors. When the temperature decreases with height, γ  is considered positive, if the temperature does not change with height, then γ = 0  the layers are called isothermal. Atmospheric layers where the temperature rises with height (γ< 0), называются inversion. Depending on the magnitude of the vertical temperature gradient, the state of the atmosphere can be stable, unstable, or indifferent to dry (not saturated) or saturated air.

The decrease in air temperature as it rises adiabatically, that is, without heat exchange of air particles with the environment. If an air particle rises, then its volume expands, while the internal energy of the particle decreases.

As the particle descends, it contracts and its internal energy increases. From this it follows that with an upward movement of the volume of air, its temperature decreases, and with a downward movement, it rises. These processes play an important role in the formation and development of clouds.

The horizontal gradient is the temperature expressed in degrees at a distance of 100 km. During the transition from cold to warm VM and from warm to cold, it can exceed 10º per 100 km.

Types of inversions.

Inversions are delay layers, they dampen the vertical movement of air, under them there is an accumulation of water vapor or other solid particles that impair visibility, the formation of fog and various forms of clouds. The layers of inversions are decelerating layers for horizontal air movements as well. In many cases, these layers are wind break surfaces. Inversions in the troposphere can be observed near the earth's surface and at high altitudes. The tropopause is a powerful layer of inversion.

Depending on the causes of occurrence, the following types of inversions are distinguished:

1. Radiation - the result of cooling the surface layer of air, usually at night.

2. Advective - when warm air moves to a cold underlying surface.

3. Compression or subsidence - formed in the central parts of inactive anticyclones.

Task:

It is known that at an altitude of 750 meters above sea level the temperature is +22 o C. Determine the air temperature at a height:

a) 3500 meters above sea level

b) 250 meters above sea level

Decision:

We know that when the altitude changes by 1000 meters (1 km), the air temperature changes by 6 ° C. Moreover, with an increase in altitude, the air temperature decreases, and with a decrease, it rises.

a) 1. Determine the height difference: 3500 m -750 m = 2750 m = 2.75 km

2. Determine the difference in air temperatures: 2.75 km × 6 o C = 16.5 o C

3. Determine the air temperature at a height of 3500 m: 22 ° C - 16.5 ° C \u003d 5.5 ° C

Answer: at an altitude of 3500 m, the air temperature is 5.5 o C.

b) 1. Determine the height difference: 750 m -250 m = 500 m = 0.5 km

2. Determine the difference in air temperatures: 0.5 km × 6 o C = 3 o C

3. Determine the air temperature at a height of 250 m: 22 o C + 3 o C = 25 o C

Answer: at a height of 250 m, the air temperature is 25 ° C.

2. Determination of atmospheric pressure depending on altitude

Task:

It is known that at an altitude of 2205 meters above sea level, atmospheric pressure is 550 mmHg. Determine the atmospheric pressure at altitude:

a) 3255 meters above sea level

b) 0 meters above sea level

Decision:

We know that with a change in altitude of 10.5 meters, atmospheric pressure changes by 1 mmHg. Art. Moreover, with an increase in altitude, atmospheric pressure decreases, and with a decrease, it increases.

a) 1. Determine the height difference: 3255 m - 2205 m = 1050 m

2. Determine the difference in atmospheric pressure: 1050 m: 10.5 m = 100 mm Hg.

3. Determine the atmospheric pressure at an altitude of 3255 m: 550 mm Hg. - 100 mm Hg = 450 mmHg

Answer: At an altitude of 3255 m, atmospheric pressure is 450 mmHg.

b) 1. Determine the height difference: 2205 m - 0 m = 2205 m

2. Determine the difference in atmospheric pressure: 2205 m: 10.5 m = 210 mm Hg. Art.

3. Determine the atmospheric pressure at a height of 0 m: 550 mm Hg. + 210 mmHg Art. = 760 mmHg Art.

Answer: At a height of 0 m, atmospheric pressure is 760 mm Hg.

3. Beaufort scale

(wind speed scale)

Practical material for a geography lesson in grade 6 - UMK: O.A. Klimanov, V.V. Klimanov, E.V. Kim. For consideration, tasks on the topic are proposed "Air temperature".

The solution of geographical problems contributes to the active assimilation of the course of geography, forms general educational and special geographical skills.

Goals:

Development of skills to calculate the air temperature at different heights, calculate the height;

Development of the ability to analyze, draw conclusions.

How does temperature change with height?

When the altitude changes by 1000 meters (1 km), the air temperature changes by 6 ° C (with an increase in altitude, the air temperature decreases, and with a decrease, it rises).

Geographic tasks:

1. At the top of the mountain, the temperature is -5 degrees, the height of the mountain is 4500 m. Determine the temperature at the foot of the mountain?

Decision:

For every kilometer up, the air temperature drops by 6 degrees, that is, if the mountain height is 4500 or 4.5 km, it turns out that:

1) 4.5 x 6 = 27 degrees. This means that the temperature has dropped by 27 degrees, and if it is 5 degrees at the top, then at the foot of the mountain it will be:

2) - 5 + 27 = 22 degrees at the foot of the mountain

Answer: 22 degrees at the foot of the mountain

2. Determine the air temperature at the top of the mountain 3 km, if at the foot of the mountain it was + 12 degrees.

Decision:

If after 1 km the temperature drops by 6 degrees, then

Answer:- 6 degrees at the top of the mountain

3. To what height did the plane rise if the temperature outside it is -30 ° C, and at the surface of the Earth + 12 ° C?

Decision:

2) 42: 6 = 7 km

Answer: the plane rose to a height of 7 km

4. What is the air temperature at the top of the Pamirs, if in July at the foot it is +36°С? The height of the Pamirs is 6 km.

Decision:

Answer: 0 degrees at the top of the mountain

5. Determine the air temperature overboard the aircraft, if the air temperature at the earth's surface is 31 degrees, and the flight altitude is 5 km?

Decision:

Answer: 1 degree outside temperature

Blue planet...

This topic was supposed to appear on the site one of the first. After all, helicopters are atmospheric aircraft. Earth's atmosphere- their, so to speak, habitat :-). BUT physical properties of air just determine the quality of this habitat :-). So that's one of the basics. And the basis is always written first. But I just realized this now. However, it is better, as you know, late than never ... Let's touch on this issue, but without getting into the wilds and unnecessary difficulties :-).

So… Earth's atmosphere. This is the gaseous shell of our blue planet. Everyone knows this name. Why blue? Simply because the "blue" (as well as blue and violet) component of sunlight (spectrum) is most well scattered in the atmosphere, thus coloring it in bluish-bluish, sometimes with a hint of violet (on a sunny day, of course :-)) .

Composition of the Earth's atmosphere.

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

Earth's atmosphere It is customary to divide into several zones following each other in height above the surface.

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

atmospheric zones.

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

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

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

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

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

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

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

Perhaps we will finish with the terms, but I will definitely add that it is conventionally assumed that the boundary of the atmosphere is located at an altitude of 100 km above sea level. This border is called the Karman Line.

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

The structure of the Earth's atmosphere.

Change in air temperature with height.

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

The aviation zone is the troposphere. Modern atmospheric aircraft can also fly in the lower layers of the stratosphere. For example, the practical ceiling of the MIG-25RB is 23000 m.

Flight in the stratosphere.

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

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

Temperature t1 at a given height H on the Celsius scale is determined:

t 1 \u003d t - 6.5N, where t is the air temperature at the ground.

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

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

T \u003d 273K + t - 6.5H

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

Air density. In aerodynamics, the most commonly used concept is the mass density of air. This is the mass of air in 1 m3 of volume. The density of air changes with height, the air becomes more rarefied.

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

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

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

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

temperature t = +15°C (288 K);

mass density ρ \u003d 1.225 kg / m 3;

For the ISA, it is assumed (as mentioned above :-)) that the temperature drops in the troposphere by 0.65º for every 100 meters of altitude.

Standard atmosphere (example up to 10000 m).

ISA tables are used for calibrating instruments, as well as for navigational and engineering calculations.

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

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

Viscosity. Determines the frictional resistance against air as the aircraft moves.

Compressibility measures the change in air density as pressure changes. At low speeds of the aircraft (up to 450 km/h), there is no change in pressure when the air flow flows around it, but at high speeds, the effect of compressibility begins to appear. Its influence on supersonic is especially pronounced. This is a separate area of ​​​​aerodynamics and a topic for a separate article :-).

Well, it seems that's all for now ... It's time to finish this slightly tedious enumeration, which, however, cannot be dispensed with :-). Earth's atmosphere, its parameters, physical properties of air are as important for the aircraft as the parameters of the apparatus itself, and it was impossible not to mention them.

For now, until the next meetings and more interesting topics 🙂 …

P.S. For dessert, I suggest watching a video filmed from the cockpit of a MIG-25PU twin during its flight into the stratosphere. Filmed, apparently, by a tourist who has money for such flights :-). Filmed mostly through the windshield. Notice the color of the sky...

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 precisely 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 drops. 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 height, 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 a level of energy is created that is suitable for the existence of terrestrial life forms. The ozonosphere absorbs some of the 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, thanks to which many types of radio communication become 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"