What is the temperature at an altitude of 20 km. How does air temperature change with altitude? Temperature fluctuations in different layers

Troposphere

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 available in the atmosphere. Turbulence and convection are highly developed in the troposphere, clouds arise, and cyclones and anticyclones develop. Temperature decreases with increasing altitude with an average vertical gradient of 0.65°/100 m

Tropopause

The transition layer from the troposphere to the stratosphere, a layer of the atmosphere in which the decrease in temperature with height stops.

Stratosphere

A layer of the atmosphere located at an altitude of 11 to 50 km. Characterized by a slight change in temperature in the 11-25 km layer (lower layer of the stratosphere) and an increase in temperature in the 25-40 km layer from −56.5 to 0.8 ° C (upper layer of the stratosphere or inversion region). 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 mesosphere.

Stratopause

The boundary layer of the atmosphere between the stratosphere and mesosphere. In the vertical temperature distribution there is a maximum (about 0 °C).

Mesosphere

The mesosphere begins at an altitude of 50 km and extends to 80-90 km. 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 the glow of the atmosphere.

Mesopause

Transitional layer between the mesosphere and thermosphere. There is a minimum in the vertical temperature distribution (about -90 °C).

Karman Line

The height above sea level, which is conventionally accepted as the boundary between the Earth's atmosphere and space. The Karman line is located at an altitude of 100 km above sea level.

Boundary of the Earth's atmosphere

Thermosphere

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 to high altitudes. Under the influence of ultraviolet and x-ray solar radiation And cosmic radiation ionization of the air (“auroras”) occurs - 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, a noticeable decrease in the size of this layer occurs.

Thermopause

The region of the atmosphere adjacent to the thermosphere. In this region, the absorption of solar radiation is negligible and the temperature does not actually change with altitude.

Exosphere (scattering sphere)

Atmospheric layers up to an altitude of 120 km

The exosphere is a dispersion zone, the outer part of the thermosphere, located above 700 km. The gas in the exosphere is very rarefied, and from here its particles leak into interplanetary space (dissipation).

Up to an altitude of 100 km, the atmosphere is a homogeneous, well-mixed mixture of gases. In higher layers, the distribution of gases over height depends on their molecular weights, 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 kinetic energy individual particles at altitudes of 200-250 km correspond to a temperature of ~150 °C. Above 200 km, significant fluctuations in temperature and gas density in time and space are observed.

At an altitude of about 2000-3500 km, the exosphere gradually turns into the so-called near-space vacuum, which is filled with highly rarefied particles of interplanetary gas, mainly hydrogen atoms. But this gas represents only part of the interplanetary matter. The other part consists of dust particles of cometary and meteoric origin. In addition to extremely rarefied dust 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 - about 20%; mass of the mesosphere - no more than 0.3%, thermosphere - less than 0.05% of total mass atmosphere. Based on the electrical properties in the atmosphere, the neutronosphere 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 affects the separation of gases, since their mixing at such a height is negligible. This implies a 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; it lies at an altitude of about 120 km.

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 the altitude:

a) 3500 meters above sea level

b) 250 meters above sea level

Solution:

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

a) 1. Determine the difference in heights: 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 an altitude of 3500 m: 22 o C - 16.5 o C = 5.5 o C

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

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

2. Let’s determine the difference in air temperatures: 0.5 km × 6 o C = 3 o C

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

Answer: at an altitude of 250 m the air temperature is 25 o C.

2. Determination of atmospheric pressure depending on altitude

Task:

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

a) 3255 meters above sea level

b) 0 meters above sea level

Solution:

We know that when the altitude changes by 10.5 meters, the atmospheric pressure changes by 1 mmHg. Art. Moreover, with increasing altitude, atmospheric pressure decreases, and with decreasing altitude, it increases.

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

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

3. Let’s 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, the atmospheric pressure is 450 mm Hg.

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

2. Let's determine the difference in atmospheric pressure: 2205 m: 10.5 m = 210 mm Hg. Art.

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

Answer: at an altitude of 0 m, the atmospheric pressure is 760 mm Hg.

3. Beaufort scale

(wind speed scale)

Points	Wind speed	Wind characteristics	Wind action
	32.7 or more	moderate very strong heavy storm fierce storm	The smoke rises vertically, the leaves on the trees are motionless Light air movement, smoke tilts slightly The movement of air is felt by the face, the leaves rustle Leaves and thin branches on the trees sway Tree tops bend, dust rises Branches and thin tree trunks sway Thick branches sway, telephone wires hum Tree trunks are swaying, it’s hard to walk against the wind Large trees sway, small branches break Minor damage to buildings, thick branches breaking Trees break and are uprooted, damage to buildings Great destruction Devastating destruction

Blue planet...

This topic should have been one of the first to appear on the site. After all, helicopters are atmospheric aircraft. Earth's atmosphere– their habitat, so to speak:-). A physical properties air This is precisely what determines the quality of this habitat :-). That is, this is one of the basics. And they always write about the basis first. But I realized this only now. However, as you know, it’s better late than never... Let’s touch on this issue, without getting into the weeds and unnecessary complications :-).

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

Composition of the Earth's atmosphere.

The composition of the atmosphere is quite broad. 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 vapor, suspended droplets or ice crystals. The amount of water is not constant and depends on temperature and, to a lesser extent, air pressure. In addition, the Earth’s atmosphere (especially the current one) contains a certain amount of, I would say, “all sorts of nasty things” :-). These are SO 2, NH 3, CO, HCl, NO, in addition there are mercury vapors Hg. True, all this is there in small quantities, God bless:-).

Earth's atmosphere It is customary to divide it into several successive zones in height above the surface.

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

Atmospheric zones.

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

So the stratosphere has an average height of 12 km to 50 km. The temperature in it remains unchanged up to 25 km (about -57ºС), then somewhere up to 40 km it rises to approximately 0ºС and then remains unchanged up to 50 km. The stratosphere is a relatively calm part of the earth's atmosphere. Unfavorable weather it is practically absent. It is in the stratosphere that the famous ozone layer at altitudes from 15-20 km to 55-60 km.

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

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

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

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

For example, homosphere and heterosphere. In the first, 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 in it are separated by gravity. The boundary between these layers is located at an altitude of 120 km, and it is called turbopause.

Let’s finish with the terms, but I’ll definitely add that it is conventionally accepted 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 one, however, is in German, but it is complete and quite easy to understand :-). It can be enlarged and seen clearly. The second shows the change in atmospheric temperature with altitude.

The structure of the Earth's atmosphere.

Air temperature changes with altitude.

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

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 23,000 m.

Flight in the stratosphere.

And exactly physical properties of air The troposphere determines what the flight will be like, how effective the aircraft’s control system will be, how turbulence in the atmosphere will affect it, and how the engines will operate.

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

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

t 1 = t - 6.5N, Where t– air temperature near 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 N on the Kelvin scale is determined by:

T = 273K + t - 6.5H

Air pressure. Atmosphere pressure measured in Pascals (N/m2), 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 mmHg. Art. called standard. In physics 1 atm. exactly equal to 760 mm Hg.

Air density. In aerodynamics, the concept most often used is the mass density of air. This is the mass of air in 1 m3 of volume. The density of air changes with altitude, 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 possible. 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.

Due to the fact that aircraft flights occur under different atmospheric conditions, their flight and aerodynamic parameters in the same flight mode may be different. Therefore, to correctly estimate these parameters, we introduced International Standard Atmosphere (ISA). It shows the change in the state of air with increasing altitude.

The basic parameters of the air condition at zero humidity are taken as follows:

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

temperature t = +15°C (288 K);

mass density ρ = 1.225 kg/m 3 ;

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

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

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

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

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

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

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

Well, that seems to be all for now... It's time to finish this slightly tedious enumeration, which, however, cannot be avoided :-). Earth's atmosphere, its parameters, physical properties of air are as important for the aircraft as the parameters of the device itself, and they could not be ignored.

Bye, until next meetings and more interesting topics :) ...

P.S. For dessert, I suggest you watch a video filmed from the cockpit of a twin MIG-25PU during its flight into the stratosphere. Apparently it was filmed by a tourist who has money for such flights :-). Mostly everything was filmed through the windshield. Pay attention to the color of the sky...

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

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

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

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

Cooling of the lower atmosphere occurs differently than heating. Earth's surface It continuously loses heat into the atmosphere surrounding it by emitting heat rays invisible to the eye. The cooling becomes especially severe after sunset (at night). Thanks to thermal conductivity, the air masses adjacent to the ground are also gradually cooled, then transferring this cooling to the overlying layers of air; in this case, the lowest layers are cooled most intensively.

Depending on solar heating, the temperature of the lower air layers varies throughout the year and day, reaching a maximum around 13-14 hours. Daily variation of air temperature in different days for the same place is not constant; its magnitude depends mainly on weather conditions. 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 air cools when it expands, and heats up when compressed. In the atmosphere at upward movement air entering areas of more low pressure, expands and cools, and, conversely, with 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 height. Change average temperature with altitude 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 name for the change in temperature for every 100 m of altitude. For technical and aeronautical calculations, the vertical temperature gradient is taken equal to 0.6. It must be kept in mind that this value is not constant. It may happen that in some layer of air the temperature does not change with height. Such layers are called layers of isotherm.

Quite often in the atmosphere there is a phenomenon when in a certain layer the temperature even increases with height. These layers of the atmosphere are called layers of inversion. Inversions arise from various reasons. One of them is cooling the underlying surface by radiation at night or winter time under clear skies. Sometimes, in the case of calm or weak wind, the surface air also cools and becomes colder than the overlying layers. As a result, the air at altitude is warmer than at the bottom. Such inversions are called radiation. Strong radiation inversions are usually observed over snow cover and especially in mountain basins, and also during calm conditions. Inversion layers extend to heights of several tens or hundreds of meters.

Inversions also occur due to the movement (advection) of warm air onto a 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 water flows in air masses to colder ones. Compression inversions occur when air is released from upper layers atmosphere. In this case, the descending air sometimes heats up so much that its underlying layers turn out to be colder.

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

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

Air temperature influences piloting technique and equipment operation. At ground temperatures below -20°, the oil freezes, so it must be poured 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 -56° in the stratosphere, special uniforms are required for the crew.

The air temperature is very great importance for weather forecast.

Air temperature is measured during an airplane flight using electric thermometers attached to the airplane. When measuring air temperature, it is necessary to keep in mind that due to the high speeds of modern aircraft, thermometers give errors. High aircraft speeds cause an increase in the temperature of the thermometer itself, due to the friction of its reservoir with the air and the influence of heating due to air compression. Heating from friction increases with increasing aircraft flight speed and is expressed by the following quantities:

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

Heating from friction...... 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 from compression...... 0°.39 1°.55 3°.5 5°.2 9°.7 14°.0

The distortion of the readings of a thermometer installed on an airplane when flying in the clouds is 30% less than the above values, due to the fact that part of the heat generated by friction and compression is spent on evaporating water condensed in the air in the form of droplets.

How does temperature change with altitude? This article will contain information that will contain answers to this and similar questions.

How does air temperature change at altitude?

When rising upward, the air temperature in the troposphere decreases by 1 km - 6 °C. That's why there's snow high in the mountains

The atmosphere is divided into 5 main layers: troposphere, stratosphere, upper atmosphere. For agricultural meteorology, the patterns of temperature changes in the troposphere, especially in its surface layer, are of greatest interest.

What is a vertical temperature gradient?

Vertical temperature gradient- this is a change in air temperature at an altitude every 100 m. The vertical gradient depends on several factors, such as: time of year (temperatures are lower in winter, higher in summer); time of day (colder at night than during the day), etc. The average temperature gradient is about 0.6 ° C / 100 m.

In the surface layer of the atmosphere, the gradient depends on the weather, time of day and the nature of the underlying surface. During the day, VGT is almost always positive, especially in summer; in clear weather it is 10 times greater than in gloomy weather. At lunchtime in summer, the air temperature at the soil surface can be 10-15 ° C higher than the air temperature at a height of 2 m. Because of this, the WGT in a given two-meter layer in terms of 100 m is more than 500 ° C / 100 m. Wind reduces VGT, since when air is mixed, its temperature at different altitudes is equalized. Clouds and precipitation reduce the vertical temperature gradient. At wet soil VGT in the surface layer of the atmosphere sharply decreases. Over bare soil (fallow field) the VGT is greater than over developed crops or alkali. In winter, above the snow cover, the VGT in the surface layer of the atmosphere is small and usually negative.

With height, the influence of the underlying surface and weather on the VGT weakens and it decreases compared to its values ​​in the surface layer of air. Above 500m, the influence of the daily variation in air temperature fades. At altitudes from 1.5 to 5-6 km, the VGT is in the range of 0.5-0.6 ° C / 100 m. At an altitude of 6-9 km, the temperature gradient increases and amounts to 0.65-0.75 ° C / 100 m. In the upper layer of the troposphere, the IHT decreases again to 0.5-0.2 ° C / 100 m.

Data on the vertical temperature gradient in various layers of the atmosphere are used in weather forecasting, in meteorological services for jet aircraft and in launching satellites into orbit, as well as in determining the conditions of release and propagation industrial waste in the atmosphere. Negative VGT in the surface layer of air at night in spring and autumn indicates the possibility of frost.

So, we hope that in this article you found not only useful and educational information, but also the answer to the question “how does air temperature change with altitude.”