divination 

What is inversion in geography definition. What is temperature inversion, where does it manifest itself? What is temperature inversion

The temperature gradient of the atmosphere can vary widely. On average, it is 0.6°/100 m. But in a tropical desert near the earth's surface, it can reach 20°/100 m. With a temperature inversion, the temperature increases with height and the temperature gradient becomes negative, i.e., it can be equal, for example , -0.6°/100 m. If the air temperature is the same at all altitudes, then the temperature gradient is zero. In this case, the atmosphere is said to be isothermal.[ ...]

Temperature inversions determine the reverse arrangement of vertical soil zones in many mountain systems of continental regions. So, in Eastern Siberia, at the foot and in the lower parts of the slopes of some mountains, there are inversion tundras, then there are mountain taiga forests and again mountain tundras above. The inversion tundra cools only in certain seasons, and in the rest of the year they are much warmer than the "upper" tundras and are used in agriculture.[ ...]

Temperature inversion manifests itself in an increase in air temperature with height in a certain layer of the atmosphere (usually in the range of 300-400 m from the Earth's surface) instead of the usual decrease. As a result, atmospheric air circulation is severely disrupted, smoke and pollutants cannot rise up and are not dispersed. Often there are fogs. Concentrations of sulfur oxides, suspended dust, carbon monoxide reach dangerous levels for human health, lead to circulatory and respiratory disorders, and often to death. In 1952, more than four thousand people died from smog in London from December 3 to 9, and up to ten thousand people became seriously ill. At the end of 1962, in the Ruhr (Germany), he was able to kill 156 people in three days. Only the wind can disperse the smog, and the reduction of pollutant emissions can smooth out the smog dangerous situation.[ ...]

Temperature inversions 12 Iodine, determination in air 30 w.[ ...]

Temperature inversions are associated with cases of mass poisoning of the population during periods of toxic fogs (the valley of the Manet River in Belgium, repeatedly in London, Los Angeles, etc.).[ ...]

Sometimes temperature ¡inversions extend to large areas of the earth (surface. The area of ​​\u200b\u200btheir distribution ¡usually coincides with the area of ​​distribution of anticyclones, ¡which occur ¡in zones of high ¡barometric (Pressure.[ ...]

Synonym: temperature inversion. FRICTION INVERSION. See turbulent inversion.[ ...]

A radiative inversion and a settling inversion can take place in the atmosphere at the same time. This situation is shown by a typical temperature profile in Fig. 3.10, c. The simultaneous presence of two types of inversion leads to a phenomenon called limited jet, which will be discussed in subsequent sections. The intensity and duration of the inversion depend on the season. In autumn and winter, as a rule, prolonged inversions take place, and their number is large. Topography also influences inversions. For example, cold air trapped between mountains at night can be trapped in a valley by warm air above it. Until the Sun is directly over the valley the next day, the air in the valley cannot get enough heat to destroy the inversion. Colorado) in winter, for example, about half of all inversions last all day.[ ...]

A - in the absence of inversion, the air temperature decreases with height; B - the location of the temperature inversion, when cold air is trapped under a warm layer. In an inversion layer, the usual temperature gradient is reversed; B - night minimum; G - quarrelsome location for hell; D - a warm section of the slope, formed as a result of the nature of air circulation.[ ...]

Under the influence of cold winters and temperature inversions, soils freeze deeply in winter, and slowly warm up in spring. For this reason, microbiological processes are weak, and despite the high content of humus in the soil, it is necessary to apply increased rates of organic fertilizers (manure, peat and compost) and mineral fertilizers readily available to plants.[ ...]

A typical diurnal temperature gradient over an open area on a cloudless day begins with an unstable rate of temperature drop, which is accelerated during the day by intense heat from the sun, resulting in severe turbulence. Immediately before or shortly after sunset, the ground layer of air cools rapidly and a steady rate of temperature drop occurs (temperature rise with height). During the night, the intensity and depth of this inversion increase, reaching a maximum between midnight and the time of day when the earth's surface has a minimum temperature. During this period, atmospheric pollutants are effectively retained within or below the inversion layer due to little or no vertical dispersion of pollutants. It should be noted that, under conditions of stagnation, pollutants discharged near the earth's surface do not spread to the upper layers of the air and, conversely, emissions from high pipes under these conditions, for the most part, do not penetrate into the layers of air closest to the ground (Church, 1949). With the onset of the day, the earth begins to heat up and the inversion is gradually eliminated. This can lead to "fumigation" (Hewso n a. Gill, 1944) due to the fact that the pollution that got into the upper layers of the air during the night begins to mix quickly and rush down. Therefore, in the early pre-noon hours, preceding the full development of turbulence, ending the diurnal cycle and providing powerful mixing, high concentrations of atmospheric pollutants often occur. This cycle can be disrupted or altered by the presence of clouds or precipitation, which prevent strong convection during the day, but can also prevent the occurrence of strong inversion at night.[ ...]

Two other types of local inversions are possible. One of them is related to the sea breeze mentioned above. Warming of air in the morning hours over land leads to a flow of colder air towards land from the ocean or a sufficiently large lake. As a result, warmer air rises and colder air takes its place, creating inversion conditions. Inversion conditions are also created when a warm front passes over a large continental area of ​​land. A warm front often tends to "crush" the denser, colder air in front of it, thus creating a localized temperature inversion. The passage of a cold front, in front of which there is an area of ​​warm air, leads to the same situation.[ ...]

The fan-shaped form of strings arises from temperature inversion. Its shape resembles a meandering river, which gradually expands with distance from the pipe.[ ...]

In the small American city of Donora, this temperature inversion caused about 6,000 people (42.7% of the total population) to become ill, with some (10%) showing symptoms that indicated the need for hospitalization of these people. Sometimes the consequences of a long-term temperature inversion can be compared to an epidemic: in London, during one of these long-term inversions, 4,000 people died.[ ...]

A fan-shaped jet (Fig. 3.2, c, d) is formed with a temperature inversion or with a temperature gradient close to isothermal, which characterizes very weak vertical mixing. The formation of a fan-shaped jet is favored by weak winds, clear skies and snow cover. Such a jet is most often observed at night.[ ...]

The fan-shaped shape of the smoke cloud exists during inversions and at temperature gradients close to isothermal. This structure of the atmosphere is observed at night, when the temperature of the earth's surface is lower than the air temperature. The fan-shaped cloud does not touch the earth's surface at all. Despite this, the fan-shaped structure poses a danger from the point of view of atmospheric pollution, since the dispersion is mainly in the horizontal direction and the pollutants remain in the lower layers of the atmosphere, not rising up. When emitted from low chimneys, the maximum concentration of pollutants is observed in these cases far from pollution sources.[ ...]

Under unfavorable meteorological situations, such as temperature inversion, increased air humidity and precipitation, the accumulation of pollution can occur especially intensively. Usually, in the surface layer, the air temperature decreases with height, while vertical mixing of the atmosphere occurs, which reduces the concentration of pollution in the surface layer. However, under certain meteorological conditions (for example, during intensive cooling of the earth's surface at night), the so-called temperature inversion occurs, i.e., the change in the course of temperature in the surface layer to the reverse - with increasing altitude, the temperature increases. Typically, this state persists for a short time, but in some cases, temperature inversion can be observed for several days. With a temperature inversion, the air near the earth's surface is, as it were, enclosed in a limited volume, and very high concentrations of pollution can occur near the earth's surface, contributing to increased pollution of insulators.[ ...]

The value of 1 /l/B increases with decreasing stability. For an inversion with y -6.5 K/km 1/1 5 = 41 s, although for a normal temperature gradient with V = +6.5 K/km 1/l/ 5 = 91 s. Thus, at II = 10 m/s and normal temperature gradients, the air flow can overcome an obstacle with a height of 545 m, and for the corresponding inversion conditions - only 245 m. If the air flow does not have the necessary kinetic energy to rise above the obstacle, then it deviates and flows across the isobars towards lower pressure, thereby acquiring kinetic energy. After some time, this deflection can propagate far enough upstream to provide the airflow with the energy needed to lift it over the obstruction. This means that isentropic surfaces (surfaces of equal potential temperature) rise above the obstruction so that air can flow parallel to them. On the leeward side of the ridge, excess energy can manifest itself in the form of waves in the air flow (kinetic energy) or turn into potential energy due to the deflection of air towards a higher pressure.[ ...]

Burnazyan A. I. et al. Pollution of the surface layer of the atmosphere during temperature inversions.[ ...]

DUST HORIZON. The upper boundary of the layer of dust (or smoke) lying under the temperature inversion. When viewed from a height, the impression of the horizon is created.[ ...]

Under certain unfavorable meteorological conditions (weak wind, temperature inversion), the release of harmful substances into the atmosphere leads to mass poisoning. An example of mass poisoning of the population are the disasters in the valley of the Meuse River (Belgium, 1930), in the city of Donore (Pennsylvania, USA, 1948). In London, mass poisoning of the population during catastrophic atmospheric pollution was observed repeatedly - in 1948, 1952, 1956, 1957, 1962; As a result of these events, several thousand people died, many received severe poisoning.[ ...]

London (winter) smog is formed in winter in large industrial centers under adverse weather conditions: lack of wind and temperature inversion. Temperature inversion manifests itself in an increase in air temperature with height (in the layer of 300-400 m) instead of the usual decrease.[ ...]

Particularly unfavorable for the dispersion of harmful substances in the air are areas with a predominance of weak winds or calm. Under these conditions, temperature inversions occur, in which there is an excessive accumulation of harmful substances in the atmosphere. An example of such an unfavorable location is Los Angeles, sandwiched between a mountain range that weakens the wind and interferes with the outflow of polluted city air, and the Pacific Ocean. In this city, temperature inversions occur on average 270 times a year, and 60 of them are accompanied by very high concentrations of harmful substances in the air.[ ...]

The ability of the earth's surface to absorb or radiate heat affects the vertical distribution of temperature in the surface layer of the atmosphere and leads to temperature inversion (deviation from adiabaticity). An increase in air temperature with height leads to the fact that harmful emissions cannot rise above a certain ceiling. Under inversion conditions, the turbulent exchange weakens, and the conditions for the dispersion of harmful emissions in the surface layer of the atmosphere worsen. For a surface inversion, the repeatability of the heights of the upper boundary is of particular importance, for an elevated inversion, the repeatability of the lower boundary.[ ...]

It is necessary to avoid the construction of enterprises with significant emissions of harmful substances on sites where long-term stagnation of impurities can occur when light winds are combined with temperature inversions (for example, in deep basins, in areas of frequent fog formation, in particular in areas with severe winters, below the dams of hydroelectric stations , as well as in areas of possible smog).[ ...]

The conditions conducive to the formation of photochemical fog at a high level of atmospheric air pollution with reactive organic compounds and nitrogen oxides are the abundance of solar radiation, temperature inversions and low wind speed.[ ...]

A typical example of the acute provoking effect of atmospheric pollution is the cases of toxic fogs that occurred at different times in cities on different continents of the world. Toxic fogs appear during periods of temperature inversions with low wind activity, i.e., under conditions conducive to the accumulation of industrial emissions in the surface layer of the atmosphere. During periods of toxic fogs, an increase in pollution was recorded, the more significant, the longer the conditions for air stagnation persisted (3-5 days). During periods of toxic fogs, the mortality of people suffering from chronic cardiovascular and pulmonary diseases increased, and exacerbations of these diseases and the appearance of new cases were recorded among those who sought medical help. Outbreaks of bronchial asthma are described in a number of populated areas with the appearance of specific pollution. It can be assumed that acute cases of allergic diseases appear when air is polluted with such biological products as protein dust, yeasts, molds and their metabolic products. An example of the acute effects of outdoor air pollution are cases of photochemical fog when a combination of factors: vehicle emissions, high humidity, calm weather, intense ultraviolet radiation. Clinical manifestations: irritation of the mucous membranes of the eyes, nose, upper respiratory tract.[ ...]

Measurements on television and radio masts, as well as special aerological observations carried out in recent years, allow us to draw a number of conclusions about the structure of the atmospheric boundary layer above the city. An analysis of experimental data shows that during periods when an inversion is observed outside the city in the presence of a heat island, the temperature stratification among buildings up to a height of several tens of meters is close to equilibrium or slightly unstable. Therefore, elevated inversion layers are more likely to form over the city. The heat island, as noted by Sekiguchi in Urban climates (1970), extends at night to a level approximately equal to 3-4 building heights.[ ...]

During the development of viscous oils and bitumens by wells of thermal methods, a local violation of the natural thermal gradient along the section occurs, which leads to a change in the chemical composition of groundwater in overlying horizons and a deterioration in their quality. Such inversions of the temperature regime of the subsoil are also poorly understood, and the regulation of this type of anthropogenic impact remains outside the scope of regulatory documents.[ ...]

Thus, nowhere on the territory of the USSR such unfavorable meteorological conditions are created for the transfer and dispersion of emissions from low emission sources as on the territory of the BAM. Calculations show that due to the high frequency of stagnant conditions in a large layer of the atmosphere and powerful temperature inversions with the same emission parameters, the level of air pollution in cities and towns of the BAM can be 2-3 times higher than in the European territory of the country. In this regard, the protection of the air basin from pollution of the newly developed territory adjacent to the BAM is especially important.[ ...]

Probably the most infamous smog area in the world is Los Angeles. Chimneys in this city are plentiful. In addition, there are a huge number of cars. Together with these generous suppliers of smoke and soot, both elements of smog formation that played such an important role in Donor work: temperature inversions and mountainous terrain.[ ...]

Industrial enterprises, urban transport and heat generating installations are the cause of smog (mainly in cities): unacceptable pollution of the outdoor air environment inhabited by humans due to the release of harmful substances into it by the indicated sources under adverse weather conditions (lack of wind, temperature inversion, etc.). [...]

The most important element of the climate of mountainous regions is undoubtedly temperature. In most mountainous regions of the world, detailed temperature observations are made and there are many statistical studies of temperature change with height. This change is a difficult problem in compiling climate atlases because of the sharp temperature gradients over short distances and their seasonal variability. Some recent studies of mountain temperatures, such as in and , use regression analysis to relate temperatures to altitude and to separate the effect of inversions from effects due to steep slopes. Pielke and Mering, in an attempt to refine the spatial distribution of temperature for an area in northwestern Virginia, used a linear regression analysis of mean monthly temperatures as a function of altitude. They showed that the correlations are maximum (r=-0.95) in summer, as is usually the case at medium altitudes. In winter, low-level inversions mow down a lot of variability, and if you choose the right polynomial functions or use potential temperatures, you can get better estimates. For the purpose of compiling topoclimatic maps for the Western Carpathians, a series of regression equations was similarly developed. To do this, as described in § 2B4, separate regression equations are used for different slope profiles. Note that there are few attempts to describe changes in mountain temperature at. help of some more general statistical model.[ ...]

Complex experiments carried out abroad are characterized by good instrumentation, the use of an optimal set of analyzers and sampling systems, the determination of meteorological parameters along with the concentration of pollutant components, and the availability of information on the solar level! ? radiation, as well as indicators of atmospheric stability in the boundary layer: temperature stratification, wind speed profile, inversion boundary height, etc.[ ...]

The main reason for the formation of photochemical fog is the strong pollution of urban air by gas emissions from the chemical industry and transport, and mainly by car exhaust gases. A passenger car emits about 10 g of nitric oxide per kilometer. In Los Angeles, where more than 4 million cars have accumulated, they emit about 1,000 tons of this gas per day into the air. In addition, there are frequent temperature inversions (up to 260 days a year), which contribute to stagnation of air over the city. Photochemical fog occurs in polluted air as a result of photochemical reactions occurring under the action of short-wave (ultraviolet) solar radiation on gaseous emissions. Many of these reactions create substances that are much more toxic than the original ones. The main components of photochemical smog are photooxidants (ozone, organic peroxides, nitrates, nitrites, peroxyacetyl nitrate), nitrogen oxides, carbon monoxide and dioxide, hydrocarbons, aldehydes, ketones, phenols, methanol, etc. These substances are always present in smaller amounts in the air large cities, in photochemical smog their concentration often far exceeds the maximum allowable norms.[ ...]

Hydrocarbons, sulfur dioxide, nitrogen oxide, hydrogen sulfide and other gaseous substances, entering the atmosphere, are relatively quickly removed from it. Hydrocarbons are removed from the atmosphere due to dissolution in the water of the seas and oceans and subsequent photochemical and biological processes occurring with the participation of microorganisms in water and soil. Sulfur dioxide and hydrogen sulfide, oxidized to sulfates, are deposited on the surface of the earth. Possessing acidic properties, they are sources of corrosion of various structures made of concrete and metal, they also destroy products made of plastics, artificial fibers, fabrics, leather, etc. A significant amount of sulfur dioxide is absorbed by vegetation and dissolved in the water of the seas and oceans. Carbon monoxide is additionally oxidized to carbon dioxide, which is intensively absorbed by vegetation in the process of photochemical synthesis. Nitrogen oxides are removed by reducing and oxidative reactions (with strong solar radiation and temperature inversion, they form smog dangerous for breathing).[ ...]

Yoshino identified four synoptic types of pressure distribution that cause bora. In winter, it is mostly associated with a cyclone over the Mediterranean or an anticyclone over Europe. In summer, cyclonic systems are rarer and the anticyclone can be located further to the west. In any system, the gradient wind should be from the east to the northeast. The development and maintenance of bora requires both a suitable pressure gradient, stagnation of cold air east of the mountains and its overflow through the mountains, which converts potential energy into kinetic energy. Bora develops best where the Dinaric Mountains are narrow and close to the coast, such as in Split. This increases the temperature gradient between the coastal and inland parts of the country and enhances the downwind effect. The Dinaric Mountains are over 1000 m high, and low passes, such as the pass at Sinj, also favor the local strengthening of the bora. On bora days, the inversion layer is usually located between 1500-2000 m on the windward side of the mountains and at the same or lower level on the lee side.

TEMPERATURE INVERSION

TEMPERATURE INVERSION, an anomalous increase in TEMPERATURE with height. Normally, air temperature decreases with increasing altitude above ground level. The average rate of decrease is 1 °C for every 160 m. Under certain weather conditions, the opposite situation is observed. On a clear, still night with an anticyclone, cold air can roll down the slopes and collect in the valleys, and the air temperature will be lower near the bottom of the valley than 100 or 200 m higher. Above the cold layer there will be warmer air, which is likely to form a cloud or light fog. Temperature inversion becomes clear in the example of smoke rising from a fire. The smoke will rise vertically and then, when it reaches the "inversion layer", bend horizontally. If this situation is created on a large scale, the dust and dirt that rises into the atmosphere stays there and accumulates, leading to serious pollution.


Scientific and technical encyclopedic dictionary.

See what "TEMPERATURE INVERSION" is in other dictionaries:

    Big Encyclopedic Dictionary

    temperature inversion- An increase in temperature with height in a certain layer of the atmosphere instead of its usual decrease. Syn.: temperature inversion … Geography Dictionary

    See Temperature Inversion. * * * TEMPERATURE INVERSION TEMPERATURE INVERSION, see Temperature Inversion (see TEMPERATURE INVERSION) … encyclopedic Dictionary

    temperature inversion- temperatūros apgrąža statusas T sritis ekologija ir aplinkotyra apibrėžtis Vietinis oro temperatūros didėjimas, kylant aukštyn, tam tikruose atmosferos sluoksniuose. Troposferoje temperatūros apgrąžos sluoksnio storis gali būti 2–3 km,… … Ekologijos terminų aiskinamasis žodynas

    See Temperature Inversion... Natural science. encyclopedic Dictionary

    An increase in air temperature with height in a certain layer of the troposphere. Inversions occur in the surface layer of air, as well as in the free atmosphere, especially in the lower 2 km. Characteristics of inversions include: high. bottom border and vertical ... ... Geographic Encyclopedia

A lot of impressions and memories are connected with the concept of “inversion” among paragliders. Usually this phenomenon is spoken of with regret, something like “again, a low inversion did not allow me to fly a good route” or “I ran into an inversion and could not gain more”. Let's deal with this phenomenon, so is it so bad? And with the usual mistakes that paragliders make when talking about “inversion”.

So let's start with Wikipedia:

Inversion in meteorology - means the anomalous nature of the change in any parameter in the atmosphere with increasing altitude. Most often this applies to temperature inversion, that is, to an increase in temperature with height in a certain layer of the atmosphere instead of the usual decrease.

So it turns out that when we talk about "inversion", we are talking about temperature inversion. That is about an increase in temperature with height in a certain layer of air.- It is very important to firmly understand this point, because speaking about the state of the atmosphere, we can distinguish that for the lower part of the atmosphere (before the tropopause):

  • Normal condition– when the air temperature with increasing altitude – decreases. For example, the average rate of temperature drop with height for a standard atmosphere is adopted by ICAO at 6.49 deg K per km.
  • Not normal condition remains constant(isotherm)

  • It's also not normal. when the temperature increases with altitude increases (temperature inversion)

The presence of isothermia or real inversion in some layer of air means that the atmospheric gradient here is zero or even negative, and this clearly indicates the STABILITY of the atmosphere ().

A freely rising volume of air, falling into such a layer, very quickly loses its difference in temperature between it and the environment. (The air rising is cooled along a dry or humid adiabatic gradient, and the air of its environment does not change temperature or even heats up. That temperature difference, which was the reason for the excess of the force of Archimedes, over the force of gravity is quickly leveled and the movement stops).

Let's give an example, suppose we have a certain volume of air that is overheated at the surface of the earth, relative to the air surrounding it, by 3 degrees K. This volume of air, breaking away from the ground, generates a thermal bubble (thermal). At the initial stage, its temperature is 3 degrees higher, and therefore the density for the same volume, compared to the air surrounding it, is lower. Therefore, the force of Archimedes will exceed the force of gravity, and the air will begin to move upward with acceleration (float). Floating up, the atmospheric pressure will fall all the time, the floating volume will expand, and as it expands, it cools according to the dry adiabatic law (air mixing is usually neglected at large volumes).

How long will it float? - depends on how quickly, in altitude, the environment around it cools. If the law of change in the cooling of the environment is the same as the dry adiabatic law, then the initial “overheating relative to the environment” will be preserved all the time, and our pop-up bubble will accelerate all the time (the friction force will increase with speed, and at significant speeds it can no longer be neglected , the acceleration will decrease).

But such conditions are extremely rare, most often we have an atmospheric gradient in the region of 6.5 - 9 deg K per km. Take for example 8 deg K per km.

The difference between the atmospheric gradient and the dry adiabatic one = 10-8=2 deg K per km, then at a height of 1 km from the surface, from the initial overheating of 3 degrees, only 1 remained. (our bubble cooled by 9.8=10 degrees, and the surrounding air by 8). Another 500m of ascent and temperatures will equalize. That is, at a height of 1.5 km, the temperature of the bubble and the temperature of the surrounding air will be the same, the Archimedes force and the force of gravity will balance. What will happen to the bubble? In all paragliding books, they write - that he will remain at this level. Yes, eventually, theoretically, that is exactly what will happen. But the dynamics of the process for us flying is also important.

The bubble will hang at a new, equilibrium level not immediately. And if there weren’t those phenomena that are neglected when describing the rise of the bubble (friction force, mixing with the surrounding air, heat exchange with the surrounding air), it would never freeze :).

At first, it “by inertia” will slip above the equilibrium level (it was accelerating all the time that it was rising and already has a decent speed, and therefore a supply of kinetic energy. Rising above this level (1.5 km), the gradient will work in the opposite direction, then if our volume of air will cool faster than the surrounding air, the force of gravity will exceed the force of Archimedes, and the resulting force will already act downward, slowing down (together with the force of friction) its movement.At some height, their action will completely stop our bubble and it will start downward movement. If we completely neglect the force of friction and assume that the air does not mix with the environment and does not exchange energy, then it would fluctuate up and down from 0 to 3000 m. But in reality, of course, this does not happen. They decay rapidly, and are limited especially rapidly by layers with different gradients.

Consider now the same example, only with an inversion layer, a gradient in -5 deg K per km (remember that in meteorology the gradient is with the opposite sign), at an altitude of 750m 300m thick.

Then for the first 750m our bubble will lose 1.5 degrees of superheat (10-8=2 deg K per km. 2 * 0.75 = 1.5 deg), rising further it will continue to cool by 1 deg for every 100m, and starting from a height of 750m the surrounding air only increases its temperature. Means the difference between the gradients. 10–5=15 deg K per km, or 1.5 deg per 100m. And after the next 100m (at an altitude of 850 meters), the temperature of the bubble will be equal to the environment.

This means that an inversion layer with a gradient of -5 deg K per km quickly stopped the bubble. (It will just as quickly extinguish the inertia of the bubble, ideally after 200m, but in fact, taking into account friction, mixing and heat transfer, much earlier).

We see that the inversion layer limits bubble oscillations (if we neglect friction, mixing and heat transfer) from 0-3000m to 0-1050m.

Is inversion so bad? If it's low and slows down our thermals, that's bad. If it is at a sufficiently high altitude and protects from the rise of air into the zones of instability in which condensation occurs, and where the humid adiabatic gradient is less than atmospheric, then the inversion is good.

What causes temperature inversion?

Indeed, strictly speaking, for the thermodynamic equilibrium of the atmosphere to the level of the tropopause, this is not a normal state.

There are 2 types of inversion at the place of manifestation:

  • surface (one that starts from the surface of the earth)
  • inversion on height (some layer on height)

And we can distinguish 4 types of inversion, according to the types of its occurrence. we can easily encounter all of them in everyday life and on flights:

  • surface radiative cooling
  • leakage inversion
  • advective transport inversion
  • subsidence inversion

WITH surface inversion it's simple, it is also called radiative cooling inversion or nighttime inversion. The surface of the earth, with the weakening of the heat from the sun, cools rapidly (including due to infrared radiation). The cooled surface also cools the layer of air adjacent to it. Since air does not transfer heat well, this cooling is no longer felt above a certain height.

Ground inversion

The thickness of the layer and the intensity of its supercooling depend on:

  • the duration of cooling, the longer the night, the more the surface and the layer of air adjacent to it cool down. In autumn and winter, surface inversions are thicker and have a more pronounced gradient.
  • cooling rate, for example, if there is cloudiness, then part of the infrared radiation with which heat escapes is reflected back to the ground, and the cooling intensity is noticeably reduced (cloudy nights are warm).
  • the heat capacities of the underlying surface of the surface, which have a large heat capacity and accumulated heat during the day, cool longer and cool the air less (for example, warm water bodies).
  • the presence of wind near the ground, the wind mixes the air and it cools more intensively, the layer (thickness) of the inversion is noticeably larger.

Leak inversion- occurs when cold air flows down the slopes into the valley, displacing warmer air up. Air can drain both from chilled slopes at night and during the day, for example, from glaciers.

Leak inversion

Advective transport inversion occurs when air moves horizontally. For example warm air masses on cold surfaces. Or just different air masses. A striking example is the atmospheric fronts, on the border of the front there will be an inversion. Another example is the advection of warm (at night) air from the water surface to cold land. In autumn, such advection is often visualized as fogs. (they are called so, advective fogs, when humid warm air is transferred from the water to cold land, or to colder water, etc.)

Occurs when external forces force some layer of air to fall down. When descending, the air will compress (as atmospheric pressure increases) and heat up adiabatically, and it may turn out that the underlying layers - have temperatures below - an inversion will occur. This process can occur under different conditions and scales, such an inversion occurs, for example, when air settles in anticyclones, when air descends in mountain-valley circulation, between a cloud with precipitation and the surrounding air nearby, or, for example, during a hair dryer. For its occurrence, a constant external influence is needed, which carries out the transfer and lowering of air.

Let's return now to myths about inversion.

Very often, paragliders talk about inversion where there is none. This is due to the fact that we are used to calling any layer that noticeably slows down and delays the vertical movement of air inversion although this is not the case. Just a layer with a small gradient, or isotherm, also quickly blocks the movement of air, but it is not a true inversion.

The second point arose due to the fact that in books, in illustrations, atmospheric gradients or an aerological diagram are usually drawn for clarity in RECTANGULAR COORDINATE SYSTEMS (ADC), where isotherms (lines of constant temperatures) are directed from bottom to top perpendicular to isobars (or lines of the same height). In such figures, inversion is any section of the stratification curve leaning to the RIGHT from vertical from bottom to top. Inversion in such coordinates is easily visible.

An example from D. Pegan's book Understand the Sky.

In practice, most people use, for example, from the site meteo.paraplan.ru and here already, the isotherms themselves are tilted to the right, so in order to see the inversion, you need to compare the SLOPE of the slope of the stratification curve with the isotherm! And to do this by eye with a cursory view is much more difficult than with a diagram in ADP. Look at the diagram below, there is a slight surface inversion near the ground. In the 400m layer, the temperature slightly increased (at an altitude of 600 meters it is about a degree warmer than near the ground) the gradient is about -2.5 degrees K per km. And at the top, NOT an inversion, but just a very small gradient, about +3.5 degrees K per km.

Inversion and Not inversion

Due to the fact that not any tilt to the right will be an inversion on the ADC, pilots often use this word in the wrong place, which annoys true meteorologists 🙂

At the same time, calculated, model aerological diagrams may not predict thin inversion layers, since they average the temperature over the layer, instead of taking into account 2 layers, the inversion layer is 100 m thick, for example, with a temperature difference at the lower and upper boundaries of -1 deg, the adjacent layer 900 meters with a temperature difference of +8 degrees. they will simply draw a thicker layer, 1 km - with about an average gradient of 7 degrees per kilometer. While in reality there will be several different layers.

For example, as in the natural diagram below (ADP). It also shows the surface inversion layer 200m thick + isothermal layer. And a thin layer of inversion at a height of 2045m, and a layer of isotherm at a height of 3120m. These thin layers are not modeled, but in fact they have a strong effect on thermals.

Full-scale ADP from a balloon-probe

Summary.

Not every part of the stratification curve sloping to the right on the ADC is an inversion, be careful! A real inversion can only be seen on an upper-air chart taken from actual atmospheric sounding data. On the "model" diagrams, they may not be calculated, but only taken into account in reducing the gradient on some layer. However, in this case, their existence can be guessed, if we take into account the possible factors for the occurrence of inversions.

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Inversion means the anomalous nature of the change in any parameter in the atmosphere with increasing altitude. Most often, this refers to a temperature inversion, that is, an increase in temperature with height in a certain layer of the atmosphere instead of the usual decrease.

Temperature inversion prevents vertical movement of air and contributes to the formation of haze, fog, smog, clouds, mirages.

Causes and mechanisms of inversion. Under certain conditions, the normal vertical temperature gradient changes in such a way that colder air is at the surface of the Earth. This can happen, for example, when a warm, less dense air mass moves over a cold, denser layer. This type of inversion occurs in the vicinity of warm fronts, as well as in areas of oceanic upwelling, such as off the coast of California. With sufficient moisture in the colder layer, fog is typically formed under the inversion "lid". On a clear, quiet night during an anticyclone, cold air can descend the slopes and collect in the valleys, where as a result the air temperature will be lower than 100 or 200 m higher. Above the cold layer there will be warmer air, which is likely to form a cloud or light fog. Temperature inversion is clearly demonstrated by the example of smoke from a campfire. The smoke will rise vertically, and then, when it reaches the "inversion layer", it will curve horizontally. If this situation is created on a large scale, the dust and dirt (smog) that rises into the atmosphere remains there and accumulates, leading to serious pollution.

Lowering inversion

Temperature inversion can occur in the free atmosphere when a wide layer of air descends and heats up due to adiabatic compression, which is usually associated with subtropical high pressure areas. Turbulence can gradually lift the inversion layer to high altitude and "pierce" it, resulting in thunderstorms and even (under certain circumstances) tropical cyclones.

How are the values ​​of the temperature gradient in the troposphere related to the stability of the atmosphere?

The stability of the atmosphere is manifested in the absence of significant vertical movements and mixing in it. Then load substances released into the atmosphere near the earth's surface will be retained there. Fortunately, the mixing of air in the lower atmosphere is conducive. many factors, one of which is the temperature gradient. The intensity of thermal mixing is determined by comparing the temperature gradient actually observed in the environment. medium, with an adiabatic vertical temperature gradient (see figure).

When the temp. hail-t in env. the environment is greater than G (suho-adiab.vertik.deg-t), the atmosphere is superadiabatic. Consider. point A in Fig. 5.1.a. If the volume of air with temperature, resp. point A, is transferred quickly upwards, its final state can be described by point B on the straight line superadiab.gr. In this comp. its temperature T (1) is higher than the actual temperature of the environment T (2) at point B. Therefore, the considered volume of air will have a lower density than the surroundings. air, and a tendency to keep going up. If this elem. the volume from t.A will start the case. move down, it will shrink adiabatically at a temperature in T.D., which is lower than T (ambient air) in T.E. Possessing, therefore, a higher density, the air will continue to move down. Thus, the atmosphere, which is characterized by superhadiab. gr-t temperatures, is unstable. When the degree of air temperature is approximately equal to superadiab. vertical (Fig.5.1.b), the stability of the atmosphere is called indifferent: if a vertical occurs. moving the volume of air, then its temp-raokaz. the same as that of the surrounding air, there is no tendency to move further. If temp. hail-t of the surrounding air is less than G, then the atmosphere is subadiabatic (Fig. 5.1.c). Similarly with the previous derivation, it can be shown that it is stable, because accidentally moved. the volume of air will tend to return to its original. position.

Just as in soil or water, heating and cooling are transferred from the surface to the depths, so in air, heating and cooling are transferred from the lower layer to the higher layers. Consequently, diurnal temperature fluctuations should be observed not only at the earth's surface, but also in the high layers of the atmosphere. At the same time, just as in soil and water the daily temperature fluctuation decreases and lags with depth, in the atmosphere it must decrease and lag with height.

Non-radiative heat transfer in the atmosphere occurs, as in water, mainly by turbulent heat conduction, i.e., with air mixing. But air is more mobile than water, and the turbulent thermal conductivity in it is much greater. As a result, diurnal temperature fluctuations in the atmosphere propagate to a more powerful layer than diurnal fluctuations in the ocean.

At an altitude of 300 m above land, the amplitude of the daily temperature variation is about 50% of the amplitude at the earth's surface, and the extreme temperatures occur 1.5-2 hours later. At an altitude of 1 km, the daily temperature amplitude over land is 1–2°, at an altitude of 2–5 km it is 0.5–1°, and the daytime maximum shifts to the evening. Over the sea, the daily temperature amplitude somewhat increases with height in the lower kilometers, but still remains small.

Small diurnal temperature fluctuations are found even in the upper troposphere and lower stratosphere. But there they are already determined by the processes of absorption and emission of radiation by air, and not by the influences of the earth's surface.

In mountains, where the influence of the underlying surface is greater than at the corresponding heights in the free atmosphere, the diurnal amplitude decreases more slowly with height. On individual mountain peaks, at altitudes of 3000 m and more, the daily amplitude can still be 3--4 °. On high vast plateaus, the daily amplitude of air temperature is of the same order as in the lowlands: the absorbed radiation and effective radiation are large here, as is the surface of contact between air and soil. The daily amplitude of air temperature at the Murgab station in the Pamirs is 15.5° on average, while in Tashkent it is 12°.

Temperature inversions

In the previous paragraphs, we repeatedly mentioned temperature inversions. Now let us dwell on them in somewhat more detail, since important features in the state of the atmosphere are associated with them.

A drop in temperature with height can be considered a normal state of affairs for the troposphere, and temperature inversions can be considered deviations from the normal state. True, temperature inversions in the troposphere are a frequent, almost daily occurrence. But they capture the air layers rather thin in comparison with the entire thickness of the troposphere.

The temperature inversion can be characterized by the height at which it is observed, the thickness of the layer in which there is an increase in temperature with height, and the temperature difference at the upper and lower boundaries of the inversion layer - a temperature jump. As a transitional case between the normal drop in temperature with height and inversion, there is also the phenomenon of vertical isotherm, when the temperature in some layer does not change with height.

In terms of altitude, all tropospheric inversions can be divided into surface inversions and inversions in the free atmosphere.

Surface inversion starts from the underlying surface itself (soil, snow or ice). Over open water, such inversions are rare and not so significant. The underlying surface has the lowest temperature; it grows with height, and this growth can extend to a layer of several tens and even hundreds of meters. Then the inversion is replaced by a normal drop in temperature with height.

Free Atmosphere Inversion observed in a certain layer of air lying at a certain height above the earth's surface (Fig. 5.20). The base of the inversion can be at any level in the troposphere; however, inversions are most frequent within the lower 2 km(if we do not talk about inversions on the tropopause, in fact, they are no longer tropospheric). The thickness of the inversion layer can also be very different - from a few tens to many hundreds of meters. Finally, the temperature jump at the inversion, i.e., the temperature difference at the upper and lower boundaries of the inversion layer, can vary from 1° or less to 10-15° or more.

frost

The phenomenon of frost, which is important in practical terms, is connected both with the diurnal variation of temperature and with its non-periodic drops, and both of these causes usually act together.

Frosts are called lowering the air temperature at night to zero degrees and below at a time when the average daily temperatures are already above zero, that is, in spring and autumn.

Spring and autumn frosts can have the most adverse effects on horticultural and horticultural crops. In this case, it is not necessary that the temperature drops below zero in the meteorological booth. Here, at a height of 2 m, it can remain slightly above zero; but in the lowest, with the soil layer of air, it at the same time drops to zero and below, and garden or berry crops are damaged. It also happens that the air temperature even at a small height above the soil remains above zero, but the soil itself or the plants on it are cooled by radiation to a negative temperature and frost appears on them. This phenomenon is called soil freeze and can also kill young plants.

Frosts most often occur when a sufficiently cold air mass, such as arctic air, enters the area. The temperature in the lower layers of this mass is still above zero during the day. At night, the air temperature drops below zero in the daily course, i.e. frost is observed.

For freezing, a clear and quiet night is needed, when the effective radiation from the soil surface is large, and the turbulence is small, and the air cooled from the soil is not transferred to higher layers, but is subjected to prolonged cooling. Such clear and calm weather is usually observed in the inner parts of areas of high atmospheric pressure, anticyclones.

A strong nighttime cooling of the air near the earth's surface leads to the fact that the temperature rises with height. In other words, during freezing, a surface temperature inversion takes place.

Frost occurs more often in lowlands than in high places or on slopes, since in concave landforms the nighttime drop in temperature is increased. In low places, cold air stagnates more and cools for a longer time.

Therefore, frost often strikes orchards, vegetable gardens or vineyards in low areas, while on the slopes of the hill they remain intact.

The last spring frosts are observed in the central regions of the European territory of the CIS in late May - early June, and the first autumn frosts are possible already in early September (maps VII, VIII).

At present, sufficiently effective means have been developed to protect gardens and orchards from night frosts. The kitchen garden or garden is wrapped in a smoke screen, which reduces the effective radiation and reduces the night temperature drop. Heating pads of various kinds can heat up the lower layers of air accumulating in the surface layer. Plots with horticultural or horticultural crops can be covered at night with a special film, straw or plastic sheds can be placed over them, which also reduce the effective radiation from the soil and plants, etc. All such measures should be taken when the temperature is already low enough in the evening and, according to the weather forecast, it will be a clear and quiet night.