Inversion in the atmosphere. Inversion (meteorology). How to behave if you receive information about an unfavorable state of the atmosphere
TEMPERATURE INVERSION. In the ocean, temperature inversion is an increase in temperature with depth instead of its decrease, which is characteristic of most of the World Ocean. Temperature inversion in different layers of the ocean occurs under the influence of various physical processes: at the surface it is heat and mass exchange between the ocean and the atmosphere, in the thickness of stratified waters it is advection, and in the bottom layer it is geothermal processes. The vertical scale of layers with temperature inversion (the so-called inversion layers) varies from a few millimeters (near the boundary with the atmosphere) to several hundred meters or more in the ocean. Inversion layers near the surface and bottom often have an unstable density distribution, which gives rise to convective mixing of waters; in the thickness of the ocean, these layers are, as a rule, characterized by a stable density distribution associated with an increase in water salinity with depth. Temperature inversions reaching several degrees Celsius are caused by water exchange between the open ocean and the seas. For example, the flow of warmer, saltier waters (from the Mediterranean Sea to the Atlantic Ocean or from the Red Sea to the Indian Ocean) and the distribution of these waters at equal density levels over distances of several thousand kilometers cause large-scale temperature inversions.
Lit.: Fedorov K.N. Fine thermohaline structure of ocean waters. L., 1976; Galerkin L.I. et al. On climatic temperature inversions in the ocean // Oceanology. 1998. T. 38. Issue. 6.
A. G. Zatsepin.
In the atmosphere, temperature inversion (temperature increasing with altitude) is typical of the stratosphere and thermosphere, while in the troposphere, temperature generally decreases with altitude. Surface temperature inversions are characterized by the thickness of the inversion layer, which can reach tens and hundreds of meters, and a temperature jump between the lower and upper boundaries of the layer (up to 15-20 °C). Elevated temperature inversions in the atmospheric boundary layer and in the free atmosphere are also described by the height of the lower boundary of the inversion layer. Multilayer temperature inversions are also encountered.
There are several types of temperature inversions in the troposphere. In the surface layer of the atmosphere, a radiation inversion of temperature can be observed, the cause of which is radiation cooling (thermal radiation from the earth's surface). In anticyclones, a subsidence inversion occurs. When a warm air mass flows onto a colder underlying surface, advective temperature inversions are formed. There are also temperature inversions that are genetically related to the life cycle of a cloud (subcloud and above-cloud temperature inversions). In the stratosphere and thermosphere, temperature inversions occur due to the absorption of solar radiation. For example, temperature inversion at altitudes from 20-30 to 50-60 km is associated with the absorption of UV radiation from the Sun by ozone.
Inversion layers of air prevent the development of vertical movements, contribute to the accumulation of gas and aerosol impurities, the formation of haze and fog, the occurrence of upper mirages, and affect the propagation of internal gravitational waves in the atmosphere and radio waves.
Lit.: Khromov S. M., Petrosyants M. A. Meteorology and climatology. 7th ed. M., 2006.
The increase in temperature in the troposphere of the atmosphere with increasing altitude is characterized as temperature inversion(Fig. 11.1, c). In this case, the atmosphere turns out to be very stable. The presence of inversion significantly slows down the vertical movement of pollutants and, as a result, increases their concentration in the ground layer.
The most commonly observed inversion occurs when a layer of air descends into an air mass with higher pressure, or during radiative heat loss from the earth's surface at night. The first type of inversion is usually called subsidence inversion. The inversion layer in this case is usually located at some distance from the earth's surface, and the inversion is formed by adiabatic compression and heating of the air layer as it descends down to the area of the high pressure center.
From equation (11.5) we obtain:
Specific isobaric heat capacity value WITH p for air does not vary significantly with temperature over a fairly large temperature range. However, due to changes in barometric pressure, the density at the upper boundary of the inversion layer is less than at its base, i.e.
. (11.11)
This means that the upper boundary of the layer heats up faster than the lower boundary. If the subsidence continues for a long time, a positive temperature gradient will be created in the layer. Thus, the descending air mass is like a giant lid for the atmosphere located below the inversion layer.
Subsidence inversion layers are usually above emission sources and, thus, do not have a significant impact on short-term air pollution phenomena. However, such an inversion can last for several days, which affects the long-term accumulation of pollutants. Pollution events with hazardous health consequences observed in urban areas in the past have often been associated with subsidence inversions.
Let's consider the reasons leading to the occurrence radiation inversion. In this case, the layers of the atmosphere located above the Earth's surface receive heat during the day due to thermal conductivity, convection and radiation from the Earth's surface and eventually warm up. As a result, the temperature profile of the lower atmosphere is usually characterized by a negative temperature gradient. If a clear night follows, the earth's surface radiates heat and cools quickly. The layers of air adjacent to the earth's surface are cooled to the temperature of the layers located above. As a result, the daily temperature profile is transformed into a profile of the opposite sign, and the layers of the atmosphere adjacent to the earth's surface are covered with a stable inversion layer. This type of inversion occurs in the early hours and is typical during periods of clear skies and calm weather. The inversion layer is destroyed by rising currents of warm air that arise when the earth's surface is heated by the rays of the morning sun.
Radiative inversion plays an important role in atmospheric pollution, since in this case the inversion layer is located inside the layer that contains the pollution sources (unlike subsidence inversion). In addition, radiation inversion most often occurs under conditions of cloudless and windless nights, when there is little likelihood of air purification from precipitation or crosswinds.
The intensity and duration of the inversion depends on the season. In autumn and winter, as a rule, long inversions take place and their number is large. Inversions are also influenced by the topography of the area. For example, cold air that accumulates in an intermountain basin at night can be “locked” there by warm air that appears above it.
Other types of local inversions are also possible, such as those associated with sea breezes as a warm air front passes over a large continental landmass. The passage of a cold front preceded by an area of warm air also leads to an inversion.
Inversions are common in many areas. For example, on the west coast of the United States they are observed for almost 340 days a year.
The degree of stability of the atmosphere can be determined by the magnitude of the “potential” temperature gradient:
. (11.12)
Where 
– temperature gradient observed in the surrounding air.
Negative value of the “potential” temperature gradient ( G sweat< 0) свидетельствует о сверхадиабатическом характере профиля температуры и неустойчивых условиях в атмосфере. В случае, когдаG sweat > 0, the atmosphere is stable. If the “potential” temperature gradient approaches zero ( G sweat 0), the atmosphere is characterized as indifferent.
In addition to the considered cases of temperature inversion, which are local in nature, two inversion zones of a global nature are observed in the Earth’s atmosphere. The first zone of global inversion from the Earth's surface begins at the lower boundary of the tropopause (11 km for the standard atmosphere) and ends at the upper boundary of the stratopause (approximately 50 km). This inversion zone prevents the spread of impurities formed in the troposphere or released from the Earth's surface to other areas of the atmosphere. The second zone of global inversion, located in the thermosphere, to a certain extent prevents the dispersion of the atmosphere into outer space.
Let us consider, using an example, the procedure for determining the “potential” temperature gradient. The temperature at the Earth's surface at an altitude of 1.6 m is –10 °C, at an altitude of 1800 m – –50 °C, –12 °C, –22 °C.
The purpose of the calculation is to assess the state of the atmosphere based on the magnitude of the “potential” temperature gradient.
To calculate the “potential” temperature gradient, we use equation (11.12)
Here G= 0.00645 degrees/m – standard, or normal adiabatic vertical temperature gradient.
Let us analyze the calculated values of the “potential” temperature gradient. The nature of temperature changes for the considered cases of atmospheric conditions is presented in Fig. 11.2.
G sweat 1< 0 свидетельствует о сверхадиабатическом характере профиля температуры и неустойчивых условиях в атмосфере.
G sweat 2 > 0 – the atmosphere is stable.
G sweat 3 ≈ 0 – the atmosphere is characterized as indifferent.
TEMPERATURE INVERSION
TEMPERATURE INVERSION, abnormal increase in TEMPERATURE with altitude. 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, calm 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 valley bottom than 100 or 200 m above. Above the cold layer there will be warmer air, which will likely 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", will bend horizontally. If this situation is created on a large scale, the dust and dirt that rises into the atmosphere remain there and, when accumulated, lead to serious pollution.
Scientific and technical encyclopedic dictionary.
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temperature inversion- An increase in temperature with height in a certain layer of the atmosphere instead of its usual decrease. Syn.: temperature inversion… Dictionary of Geography
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 aiškinamasis 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... ... Geographical encyclopedia
The temperature gradient of the atmosphere can vary widely. On average, it is 0.6°/100 m. But in a tropical desert near the surface of the earth it can reach 20°/100 m. With temperature inversion, the temperature increases with height and the temperature gradient becomes negative, i.e. it can be equal to, 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. Thus, 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 higher again mountain tundras. Inversion tundras cool only in certain seasons, and during 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, the circulation of atmospheric air is sharply disrupted, smoke and pollutants cannot rise upward and do not dissipate. Fogs often occur. Concentrations of sulfur oxides, suspended dust, and carbon monoxide reach levels dangerous to human health, leading to circulatory and respiratory disorders, and often to death. In 1952, in London, more than four thousand people died from smog from December 3 to December 9, and up to ten thousand people became seriously ill. At the end of 1962, in the Ruhr (Germany), smog killed 156 people in three days. Only the wind can dispel smog, and reducing the emissions of pollutants can smooth out a smog-dangerous situation.[...]
Temperature inversions are associated with cases of mass poisoning of the population during periods of toxic fog (the Manet River valley in Belgium, more than once in London, Los Angeles, etc.).[...]
Sometimes temperature inversions spread over large areas of the earth's surface. The area of their distribution usually coincides with the area of distribution of anticyclones, which arise in zones of high barometric (Pressure.[...]
Synonym: temperature inversion. FRICTION INVERSION. See turbulent inversion.[...]
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 humus content in the soil, it is necessary to introduce increased rates of organic fertilizers (manure, peat and composts) and mineral fertilizers that are easily accessible to plants.[...]
Two other types of local inversions are possible. One of them is related to the sea breeze mentioned above. Warming of the morning air over land causes cooler air to flow landward from the ocean or large enough lake. As a result, warmer air rises and cooler air takes its place, creating inversion conditions. Inversion conditions are also created when a warm front passes over a large continental land area. A warm front often tends to "crush" denser, cooler air ahead of it, thereby creating a local temperature inversion. The passage of a cold front, in front of which there is an area of warm air, leads to the same situation.[...]
Temperature inversion associated with vertical air movements can lead to the same consequences.[...]
The fan-shaped shape of the strings occurs during a temperature inversion. Its shape resembles a meandering river, which gradually widens with distance from the pipe.[...]
In the small American city of Donora, such a temperature inversion caused illness in about 6,000 people (42.7% of the total population), with some (10%) showing symptoms indicating the need for hospitalization of these people. Sometimes the consequences of a long-term temperature inversion can be compared to an epidemic: in London, 4,000 people died during one of these long-term inversions.[...]
A fan-shaped jet (Fig. 3.2, c, d) is formed during temperature inversion or at 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. This jet is most often observed at night.[...]
During unfavorable meteorological situations, such as temperature inversion, high air humidity and precipitation, the accumulation of pollution can occur especially intensively. Typically, in the surface layer, the air temperature decreases with height, and vertical mixing of the atmosphere occurs, reducing the concentration of pollution in the surface layer. However, under certain meteorological conditions (for example, during intense cooling of the earth's surface at night), a so-called temperature inversion occurs, i.e., the temperature in the surface layer changes to the opposite direction; with increasing altitude, the temperature increases. Typically, this condition lasts a short time, but in some cases, a temperature inversion can be observed for several days. During a temperature inversion, the air near the earth's surface appears to be enclosed in a limited volume, and very high concentrations of pollution can occur near the earth's surface, contributing to increased contamination of insulators.[...]
Burnazyan A.I. et al. Pollution of the surface layer of the atmosphere during temperature inversions.[...]
DUST HORIZON. The upper boundary of the dust (or smoke) layer underlying the temperature inversion. When observed from a height, the impression of a horizon is created.[...]
Under some unfavorable meteorological conditions (low 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 Meuse River valley (Belgium, 1930), in the city of Donora (Pennsylvania, USA, 1948). In London, mass poisoning of the population during catastrophic air pollution was observed repeatedly - in 1948, 1952, 1956, 1957, 1962; As a result of these events, several thousand people died, many were seriously poisoned.[...]
In areas with anticyclonic weather and in the presence of significant inversions, the maximum accumulation of impurities is observed in valleys and basins in the zone of “cold lakes,” i.e., at a level of 200-300 m from their bottom, therefore, when forming the functional-planning structure of a city settlement, it is necessary In addition to the wind rose, take into account the rose of temperature inversions and their duration. The settlement zone is located on the slopes above the “cold lakes”, and the industrial zone is located lower in relief in relation to the residential area; streets and open retail spaces are oriented in the direction of prevailing winds to enhance ventilation. When forming an industrial zone at the foot of hills and mountains, planning methods are used to organize the passage of cold air masses flowing into depressions, using protective zones, streets, driveways, etc.[...]
In the depressions of cities (for example, Los Angeles, Kemerovo, Alma-Ata, Yerevan), a temperature inversion is observed, as a result of which natural mixing of air masses does not occur, and harmful substances accumulate in it. The problem of photochemical smog also exists in other large cities where sunny weather prevails (Tokyo, Sydney, Mexico City, Buenos Aires, etc.).[...]
Old-timers of New York know well what poisonous air is. In 1935, more than 200 people died in a few days of temperature inversion, in 1963 - more than 400, and in 1966 - about 200 people.[...]
Los Angeles (summer, photochemical) smog occurs in the summer also in the absence of wind and temperature inversion, but always in sunny weather. It is formed when solar radiation affects nitrogen oxides and hydrocarbons entering the air as part of vehicle exhaust gases and industrial emissions. As a result, highly toxic pollutants are formed - photooxidants, consisting of ozone, organic peroxides, hydrogen peroxide, aldehydes, etc. [...]
Products of incomplete combustion of fuel, which react with airborne fog during periods of temperature inversion, are the cause of the formation of smog, which has claimed many lives in the past.[...]
The acute effect of atmospheric pollution is provoked by a sharp change in weather conditions in a given territory (temperature inversion, calm, fog, strong steady wind from the industrial zone), as well as accidents at industrial enterprises of the city or at wastewater treatment plants, as a result of which the concentration of pollution in the atmospheric air of residential areas areas increases significantly, often exceeding permissible levels by tens of times. A particularly difficult situation arises in cases where both of these events occur simultaneously.[...]
In a number of cities, atmospheric emissions are so significant that in weather unfavorable for self-purification of the atmosphere (calm air, temperature inversion, in which smoke spreads to the ground, anticyclonic weather with fog), the concentration of pollutants in the surface air reaches a critical value, at which an acutely expressed reaction of the body to harmful atmospheric emissions. In this case, two situations are distinguished (dense fog mixed with smoke) of the London type and photochemical fog (Los Angeles). [...]
London type; smog occurs in winter in large industrial cities under unfavorable weather conditions (lack of wind and temperature inversion).[...]
London (winter) smog is formed in winter in large industrial centers under unfavorable weather conditions: lack of wind and temperature inversion. Temperature inversion manifests itself in an increase in air temperature with height (in a layer of 300-400 m) instead of the usual decrease.[...]
Atmospheric air pollution negatively affects public health and sanitary living conditions. When there is no wind, fog and temperature inversions, when the dispersion of emissions is difficult, the concentration of impurities in the air increases, especially sulfur dioxide and photooxidants, which has an acute effect on people, causing lacrimation, conjunctivitis, cough, bronchitis, as well as exacerbation of diseases, chronic obstructive pulmonary diseases , cardiovascular diseases.[ ...]
The accumulation of photochemical reaction products in the atmospheric air as a result of unfavorable meteorological conditions (lack of wind, temperature inversions) leads to a situation called photochemical smog, or Los Angeles-type smog. The main symptoms of such smog are irritation of the mucous membranes of the eyes and nasopharynx in humans, decreased visibility, a characteristic unpleasant odor, as well as the death of vegetation and damage to rubber products. At the same time, the oxidizing capacity of air significantly increases due to the presence of oxidizing agents in it, primarily ozone and some others. [...]
Areas with a predominance of weak winds or calm conditions are especially unfavorable for the dispersion of harmful substances in the air. Under these conditions, temperature inversions occur, during 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 prevents the flow of polluted urban 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.[...]
Here, per capita, a much larger amount of petroleum products, including motor gasoline, is consumed per capita than anywhere else. At the same time, almost no coal is used. The air is polluted mainly by hydrocarbons and other products of petroleum combustion, as well as products from the burning of household and garden waste by private homeowners. Recently, measures have been taken to centralize the collection and disposal of household waste. Legislation prohibits the release into the atmosphere of smoke with a density of 2 or more units on the Ringelmann scale for more than 3 minutes per hour. Sulfur compounds may be released into the atmosphere in concentrations not exceeding 0.2% by volume. This emission limitation is not too stringent, since it fully allows the use of oil with a sulfur content of 3% in power plants. Regarding dust emissions, this county's ordinance provides: a scale that varies depending on the total amount of fuel consumed. The maximum emission should not exceed 18 kg per hour. Such a restriction would be impractical in many areas, but in Los Angeles County almost no coal is used and there are several plants that emit large amounts of dust into the atmosphere.[...]
The ability of the earth's surface to absorb or emit 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 altitude means that harmful emissions cannot rise above a certain ceiling. Under inversion conditions, turbulent exchange is weakened and conditions for the dispersion of harmful emissions in the surface layer of the atmosphere worsen. For the surface inversion, the repeatability of the heights of the upper boundary is of particular importance; for the elevated inversion, the repeatability of the lower boundary is of particular importance.[...]
In the Soviet Union, there was also a case of poisoning of the population of an industrial city with sulfur dioxide in winter as a result of the formation of a powerful layer of temperature inversion near the ground, which contributed to the pressing of a jet of flue gases to the ground. [...]
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 weak winds and temperature inversions are combined (for example, in deep basins, in areas of frequent fog formation, in particular in areas with severe winters below hydroelectric dams, as well as in areas where smog may occur).[...]
In some cases, the determination of gross production is carried out according to the daily curve of the CO2 level in the cenosis. In an oak-pine forest, for example, the air drops some nights as a result of a temperature inversion (temperature increases from the soil up into the canopy). In this case, CO2 released during breathing accumulates below the inversion layer and its amount can be measured. By summarizing the results of studying the distribution of CO2 depending on the environmental temperature in different seasons of the year, it is possible to obtain approximate estimates of the respiration rate of the entire community as a whole. Thus, the cost of respiration for the oak-pine community is 2110 g/m2-year. Measurements in a gas chamber show that plants directly spend 1450 g/m2-year on respiration. The difference between these two figures, equal to 660 g/m2-year, is the result of the respiration of animals and saprobes.[...]
The distribution of technogenic impurities depends on the power and location of the sources, the height of the pipes, the composition and temperature of the exhaust gases and, of course, on meteorological conditions. Calm, fog, and temperature inversion sharply slow down the dispersion of emissions and can cause excessive local air pollution and the formation of a gas-smoke “cap” over the city. This is how the catastrophic London smog arose at the end of 1951, when 3.5 thousand people died in two weeks from a sharp exacerbation of pulmonary and heart diseases and direct poisoning. Smog in the Ruhr region at the end of 1962 killed 156 people in three days. There are known cases of very serious smog phenomena in Mexico City, Los Angeles and many other large cities.[...]
Mountain valleys oriented along the direction of prevailing winds are characterized by increased average wind speed, especially with large horizontal atmospheric pressure gradients. Under such conditions, temperature inversions occur less frequently. In addition, if temperature inversions occur simultaneously with moderate and strong winds, then their effect on the dissipative properties of the atmosphere is small. The conditions for the dispersion of impurities in valleys of this type are more favorable than in valleys where the wind lash is weaker than in flat conditions. [...]
Conditions conducive to the formation of photochemical fog at high levels of atmospheric air pollution with reactive organic compounds and nitrogen oxides are an abundance of solar radiation, temperature inversions and low wind speeds.[...]
A typical example of the acute provoking influence 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., in conditions conducive to the accumulation of industrial emissions in the surface layer of the atmosphere. During periods of toxic fog, an increase in pollution was recorded, the more significant the longer the conditions for air stagnation persisted (3-5 days). During periods of toxic fog, the mortality rate of people suffering from chronic cardiovascular and pulmonary diseases increased, and exacerbations of these diseases and the emergence of new cases were recorded among those who sought medical help. Outbreaks of bronchial asthma have been described in a number of populated areas when specific contaminants appear. It can be assumed that acute cases of allergic diseases will occur when air is polluted with biological products such as protein dust, yeast, mold and their waste products. An example of the acute effects of air pollution are cases of photochemical fog due to 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.[...]
Thus, nowhere on the territory of the USSR are such unfavorable meteorological conditions created for the transfer and dispersion of emissions from low emission sources as on the territory of the Baikal-Amur Mainline. 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 the cities and towns of BAM can be 2-3 times higher than in the European territory of the country. In this regard, protecting the air basin from pollution of the newly developed territory adjacent to the BAM is especially important.[...]
Probably the most notorious smog area in the world is Los Angeles. There are plenty of chimneys in this city. In addition, there is 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 Donora act: temperature inversions and the mountainous nature of the terrain. [...]
The Norilsk industrial region is located in the extreme northwestern part of the Central Siberian Plateau, due to which it is characterized by the presence of a sharply continental Arctic climate (average annual temperature -9.9°C, average July temperature +14.0°C, and January -27.6°C . Winter in Norilsk lasts about 9 months. Long winters - little snow, frequent air temperature inversions. During periods of cyclonic activity, in a snowstorm, wind speeds can reach 40 m/s. Summer begins after July 5-10 and lasts two to three weeks ; the rest falls in spring and autumn. Up to 1000-1100 mm of precipitation falls on the plateau, in depressions - a little less than half of this amount. About 2/3 of precipitation is rain. This is not bad at all, because acid precipitation is less damaging to vegetation than dry precipitation sulfur.[...]
Industrial enterprises, urban transport and heat-generating installations are the cause of the occurrence (mainly in cities) of smog: unacceptable pollution of the outdoor air environment inhabited by humans due to the release of harmful substances into it by the indicated sources under unfavorable weather conditions (lack of wind, temperature inversion, etc.). [...]
The next stage of research into the properties of the DBC coenzyme was the study of the circular dichroism (CD) curves of the coenzyme and its analogues. Although a clear interpretation of CD curves does not yet exist, examination of the CD spectra of various corrin compounds shows that there is a parallel between CD curves and ultraviolet spectra. Particularly important was the property of CD curves to undergo inversion upon substitution of the cross-axial ligands X and Y, while such substitution has little effect on the ultraviolet spectra. The results we obtained when studying the CD curves of 5-deoxynucleoside analogues of the DBA coenzyme turned out to be interesting. In this case, it turned out that at 300-600 nm the curves of the CD coenzyme and analogues are almost identical, and in the region of 230-300 nm in some cases a large difference is observed. These results certainly need to be taken into account in a comparative study of CD curves of B-dependent enzymes. [...]
In table Table 5.3 provides estimates of the amounts of five major air pollutants emitted into the atmosphere over the continental United States in selected years. About 60% of pollutants are brought from other areas, industry provides 20%, power plants - 12%, heating - 8%. While the greatest direct threat to human health comes from pollutants that accumulate in high concentrations during temperature inversions over cities such as Tokyo, Los Angeles and New York (layers of warm air prevent pollutants from rising and dissipating), their impact on a national scale and the whole world also cannot be neglected. As can be seen from table. 5.3, the amount of pollutants peaked in the early 70s, and by the end of the decade it had fallen by about 5%, with the amount of suspended particles falling by 43%. Air quality in the United States is improving: A 1980 report from the Council on Environmental Quality noted that in 23 cities, the number of "unhealthy" or hazardous days (as measured by a fairly arbitrary clean air standard) fell by 18% from 1974 to 1978. It appears that fuel and energy conservation measures and the installation of federally mandated air pollution control devices have at least stopped the increase in air pollution. A similar stop in the growth of air pollution has been noted in Europe.[...]
The main reason for the formation of photochemical fog is severe pollution of urban air with gas emissions from chemical industry and transport enterprises and mainly from vehicle exhaust gases. For every kilometer of travel, a passenger car emits about 10 g of nitrogen oxide. In Los Angeles, where over 4 million cars have accumulated, they emit about 1 thousand tons of this gas per day into the air. In addition, temperature inversions are frequent here (up to 260 days a year), contributing to air stagnation over the city. Photochemical fog occurs in polluted air as a result of photochemical reactions occurring under the influence of short-wave (ultraviolet) solar radiation on gas emissions. Many of these reactions create substances that are significantly more toxic than the original ones. The main components of photochemical smog are photooxidants (ozone, organic peroxides, nitrates, nitrites, peroxylacetyl nitrate), nitrogen oxides, carbon monoxide and dioxide, hydrocarbons, aldehydes, ketones, phenols, methanol, etc. These substances are always present in the air in smaller quantities large cities, in photochemical smog their concentration often far exceeds the maximum permissible standards.[...]
Hydrocarbons, sulfur dioxide, nitrogen oxide, hydrogen sulfide and other gaseous substances entering the atmosphere are removed from it relatively quickly. Hydrocarbons are removed from the atmosphere due to the dissolution of seas and oceans in water and subsequent photochemical and biological processes occurring with the participation of microorganisms in water and soil. Sulfur dioxide and hydrogen sulfide, oxidizing 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 oxidized to carbon dioxide, which is intensively absorbed by vegetation in the process of photochemical synthesis. Nitrogen oxides are removed due to reduction and oxidation reactions (with strong solar radiation and temperature inversion, they form smog that is dangerous for breathing).
A decrease in temperature with height can be considered the 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 everyday phenomenon. But they capture air layers that are quite thin compared to the entire thickness of the troposphere.
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 decrease in temperature with height and inversion, the phenomenon of vertical isothermia is also observed, when the temperature in a certain layer does not change with height.
By height, all tropospheric inversions can be divided into surface inversions And inversions in free atmosphere.
Surface inversion starts from the underlying surface itself (soil, snow or ice). Over open water, such inversions are rarely observed and are not so significant. The temperature of the underlying surface is the lowest; it increases with height, and this increase can extend to a layer of several tens or even hundreds of meters. The inversion is then replaced by a normal decrease in temperature with height.
Surface temperature inversions over land or ocean ice are largely due to nighttime radiative cooling of the underlying surface. Such inversions are called radiative . The lower layers of air are cooled from the earth's surface more than the overlying layers. Therefore, near the earth's surface the temperature drops the most and an increase in temperature with height is established.
Inversion in the free atmosphere is observed in a certain layer of air lying at a certain height above the earth's surface (Fig. 8). The base of an inversion can be at any level in the troposphere, but inversions are most common within the lower 2 km. 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.
It happens that a surface inversion, extending to a considerable height, merges with an overlying inversion in the free atmosphere. Then the temperature increase begins from the earth’s surface itself and continues to high altitudes, and the temperature jump turns out to be especially significant.
It also happens that the inversion directly transforms into the overlying isotherm. Often, two (or more) inversions are observed in the free atmosphere over a particular region, separated by layers with a normal decrease in temperature.
Fig.8. Types of temperature distribution with height: A - ground inversion, b- surface isothermia, V - free atmosphere inversion
Inversions are not observed over individual points on the earth's surface. The inversion layer extends continuously over a large area, especially in the case of inversions in the free atmosphere.