Answer: The ozone layer is a layer of the atmosphere with a high content of ozone. The concentration of ozone in the layer is very low, and if it is isolated in its pure form and compressed to the density that air has at the surface of the Earth, then the thickness of the ozone layer will not exceed 5 mm. Ozone absorbs short-wave radiation from the Sun, protecting living organisms from its harmful effects. The depletion of the ozone layer first attracted the attention of the general public in 1985, when a large area with low (up to 50%) ozone content, called the “ozone hole,” was discovered above Antarctica. It is believed that the main reason for the occurrence of “ozone holes” is the significant content of freons in the atmosphere. Freons(chlorofluorocarbons) are highly volatile, chemically inert substances near the earth’s surface, widely used in production and everyday life as refrigerants (air conditioners, refrigerators, refrigerators), sprayers (aerosols), and foaming agents. Freons, rising into the upper layers of the atmosphere, undergo photochemical decomposition with the formation of chlorine oxide, which intensively destroys ozone. However, a number of scientists continue to insist on the natural origin of the “ozone hole.” They see the reasons for its occurrence in the natural variability of the ozonosphere, the cyclical activity of the Sun, the processes of degassing of the Earth, etc. Depletion of the ozone layer leads to higher levels of ultraviolet radiation on the Earth's surface, which contributes to an increase in cases of skin cancer, a decrease in the productivity of agricultural crops, and a slowdown in the process of photosynthesis in plants, etc.

7. Reasons for the formation of acid rain and their impact on ecosystems

Answer: Any precipitation (rain, fog, snow) whose acidity is higher than normal is called acidic. The acidic properties of the medium are determined by hydrogen ions. The higher the concentration of hydrogen ions in a solution, the higher its acidity. Hydrogen index units, or pH, are used to express the concentration of hydrogen ions. The pH scale ranges from 0 (extremely acidic) through 7 (neutral) to 14 (extremely alkaline). Acid rain contains solutions of sulfuric, nitric and other acids, into which air moisture is converted, absorbing sulfur dioxide and other gases contained in the air. Acid rain depresses vegetation, reduces forest growth and agricultural yields, and causes acidification of lakes, which leads to the death of eggs, fry, plankton, algae and fish. The negative consequences of acid rain have been recorded in the USA, Europe, Canada, Russia, Ukraine, Belarus and other countries.

8. Main causes of environmental problems

Answer: Unbalanced relationships between society and nature, that is, irrational environmental management, often lead to an environmental crisis and environmental disaster. Ecological crisis(ecological emergency) is an environmental disaster characterized by persistent negative changes in the environment and posing a threat to human health. Under environmental disaster(ecological disaster) understand environmental distress, characterized by irreversible changes in the environment and a significant deterioration in public health. The main and most common type of negative human impact on the biosphere is pollution. Under pollution understand the entry into the environment of substances and (or) energy, the properties, location or quantity of which have a negative impact on the environment (Law “On Environmental Protection”). Pollution also refers to the entry into the natural environment of any solid, liquid or gaseous substances, microorganisms or energies (in the form of sounds, noise, radiation) in quantities harmful to human health, animals, the state of plants and ecosystems. Typically, two types of pollution of different origin are considered: natural, arising as a result of natural phenomena without human participation; anthropogenic, associated with human activity, the main component of which is technogenic pollution caused by industrial activities. By state of aggregation All pollutants of anthropogenic origin are divided into solid, liquid and gaseous. Based on the nature of pollutants, the following types of pollution are distinguished: biological(pathogenic microorganisms, genetic engineering products, etc.), chemical(biosphere pollution with pesticides, heavy metals, plastics, certain chemicals and elements), physical(noise, thermal, electromagnetic, radiation). Based on spatial characteristics, they distinguish global, regional, local(observed in a small area) pollution. By objects of pollution, they distinguish between atmospheric air pollution, surface and groundwater pollution, soil pollution, etc., and even pollution of near-Earth space. In 2005, 78 accidents were observed on the territory of the Russian Federation (59 in 2004), leading to environmental pollution. In the same year, the stationary observation network of Roshydromet registered 541 cases of extremely high pollution of surface water and 3 cases of extremely high pollution of atmospheric air based on visual and organoleptic signs.

Recently, newspapers and magazines have been full of articles about the role of the ozone layer, in which people are intimidated by possible problems in the future. You can hear from scientists about upcoming climate changes, which will negatively affect all life on Earth. Will a potential danger far removed from humans really turn into such horrific events for all earthlings? What consequences does humanity expect from the destruction of the ozone layer?

The formation process and significance of the ozone layer

Ozone is a derivative of oxygen. While in the stratosphere, oxygen molecules are chemically exposed to ultraviolet radiation, after which they break down into free atoms, which, in turn, have the ability to combine with other molecules. With this interaction of oxygen molecules and atoms with third bodies, a new substance arises - this is how ozone is formed.

Being in the stratosphere, it affects the thermal regime of the Earth and the health of its population. As a planetary “guardian,” ozone absorbs excess ultraviolet radiation. However, when it enters the lower atmosphere in large quantities, it becomes quite dangerous for the human species.

An unfortunate discovery by scientists - an ozone hole over Antarctica

The process of ozone layer depletion has been the subject of much debate among scientists around the world since the late 60s. In those years, environmentalists began to raise the problem of emissions of combustion products into the atmosphere in the form of water vapor and nitrogen oxides, which were produced by jet engines of rockets and airliners. The concern has been that nitrogen oxide emitted by aircraft at 25 kilometers altitude, which is where the Earth's shield forms, can destroy ozone. In 1985, the British Antarctic Survey recorded a 40% decrease in the concentration of ozone in the atmosphere above their Hally Bay base.

After the British scientists, many other researchers illuminated this problem. They managed to outline an area with low ozone levels already outside the southern continent. Because of this, the problem of ozone hole formation began to arise. Soon after this, another ozone hole was discovered, this time in the Arctic. However, it was smaller in size, with ozone leakage up to 9%.

Based on the results of the research, scientists calculated that in 1979-1990 the concentration of this gas in the earth’s atmosphere decreased by about 5%.

Depletion of the ozone layer: the appearance of ozone holes

The thickness of the ozone layer can be 3-4mm, its maximum values ​​are located at the poles, and its minimums are located along the equator. The highest concentration of gas can be found 25 kilometers in the stratosphere above the Arctic. Dense layers are sometimes found at altitudes up to 70 km, usually in the tropics. The troposphere does not contain much ozone because it is highly susceptible to seasonal changes and various types of pollution.

As soon as the gas concentration decreases by one percent, there is an immediate increase in the intensity of ultraviolet radiation above the earth's surface by 2%. The influence of ultraviolet rays on planetary organics is compared to ionizing radiation.

Depletion of the ozone layer could cause disasters associated with excessive heating, increased wind speeds and air circulation, which could lead to new desert areas and reduce agricultural yields.

Meeting ozone in everyday life

Sometimes after rain, especially in the summer, the air becomes unusually fresh and pleasant, and people say that it “smells like ozone.” This is not a figurative formulation at all. In fact, some part of the ozone reaches the lower layers of the atmosphere with air currents. This type of gas is considered the so-called beneficial ozone, which brings a feeling of extraordinary freshness to the atmosphere. Mostly such phenomena are observed after thunderstorms.

However, there is also a very harmful type of ozone that is extremely dangerous for people. It is produced by exhaust gases and industrial emissions, and when exposed to the sun's rays, it enters into a photochemical reaction. As a result, the formation of so-called ground-level ozone occurs, which is extremely harmful to human health.

Substances that destroy the ozone layer: the effect of freons

Scientists have proven that freons, which are used en masse to charge refrigerators and air conditioners, as well as numerous aerosol cans, cause the destruction of the ozone layer. Thus, it turns out that almost every person has a hand in the destruction of the ozone layer.

The causes of ozone holes are that freon molecules react with ozone molecules. Solar radiation causes freons to release chlorine. As a result, ozone splits, resulting in the formation of atomic and ordinary oxygen. In places where such interactions occur, the problem of ozone depletion occurs and ozone holes occur.

Of course, the greatest harm to the ozone layer is caused by industrial emissions, but the household use of preparations that contain freon, one way or another, also has an impact on the destruction of ozone.

Protecting the ozone layer

After scientists documented that the ozone layer is still being destroyed and ozone holes appear, politicians began to think about preserving it. Consultations and meetings have been held around the world on these issues. Representatives of all states with well-developed industry took part in them.

Thus, in 1985, the Convention for the Protection of the Ozone Layer was adopted. Representatives from forty-four conference participating states signed this document. A year later, another important document was signed, called the Montreal Protocol. In accordance with its provisions, there should have been a significant restriction of global production and consumption of substances that lead to ozone depletion.

However, some states were unwilling to submit to such restrictions. Then, specific quotas for dangerous emissions into the atmosphere were determined for each state.

Protection of the ozone layer in Russia

In accordance with current Russian legislation, the legal protection of the ozone layer is one of the most important and priority areas. Legislation related to environmental protection regulates a list of protective measures aimed at protecting this natural object from various types of damage, pollution, destruction and depletion. Thus, Article 56 of the Legislation describes some activities related to the protection of the planet’s ozone layer:

• Organizations for monitoring the effect of the ozone hole;
• Continued control over climate change;
• Strict compliance with the regulatory framework on harmful emissions into the atmosphere;
• Regulating the production of chemical compounds that destroy the ozone layer;
• Application of penalties and punishments for violation of the law.

Possible solutions and first results

You should know that ozone holes are not a permanent phenomenon. With a reduction in the amount of harmful emissions into the atmosphere, a gradual tightening of ozone holes begins - ozone molecules from neighboring areas are activated. However, at the same time, another risk factor arises - neighboring areas are deprived of a significant amount of ozone, the layers become thinner.

Scientists around the world continue to engage in research and are intimidated by bleak conclusions. They calculated that if the presence of ozone decreased by just 1% in the upper atmosphere, there would be an increase in skin cancer of up to 3-6%. Moreover, a large number of ultraviolet rays will negatively affect people's immune system. They will become more vulnerable to a wide variety of infections.

It is possible that this may actually explain the fact that in the 21st century the number of malignant tumors is increasing. Increasing levels of ultraviolet radiation also negatively affect nature. The destruction of cells in plants occurs, the process of mutation begins, as a result of which less oxygen is produced.

Will humanity cope with the challenges ahead?

According to the latest statistics, humanity is facing a global catastrophe. However, science also has optimistic reports. After the adoption of the Convention for the Protection of the Ozone Layer, all of humanity became involved in the problem of preserving the ozone layer. Following the development of a number of prohibitive and protective measures, the situation was slightly stabilized. Thus, some researchers argue that if all of humanity engages in industrial production within reasonable limits, the problem of ozone holes can be successfully solved.

If you have any questions, leave them in the comments below the article. We or our visitors will be happy to answer them

Introduction

1.2 Ozone hole over Antarctica

2. Main measures to protect the ozone layer

3. Rule of optimal component complementarity

4. Law N.F. Reimers on the destruction of the hierarchy of ecosystems

Conclusion

List of used literature

Introduction

The modern oxygen atmosphere of the Earth is a unique phenomenon among planets solar system, and this feature is associated with the presence of life on our planet.

The environmental problem is undoubtedly the most important for people now. The reality of an environmental catastrophe is indicated by the destruction of the Earth's ozone layer. Ozone is a triatomic form of oxygen, formed in the upper layers of the atmosphere under the influence of hard (short-wave) ultraviolet radiation from the Sun.

Today, ozone worries everyone, even those who previously did not suspect the existence of an ozone layer in the atmosphere, but only believed that the smell of ozone was a sign of fresh air. (It’s not for nothing that ozone means “smell” in Greek.) This interest is understandable - we are talking about the future of the entire biosphere of the Earth, including man himself. Currently, there is a need to make certain decisions that are binding on everyone, which would allow us to preserve the ozone layer. But for these decisions to be correct, we need complete information about those factors that change the amount of ozone in the Earth’s atmosphere, as well as about the properties of ozone, and how exactly it reacts to these factors.

1. Ozone holes and the causes of their occurrence

The ozone layer is a wide atmospheric belt extending from 10 to 50 km above the Earth's surface. Chemically, ozone is a molecule consisting of three oxygen atoms (an oxygen molecule contains two atoms). The concentration of ozone in the atmosphere is very low, and small changes in the amount of ozone lead to large changes in the intensity of ultraviolet radiation reaching the earth's surface. Unlike ordinary oxygen, ozone is unstable; it easily transforms into the diatomic, stable form of oxygen. Ozone is a much stronger oxidizing agent than oxygen, and this makes it capable of killing bacteria and inhibiting the growth and development of plants. However, due to its low concentration in the surface layers of air under normal conditions, these features have practically no effect on the state of living systems.

Much more important is its other property, which makes this gas absolutely necessary for all life on land. This property is the ability of ozone to absorb hard (short-wave) ultraviolet (UV) radiation from the Sun. Hard UV quanta have energy sufficient to break some chemical bonds, so it is classified as ionizing radiation. Like other radiations of this kind, x-rays and gamma radiation, it causes numerous disturbances in the cells of living organisms. Ozone is formed under the influence of high-energy solar radiation, which stimulates the reaction between O 2 and free oxygen atoms. When exposed to moderate radiation, it disintegrates, absorbing the energy of this radiation. Thus, this cyclical process “eats” dangerous ultraviolet radiation.

Ozone molecules, like oxygen, are electrically neutral, i.e. do not carry an electrical charge. Therefore, the Earth's magnetic field itself does not affect the distribution of ozone in the atmosphere. The upper layer of the atmosphere, the ionosphere, practically coincides with the ozone layer.

In the polar zones, where the Earth's magnetic field lines close on its surface, the distortions of the ionosphere are very significant. The number of ions, including ionized oxygen, in the upper layers of the atmosphere of the polar zones is reduced. But main reason low ozone content in the region of the poles - low intensity of solar radiation, falling even during the polar day at small angles to the horizon, and during the polar night it is completely absent. The area of ​​polar “holes” in the ozone layer is a reliable indicator of changes in the total ozone content in the atmosphere.

The ozone content in the atmosphere fluctuates due to many natural reasons. Periodic fluctuations are associated with solar activity cycles; Many components of volcanic gases are capable of destroying ozone, so an increase in volcanic activity leads to a decrease in its concentration. Due to the high, hurricane-like speeds of air flows in the stratosphere, ozone-depleting substances are carried over large areas. Not only ozone depleters are transported, but also ozone itself, so disturbances in ozone concentration quickly spread over large areas, and local small “holes” in the ozone shield, caused, for example, by a rocket launch, heal relatively quickly. Only in the polar regions is the air inactive, as a result of which the disappearance of ozone there is not compensated by its import from other latitudes, and the polar “ozone holes,” especially at the South Pole, are very stable.

1.1 Sources of ozone depletion

Among the ozone layer depleters are:

1) Freons.

Ozone is destroyed by chlorine compounds known as freons, which, also destroyed by solar radiation, release chlorine, which “tears off” the “third” atom from ozone molecules. Chlorine does not form compounds, but serves as a “breaking” catalyst. Thus, one chlorine atom can “destroy” a lot of ozone. It is believed that chlorine compounds can remain in the atmosphere from 50 to 1500 years (depending on the composition of the substance) of the Earth. Observations of the planet's ozone layer have been carried out by Antarctic expeditions since the mid-50s.

The ozone hole over Antarctica, which increases in size in the spring and decreases in the fall, was discovered in 1985. The discovery of meteorologists caused a chain of economic consequences. The fact is that the existence of the “hole” was blamed on the chemical industry, which produces substances containing freons that contribute to the destruction of ozone (from deodorants to refrigeration units).

There is no consensus on the question of how much humans are to blame for the formation of “ozone holes.”

On the one hand, yes, definitely guilty. The production of compounds that lead to ozone depletion should be minimized, or better yet stopped altogether. That is, to abandon an entire industry sector with a turnover of many billions of dollars. And if you don’t refuse, then transfer it to “safe” rails, which also costs money.

The point of view of skeptics: human influence on atmospheric processes, for all its destructiveness on a local level, is negligible on a planetary scale. The anti-freon campaign of the “greens” has a completely transparent economic and political background: with its help, large American corporations (Dupont, for example) are strangling their foreign competitors, imposing agreements on “environmental protection” at the state level and forcibly introducing a new technological stage that is more economically weak states are unable to withstand.

2) High altitude aircraft.

The destruction of the ozone layer is facilitated not only by freons released into the atmosphere and entering the stratosphere. Nitrogen oxides, which are formed during nuclear explosions, are also involved in the destruction of the ozone layer. But nitrogen oxides are also formed in the combustion chambers of turbojet engines of high-altitude aircraft. Nitrogen oxides are formed from the nitrogen and oxygen that are found there. The higher the temperature, i.e., the greater the engine power, the greater the rate of formation of nitrogen oxides.

It's not just the power of an airplane's engine that matters, but also the altitude at which it flies and releases ozone-depleting nitrogen oxides. The higher the nitrous oxide or oxide is formed, the more destructive it is to ozone.

The total amount of nitrogen oxide that is emitted into the atmosphere per year is estimated at 1 billion tons. About a third of this amount is emitted by aircraft above the average tropopause level (11 km). As for aircraft, the most harmful emissions are from military aircraft, the number of which amounts to tens of thousands. They fly primarily at altitudes in the ozone layer.

3) Mineral fertilizers.

Ozone in the stratosphere can also decrease due to the fact that nitrous oxide N2O enters the stratosphere, which is formed during the denitrification of nitrogen bound by soil bacteria. The same denitrification of fixed nitrogen is also carried out by microorganisms in the upper layer of oceans and seas. The denitrification process is directly related to the amount of fixed nitrogen in the soil. Thus, you can be sure that with an increase in the amount of mineral fertilizers applied to the soil, the amount of nitrous oxide N2O formed will also increase to the same extent. Further, nitrogen oxides are formed from nitrous oxide, which lead to the destruction of stratospheric ozone.

4) Nuclear explosions.

Nuclear explosions release a lot of energy in the form of heat. A temperature of 6000 0 K is established within a few seconds after a nuclear explosion. This is the energy of the fireball. In a highly heated atmosphere, such transformations occur chemical substances, which under normal conditions either do not occur or occur very slowly. As for ozone and its disappearance, the most dangerous for it are the nitrogen oxides formed during these transformations. Thus, during the period from 1952 to 1971, as a result of nuclear explosions, about 3 million tons of nitrogen oxides were formed in the atmosphere. Their further fate is as follows: as a result of atmospheric mixing, they end up at different heights, including the atmosphere. There they enter into chemical reactions with the participation of ozone, leading to its destruction.

5) Fuel combustion.

This huge hole in the earth's ozone layer was discovered in 1985; it appeared over Antarctica. It is more than one thousand kilometers in diameter and approximately nine million kilometers square in area.

Every year in the month of August, the hole disappears and it happens as if this huge ozone gap never existed.

Ozone hole - definition

An ozone hole is a decrease or complete absence of ozone concentration in the Earth's ozone layer. According to the report of the World Meteorological Organization and the generally accepted theory in science, a significant decrease in the ozone layer is caused by an ever-increasing anthropogenic factor - the release of bromine- and chlorine-containing freons.

There is another hypothesis, according to which the very process of formation of holes in the ozone layer is natural and in no way connected with the results of the activities of human civilization.

A combination of factors causes a decrease in ozone concentration in the atmosphere. One of the main ones is the destruction of ozone molecules during reactions with various substances of natural and anthropogenic origin, as well as the absence sunlight and radiation during the polar winter. This includes the polar vortex, which is particularly stable and prevents the penetration of ozone from the circumpolar latitudes, and the resulting stratospheric polar clouds, the surface of which particles act as a catalyst for the ozone decay reaction.

These factors are typical for Antarctica, and in the Arctic the polar vortex is much weaker due to the fact that there is no continental surface there. The temperature here is higher by some amount, unlike Antarctica. Polar stratospheric clouds are less common in the Arctic and tend to break up in early autumn.

What is Ozone?

Ozone is a toxic substance that is harmful to humans. In small quantities it has a very pleasant smell. To make sure of this, you can take a walk in the forest during a thunderstorm - we’ll enjoy it in time fresh air, but later you will feel very bad.

Under normal conditions, there is practically no ozone at the bottom of the Earth's atmosphere - this substance is present in large quantities in the stratosphere, starting somewhere around 11 kilometers above the earth and extending to 50-51 kilometers. The ozone layer lies right at the very top, that is, approximately 51 kilometers above the earth. This layer absorbs the deadly rays of the sun and thereby protects our lives and not only ours.

Before the discovery of ozone holes, ozone was considered a substance that poisons the atmosphere. It was believed that the atmosphere was full of ozone and that it was this that was the main culprit of the “greenhouse effect”, with which something needed to be done.

In the present, humanity, on the contrary, is trying to take steps to restore the ozone layer, since the ozone layer is becoming thinner throughout the Earth, and not just over Antarctica.

Ozone holes - “children” of stratospheric vortices

Although there is little ozone in the modern atmosphere - no more than one three-millionth of the other gases - its role is extremely large: it delays hard ultraviolet radiation (the short-wave part of the solar spectrum), which destroys proteins and nucleic acids. In addition, stratospheric ozone is an important climatic factor that determines short-term and local weather changes.

The rate of ozone destruction reactions depends on catalysts, which can be either natural atmospheric oxides or substances released into the atmosphere as a result of natural disasters (for example, powerful volcanic eruptions). However, in the second half of the last century, it was discovered that substances of industrial origin can also serve as catalysts for ozone destruction reactions, and humanity became seriously worried...

Ozone (O3) is a relatively rare molecular form of oxygen consisting of three atoms. Although there is little ozone in the modern atmosphere - no more than one three-millionth of the other gases - its role is extremely large: it blocks hard ultraviolet radiation (the short-wave part of the solar spectrum), which destroys proteins and nucleic acids. Therefore, before the advent of photosynthesis - and, accordingly, free oxygen and the ozone layer in the atmosphere - life could only exist in water.

In addition, stratospheric ozone is an important climatic factor that determines short-term and local weather changes. By absorbing solar radiation and transferring energy to other gases, ozone heats the stratosphere and thereby regulates the nature of planetary thermal and circular processes throughout the atmosphere.

Under natural conditions, unstable ozone molecules are formed and disintegrated under the influence of various factors of living and inanimate nature, and in the course of long evolution this process has reached a certain dynamic equilibrium. The rate of ozone destruction reactions depends on catalysts, which can be either natural atmospheric oxides or substances released into the atmosphere as a result of natural disasters (for example, powerful volcanic eruptions).

However, in the second half of the last century, it was discovered that substances of industrial origin can also serve as catalysts for ozone destruction reactions, and humanity was seriously worried. Public opinion was especially excited by the discovery of the so-called ozone “hole” over Antarctica.

"Hole" over Antarctica

A noticeable loss of the ozone layer over Antarctica - the ozone hole - was first discovered back in 1957, during the International Geophysical Year. Her real story began 28 years later with an article in the May issue of the magazine Nature, where it was suggested that the cause of the anomalous spring TO minimum over Antarctica is industrial (including freons) atmospheric pollution (Farman et al., 1985).

It was found that the ozone hole over Antarctica usually appears once every two years, lasts about three months, and then disappears. It is not a through hole, as it might seem, but a depression, so it is more correct to talk about “sagging of the ozone layer.” Unfortunately, all subsequent studies of the ozone hole were mainly aimed at proving its anthropogenic origin (Roan, 1989).

Today, there are different hypotheses regarding the chemical and dynamic mechanisms of ozone hole formation. However, many known facts do not fit into the chemical anthropogenic theory. For example, an increase in stratospheric ozone levels in certain geographic regions.

Here is the most “naive” question: why does a hole form in the southern hemisphere, although freons are produced in the northern, despite the fact that it is unknown whether there is air communication between the hemispheres at this time?

None of the existing theories is based on large-scale detailed measurements of TOC and studies of processes occurring in the stratosphere. It was possible to answer the question about the degree of isolation of the polar stratosphere over Antarctica, as well as a number of other questions related to the problem of the formation of ozone holes, only with the help of a new method of tracking air flow movements proposed by V. B. Kashkin (Kashkin, Sukhinin, 2001; Kashkin et al., 2002).

Air flows in the troposphere (up to a height of 10 km) have been tracked for a long time by observing the translational and rotational movements of clouds. Ozone, in fact, is also a huge “cloud” over the entire surface of the Earth, and by changes in its density we can judge the movement of air masses above 10 km, just as we know the direction of the wind by looking at a cloudy sky on a cloudy day. For these purposes, ozone density should be measured at spatial grid points at a certain time interval, for example, every 24 hours. By tracking how the ozone field has changed, you can estimate the angle of its rotation per day, the direction and speed of movement.

Using a new method, the dynamics of the ozone layer was studied in 2000, when a record large ozone hole was observed over Antarctica (Kashkin et al., 2002). To do this, they used satellite data on ozone density throughout the southern hemisphere, from the equator to the pole. As a result, it was found that the ozone content is minimal in the center of the funnel of the so-called circumpolar vortex, which formed above the pole, which we will discuss in detail below. Based on these data, a hypothesis was put forward about the natural mechanism for the formation of ozone “holes”.

Global dynamics of the stratosphere: a hypothesis

Circumpolar vortices are formed when stratospheric air masses move in the meridional and latitudinal directions. How does this happen? At the warm equator the stratosphere is higher, and at the cold pole it is lower. Air currents (along with ozone) roll down from the stratosphere as if down a hill, and move faster and faster from the equator to the pole. Movement from west to east occurs under the influence of the Coriolis force associated with the rotation of the Earth. As a result, air flows seem to be wound, like threads on a spindle, on the southern and northern hemispheres.

The “spindle” of air masses rotates throughout the year in both hemispheres, but is more pronounced at the end of winter and beginning of spring, because the height of the stratosphere at the equator remains almost unchanged throughout the year, and at the poles it is higher in summer and lower in winter, when it is especially Cold.

The ozone layer in mid-latitudes is created by a powerful influx from the equator, as well as by photochemical reactions that occur in situ. But ozone in the polar region owes its origin mainly to the equator and mid-latitudes, and its content there is quite low. Photochemical reactions at the pole, where the sun's rays fall at a low angle, proceed slowly, and a significant part of the ozone coming from the equator manages to be destroyed along the way.

But air masses do not always move this way. In the coldest winters, when the stratosphere above the pole drops very low above the Earth's surface and the “slide” becomes especially steep, the situation changes. The stratospheric currents roll down so quickly that the effect is familiar to anyone who has watched water flow through a hole in a bathtub. Having reached a certain speed, the water begins to rotate rapidly, and a characteristic funnel is formed around the hole, created by centrifugal force.

Something similar happens in the global dynamics of stratospheric flows. When stratospheric air flows gain sufficiently high speed, centrifugal force begins to push them away from the poles towards the middle latitudes. As a result, air masses move from the equator and from the pole towards each other, which leads to the formation of a rapidly rotating vortex “shaft” in the mid-latitude region.

The exchange of air between the equatorial and polar regions ceases; ozone does not flow from the equator and from the middle latitudes to the pole. In addition, the ozone remaining at the pole, as in a centrifuge, is pressed toward the middle latitudes by centrifugal force, since it is heavier than air. As a result, the ozone concentration inside the funnel drops sharply - an ozone “hole” is formed above the pole, and in the middle latitudes - a region of high ozone content corresponding to the “shaft” of the circumpolar vortex.

In spring, the Antarctic stratosphere warms up and rises higher - the funnel disappears. Air communication between middle and high latitudes is restored, and photochemical reactions of ozone formation are accelerated. The ozone hole disappears before a new one cold winter at the South Pole.

What's in the Arctic?

Although the dynamics of stratospheric flows and, accordingly, the ozone layer in the northern and southern hemispheres are generally similar, the ozone hole only appears from time to time over the South Pole. There are no ozone holes over the North Pole because winters there are milder and the stratosphere never drops low enough for air currents to reach the speed necessary to form a hole.

There is another important difference. In the southern hemisphere, the circumpolar vortex rotates almost twice as fast as in the northern hemisphere. And this is not surprising: Antarctica is surrounded by seas and there is a circumpolar sea current around it - essentially, giant masses of water and air rotate together. The picture is different in the northern hemisphere: in the middle latitudes there are continents with mountain ranges, and the friction of the air mass on the earth's surface does not allow the circumpolar vortex to gain a sufficiently high speed.

However, in the middle latitudes of the northern hemisphere, small ozone “holes” of a different origin sometimes appear. Where do they come from? The movement of air in the stratosphere of the mid-latitudes of the mountainous northern hemisphere resembles the movement of water in a shallow stream with a rocky bottom, when numerous whirlpools form on the surface of the water. In the middle latitudes of the northern hemisphere, the role of the bottom surface topography is played by temperature differences at the boundaries of continents and oceans, mountain ranges and plains.

A sharp change in temperature on the Earth's surface leads to the formation of vertical flows in the troposphere. Stratospheric winds, encountering these flows, create vortices that can rotate in both directions with equal probability. Inside them, areas with low ozone content appear, that is, ozone holes that are much smaller in size than at the South Pole. And it should be noted that such vortices with different directions of rotation were discovered on the first attempt.

Thus, the dynamics of stratospheric air flows, which we tracked by observing the ozone cloud, allows us to provide a plausible explanation for the mechanism of formation of the ozone hole over Antarctica. Apparently, similar changes in the ozone layer, caused by aerodynamic phenomena in the stratosphere, took place long before the advent of man.

All of the above does not mean that freons and other gases of industrial origin do not have a destructive effect on the ozone layer. However, scientists have yet to find out what is the relationship between natural and anthropogenic factors influencing the formation of ozone holes - to draw hasty conclusions in such a important issues unacceptable.