The stratosphere is what? Height of the stratosphere

The stratosphere is one of the upper layers of the air envelope of our planet. It starts at an altitude of about 11 km above the earth. Here, aircraft of passenger aviation do not fly anymore and clouds are extremely rare. In the stratosphere is the ozone layer of the Earth - a thin shell, protecting the planet from the penetration of the destructive ultraviolet.

Aerial shell of the planet

The atmosphere is the gas shell of the Earth, which adjoins the inner surface to the hydrosphere and the earth's crust. Its outer boundary gradually turns into outer space. The composition of the atmosphere includes gases: nitrogen, oxygen, argon, carbon dioxide and so on - as well as impurities in the form of dust, water droplets, ice crystals, combustion products. The ratio of the basic elements of the air shell remains constant. Exceptions are carbon dioxide and water - their amount in the atmosphere often changes.

Gas shell layers

The atmosphere is divided into several layers, arranged one above the other and having features in the composition:

• Boundary layer - directly adjacent to the surface of the planet, extends to a height of 1-2 km;

• The troposphere is the second layer, the outer boundary is on average located at an altitude of 11 km, practically the entire water vapor of the atmosphere is concentrated here, clouds are formed, cyclones and anticyclones arise, as the altitude is increased, temperature is applied;

• Tropopause - a transition layer characterized by cessation of temperature decrease;

• The stratosphere is a layer that extends to a height of 50 km and is divided into three zones: from 11 to 25 km the temperature varies slightly, from 25 to 40 - the temperature rises, from 40 to 50 - the temperature remains constant (stratopause);

• The mesosphere extends to a height of 80-90 km;

• The thermosphere reaches 700-800 km above sea level, here at an altitude of 100 km the Karman line is located, which is taken abroad between the atmosphere of the Earth and the cosmos;

• The exosphere is also called the scattering zone, here a strongly rarefied gas loses particles of matter, and they fly away into space.

Temperature changes in the stratosphere

So, the stratosphere is part of the gas shell of the planet, following the troposphere. Here the air temperature, constant throughout the tropopause, begins to change. The height of the stratosphere is about 40 km. The lower boundary is 11 km above sea level. Starting from this mark, the temperature undergoes slight changes. At a height of 25 km, the heating index begins to grow slowly. To a mark of 40 km above sea level, the temperature rises from -56.5º to + 0.8ºС. Further, it remains close to zero degrees up to an altitude of 50-55 km. The zone between 40 and 55 kilometers is called a stratopause, since the temperature does not change here. It is a transition zone from the stratosphere to the mesosphere.

Features of the stratosphere

The stratosphere of the Earth contains about 20% of the mass of the entire atmosphere. The air here is so rarefied that it is impossible to stay without a special space suit. This fact is one of the reasons why flights to the stratosphere began to be carried out only relatively recently.

Another feature of the gas shell of the planet at an altitude of 11-50 km is a very small amount of water vapor. For this reason, clouds are almost never formed in the stratosphere. For them, there is simply no building material. However, it is rarely possible to observe the so-called mother-of-pearl clouds, which "decorate" the stratosphere (the photo is shown below) at an altitude of 20-30 km above sea level. Thin, as if glowing from within the formation can be observed after sunset or before sunrise. The shape of pearlescent clouds is similar to cirrus or cirrocumulus.

Ozone layer of the Earth

The main distinguishing feature of the stratosphere is the maximum concentration of ozone in the entire atmosphere. It is formed by the action of sunlight and protects all life on the planet from their harmful radiation. The ozone layer of the Earth is located at an altitude of 20-25 km above sea level. O ₃ molecules are distributed throughout the stratosphere and even there are near the surface of the planet, but at this level their greatest concentration is observed.

It should be noted that the ozone layer of the Earth is only 3-4 mm. This will be its thickness, if you place the particles of this gas under normal pressure conditions, for example, near the surface of the planet. Ozone is formed as a result of the decomposition of an oxygen molecule under the action of an ultraviolet into two atoms. One of them combines with a "full" molecule and ozone - O _{3 is formed} .

Dangerous defender

Ozone molecules absorb ultraviolet radiation with a wavelength shorter than 0.1-0.2 microns. This is his protective role. A thin layer of bluish gas prevents the ingress of solar radiation to the Earth, which is harmful to living organisms.

With the flow of wind, ozone gets close to the surface of the planet. It is also formed on Earth during a thunderstorm, the work of copying equipment or X-rays. Interestingly, a large concentration of ozone is harmful to humans. It is formed under the action of sunlight in highly gassed areas. Arrival in conditions of so-called ozone smog is dangerous for life. Bluish gas can destroy the lungs. Affects its presence on plants - they cease to develop normally.

The destruction of the ozone layer

The problem of ozone holes began to be actively discussed in the scientific community around the 1970s. Now it is known that pollution of the atmosphere, the industrial use of freons and some other compounds, the destruction of forests, the launching of space rockets and high-altitude aviation lead to the destruction of the protective screen. The international community has adopted a number of agreements that imply a reduction in the production of harmful substances. First of all, we are talking about freons used in the creation of aerosols, refrigerators, fire extinguishers, disposable dishes and so on.

At the same time, there are data that allow one to assume that the formation of ozone holes is due to natural causes. Harmful substances enter the atmosphere as a result of volcanic eruptions and earthquakes, from faults in the oceanic crust. Today, the question of the man's main role in the destruction of the ozone layer for a number of scientists remains controversial.

Flights in the stratosphere

The development of the stratosphere began in the 30s of the last century. Today, up to an altitude of 20 km, combat and supersonic commercial aircraft are being raised. Elevations of 40 km above sea level reach the meteosound. The record height reached by the unmanned aerostat is 51.8 km.

Gradually master this part of the air shell and lovers of extreme sports. In 2012, the Austrian parachutist Felix Baumgartner made a jump from the stratosphere from a height of almost 39 km. Overcoming the sound barrier during the flight , he landed safely. Baumgartner's record was broken by Google's vice president Alan Eustace. In 15 minutes he flew, also reaching the speed of sound, 40 km.

Thus, today the stratosphere is a more known layer of the atmosphere than at the beginning of the last century. However, the future of the ozone layer is still not very clear, without which life would not have arisen on Earth. While countries are reducing the production of freon, some scientists say that this will not bring much benefit, at least at such a rate, and others that it is not necessary at all, since most of the harmful substances are formed naturally. Who is right - time will judge.