The stratosphere is one of the upper layers of the air shell of our planet. It starts at an altitude of about 11 km above the ground. Passenger aircraft no longer fly here and clouds rarely form. The Earth's ozone layer is located in the stratosphere - a thin shell that protects the planet from the penetration of harmful ultraviolet radiation.
Air shell of the planet
The atmosphere is the gaseous shell of the Earth, adjacent to the inner surface of the hydrosphere and the earth's crust. Its outer boundary gradually passes 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 drops, ice crystals, combustion products. The ratio of the main elements of the air shell is kept constant. The exceptions are carbon dioxide and water - their amount in the atmosphere often changes.
Gas shell layers
The atmosphere is divided into several layers, located one above the other and having features inline-up:
- boundary layer - directly adjacent to the surface of the planet, extending to a height of 1-2 km;
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troposphere - the second layer, the outer boundary is located on average at an altitude of 11 km, almost all the water vapor of the atmosphere is concentrated here, clouds form, cyclones and anticyclones appear, as the height increases, the temperature rises;
- tropopause - a transitional layer characterized by the cessation of temperature decrease;
- stratosphere is a layer that extends up to a height of 50 km and is divided into three zones: from 11 to 25 km the temperature changes slightly, from 25 to 40 - the temperature rises, from 40 to 50 - the temperature remains constant (stratopause);
- mesosphere extends to a height of 80-90 km;
- thermosphere reaches 700-800 km above sea level, here at an altitude of 100 km is the Karman line, which is taken as the boundary between the Earth's atmosphere and space;
- the exosphere is also called the scattering zone, here highly rarefied gas loses particles of matter, and they fly away into space.
Temperature changes in the stratosphere
So, the stratosphere is a part of the planet's gaseous envelope following the troposphere. Here, the air temperature, which is constant throughout the tropopause, begins to change. The height of the stratosphere is approximately 40 km. The lower limit is 11 km above sea level. Starting from this mark, the temperature undergoes slight changes. On theat an altitude of 25 km, the heating index begins to slowly increase. By the 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 the stratopause, since the temperature here does not change. It is a transition zone from the stratosphere to the mesosphere.
Features of the stratosphere
Earth's stratosphere contains about 20% of the mass of the entire atmosphere. The air here is so rarefied that it is impossible for a person to stay without a special space suit. This fact is one of the reasons why flights into the stratosphere began to be carried out only relatively recently.
Another feature of the gaseous shell of the planet at an altitude of 11-50 km is a very small amount of water vapor. For this reason, clouds almost never form 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 presented below) at an altitude of 20-30 km above sea level. Thin, as if luminous formations from the inside can be observed after sunset or before sunrise. The shape of mother-of-pearl clouds is similar to cirrus or cirrocumulus.
Earth's Ozone Layer
The main distinguishing feature of the stratosphere is the maximum concentration of ozone in the entire atmosphere. It is formed under the influence of sunlight and protects all life on the planet from their destructive radiation. The ozone layer of the Earth is located at an altitude of 20-25 km above the levelseas. O3 molecules are distributed throughout the stratosphere and even near the surface of the planet, but their highest concentration is observed at this level.
It should be noted that the Earth's ozone layer is only 3-4 mm. This will be its thickness if particles of this gas are placed under conditions of normal pressure, for example, near the surface of the planet. Ozone is formed as a result of the breakdown of an oxygen molecule under the action of ultraviolet radiation into two atoms. One of them combines with a "full-fledged" molecule and ozone is formed - O3.
Dangerous defender
Ozone molecules absorb ultraviolet radiation with a wavelength shorter than 0.1-0.2 microns. This is its protective role. A thin layer of bluish gas prevents solar radiation from reaching the Earth, which is detrimental 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 copiers or X-rays. Interestingly, a large concentration of ozone is detrimental to humans. It is formed under the action of sunlight in heavily polluted areas. Staying in the conditions of the so-called ozone smog is life-threatening. The bluish gas can destroy the lungs. Its presence also affects plants - they stop developing normally.
Ozone depletion
The problem of ozone holes has been actively discussed in the scientific community since about the 70s of the last century. It is now known that destructionThe protective screen leads to atmospheric pollution, the industrial use of freons and some other compounds, the destruction of forests, the launch of space rockets and high- altitude aviation. The international community has adopted a number of agreements to reduce the production of harmful substances. First of all, we are talking about freons used in the creation of aerosols, refrigeration units, fire extinguishers, disposable tableware, and so on.
At the same time, there is evidence to suggest that the formation of ozone holes occurs 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 main role of man in the destruction of the ozone layer remains controversial for a number of scientists.
Stratosphere flights
Development of the stratosphere began in the 30s of the last century. Today, combat and supersonic commercial aircraft rise to a height of 20 km. Meteorological balloons reach 40 km above sea level. The record height reached by an unmanned balloon is 51.8 km.
Extreme sports enthusiasts are gradually mastering this part of the air shell. In 2012, Austrian skydiver Felix Baumgartner made a jump from the stratosphere from a height of almost 39 km. Having overcome the sound barrier during the flight, he landed safely. Baumgartner's record was broken by Google Vice President Alan Eustace. In 15 minutes, he flew, also reaching the speed of sound, 40 km.
Thus, today the stratosphere ismore explored layer of the atmosphere than at the beginning of the last century. However, the future of the ozone layer, without which life on Earth would not have arisen, is still not very clear. While countries are reducing the production of freon, some scientists say that this will not bring much benefit, at least at such a pace, while others say that this is not necessary at all, since most of the harmful substances are formed naturally. Who is right - time will judge.
