- What is the stratosphere?
- Characteristics of the stratosphere
- Composition of the stratosphere
- Importance of the stratosphere
- Ozone layer
We explain what the stratosphere is, how it is composed, its importance and other characteristics. Also, what is the ozone layer.
What is the stratosphere?
The stratosphere or stratosphere is one of the lower layers of the atmosphere of planet Earth, located between the troposphere and the mesosphere. It is located at altitude variable between 9 kilometers in height (in the polar regions) or 20 kilometers in height (in the equatorial region), and 50 kilometers in height.
It is the atmospheric stratum in which weather balloons fly, and most commercial flights. Just a few species of birds and some bacteria areas inhabit this region.
On the other hand, in the stratosphere is the ozone layer, so essential for life as we know it. It also contains 19% of the total atmospheric gases, and represents 24% of the mass total of the atmosphere.
Before starting the stratosphere, there is the tropopause, which is the transitional region of the troposphere; similar to the stratopause that marks the end of the stratosphere and the beginning of the mesosphere.
Characteristics of the stratosphere
In the initial portions of the stratosphere, the temperature it remains constant, that is, it is isothermal, holding the -60 degrees Celsius that is usually found in the tropopause.
However, as the height increases the temperatures a rise, reaching 0 ° C or even 17 ° C in some regions of the globe, due to the amount of Energy that absorb the molecules of ozone in this region and is trapped. Due to all of the above, the stratosphere is a region with very little margin of humidity.
In the stratosphere the gas mixture of the air It is much faster in horizontal than vertical conditions, therefore it is made up of fairly homogeneous and identifiable strata. Almost at the end of it is the ozone layer, in conditions of Pressure and temperature that allow the formation of these unstable molecules from oxygen (O3).
Composition of the stratosphere
Due to the difference of heat between the stratosphere and the layers that precede and follow it, there is little exchange of gases between them. This causes the absence of water steam in the stratosphere, which translates into the almost total absence of clouds.
The most abundant compound in this entire region is ozone: almost all of the ozone in the atmosphere is concentrated in its almost 30 kilometers thick.
This substance is formed due to the action of ultraviolet rays on atmospheric oxygen. It shares space with other more complex and long-lived compounds, such as chlorofluorocarbons (CFCs) and compounds rich in nitrogen and sulfur, some of which come from Volcanic eruptions of yesteryear, and others of the action pollutant of human being.
There is also a certain content of halogen oxides and nitric acid in the stratosphere, and sulfuric acid.
Importance of the stratosphere
This atmospheric region is fundamental for the climatic and biotic stability of the planet, since it supports an enormous amount of energy that, otherwise, would be received directly by the surface.
Without the stratosphere, the heat would increase considerably, destabilizing the climate by melting the poles, increasing the evaporation of water and also bathe carcinogenic ultraviolet radiation to all living creatures. In this sense, the stratosphere operates as a protective shield of the Earth against the Sun.
On the other hand, it is a slightly turbulent layer, which facilitates the air Transport, especially in its lower layers, since it does not have an intense mixture of air components.
Ozone layer
Perhaps the most important element in the stratosphere is the ozone layer, which absorbs a significant percentage of the solar radiation that enters Earth from space.
Said radiation, to impact directly on the land surface, would have harmful consequences for the life and for the world's climatic stability. For this reason, the presence of this thin envelope of gases (around 3 ozone molecules for every 10 million air molecules) is essential for the biotic support of the planet.
The ozone layer, however, has been threatened several times. Many of them as a consequence of volcanic explosions and other similar phenomena that dumped tons of materials rich in sulfur and others into the atmosphere. chemical elements that react with ozone, reducing its presence.
On other occasions, however, the creation of "holes" in the ozone layer, that is, of unprotected regions, was due to indiscriminate use by the humanity of chlorofluorocarbonated gases (CFCs) in aerosols and refrigeration gases, which, when escaping upwards, are stored in the stratosphere preventing the formation of ozone.
The latter set off the alarms of the ecological community at the end of the 20th century, at such levels that it was possible to prohibit or limit the use of these substances and thus allow the ozone layer to recover naturally.
Since 2000, it is estimated that the presence of these compounds in the atmosphere has decreased at the rate of 1% per year, so there is hope that, by mid-century, the ozone layer will have been almost completely restored .