What is the stratosphere?

What Does Stratosphere Mean

We explain what the stratosphere is, how it is composed, its importance and other characteristics. Also, what is the ozone layer.

In the stratosphere airplanes travel and living beings almost do not exist.

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 found at a variable altitude between 9 kilometers high (in the polar regions) or 20 kilometers high (in the equatorial region), and 50 kilometers high.

It is the atmospheric layer in which weather balloons fly, and most commercial flights. Only some species of birds and some airborne bacteria 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 total mass 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.

It can serve you: Lithosphere

Characteristics of the stratosphere

In the initial portions of the stratosphere, the temperature remains constant, that is, it is isothermal, holding the -60 degrees Celsius that is usually found in the tropopause.

However, as the altitude increases, temperatures rise, reaching 0 ° C or even 17 ° C in some regions of the globe, due to the amount of energy absorbed by ozone molecules in this region and is trapped. Due to all the above, the stratosphere is a region with very little margin of humidity .

In the stratosphere, the air gas mixture is much faster in horizontal than vertical conditions, which is why it is made up of fairly homogeneous and identifiable strata . Almost at the end of it is the ozone layer, under pressure and temperature conditions that allow the formation of these unstable molecules from oxygen (O 3 ).

Composition of the stratosphere

Due to the difference in heat between the stratosphere and the preceding and succeeding layers, there is little gas exchange between them. This causes the absence of water vapor 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 from the polluting action of humans .

There is also a certain content of halogen oxides and of nitric acid and sulfuric acid in the stratosphere .

Importance of the stratosphere

The stratosphere (mainly the ozone layer) filters much of the solar radiation.

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 showering all living beings with carcinogenic ultraviolet radiation . In that sense, the stratosphere acts as a protective shield Earth from the sun .

On the other hand, it is a slightly turbulent layer, which facilitates air transport , especially in its lower layers, since there is no 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.

Such radiation, if it hits the earth's surface directly , would have harmful consequences for 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 result of volcanic explosions and other similar phenomena that released into the atmosphere tons of materials rich in sulfur and other 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 the indiscriminate use by 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 almost completely restored. .

Follow on: Layer of Ozone

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