The gaseous shell of our planet, which protects it from harsh cosmic influences from the outside, is called the atmosphere. Without it, life on Earth would not be possible. Its thickness is several thousand kilometers, and the atmosphere consists of several layers. Which one is called the troposphere?
Definition
What is the troposphere and how thick is it? All changes that occur in this layer of the atmosphere have a significant impact on weather conditions on Earth. The troposphere is the lowest layer of the atmosphere. It makes up about 75% of its total mass. The troposphere contains 99% of the total mass of atmospheric aerosols and water vapor.
This word comes from the ancient Greek language. It consists of two roots - "tropos" (turn, change) and "sphere" (ball). The troposphere is the lower layer of the gaseous envelope, which most closely interacts with the upper layers of our planet - the hydrosphere and lithosphere. It is a constant exchange of moisture, heat, and chemical elements.
Properties
For those who are interested in what the troposphere is, it will be interesting to know that its thickness varies. In temperatelatitudes it does not exceed 17 km, in the tropics - 20 km. Near the poles of the globe, it is no more than 10 km. The lower layer of the troposphere is borderline, and its depth ranges from several hundred meters to 2 km.
It is greatly influenced by air currents on the surface of the planet, the outlines of the land, as well as the daily rhythm. Every 100 m of ascent in the tropospheric layer of the gas envelope, the air temperature in the troposphere drops by an average of 0.65 degrees Celsius. The total thickness of the atmosphere does not exceed 25 thousand km.
As the density of the air decreases, the atmosphere without any clear boundary passes into outer space. In this case, the upper boundary of the gas envelope ends at the level of 20 thousand km. The lower boundary of the troposphere runs along the surface of the planet.
Composition of the troposphere
The surface layer consists of two important chemical elements - nitrogen and oxygen. The nitrogen content is 78% of the entire gaseous envelope of the Earth; oxygen - 21%. Water, oxygen and carbon dioxide play the most important role in sustaining life on our planet. The nitrogen cycle plays an important role in plant nutrition. Water vapor is also an important component, thanks to which the required temperature level is maintained. Steam enters the troposphere thanks to evaporation from the surface of the ocean.
Nitrogen, a large proportion of which is contained in the atmosphere, serves as a kind of diluent for oxygen. It can be said about carbon dioxide that its content in the gaseous envelope of the planetpretty changeable. Carbon dioxide enters the troposphere from various sources - volcanic eruptions, from organisms, from soil, biological decay products, etc. Despite the low content of this gas in the troposphere, its role in sustaining life is exceptionally great, because it is necessary for plants for photosynthesis processes.
Also of great importance for the troposphere is dust, most of which rises from the continents. It consists of particles of various minerals, s alts, spores and microorganisms. Cloudy atmosphere due to dust weakens the protection of the planet from solar radiation.
Processes in the troposphere
The layer following the troposphere is the stratosphere. The atmosphere also includes other layers - the mesosphere, exosphere and thermosphere. However, the most important layer for sustaining life on Earth is the troposphere, more precisely, its lower layer. The two layers are separated from each other by a tropopause - a thin transitional area where the temperature ceases to decrease in proportion to the increase in height.
The biosphere, as well as most of the atmospheric air, is located in the troposphere. It is here that various types of clouds are formed, weather fronts and air masses, cyclones and anticyclones are formed. The entire system of air currents is located in the troposphere. As a result of condensation processes, clouds are formed that cause precipitation in the form of rain, hail or snow.
Transitions of water from one state to another are carried out in the troposphere. At the surface of the planet, air pressurehigher than in the upper layers. The processes occurring in this layer of the atmosphere affect the climate and weather conditions.
Meaning of the atmosphere
What is the role of the gas shell of our planet? Firstly, in its lower layer - namely, in the troposphere - almost all air reserves are concentrated. Thanks to these reserves, living organisms are able to breathe. The importance of the atmosphere for life on Earth cannot be overestimated - after all, without air, our planet would be uninhabited, like other celestial bodies in the solar system. And in the upper part of the gas shell is the ozone layer, which protects the Earth from cosmic influences. Thanks to him, dangerous cosmic radiation does not fall on our planet.
Surface layer
Those who study what the troposphere is should also know about its lowest layer, which is called the surface. It contains a large amount of dust, as well as various volatile microorganisms. In the surface layer, daily temperature fluctuations are well expressed, as well as air humidity. As the altitude increases, the wind speed increases. In this layer, a vertical distribution of air temperature is observed.
What is the troposphere and what is its significance for all life on Earth, every student knows. After all, it is its surface layer that is the habitat for all living organisms. The composition and structure of the surface layer of the troposphere are greatly influenced by gases from the faults of the lithosphere, as well as the existence of life.
