The atmosphere of our planet is an air envelope.of the earth, protecting the surface from the deadly impact on all living things by the ultraviolet rays of the sun. In addition, the atmosphere prevents the penetration of dust and meteorites from space.
Atmosphere structure: composition
The containment shell consists of a mixture of gases:two-thirds of its volume is nitrogen, one-fifth is oxygen, and one percent comes from inert gases (krypton, argon, helium, and others). The volume of nitrogen and oxygen almost does not change, since nitrogen practically does not react with other substances and compounds, and oxygen, despite its expenditure, is filled with plants all the time.
Up to a 100-kilometer altitude, the ratio of these gases in percentages remains almost unchanged. This is due to the constant mixing of air masses.
In addition to the described components, the composition of the atmosphereIncludes about 0.030 percent carbon dioxide, which is concentrated closer to the earth’s surface. Most of it is in industrial centers, cities, in areas of volcanic activity.
Also the atmosphere includes in its structure.low dust and water vapor content. The volume of the last component depends on the ambient air temperature: with increasing, a larger amount of steam is formed. The presence in the air of water in the vapor state makes it possible to observe such natural phenomena as the refraction of sun rays, rainbows, etc.
Dust in the atmosphere occurs during volcanic eruptions, dust and sandstorms, as a result of incomplete combustion of fuel at thermal stations.
The density of the air envelope is not the same everywhere.This indicator is influenced by the height of the atmosphere. The most dense shell at the surface of the planet, and with the height it becomes less. Already at a distance of 11 km, the atmosphere is 4 times less common than in the surface layer.
Atmospheric structure: vertical section (stratification)
Depending on the properties of gas, composition and density, the air envelope is divided into 5 main parts - concentric layers.
The bottommost layer is the troposphere, the topthe boundary of which is located at a distance of 10 km from the surface of the planet at the equator; at the poles, this figure is 18 km. The bottom layer contains almost all the water gas and almost 80 percent of the total atmosphere.
In the troposphere, with a height, the air temperature drops: every hundred meters it gets colder by 0.6 degrees, and minus 45-50 degrees is observed at the upper border.
In this shell there is a constant movement of air, which moves, mixes. Only here it rains, thunderstorms, fogs, storms or snowfall are observed.
The second layer included in the structure of the atmosphereis the stratosphere, which extends to a height of 55 km. This shell has a slight pressure and air density. Sparse masses consist of the same gases as the troposphere, however, there is more ozone here. The maximum concentration of this oxygen isotope is observed at a distance of 20–30 km from the surface. The temperature of the stratosphere rises with altitude, and at the upper boundary this figure is 0 degrees. This is due to the absorption of the shortwave part of solar energy by ozone, due to which the air is heated.
Above the stratosphere is the mesosphere, heightwhich is 80 km from the surface. Here again, the temperature drops to minus 90 degrees at the upper boundary, the air density is two hundred times less than in the surface layers of the planet’s atmosphere.
The distance from 80 to 800 kilometers takesThe mesosphere is the fourth shell, which is part of the structure of the atmosphere. Here the gases are in the ionized state, and the temperature at an altitude of 160 km is 200 degrees, and at 650 km it reaches 1500 C. Here electric currents are generated that act on the magnetic field, and auroras occur.
The last outer shell is called the exosphere,which is located above 800 km. Here, the speed of movement of the particles reaches a critical point at which they can go into space, overcoming the earthly force.
