atmosphere of our planet - it's the air environment of the earth, which protects the surface from deadly effects on all living ultraviolet rays of the sun.In addition, the atmosphere prevents the penetration of space dust and meteorites.
structure of the atmosphere: composition
protective shell consists of a mixture of gases, two-thirds of its volume takes nitrogen, the fifth part - oxygen, and one percent accounted for noble gases (krypton, argon, helium, etc.).The volume of nitrogen and oxygen is almost unchanged as nitrogen practically does not react with other substances and compounds, and oxygen, despite the expenditure of all time filled plants.
Up to 100-kilometer height ratio of these gases as a percentage virtually unchanged.This is due to the air mass constant stirring.
Besides these components in the composition of the atmosphere consists of about 0.030 percent carbon dioxide, which is concentrated closer to the earth's surface.Most of its industrial centers, cities, in areas of volcanic activity.
atmosphere also includes within its structure a small amount of dust and water vapor.The volume of the last component depends on the ambient air temperature: an increase, a large number of steam.The presence of water in the air in the vapor phase provides an opportunity to observe natural phenomena such as the refraction of the sun's rays, rainbow, etc.
Dust in the atmosphere occurs when volcanic eruptions, dust and sand storms as a result of incomplete combustion of fuel at thermal power stations.
density air bag is not the same everywhere.At this rate, it affects the height of the atmosphere.The most dense skin at the surface of the planet, and with the height, it becomes less likely.Even at a distance of 11 km of the atmosphere by 4 times less than in the surface layer.
structure of the atmosphere: a vertical section (stratification)
Depending on the properties of the gas composition and density of the air envelope is divided into 5 main parts - concentric layers.
The lowest layer is the troposphere, which is the upper limit of 10 km from the surface of the planet at the equator to the poles, the figure is 18 km away.The bottom layer contains virtually all the water gas and nearly 80 percent of the total volume of the atmosphere.
In the troposphere with height occurs decrease of temperature: every hundred meters becomes colder by 0.6 degrees, and the upper limit is observed minus 45-50 degrees.
This shell is a constant movement of air that moves is mixed.Only here it rains, there are thunderstorms, fog, snow or storm.
second layer within the structure of the atmosphere is the stratosphere, which extends to a height of 55 km.This shell has a slight air pressure and density.Sparse array consists of the same gases, and the troposphere, however, there is more ozone.The maximum concentration of oxygen isotope is observed in the region of 20 - 30 km from the surface.The temperature of the stratosphere increases with height, and the upper boundary of the figure is 0 degrees.This is due to the absorption of short-wavelength part of the solar energy by ozone, due to which the air is heated.
Above the stratosphere is the mesosphere which reaches 80 km from the surface.There is already happening again lowering the temperature to minus 90 degrees at the upper limit, the air density is two hundred times less than in the surface layers of the planet's atmosphere.
distance of 80 to 800 kilometers takes mesosphere - the fourth shell, part of the structure of the atmosphere.Here, the gases are ionized, and the temperature at 160 km altitude is 200 degrees, and 650 km - reaches 1500 C. There are formed electric currents affecting the magnetic field occurring aurora.
last outer shell called the exosphere, which is located more than 800 km.There particle velocity reaches a critical point at which they can go into space, overcoming the Earth's gravity.
