The troposphere is one of the layers of the Earth's atmosphere. It has the greatest impact on the planet and is best studied by man. What is the composition of the troposphere? What properties does it have?
Layers of the atmosphere
The gaseous shell of our planet is called the atmosphere. It seems to envelop the Earth. In the lower part it comes into contact with the earth's crust and the surface of the hydrosphere, in the upper part it connects with outer space.
The atmosphere moves with the planet and is kept around it due to the forces of gravity. Its properties, such as density, composition, temperature, humidity, are not the same at different levels. Depending on their nature, the gas envelope is divided into several zones - layers. What are the layers of the atmosphere?
The troposphere is the lowest. Weather is formed here, clouds appear. Next comes the stratosphere. It contains a lot of ozone, which traps some of the ultraviolet radiation, making it less dangerous for us. The coldest layer is the mesosphere. The temperature in it drops below -90 degrees.
Roughly from a height of 90 to 500 kilometers is the thermosphere. It is in this layer that the aurora occurs. Because ofa large number of ionized atoms, the mesosphere and thermosphere are combined under the name "ionosphere". The last layer is the exosphere. It is very rarefied and does not have a clear outer boundary, smoothly merging with interplanetary space.
Troposphere
The troposphere is the layer of the atmosphere that starts from the very surface of the Earth. It has the greatest impact on the planet. The height of the troposphere depends on geographic latitude. In the polar regions, it ends at an altitude of 10 kilometers, in the equatorial regions, its upper limit reaches 18 kilometers.
The lower part of the troposphere is called the planetary boundary level. Its thickness is from one to two kilometers. Here the most active interaction of the air shell with the hydrosphere and the solid earth's surface takes place.
The troposphere is not directly adjacent to the stratosphere. Between them there is an intermediate layer - the tropopause, the thickness of which ranges from several hundred meters to two kilometers. The temperature in it does not change with height, unlike the troposphere. The height of the layer can change: with cyclones it decreases, with anticyclones it increases.
Composition
The troposphere is the most significant part of the atmosphere. It accounts for more than 75% of the mass of the gas envelope. The troposphere contains almost all of the atmospheric water vapor (98%). The remaining layers are practically devoid of this component.
At the lower, surface level of the layer is 99% of the aerosols present in the gas envelope. They representsmall particles raised from the surface of the earth by air masses: dust, smoke molecules, plant spores, sea s alt.
The air of the troposphere is heavily saturated with oxygen and nitrogen. They are involved in the cycle of substances in nature and are the main components that are necessary to sustain life on Earth. In total, oxygen accounts for 21% of the mass in the atmosphere, and 78% for nitrogen.
The troposphere has a high content of argon and carbon dioxide compared to other layers. In addition, it contains other atmospheric constituents (neon, ammonia, xenon, radon, helium, hydrogen, ozone, etc.), but in small quantities.
Physical properties
The main physical parameters of the layer are density, humidity, temperature and pressure. These properties are an important factor in the formation of climate and weather on Earth. In different areas and different latitudes, their performance is not the same.
The surface of the planet, especially the World Ocean, accumulates solar heat and gives it to the air. Therefore, the temperature in the troposphere is higher below. Humidity is also increased in the lower parts of the layer and decreases with height. This also affects the temperature - for every hundred meters of elevation, it decreases by 0.65 degrees until it reaches the tropopause.
Density and pressure also decrease with altitude. For example, the pressure in the upper part of the layer is 6-7 times less than at sea level. Density decreases a little slower, but its changes are also noticeable.
The air becomes rarefied and contains less oxygen and nitrogen per unit volume. Because of thisin the mountains, as a rule, it is more difficult to breathe, and a long stay at high altitudes is manifested by oxygen starvation.
Shaping the weather
The troposphere is the layer of the atmosphere that most actively interacts with the Earth's surface. Its physical properties affect the weather on the planet.
The difference in pressure, density and temperature creates air movement. Colder and denser air masses move towards areas of lower density and temperature. Due to this, fronts, cyclones and anticyclones are formed that determine the weather.
Wind in the troposphere increases with height. At the border with the tropopause, it is three times higher than at the earth's surface. It ensures the circulation of the atmosphere, moving both in the meridian and in the latitudinal direction.
Wind is also involved in the transfer of moisture and aerosols. Greenhouse gases (methane, ozone, carbon dioxide) keep them in the troposphere, preventing them from rising higher. They accumulate in the atmosphere, contributing to the formation of various types of clouds. And their condensation leads to precipitation.
