The troposphere is one of the layers of the Earth’s atmosphere. It has the greatest influence on the planet and is best studied by man. What is the composition of the troposphere? What properties does it have?
Atmospheric layers
The gas shell of our planet is called the atmosphere. It is as if enveloping the Earth. In the lower part, it is in contact with the earth's crust and the surface of the hydrosphere, in the upper part it is connected with outer space.
The atmosphere moves with the planet and is held near 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 shell is divided into several zones - layers. What layers does the atmosphere have?
The troposphere is the lowest. Here the weather forms, clouds arise. The stratosphere follows. It contains a lot of ozone, which delays part of the ultraviolet radiation, making it less dangerous for us. The coldest layer is the mesosphere. The temperature in it drops below -90 degrees.
From about 90 to 500 kilometers, there is a thermosphere. It is in this layer that the aurora occurs. Due to the 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 a layer of the atmosphere that starts from the very surface of the Earth. He 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 boundary 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 envelope with the hydrosphere and the solid earth surface takes place.
The troposphere does not directly adjoin the stratosphere. Between them there is an intermediate layer - the tropopause, whose thickness is from several hundred meters to two kilometers. The temperature in it does not change with height, in contrast to the troposphere. The layer height may vary: 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 shell. The troposphere contains almost the entire amount of 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 shell. They are small particles raised from the surface of the earth by air masses: dust, smoke molecules, plant spores, sea salt.
The air of the troposphere is very saturated with oxygen and nitrogen. They participate in the cycle of substances in nature and are the main components that are necessary to maintain life on Earth. In total, in the atmosphere, oxygen accounts for 21% of the mass, and nitrogen - 78%.
The troposphere has a high content of argon and carbon dioxide, compared to other layers. In addition, it contains the remaining components of the atmosphere (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 for the formation of climate and weather on Earth. In different places and different latitudes, their indicators are not the same.
The surface of the planet, especially the oceans, accumulates solar heat and gives it to the air. Therefore, below the temperature in the troposphere is greater. 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 the rise in height, it decreases by 0.65 degrees until it reaches the tropopause.
Density and pressure also decrease with height. For example, the pressure in the upper part of the layer is 6-7 times less than at sea level. Density decreases slightly more slowly, but its changes are also noticeable.
Air becomes thinner and contains less oxygen and nitrogen per unit volume. Because of this, it is usually more difficult to breathe in the mountains, and a long stay at high altitudes is manifested by oxygen starvation.
Weather formation
The troposphere is a 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 movements. Cooler and denser air masses tend to areas with 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 provides the circulation of the atmosphere, moving both in the meridian and in the latitudinal direction.
Wind is also involved in the transport of moisture and aerosols. In the troposphere they are held by greenhouse gases (methane, ozone, carbon dioxide), not allowing them to rise higher. They accumulate in the atmosphere, contributing to the formation of various types of clouds. And their condensation leads to precipitation.