The troposphere is ...? Properties and composition of the troposphere

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 composition does the troposphere have? What properties does it have?

Layers of the atmosphere

The gas envelope of our planet is called the atmosphere. It's like enveloping 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 held near it by 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 is formed, clouds arise. Then follows the stratosphere. It contains a lot of ozone, which detains 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.

Approximately from a height of 90 and up to 500 kilometers there is a thermosphere. It is in this layer that there is a polar light. Because of the large number of ionized atoms, the mesosphere and the thermosphere are united under the name "ionosphere". The last layer is the exosphere. It is strongly 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. He has the greatest influence on the planet. The height of the troposphere depends on the geographical 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 a solid earth surface occurs.

The troposphere does not directly connect to the stratosphere. Between them there is an intermediate layer - a tropopause, the thickness of which is from several hundred meters to two kilometers. The temperature in it does not change with altitude, unlike the troposphere. The height of the layer can vary: with cyclones it decreases, with anticyclones 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, near-ground layer level, 99% of the aerosols present in the gas shell are located. They are small particles raised from the ground by air masses: dust, smoke molecules, plant spores, sea salt.

The air of the troposphere is highly saturated with oxygen and nitrogen. They participate 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, and for nitrogen, 78%.

In the troposphere, a large content of argon and carbon dioxide, compared with other layers. In addition, it contains the rest 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 localities and different latitudes, their indicators are 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 lower at the bottom. Humidity is also increased in the lower portions of the layer and decreases with height. This also affects the temperature - for every hundred meters of 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.

The air becomes sparse and contains less oxygen and nitrogen per unit volume. Because of this, in the mountains, as a rule, breathing is more difficult, and a long stay at high altitudes is manifested by oxygen starvation.

Weather shaping

The troposphere is the layer of the atmosphere that interacts most actively 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 dense air masses tend to an area with lower density and temperature. Due to this, fronts, cyclones and anticyclones determining the weather are formed.

The wind in the troposphere increases with height. At the border with the tropopause, it is three times higher than that of the earth's surface. It ensures the circulation of the atmosphere, moving both in the meridian and in the latitudinal direction.

The wind is also involved in the transfer of moisture and aerosols. In the troposphere they are kept by greenhouse gases (methane, ozone, carbon dioxide), not allowing to rise higher. They accumulate in the atmosphere, contributing to the formation of various types of clouds. And their condensation leads to precipitation.