The Earth

Troposphere: Wht is its average height and importance?

Troposphere: Wht is its average height and importance?

The troposphere is the lowest layer of the Earth's atmosphere, with an average height of 16 km from sea level. However, its height depends on the planet's point where we are.

The layer of the troposphere directly adjacent to the Earth's surface is called the atmosphere's boundary layer.

This part of the troposphere is under the constant influence of the conditions of the current state of the earth's surface. Above the boundary layer of the atmosphere is the so-called free atmosphere, in which the thermal and aerodynamic influence of the landscape is usually negligible.

The troposphere is heterogeneous in the vertical direction along the Earth's surface. Its electrical parameters change when weather conditions change. The refraction of radio waves occurs in this layer.

The next layer of the atmosphere above the troposphere is called the stratosphere, which reaches an altitude of about 50 km from sea level.

What is the average height of the troposphere?

Its thickness is between 8 and 10 km high in the polar regions, 10 to 12 km in temperate latitudes, and 16 km at the equator.

Due to its properties, the surface layers of the troposphere up to several tens of meters in height are the primary habitat of many living organisms: plants, animals, and humans. It is also the layer where meteorological phenomena occur.

What is the importance of the troposphere?

We can say that the troposphere is essential for life on Earth since, thanks to it, the earth's surface presents favorable conditions for developing the various forms of life that exist on Earth.

Even though the importance of the troposphere is indisputable, it is a highly polluted layer of the atmosphere resulting from the development of human activities. So, when we talk about atmospheric pollution or air pollution, we are actually talking about the pollution of the troposphere. 

The smog that hangs over some cities is one of the best-known examples of air pollution because it is so easily visible. Another way contamination of the troposphere manifests itself is through acid rain and, as we mentioned in previous sections, climate change.

Due to what has been described so far, it is of particular relevance to become aware of the issue and modify our daily habits that have led to the troposphere being severely contaminated.

What is the composition of the troposphere?

The troposphere is made up of:

  • Nitrogen (78%)

  • Oxygen (21%)

  • Argon, atmospheric water vapor, and carbon dioxide (1%)

The air density in this layer is denser than in the upper layers and represents three-quarters of the total mass of the atmosphere. 

What is the average temperature of the troposphere?

At the Earth's surface, the average temperature in the lower layers (at the Earth's surface) is about 59°F, while the temperature at the top of the layer drops to -81,4°F. It corresponds to the ambient temperature.

For every 100 meters gained in height, the air temperature drops by a lapse rate of 1.17 degrees Fahrenheit. The upper layer of the troposphere, in which the decrease in temperature with height stops, is called tropopause.

Inversion is an effect in which the temperature increases with height. It occurs in the lower layers of air and in the free atmosphere. 

Tropospheric pressure

Atmospheric pressure, like temperature, decreases with height. So much so that the pressure in the tropopause is about 4.5 times less than the pressure in the troposphere near the Earth's surface.

For every 100 meters gained in height, the air pressure drops by about ten millibars.

In turn, pressure is a variable factor that influences meteorological phenomena. Therefore, the pressure study is used to evaluate the weather forecast. Likewise, the altitude sickness that we suffer when ascending a mountain is explained by the decrease in atmospheric pressure with height. With lower atmospheric pressure, the oxygen density that we use to breathe is lower.

Tropospheric ozone: formation and effects

Tropospheric ozone is the ozone found in this layer. It is a gas made up of molecules made up of three oxygen atoms. The surface ozone layer is basically found in the first 10 meters of the layer and is where the highest concentrations of this gas are recorded.

Ozone is formed by the action of ultraviolet rays from solar radiation breaking O2 molecules into two oxygen atoms. When these atoms collide with an O2 molecule, an ozone molecule (O3) is formed. In the troposphere, the presence of volatile organic compounds (VOCs) favors ozone creation.

Unlike the ozone layer in the stratosphere, which acts as a thermal regulator for the planet, surface ozone has polluting consequences. These drawbacks include climate change because ozone is a greenhouse gas.

In general, ozone is not emitted directly but is formed in urban areas by the emission of polluting gases.

Elevated surface ozone concentrations have adverse effects on human health and vegetation.

However, ozone concentrations also have some advantages as it chemically reacts with other trace gases such as nitrogen oxides (NOx and NO2), carbon monoxide, and methane. In this way, these polluting gases are eliminated, improving air quality.

Data de publicació: April 20, 2022
Última revisió: April 20, 2022