The troposphere is the region within the atmosphere between the earth's surface and the tropopause that is centred at an altitude of about 8-15 kilometres. This region is characterized by decreasing temperature with increasing altitude.
Importance of troposphere to life on earth
- The study of the troposphere is very important because we breathe the air in this layer of air.
The troposphere contains about 85% of the atmosphere’s total mass. Tropospheric processes, such as the water or hydrologic cycle (the formation of clouds and rain) and the greenhouse effect, have a great influence on meteorology and the climate.
- The chemical composition determines the air quality. Certain components, even if they are only present in small amounts, may harm health and vegetation.
Therefore, it is of utmost importance to understand how the activities of humans influence the troposphere.
The troposphere has a direct contact with the Earth's surface
The troposphere has a direct contact with the Earth's surface. It is therefore very sensitive to processes occurring at this level, like:
- evaporation of oceans
- photosynthesis in plants
- respiration of living creatures
- human activities
Temperature decrease with altitude in troposphere
The troposphere differs from the stratosphere by the usually more rapid mixing of tropospheric air. One says that the troposphere is "turbulent". This turbulence is partly connected to the "thermal profile" of the troposphere: the temperature decreases with the altitude, at an average of 6°C per kilometre.
This phenomenon favours the fast convection of air from the lowest layers to higher altitudes in the troposphere. This convection goes hand in hand with the formation of clouds, the so-called convective clouds.
Troposphere is protected from hard UV radiation
Furthermore, the troposphere is protected from the hard ultraviolet radiation of the Sun by the higher layers of the atmosphere, namely by the stratospheric ozone layer. Because of this protection, many molecules are more stable in the troposphere then elsewhere in the atmosphere. This protection makes life possible on Earth.