Atmospheric envelope, Characteristics and importance of Troposphere layer
The atmospheric envelope
There is a region between each successive layers, In these regions, the temperature remains constant, There is the tropopause which is the region between the troposphere layer and the stratosphere layer.
The characteristics and the importance of the troposphere layer
The troposphere layer extends for 13 km above the sea level to the tropopause, The thickness of the troposphere layer is 13 km, and it contains 99 % of the atmospheric water vapour which organizes the Earth’s temperature.
The troposphere layer is the lowest layer of Earth’s atmosphere, where nearly all weather conditions take place, The average height of the troposphere is 18 km in the tropics, 17 km in the middle latitudes, and 6 km in the polar regions in winter.
The temperature decreases with a rate (6.5 degree Celsius) for each (1 km) height until it reaches the lowest value of about (- 60 degree Celsius) at the tropopause, The air movement in this layer is vertical where, the hot air currents move upwards, while the cold air currents move downwards.
The atmospheric pressure in the troposphere layer decreases as we go up until it becomes 100 mb at its top, It contains about 75 % of the mass of the atmospheric air and aerosols, All the atmospheric phenomena such as rains, wind, clouds, ………take place in this layer.
Almost all of the water vapor and the dust particles in the atmosphere are in the troposphere, So, most clouds are found in this lowest layer, the bottom of the troposphere, right next to the surface of Earth, is called the boundary layer.
The lowest part of the troposphere, where the friction with the Earth’s surface influences airflow, is the planetary boundary layer, This layer is a few hundred meters to 2 km deep depending on the landform and time of day, A top of the troposphere is the tropopause, which is the border between the troposphere and stratosphere.