Atmosphere

Atmosphere

The atmosphere is the external part of earth surrounded by the layer of air. It consists of various gasses like Nitrogen, Oxygen, Carbon dioxide, inert gasses, water vapor, dust particles and much more.

Classification of Atmosphere

On the basis of altitude from the earth surface and its pressure, atmosphere is divided into five different parts,

1. Troposphere (0-16)
2. Stratosphere (16-50)
3. Mesosphere (50-80)
4. Thermosphere (80-720)
5. Exosphere (above 720 km)

1. Troposphere

   It is the thinnest layer of atmosphere, which extends from ground surface of the earth to 16 km.About 95% of the total volume of air is present in this layer. In this layer, the temperaturedecreases by 6.5 degree Celsius with each kilometer going up from sea level. All the metrological change like rainfall, snowfall, cloud formation, occur in this layer. This layer is most affected by human activities. The average temperature of this layer is 25 degree Celsius. The outermost region of this layer is called TROPOPAUSE.

2. Stratosphere

   It is the second layer of atmosphere which extends from 16-50 km from the ground level. Stratosphere is the protective layer of atmosphere as it contains ozone layer which prevents the entrance of UV rays from the sun towards earth. This layer is also called ozonosphere as the protective ozone layer is present in it. In this layer, the temperature will increase as we go up because of the presence of ozone gas. So, in this layer, no cloud is found and jet planes fly from the lower region of this layer. The outermost region of this layer is called STRATOPAUSE.

3. Mesosphere

   It is the third layer of the atmosphere which extends from 50 km up to 80 km up from the ground level. It is the coldest layer of the atmosphere where the temperature decreases from 2 degree Celsius to 110 degree Celsius. The meteors (shooting star) fall in this layer. In this layer, the wind blows with high speed in eastward direction in winter and westward direction in summer. The outermost region of this layer is called MESOPAUSE.

4. Thermosphere

   It is the fourth layer of the atmosphere which extends from 80km up to 720km up from the ground level. The lower part of this layer contains nitrogen and oxygen gas but in its upper part contains hydrogen and helium gas. While going up the temperature increase from 110 degree Celsius to 1200 degree Celsius. Due to high temperature, the air is present in ionic form so this layer is also called ionosphere. This layer is important for radio broadcasting and telecommunication as their wave travel from one part to another part of the world by bounding in the ions of gasses.

5. Exosphere

   It is the outermost layer of atmosphere which extends to above 720 km from the ground surface. In this layer, very few hydrogen and helium gasses are present and due to less gravity sometimes they may escape into space. In this layer, temperature rises up to 6000 degree Celsius and this layer is also called fringe zone of atmosphere.