Atmosphere| The layers of the atmosphere|

The Atmosphere And it's layers......

Atmosphere

Atmosphere is a sea of gases surrounding the Earth. In a sense, we are all swimming in a sea of gases(just as fishes swim in a sea of water). When we compare it with the size of the Earth, atmosphere is a very thin blanket surrounding Earth. The atmosphere is about 1,000 kms thick. There are many gases in the atmosphere, but oxygen (about 21% in volume) and nitrogen (about 78% in volume) dominate. Other gases are present in Very small percentages; these include argon, neon, carbon dioxide (about 0.03% by volume), methane, ammonia, ozone etc.

Structures of the Atmosphere

Just like the interior of the earth is arranged as layers, atmosphere too is arranged into various layers, having different compositions. Scientist research about it through air balloons, satellites etc. On the basis of chemicals composition, the atmosphere is divided into two broad layers:

1. Homosphere
2. Heterosphere

Homosphere: Homosphere extends up to height of 90kms. It consists of three layers: Troposphere, stratosphere, mesosphere. It is characterized by uniformity in composition of gases like nitrogen, oxygen, argon and carbon dioxide.

Heterosphere: The layer above 90kms of the homosphere is called heterosphere. It has a heterogeneous composition and hence, the name heterosphere. It has two layers called Thermosphere and Exosphere.

             Atmosphere can also be divided into various layers based on density and temperature.

1. Troposphere: Troposphere is the lower most layer of the atmosphere. It's average height is 13kms and extends roughly to a height of 8kms near the poles and about 18kms at the equator. Thickness of the troposphere is greatest at the equator because heat is transported to greater heights by strong convectional currents, greater sinking of air near the poles. It contains about 75% of the total gaseous mass of the atmosphere and practically all the moisture and dust particles. The entire weather phenomenon happens in this sphere. The temperature in this layer decreases as we go higher which is known as Normal Lapse Rate. Condensation, evaporation, precipitation, rainfall, cyclones etc. Occur in this layer.
2. Stratosphere: This layer extends up to a height of 50kms. This layer is almost free from clouds and associated weather phenomenon, making conditions most ideal for flying jet aircrafts. One important feature of stratosphere is that it contains ozone layer. The temperature increases as there is increase in altitude.
3. Mesosphere: It extends up to a height of 80kms. Meteorites burn up as they enter this layer from the space. Temperature starts decreasing with the increase in altitude.
4. Thermosphere: It extends up to 400kms. In Thermosphere, temperature rises rapidly with the increase in height. It contains electrically charged particles known as ions. Radio waves transmitted from the earth are reflected back to the earth by these ions. It is also known as Ionosphere.
5. Exosphere: It is the upper most layer of the atmosphere. This is the highest layer and very little is known about it.

        

Written by R Gowtham.....

       ||Thanks for reading||