Structure of Atmosphere Part -2(in Hindi)

Lesson 2 of 10 • 24 upvotes • 15:00mins

R K Shukla

(UPSC/ MPPSC SPECIAL) Troposphere is the lowest layer of atmosphere and it is very important for all the living organisms because all the activities and aspects related with weather e.g. Evaporations, condensation, precipitation, storm, lightening etc. originate in this sphere. Around 75% mass of gases and nearly all water vapours and aerosols are present in this layer. Teissesence de Bort was the first scientist who used this name ‘…T..ro..po…. sphere’ it has been derived from Greek word ‘Tropos’ which means mixing or Turbulence, overall we can say ‘region of mixing’. One of the important feature of this sphere is that in this part of atmosphere, temperature decreases with increase in height. In normal conditions the rate of decrease is 6.5 degree Celsius per kilometer or 3.6 degree F per 1000 feet. This is also known as mean temperature fall rate. This happens because of decrease in gases with increase in height, air pressure, decrease in aero sides with increasing height. However, due to local reasons, at some places this phenomenon reverses also. The height of Troposphere changes with change of weather. The change is registered lesser towards poles as compared to tropical regions and in winters as compared to summers. According to scientists the height of this sphere on Equator is 16 km and on poles it is 8 km. Interesting fact is that the temperature decreases at the upper part of this sphere at Equator not on poles. At average its height is upto 12 kilometer from ground. Tropopause: The region between Troposphere and Stratosphere which is 1.5 kilometer high, known as boundary of troposphere. The fall in temperature comes to an end in this region named as tropopause. Turbulent mixing of gases, winds, and radiation etc. none of the weather activities take place in this region. The minimum temperature in winters, at Equator (At the height of 17 kilometer) is 70° C and in summers over the poles it is – 45° C (At the height of 9 kilometer). Air pressure in this region is also between 100 millibar over Equator and 250 millibar over poles.