Figure 1 – Structure of atmosphere on the basis of temperature

2.2. Stratosphere

The stratosphere is found above the tropopause and extends up to a height of 50 km. The lower stratosphere is isothermal in character. This temperature region is found to be present up to about 20 km and after this temperature rises. In summers, the increase in the stratospheric temperature with latitudes continues upto the poles. But during the winter season the stratosphere is warmest between latitudes 500 – 600. Onwards, temperature decreases again. The thickness of the stratosphere is highest at the poles.

This layer is free of any clouds of weather changes. It is an ideal place for flying of big planes. At about 50 km, temperature begins to fall. This is end of stratosphere, and is called the stratopause.

The portion of the stratosphere having maximum concentration of ozone is called ozonosphere. The rise in temperature with height in stratosphere is because of the absorption of ultra-violet by the ozone gas. Details of ozone gas are already discussed above.