Tag: the earth and its living world

The stratosphere is the second layer of the atmosphere. At the equator, it is at the height of 20 km and at poles at 7 km. The stratosphere shows the presence of the ozone layer that has formed due to the reaction of the UV rays with the atmosphere. The ozone so formed in capable of absorbing the UV rays emanating from the sun, including the UV-B which is the most harmful. Due to this absorption, the stratosphere shows the stratification of temperature. The temperature is more towards the upper layers of the atmosphere and less towards the troposphere. 

The tropopause is the boundary in the Earth's atmosphere between the troposphere and the stratosphere. Therefore it would serve as the upper part of the troposphere. So the correct answer is ' Upper part of troposphere'. 

Location in Earth's atmosphere. In the midlatitudes, the peak concentrations of ozone occur at altitudes from 20 to 25 km (about 12 to 16 miles). Most of the remaining ozone occurs in the troposphere, the layer of the atmosphere that extends from Earth's surface up to the stratosphere. The Ozone layer or ozone shield is a region of Earth's stratosphere that absorbs most of the Sun's ultraviolet radiation. The ozone layer contains less than 10 parts per million of ozone, while the average ozone concentration in Earth's atmosphere as a whole is about 0.3 parts per million

If there were no atmosphere around the earth, the temperature of the earth will increase during day and decrease during night. In the absence of atmosphere around the earth, it will be like a moon. There would be no life, no winds, no rains, no fires, no protection against harmful solar radiations. Due to absence of atmosphere around the moon, the temperature ranges from -190$^0$C to 110$^0$C. Air is a bad conductor of heat. The atmosphere has an average temperature of the earth almost steady during the day and night. It prevents sudden increase in temperature during the day time. Also, it decreases the rate of escape of heat during night time.

The ozone layer was discovered by Charles Fabry and Henri Buisson in 1913. The depletion of ozone was discovered by Farman, Gardiner and Shanklin in 1985.