Question

Give reasons.

Temperature decreases with increasing height in the troposphere.

Answer 1

The temperature decreases with increasing height in the troposphere because:

1. The troposphere is heated mainly from the Earth’s surface by the terrestrial radiation (heat radiated from the ground), rather than directly from the Sun. Hence, the air near the surface is warmer, and as we move higher, the distance from the heat source increases.
2. The density of air decreases with altitude, so the higher layers of air have fewer air molecules to absorb and retain heat. This reduces the capacity of the atmosphere to hold heat at greater heights.
3. Consequently, the temperature falls at an average rate of about 6.4°C per kilometer ascent (normal lapse rate) in the troposphere.

That’s why mountains and hill stations are cooler than the plains, and the temperature generally gets lower as we go higher in altitude within the troposphere.