Consider the following statements : Statement-I Thickness of the troposphere at the equator is much greater as compared to poles. Statement-II : At the equator, heat is transported to great heights by strong convectional currents. Which one of the following is correct in respect of the above statements ?

1. A. Bothe Statement-I and Statement-II are correct and Statement- II explains Statement-I
2. B. Both Statement-I and Statement-II are correct, but Statement-II does not explain Statement-I
3. C. Statement-I is correct, but Statement-II is incorrect
4. D. Statement-I is incorrect, but Statement-II is correct

Answer: A

Explanation

Both Statement-I and Statement-II are correct, and Statement-II explains Statement-I. The troposphere, the lowest layer of the atmosphere, is indeed thicker at the equator (around 18 km) compared to the poles (around 8 km). This variation in thickness is directly attributable to the intense heating at the equator. The high solar insolation at the equator leads to strong convectional currents, which lift warm air to greater heights. This upward movement of air effectively pushes the tropopause (the boundary between the troposphere and stratosphere) higher, resulting in a thicker troposphere. This is a fundamental concept in climatology and atmospheric science, relevant for the UPSC Geography syllabus.