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?
- ABoth Statement-I and Statement-II are correct and Statement-II explains Statement-ICorrect
- BBoth Statement-I and Statement-II are correct, but Statement-II does not explain Statement-I
- CStatement-I is correct, but Statement-II is incorrect
- DStatement-I is incorrect, but Statement-II is correct
Explanation
Statement-I is correct. The thickness of the troposphere, the lowest layer of Earth's atmosphere where most weather phenomena occur, varies with latitude. It is thickest at the equator (around 18 km) and thinnest at the poles (around 8-9 km). This variation is primarily due to the intense heating at the equator, which causes air to expand and rise.
Statement-II is correct. At the equator, there is significant solar insolation, leading to high temperatures. This intense heating causes the air to become less dense and rise rapidly through strong convectional currents. These rising air currents carry heat to greater heights, pushing the tropopause (the boundary between the troposphere and stratosphere) higher up. Conversely, at the poles, the air is cold and dense, leading to subsidence and a lower tropopause. This direct relationship means Statement-II correctly explains Statement-I.
Therefore, both statements are correct, and Statement-II explains Statement-I.
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