UPSC Prelim 2025 Paper I

Consider the following statements : Statement I: In January, in the Northern Hemisphere, the isotherms bend equatorward while crossing the landmasses, and poleward while crossing the oceans. Statement II: In January, the air over the oceans is warmer than that over the landmasses in the Northern Hemisphere. Which one of the following is correct in respect of the above statements?

Verified Answer
A. Both Statement I and Statement II are correct and Statement II explains Statement I
B. Both Statement I and Statement II are correct but Statement II does not explain Statement I
C. Statement I is correct but Statement II is not correct
D. Statement I is not correct but Statement II is correct

Explanation:

Both statements are correct. In the Northern Hemisphere winter (January), land cools down much faster and to a greater extent than oceans, making the air over oceans warmer than over land (Statement II). This temperature difference causes isotherms (lines of equal temperature) to bend equatorward over the colder landmasses and poleward over the relatively warmer oceans (Statement I). Therefore, Statement II explains Statement I.