Previous Year Question

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?

Both Statement I and Statement II are correct and Statement II explains Statement I

Both Statement I and Statement II are correct but Statement II does not explain Statement I

Statement I is correct, but Statement II is not correct

Statement I is not correct, but Statement II is correct

Correct Answer: A

Detailed Solution

Isotherms are lines connecting places having equal temperatures. They generally run approximately parallel to latitudes, but bend because of the differential heating of land and oceans.
Water has a high specific heat capacity, and mixing and evaporation also occur in oceans. Therefore, oceans heat and cool more slowly than land. In January, Northern Hemisphere landmasses cool rapidly, while oceans remain relatively warmer.
Over cold landmasses, temperatures are lower than the normal temperature for the same latitude; therefore, isotherms bend equatorward. Over relatively warm oceans, they bend poleward.
Warm ocean currents such as the Gulf Stream and the North Atlantic Drift make this poleward bending more pronounced over the North Atlantic.
Therefore, both Statement I and Statement II are correct, and the temperature difference between oceans and landmasses explains this deviation of isotherms.

Continue practicing free PYQs with your JAGTIV account.