UPSC Prelims 2025 · Question 47 of 100
UPSC Prelims 2025 question on January Isotherms Bending
- ExamUPSC CSE
- Year2025
- PaperGeneral Studies Paper I
- SubjectGeography
- TopicClimatology
- DifficultyMedium
- TypeAssertion
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?
Show answer
Answer: A. Both Statement I and Statement II are correct and Statement II explains Statement I
Verdict
Both Statements I and II are correct and Statement II explains Statement I → Option (a).
Analysis
Statement II explains Statement I because the warmer ocean air (Statement II) is the reason isotherms bend poleward over oceans and equatorward over colder landmasses (Statement I).
Statement by statement
Statement I – CORRECT: In general, the effect of latitude on temperature is well pronounced on the map, as the isotherms are generally parallel to the latitude. The deviation from this general trend is more pronounced in January in the Northern Hemisphere. In January, the isotherms deviate to the north over the ocean and to the south over the continent — meaning they bend equatorward while crossing the landmasses, and poleward while crossing the oceans. Hence Statement I is correct.
Statement II – CORRECT: In January, the air over the oceans is warmer than that over the landmasses in the Northern Hemisphere. The presence of warm ocean currents, Gulf Stream and North Atlantic drift, make the Northern Atlantic Ocean warmer and the isotherms bend towards the north. Over the land the temperature decreases sharply and the isotherms bend towards south in Europe. Hence Statement II is correct.