UPSC Prelims 2023 Q64: Geography – Atmosphere & Climatology
- (a) Both Statement - I and Statement - II are correct and Statement - II is the correct explanation for Statement - I
- (b) Both Statement - I and Statement - II are correct and Statement - II is not the correct explanation for Statement - I
- (c) Statement - I is correct but Statement - II is incorrect
- (d) Statement - I is incorrect but Statement - II is correct
Answer: (d) Statement - I is incorrect but Statement - II is correct
Explanation
Land–sea temperature contrast and specific heat
| Property | Land | Water |
|---|---|---|
| Specific heat | Lower — heats and cools fast | Higher — heats and cools slowly |
| Heat spread | Only the top few centimetres heat up | Heat mixes down through many metres |
| Result | Larger temperature swings | Smaller temperature swings |
Statement II — correct. Water's specific heat is much higher than that of land.
Statement I — incorrect (as per the UPSC key). In the mid- and high-latitude Northern Hemisphere, the land–sea temperature contrast is sharper in winter. Continental interiors like Siberia fall to −40°C or lower, while nearby oceans stay much warmer. The January isotherm map bends far more over the continents than the July map.
| Season (Northern Hemisphere) | Land vs ocean |
|---|---|
| Winter (January) | Land far colder than ocean — largest contrast |
| Summer (July) | Land warmer than ocean, but the gap is smaller |
Answer: (d) Statement - I is incorrect but Statement - II is correct.
Why each option is right or wrong
- (a) Incorrect. Statement I is false as per the key; the contrast is greater in winter.
- (b) Incorrect. Both are not correct; Statement I does not hold.
- (c) Incorrect. It reverses the verdicts: Statement II is the true one.
- (d) CORRECT. Water has higher specific heat, but the land–sea contrast is sharper in winter, not summer.
Key point
Water has higher specific heat than land; in the Northern Hemisphere the land–sea contrast peaks in winter (cold continental interiors).
Remember
Water's specific heat is higher than land's, and the land–sea contrast is greater in winter.
Common mistakes
- Assuming the hottest season has the biggest contrast; frozen winter continents create the largest gap.
- Thinking land has higher specific heat because it feels hot in summer.
- Forgetting that isotherms bend most sharply in the January map.
Exam tip
Picture Siberia in January (−40°C) beside the North Atlantic (about +5°C). That gap beats any summer gap.
Sources
- NCERT Class XI — Fundamentals of Physical Geography, Ch 9 (Distribution of Temperature)
- G.C. Leong — Certificate Physical and Human Geography (Climate)