UPSC Prelims 2007 Q89: Geography – Atmosphere & Climatology
Consider the following statements:
1. The annual range of temperature is greater in the Pacific Ocean than in the Atlantic Ocean.
2. The annual range of temperature is greater in the Northern Hemisphere than in the Southern
Hemisphere.
Which of the statements given above is/are correct?
- (a) 1 only
- (b) 2 only
- (c) Both 1 and 2
- (d) Neither 1 nor 2
Answer: (b) 2 only
Explanation
Annual range of temperature — land vs water
Rule: Land heats and cools fast; water heats and cools slowly.
So more land → bigger annual range of temperature.
| Statement | Reasoning | Verdict |
|---|---|---|
| 1. Annual range is greater in the Pacific than in the Atlantic | The Pacific is much larger and wider, so it is less affected by surrounding land. The narrower Atlantic is more influenced by the continents on both sides. | FALSE |
| 2. Annual range is greater in the Northern Hemisphere | The NH has about 39% land; the SH only about 19% | TRUE |
Answer: (b) 2 only.
Why each option is right or wrong
- (a) Incorrect. Statement 1 is false — the vast Pacific has the smaller range.
- (b) CORRECT. Only Statement 2 is true — more land in the Northern Hemisphere gives a larger range.
- (c) Incorrect. Statement 1 is false.
- (d) Incorrect. Statement 2 is true.
Key point
More land → larger annual temperature range. NH (more land) > SH. Atlantic (narrow, land-hemmed) > Pacific.
Remember
Northern Hemisphere has the larger annual temperature range because it has more land.
Common mistakes
- Thinking a bigger ocean means more variation — a bigger ocean stabilises temperature.
- Forgetting the land-water ratio of the two hemispheres.
- Mixing up diurnal range (daily) and annual range (yearly).
Exam tip
Water = thermal buffer. Where water dominates (SH, Pacific), the range is small. Where land dominates (NH, interiors like Siberia), the range is large.
Sources
- NCERT Class XI — Fundamentals of Physical Geography, Ch 9 (Solar Radiation, Heat Balance and Temperature)
- NCERT Class XI — Ch 13 (Water: Oceans)