UPSC Prelims 2020 · Question 59 of 100
UPSC Prelims 2020 question on Jet Streams Cyclones
- ExamUPSC CSE
- Year2020
- PaperGeneral Studies Paper I
- SubjectGeography
- TopicClimatology
- DifficultyMedium
- TypeStatement
Consider the following statements:
1. Jet streams occur in the Northern Hemisphere only.
2. Only some cyclones develop an eye.
3. The temperature inside the eye of a cyclone is nearly 10°C lesser than that of the surroundings.
Which of the statements given above is/are correct?
Show answer
Answer: C. 2 only
Verdict
Correct statement: 2 only → Option (c).
Statement by statement
Statement 1 – INCORRECT: Jet streams occur in both the Northern and Southern Hemispheres. The actual appearance of jet streams result from the complex interaction between many variables — such as the location of high and low pressure systems, warm and cold air, and seasonal changes. Hence statement 1 is not correct.
Statement 2 – CORRECT: The hurricane's center is a relatively calm, generally clear area of sinking air and light winds that usually do not exceed 15 mph (24 km/h) and is typically 20-40 miles (32-64 km) across. An eye will usually develop when the maximum sustained wind speeds go above 74 mph (119 km/h) and is the calmest part of the storm. Only some cyclones (those of sufficient intensity) develop an eye. Hence statement 2 is correct.
Statement 3 – INCORRECT: The eye is the region of lowest surface pressure and warmest temperatures aloft — the eye temperature may be 10°C warmer or more at an altitude of 12 km than the surrounding environment, but only 0-2°C warmer at the surface in the tropical cyclone. The temperature inside the eye is WARMER than the surroundings, not 10°C lesser. Hence statement 3 is not correct.