UPSC Prelims 2002 · General Studies
Question 12: Geography
For short-term climate prediction, which one of the following events, detected in the last decade, is associated with occasional weak monsoon rains in the Indian sub-continent?
AnswerThe answer is (c).
El Nino is the periodic warming of the eastern Pacific, linked with the Southern Oscillation, a see-saw of air pressure between the Pacific and the Indo-Australian region. Together, as ENSO, they are associated with weak monsoon rain in many years, so ENSO is watched in short-term (seasonal) monsoon forecasts. La Nina, the cool phase, generally goes with good rain.
Why each option is right or wrong
- (a) La Nina usually goes with a good monsoon, not a weak one.
- (b) Jet-stream shifts help time the monsoon onset, but the weak-rain link used in forecasting is ENSO.
- (c) Right: El Nino and the Southern Oscillation are linked with occasional weak monsoon rains.
- (d) Greenhouse warming works over decades, not as an occasional event for short-term prediction.
Explanation: written by UPSC Grade, not by UPSC.
Source: UPSC, Civil Services (Preliminary) Examination 2002, General Studies. UPSC's own paper isn't online; the words are from a published compilation. The paper on upsc.gov.in.