With reference to ‘Indian Ocean Dipole (IOD)’ sometimes mentioned in the news while forecasting Indian monsoon, which of the following statements is/are correct ?
- 1.IOD phenomenon is characterised by a difference in sea surface temperature between tropical Western Indian Ocean and tropical Eastern Pacific Ocean.
- 2.An IOD phenomenon can influence an El Nino’s impact on the monsoon.
Select the correct answer using the code given below :
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Answer: B. Statement 1 is wrong: the IOD is the difference in sea surface temperature between the western Indian Ocean (near Africa) and the eastern Indian Ocean (near Indonesia). The Pacific is not involved. Statement 2 is correct: a positive IOD can weaken the drying effect of an El Nino on the Indian monsoon, as in 1997. So 2 only.
Watch for: The word 'Pacific' slips in from El Nino; the IOD is an Indian Ocean pattern only.
Why the other options are wrong
- A. Wrong because the IOD compares the western and eastern Indian Ocean, not the Pacific.
- C. Wrong because statement 1 is false.
- D. Wrong because statement 2 is true.
Source to check: India Meteorological Department and Bureau of Meteorology (Australia) pages on the Indian Ocean Dipole
Answer from the official UPSC key. Written and fact-checked by AI against the official key. Spotted a mistake? Report it.