UPSC Previous Year Question | Prelims GS | 2017

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:

  1. 1 only
  2. 2 only
  3. Both 1 and 2
  4. Neither 1 nor 2

Answer

Correct Answer

2 only

Explanation

IOD is defined by a sea surface temperature difference between the tropical Western Indian Ocean and the tropical Eastern Indian Ocean (not the Eastern Pacific Ocean), so statement 1 is wrong. A positive IOD can offset/moderate an El Nino's adverse impact on the Indian monsoon, making statement 2 correct.

Topics: climatology and monsoon dynamics, geography, indian ocean dipole, iod definition and effect on monsoon