UPSC Prelims 2017·GS1·geography·climatology

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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  1. A1 only
  2. B2 onlyCorrect
  3. CBoth 1 and 2
  4. DNeither 1 nor 2

Explanation

Statement 1 is incorrect. The Indian Ocean Dipole (IOD) is characterized by a difference in sea surface temperature between the tropical Western Indian Ocean (Arabian Sea region) and the tropical Eastern Indian Ocean (south of Indonesia). It does not involve the Eastern Pacific Ocean — that would be ENSO/El Nino. Statement 2 is correct. IOD events can influence the amount and timing of rainfall received by India, particularly during the monsoon season. A positive IOD generally enhances Indian monsoon rainfall. Therefore, only statement 2 is correct.
geography: With reference to 'Indian Ocean Dipole (IOD)' sometimes mentioned in the news while forecasting Indian monsoon, which of

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