With reference to the Indian Ocean Dipole (IOD) and El Nino, consider the following statements:

While the El Nino causes the warming of the surface of Pacific Ocean, IOD causes warming of the Indian Ocean

While the El Nino always brings deficient rainfall in India, IOD always brings more rains in India

Which among the above statements is / are correct?

Question

While the El Nino causes the warming of the surface of Pacific Ocean, IOD causes warming of the Indian Ocean: This statement is incorrect. IOD does not cause a warming of the entire Indian Ocean. Instead, it leads to anomalous cooling of sea surface in the tropical eastern Indian Ocean and anomalous warming in the tropical western part.
While the El Nino always brings deficient rainfall in India, IOD always brings more rains in India: This statement is also incorrect. El Niño does often (but not always) cause droughts and rainfall deficiency in India. But a positive IOD doesn\'t necessarily mean excess Indian rainfall. A positive IOD increases this probability but doesn\'t guarantee it.

GKToday Admin · Accepted Answer

Neither 1 nor 2

While the El Nino causes the warming of the surface of Pacific Ocean, IOD causes warming of the Indian Ocean: This statement is incorrect. IOD does not cause a warming of the entire Indian Ocean. Instead, it leads to anomalous cooling of sea surface in the tropical eastern Indian Ocean and anomalous warming in the tropical western part.
While the El Nino always brings deficient rainfall in India, IOD always brings more rains in India: This statement is also incorrect. El Niño does often (but not always) cause droughts and rainfall deficiency in India. But a positive IOD doesn\'t necessarily mean excess Indian rainfall. A positive IOD increases this probability but doesn\'t guarantee it.

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