- The IOD phenomenon is characterised by a difference in sea surface temperature between tropical Western Indian Ocean and tropical Eastern Pacific Ocean.
- An IOD phenomenon can influence an El Nino’s impact on the monsoon.
Select the correct answer using the code given below:
(a) 1 only
(b) 2 only
(c) Both 1 and 2
(d) Neither 1 nor 2
Answer: (b)
Statement 1 is not correct:
The Indian Ocean Dipole (IOD) is the Indian Ocean counterpart of the Pacific El Niño and La Niña. The term dipole means two “poles” or two areas of differences. The IOD measures differences in SSTs between the Arabian Sea (western pole) and the eastern Indian Ocean south of Indonesia (eastern pole).
Statement 2 is correct: About 50% per cent of the IOD events in the past 100 years have co-occurred with El Nino Southern Oscillation (ENSO) and the other half independently. El Nino and negative or neutral IOD in the Indian Ocean, the chances of a bad monsoon are very high. During the positive IOD phase, India experiences anomalously high rainfall along the latitude belts covering Central India, and during the negative phase of the IOD, the rainfall is anomalously high along the longitudinal belt, with the western part of the country receiving high rainfall. Positive IOD events are often associated with El Niño and negative events with La Niña.