Indian Ocean Dipole: What is it, how it can limit El Nino effects

Source: The post is based on the article “Indian Ocean Dipole: What is it, how it can limit El Nino effects” published in Indian Express on 28th June 2023

What is the News?

The  El Nino phenomenon is likely to impact the Indian monsoon this year.

Therefore, high hopes are pinned on the development of a positive Indian Ocean Dipole (IOD) and its ability to counterbalance the El Nino effect.

What is El Nino?

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What is the Indian Ocean Dipole(IOD)?

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The IOD was identified as an independent system only in 1999.

A positive IOD event is often seen developing at times of an El Nino while a negative IOD is sometimes associated with La Nina.

During El Nino, the Pacific side of Indonesia is cooler than normal because of which the Indian Ocean side also gets cooler. That helps the development of a positive IOD.

What is the impact of the Indian Ocean Dipole(IOD)?

A positive IOD helps rainfall along the African coastline and also over the Indian sub-continent while suppressing rainfall over Indonesia, southeast Asia and Australia.The impacts are opposite during a negative IOD event.

Compared to El Nino Southern Oscillation(ENSO) events, the impacts of IODs are much weaker.

Can Positive Indian Ocean Dipole(IOD) offset the impact of El Nino this year?

Positive IOD does have the potential to offset the impacts of El Nino to a small measure in neighboring areas and it has at least once in the past (1997) delivered on this potential.

Currently, El Nino is already firmly established in the Pacific Ocean this year.But the IOD is still in the neutral phase.

All international climate models suggest a positive IOD event may develop in the coming months

The India Meteorological Department (IMD) had also said there was an 80% chance of a positive IOD in the coming months.

Hence, high hopes are pinned on the development of a positive Indian Ocean Dipole (IOD) and its ability to counterbalance the El Nino effect.