Indian Ocean Dipole turns positive, may prove too late for monsoon

Source: The post is based on the article “Indian Ocean Dipole turns positive, may prove too late for monsoon”  published in Hindu Business Line on 23rd August 2023.

What is the News?

A report by the Australian Bureau of Meteorology said that the Indian Ocean Dipole(IOD) index has risen beyond the positive threshold.

What is the Indian Ocean Dipole(IOD)?

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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.

How much rainfall has India recorded this year till now?

India has collectively recorded 824 mm precipitation since the start of the southwest monsoon period on June 1, suffering a 19% deficit compared to its rainfall average for the period so far (1016.1 mm).

Can positive IOD help the Indian Monsoon now?

Most models indicate that the positive IOD will likely take hold from September through November. But by this time, India’s southwest monsoon season would have tragically withdrawn from the subcontinent.

However, the northeast monsoon season that reigns over South India from October to December could receive a boost in the initial rains if the positive IOD continues to stick around during that time.

What will be the impact of Positive IOD on Australia?

In Australia, when a positive Indian Ocean Dipole (IOD) event occurs, it typically leads to: 1) Low rainfall from October to December 2) A delayed start to the monsoon season and 3) Reduced tropical cyclone activity.

If an El Niño event were to also happen in 2023 alongside a positive IOD, these effects could become even more severe and potentially extend into the wet season.