Chances of good Indian monsoon improve as the dreaded El Niño enters its final weeks

The dreaded 2015–16 El Niño is in its last stages, the Australia Bureau of Meteorology, adding that there was a good chance that its alter ego La Nina will starting forming later this year.

Recent changes in the tropical Pacific Ocean and atmosphere, combined with current climate model outlooks, suggest the likelihood of La Niña forming later in 2016 is around 50 percent, meaning the Bureau is now on La Niña watch.

The agency said that the eastern tropical Pacific sea surface temperatures have cooled significantly in the past fortnight, and are now approaching neutral levels.

“As temperatures under the surface are below average, more surface water cooling is expected. However, the atmosphere is only slowly responding to these changes, and hence the Southern Oscillation Index (SOI) and cloudiness near the Date Line continue to fluctuate around El Niño thresholds,” it said in its latest report.

Six of eight international climate models suggest the tropical Pacific Ocean will return to neutral levels within the next month. By September, seven of eight models suggest La Niña thresholds are likely. However, individual model outlooks show a large spread between neutral and La Niña scenarios, it added.

La Nina is generally know to trigger a good Indian monsoon, though with exceptions, but overall build-up in India towards May/June as evidenced in the sustained heating of the land suggests that the ground is being prepared for a good monsoon this year, the BusinessLine newspaper reported.

While large parts of India are battling with heat and drought conditions, the high temperatures during summer months play a positive role in creating the right conditions for a good monsoon.

The extent to which the plains heat up determines how far the atmospheric pressure can climb down over North India, setting up an ideal gradient from the South-West (around Kerala). The moisture-laden monsoon winds ride this pressure gradient to blow in with full force into the land and drain down its moisture in the form of heavy rain, BusinessLine said.

 

 

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