Japanese scientists now say that threat to monsoon in India may not come from an El Nino in the equatorial Pacific but from the seas in its own backyard.
The Tokyo-based Regional Institute for Global Change (RIGC) is concerned more about a building negative Indian Ocean Dipole (IOD) event.
“We are afraid that warmer and drier than normal conditions will continue in India owing to the negative IOD,” Mr Wataru Sasaki of RIGC, informed Business Line.
Australia and Brazil will be relatively colder and wetter than normal during the southern hemisphere spring, he said.
On El Nino, the RIGC said that the warm sea surface temperature anomaly near the eastern boundary of the Pacific may disappear towards the end of the monsoon.
The ‘neutral’ state (neither El Nino nor La Nina) will return to the east Pacific basin, and may continue until March-April next.
MINIATURE VERSION
The IOD is a miniature version of the El Nino-La Nina phenomenon being enacted in the Indian Ocean from time to time.
It has negative and positive phases. In the negative phase, as in the instant case, the sea surface warms up to the east of the ocean basin relative to the west.
This causes convection and precipitation to be confined to the East Indian Ocean, robbing mainland India of its share and affecting rainfall.
During a positive IOD phase, exactly the reverse happens; but a warmer West Indian Ocean has been found to fuel a concurrent Indian monsoon.
DIRECT IMPACT
The IOD event has a more direct and immediate impact on the monsoon than the El Nino-La Nina event.
The emerging negative IOD is forecast to bring less rain for northeast China, Korea, and Japan during the ensuing season.
In other forecasts, the RIGC said that most parts of the globe except Canada, Alaska, and Australia will experience warmer-than-normal season ahead.
The winter will be colder-than-normal for most parts of the Eurasian continent.