Comments
The El Nino event generated by the warming of the tropical Pacific Ocean has not still got the desired response from the atmosphere to make it the ‘feared wholesome’ for the Indian monsoon.
A general lack of atmospheric response over last month has resulted in some cooling of the tropical Pacific and averted a full-fledged El Nino just yet, the Australian Bureau Meteorology said.
NO All-CLEAR YET
Now, will this trend hold to give the grudging all-clear for the Indian monsoon?
No, not yet, the Bureau appeared to warn. This is because of likely adverse weather signals arising from India’s own backyard.
The agency is referring to a tendency for a negative phase of the Indian Ocean Dipole event to develop in the Indian Ocean, something that even other models have been referring to over the past month or so.
The Indian Ocean Dipole or IOD in short mimics the El Nino-La Nina events of the tropical Pacific in the Indian Ocean to trigger associated impact for a concurrent Indian response.
CHANGES TRIGGERED
Changes are occurring in the Indian Ocean, the Australian agency noted. The Indian Ocean Dipole (IOD) index has been below -0.4 deg Celsius (the negative IOD threshold) since mid-June.
But this would need to remain negative into August to be considered as an event. Negative values are rare when the central Pacific is warmer than normal. Which now explains why the monsoon has suffered thus far during the monsoon - a rare negative IOD tending to coincide with a warming phase in the tropical Pacific.
A negative phase of the IOD, of the type which is apparently being triggered, results from the anomalous warming of the East Indian Ocean relative to the west.
This causes monsoon flows from below the Equator to stop short and rain down over the vast ocean far to the south and southeast, with only residual moisture allowed to proceed into the Bay of Bengal.
In the positive phase of the IOD, the exact reverse is enacted, in which the west of the Indian Ocean adjoining south Arabian Sea warms boosting monsoon flows into mainland India.
The Australian Bureau noted that the warming of the tropical Pacific Ocean over the past several months had primed the climate system for an El Nino in 2014.
While the majority of climate models suggest an El Nino remains likely for the spring of 2014, most have eased their predicted strength.
If an El Nino were to occur, it is increasingly unlikely to be a strong event, the Bureau said.
Comments
COMMENT NOW
Comments
Comments have to be in English, and in full sentences. They cannot be abusive or personal. Please abide by our community guidelines for posting your comments.
We have migrated to a new commenting platform. If you are already a registered user of TheHindu Businessline and logged in, you may continue to engage with our articles. If you do not have an account please register and login to post comments. Users can access their older comments by logging into their accounts on Vuukle.