The official Australian forecaster has reiterated that ‘El Nino’ conditions cannot be wished away in the east equatorial Pacific.

El Nino refers to the warming of tropical east Pacific relative to the west and has been associated with some of the worst Indian drought years, including 2009.

DIRECT LINK

But there is still no direct one-to-one relationship to comprehensively establish this fact. For instance, El Nino year of 1997 had brought a normal monsoon to India.

The Australian Bureau of Meteorology (BoM) said in an update on Tuesday that the past fortnight has seen climate indicators ease slightly, showing values near the threshold for an El Nino event.

But such short-term fluctuations are common and to be expected, and indicators still clearly remain near El Nino thresholds, the BoM added.

The Tokyo-based Regional Institute for Global Change (RIGC) too had suggested that El Nino may not pose a major threat to Indian monsoon this year.

IOD FEARS

What will is a sea-based phenomenon within India’s neighbourhood, called the Indian Ocean Dipole (IOD).

The IOD results from the seesawing of temperatures in the Indian Ocean, and nearly mimics the El Nino-La Nina processes in the tropical Pacific.

Warming of the west of Indian Ocean sets up a positive phase of the IOD, which is beneficial to the Indian monsoon.

When it shifts to the east, it results in the negative IOD, which suppresses rainfall over mainland India.

The RIGC expects a negative IOD to emerge in the Indian Ocean in August-September.

vinson.kurian@thehindu.co.in

(This article was published on July 17, 2012)
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