Vinson Kurian

Thiruvananthapuram , June 16

THERE is little sign of a classical El Nino episode unfolding during the year, according to the Australian Bureau of Meteorology that tracks the Pacific Ocean phenomenon on a regular basis.

In its update, the bureau said despite observations at mid-June suggesting some indicators to the contrary, the risk of an El Nino event was going to be `substantially reduced' .

This only confirms similar predictions made earlier by India Meteorological Department (IMD) as well as other international computer models, including the International Research Institute for Climate Prediction (IRI) at the University of Columbia.

Though no one-to-one correlation has been established, El Nino has been known to hold `nuisance value' for the prevailing Indian monsoon. Ruling out an El Nino episode would, in effect, help meteorologists tracking the monsoon strike off a probable irritant.

For instance, 1982 and 1987 were El Nino years, which led to deficient rainfall in India. Similarly, 1983 and 1988 were La Nina (cooling episode) years, causing excessive rainfall and floods. But in 1997, the severest El Nino year of the 20th century, the monsoon was better than usual, with 102 per cent recorded rainfall. From 2002, El Nino's effects have been weak or moderate.

However, the Australian Bureau warned that low values of the Southern Oscillation Index (SOI - value of mean sea level pressure differential between Darwin and Tahiti), coupled with the continuation of warmer than normal surface waters in the Central Equatorial Pacific Ocean, still have to be contended with.

History has shown that while these conditions continue, there is potential for El Nino to be triggered any time up to June-end, after which that probability becomes increasingly less likely. Sustained negative values of the SOI often indicate El Nino episodes.

Dr P. V. Joseph, a meteorologist and former director with the IMD, had earlier told Business Line that a `warming anomaly' in the Central Equatorial Pacific had been persisting for the past several months. But this was unlikely to result in El Nino conditions.

He had quoted from the observations made by the National Oceanic and Atmospheric Administration (NOAA) of the US that the warming anomaly was likely to die down by September/October when El Nino conditions were known to peak.

This has been the consensus of the majority of climate scientists watching the El Nino phenomenon.

What seemed to have set off alarm bells was the unexpected warming of the Pacific Ocean in February this year, reducing the SOI to a 22-year low. A similar change eight years ago had developed into an intense El Nino that caused droughts in Asia, floods in South America and tornadoes in the US.

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