The Hindu Business Line : El Nino will not affect monsoons, say meteorologists

Reasons for confidence
El Nino would be too late to affect the southwest monsoon while being on time to aid the impending northeast monsoon
Further, El Nino will die out by the time the 2007 southwest monsoon gets going

Thiruvananthapuram , Sept. 15

India may have had a history of monsoons withering in the face of an El Nino, but signals of a preparatory warming of the equatorial Pacific in recent times do not seem to have bothered meteorologists much.

In fact, the sheer timing of this climatological event this year is considered beneficial for the country either way - too late to impact the ongoing southwest monsoon while being just-in-time, and to the benefit of, the impending northeast (or winter) monsoon.

Forward cover

Dr Akhilesh Gupta of the Department of Science and Technology said that a `forward cover' was also available in that the effect of the El Nino event would have died out by the time the 2007 southwest monsoon got going.

He said the situation was favourable for the northeast monsoon and the precipitation would be more than normal in the southern peninsula. This would result from the predominantly westward movement of tropical disturbances towards the Tamil Nadu/Andhra Pradesh coast.

Late in coming

It may be recalled that the US National Oceanographic and Atmospheric Administration (NOAA) had come out with its EL Nino outlook a few days back.

Compared to 2002 and 2004 (moderate El Nino years), the emergence of El Nino condition this year (in September) is somewhat late in the season, said Dr Gupta. During both these two preceding years, the warming trend had started as early as in Feb-Mar-April (2002) and in Mar-April-May (2004).

"But we need to watch at least two to three successive quarters (Sept-Oct-Nov; Oct-Nov-Dec; and Nov-Dec-Jan) of a persisting warming trend to confirm the emergence of El Nino conditions," he said.

Magnitude crucial

Another crucial aspect to monitor is the magnitude of the observed trend, which is much less compared to the typical El Nino years. But the `peaking' would need to be closely watched. Writing to Business Line, Mr Tony Barnston of Colombia University said that the outlook on the probability for El Nino had increased in the last few weeks due to the actual observed developments. Mr Barnston is Director, Forecast Operations, Climate, Prediction and Dynamics with the university's International Research Institute for Climate and Society.

More rains

"Our September climate forecasts will be issued next Thursday (September 21). The model runs are now coming in, and it looks like we will show a slight enhancement of the probability for above normal rainfall in Sri Lanka and the southern Indian peninsula for Oct-Nov-Dec and Nov-Dec-Jan.

"This could come as `normal' rain shower systems or as tropical cyclones. We cannot distinguish which will dominate, and do not know if the number of cyclones will be increased."

Mr Barnston said he did not yet know what probability the IRI would assign for the region getting above normal precipitation. "But 40 to 45 per cent (instead of the neutral 33) seems most likely.

"With at least weak (and possible moderate) El Nino conditions likely, we think the Bay of Bengal will indeed warm further by mid-October. The northern-most part, however, may not warm appreciably", he added.

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