Vinson Kurian

Thiruvananthapuram, Jan. 24

THE cyclonic circulations over the Bay of Bengal during the just-concluded northeast monsoon could well have provided the best available indicator from this side of the equatorial Pacific of a La Nina brewing close.

The US-based International Research Centre for Climate and Society (IRI) and the National Oceanographic and Atmospheric Administration (NOAA) have already gone on record saying signs of a developing `weak' La Nina have emerged.

La Nina conditions develop when eastern and central equatorial Pacific (near the South American coast) cool down concurrently with a comparative warming of the equatorial western Pacific.

This is just the reverse of El Nino and is widely believed seen as aiding annual precipitation over Australia, India and Indonesia.

If the observed sea surface temperature (SST) anomalies persist beyond the month of March, a La Nina in the making will be officially confirmed. According to experts, the anomalies have been recorded right from November 2005.

The Indian link to evolving weather conditions over equatorial Pacific, though not comprehensively one-to-one in cause-effect relationship, was evident in the pattern of Bay-generated systems slamming down one after the other on the Tamil Nadu coast during the just-concluded season.

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, Dr Akhilesh Gupta of the National Centre for Medium Range Weather Forecasting (NCMRWF) said the 2005 season fell nicely into a list of those, which had preceded a La Nina year (expressed as `La Nina minus one').

(This article was published in the Business Line print edition dated January 25, 2006)
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