Date:21/04/2005 URL: http://www.thehindubusinessline.com/2005/04/21/stories/2005042102640100.htm

Back Met dept predicts `normal' monsoon

Our Bureau

New Delhi , April 20

THE India Meteorological Department (IMD) has predicted yet another `normal' monsoon this year.

According to its operational Long Range Forecast released here on Wednesday, rainfall for the country as a whole during the 2005 South-West monsoon (June-September) would be "98 per cent of the long period average (LPA) with a model error of plus or minus 5 per cent."

The Union Minister of State for Science and Technology, Mr Kapil Sibal, told newspersons here today, "Our probabilistic model suggests a very high (75 per cent) probability of the monsoon being near normal and above."

He said that the IMD would release an LRF `update' by end-June, which will also provide rainfall forecasts for the country's four broad homogenous regions as well as for the agriculturally crucial month of July.

The prediction of rainfall being 98 per cent of the LPA (the area-weighted average rainfall received by the country during the four-month monsoon period since 1941, which is 893.3 millimetres) is based on an eight-parameter power regression and parametric model employed by the IMD since 2003.

"Two out of the eight parameters — Eurasian Snow Cover (December) and 50 hPa Wind Pattern (January-February) — have been found to be unfavourable this year. The other six — Arabian Sea Surface Temperature or SST (January-February), North-West Europe Temperature (January), Nino 3 SST Anomaly for Previous Year (July-September), South Indian Ocean SST Index (March), East Asian Pressure (February-March) and European Pressure Gradient (January) — are favourable," said Dr M. Rajeevan, Director of the Pune-based Indian Institute of Tropical Meteorology.

A clearer picture, he added, would emerge by end-June, when data would be available for two additional parameters, namely South Indian Ocean Zonal Wind (June) and Nino 3.4 SST Tendency, better known as the `El Nino' factor.

"Last year, there was a sharp rise in sea surface temperatures in the equatorial Pacific region from July right up to December. But since then, there has been substantial cooling, suggesting a transition to neutral conditions," Dr Rajeevan said.

According to him, most statistical models, including those of international forecasting agencies, indicate that the transition from El Nino to `ENSO-neutral' conditions will continue during the next three months. It is the likelihood of ENSO-neutral conditions prevailing during the monsoon season that seems to be the basis for the IMD's optimistic prognosis for this year.

The IMD's forecast had gone widely off the mark during 2004. As against the predicted `100 per cent normal' monsoon, the country ended up with a 13 per cent deficient monsoon. The country as a whole recorded an average precipitation of 781.2 mm, compared to the LPA of 781.2 mm.