By Seema Singh
The Times of India News Service (April 25, 2000)
BANGALORE: It seems the country's run of luck with good monsoons is over. After 12 consecutive good monsoons, the country is poised for a deficit south-west monsoon this year which can play havoc with the food security. According to the Centre for Mathematical Modelling and Computer Simulation (C-MMACS) here, which has been making accurate, long-range forecasts for the summer monsoon during the last four years, this year will have deficit rainfall in the entire country. The prediction is 789 mm of rain this year against the actual 840 mm last year.
The India Meteorology Department (IMD) discloses the annual forecast for the summer monsoon only in the last week of May based on a 16-parameter model. C-MMACS has been predicting rainfall based on a neural network model which it calls experimental as it is not authorised by the Union government. The neural network makes use of a processing device, either an algorithm or actual hardware, whose design is inspired by the design and functioning of animal brains and components thereof. Like the brain, the neural network consists of a large number of simple processors that are densely interconnected. A quick look at the C-MMACS' predictions in the past: the forecast for 1998 was 945 mm and the actual rainfall was 932.5 mm (IMD had predicted only 871 mm); in 1999 the C-MMACS forecast was 861 mm with a standard deviation of 43 mm and the actual recorded was 840 mm, much within the error zone.
Says the research scientist at C-MMACS, Prashant Goswami: ``Such long range forecasts can have a tremendous impact on areas like agricultural planning. In fact, even a moderate success in the all-India monthly rainfall forecast can help farmers as well as the agriculture departments. For instance, the monthly forecast for this year is seen to peak in July and August.'' The low value for the summer monsoon is due to significant deficit in the monthly forecast for September.
These features have practical and significant implications for issues like crop choice, irrigation planning and sowing schedule, he adds. However, the pre-monsoon rainfall beginning March 1 was better in 23 of the 35 meteorological sub-divisions than in the corresponding period last year. The forecast of a deficit monsoon no doubt casts a shadow in the drought-prone areas, especially with semi-arid states like Rajasthan and Gujarat and parts of Andhra Pradesh already reeling under severe heat and water-scarcity. For the dry districts of Ka rnataka like Gulbarga, Bijapur, Raichur, Bellary and Chitradurga, meteorologists predict it's going to be a hard summer.