The Indian Meteorological Department has predicted a normal rainfall for the country this year.
For the first time the IMD has based its forecasts on a newly developed operational model to forecast the weather.
In a chat with Deputy Managing Editor George Iype, IMD Director General Dr S K Srivastava, explains how Indian weathermen predict the vagaries of nature.
You have predicted that there will be ac near normal monsoon across the country this year. Is there any possibility of errors in this prediction?
The monsoon this year across the country will be absolutely normal. It will hit the Kerala coast in the first week of June. We will forecast the exact date of the monsoon's arrival next month. As per our current calculations, the rainfall for the country is likely to be 100 percent of the long period average. We have also calculated that there could occur a plus or minus five per cent error in the monsoon.
You have used a new weather forecast model this time. What is the new model?
Our new long-range forecast model is statistical in nature. In fact, the co-relation between monsoon rainfall and the predictors can never be perfect. So we have developed eight parameters for the weather forecast. They are Arabian Sea index, Eurasian snow cover, the North West Europe temperature, the El Nino anomaly, South Indian Ocean index, East Asia pressure and Europe pressure gradient.
But often in the past, your predictions have gone haywire as the monsoon failed.
The monsoon is part of the changing global system. Most of our predictions over the years have been upto the mark, though there have been minor variations. For instance, 2002 turned to be a particularly severe drought year, and the entire monsoon season had many intriguing features then. That situation could not be foreseen by any of our operational statistical or dynamical model.
Does the new model make the weather forecasting error-free?
We always forecast the rainfall by giving plus or minus error percentage. But the new model of weather forecast gives us a higher resolution in time and space. For a country like India with a complex regional-scale interactions and manifestations of regional rainfall variability, the new forecast system is the perfect model.
Are you confident that this year's rainfall will be as per your forecast?
Yes. We expect this year's monsoon to be perfectly based on what we have predicted. In 2003, the Southwest monsoon season rainfall was as per our exact prediction. In fact, the good distribution of the rainfall last year coming after four years was a boon for the country's economy. Also at present, our El Nino predictions suggest near neutral conditions during the Southwest monsoon season; that is July to September.
What is the rainfall considered normal for India?
88 centimetres of rainfall is considered normal for the country.
Did you require the Election Commission's permission to announce the weather forecasts?
No. We don't come under the Election Commission's preview.
Does politics play any role in announcing the monsoon forecasts?
Our monsoon forecast has nothing to do with elections or politics. It has everything to do with science only. We forecast the monsoon irrespective of whether there is election or not in the country. Last year, we announced it on April 16. This year, we announced it on April 15.
Image: Uday Kuckian