Given the impact of climate change, the India Meteorological Depar-tment (IMD) is set to revise the arrival and withdrawal dates of the monsoon. Although the IMD has been recording the monsoon from 1886, scientists believe there has been a shift in monsoon activity in the last six decades and this needs to be incorporated into the forecasts.
IMD experts believe there has been a delay in the arrival and withdrawal of the monsoon by over a week to ten days. The maximum deviation has been noted in the Andaman and Nicobar Islands with the rain arriving often a week later than usual.
Dr Ajit Tyagi, director general of IMD, along with deputy director general S.D. Attri, have been following this phenomena closely and have prepared a report on this trend. Assisted by complicated statistical models and aided by super computers and satellite data to predict weather patterns, experts believe they are in a better position to provide more accurate forecasting.
Dr. Tyagi points out, “Earlier forecasting data was up to 1950. Need to incorporate recent data to look at monsoon onsets and withdrawals during the last five decades.”
But international weather forecasters following IMD predictions have warned that the weather office has managed to correctly forecast the monsoon outcome from 1994 only five times and has gone wrong on many occasions.
Heads of other IMD branches believe the dates need to be updated. They are presently in the process of collecting onset and withdrawal monsoon dates from across the country. This they believe will help them provide them with more accurate leads.
Shailesh Nayak, secretary, ministry of earth sciences, under which the India Meteorological Depar-tment falls, admits a need to “augment the capabilities to forecast monsoon more accurately.”
Mr Tyagi himself has been in the forefront of admitting that there is a need to bring in uncertainties of monsoon forecast to forefront to better understand complexities of weather prediction.
The revision of dates will immediately impact the farm sector. But more important, as agricultural expert Devender Sharma points out, “Already, delayed rainfall has made farmers delay sowing. A further delay, will see them postpone paddy sowing and transplanting even further.”