Tuesday, November 12, 2019

Posted at: Jul 21, 2019, 8:58 PM; last updated: Jul 21, 2019, 8:58 PM (IST)

Changes in decades-old monsoon schedule on cards

Changes in decades-old monsoon schedule on cards
Motorcyclists stop at a place during heavy monsoon rain, in New Delhi, July 21, 2019. PTI

Vibha Sharma
Tribune News Service
New Delhi, July 17

With variations in the pattern of its most-awaited weather phenomenon—Southwest Monsoon—becoming increasingly visible year after year, India too appears to be preparing to reset the schedule it has been following since 1941. 

A committee looking into the issue is finalising the report and changes in the four-month June to September season may be effected as soon as next year, Ministry of Earth Science Secretary M Rajeevan recently said.

Head of the IMD’s long-range weather forecast division in Pune, DS Pai, also told The Tribune that changes need to be made in the official schedule India has been following for many years keeping in mind changed monsoon pattern.

The season is key not just to the agriculture sector but the country’s entire economy. But significant changes are being seen in the pattern of monsoon in the past 10 years or so. This year, for example, though its official arrival date was June 1, it hit the Indian mainland in Kerala on June 8.

Weak and tardy in the initial days, its further progress was slowed down by development of cyclones in the Bay of Bengal and Arabian Sea, further causing delay in the sowing of kharif crops across the country. It is not just the onset and withdrawal dates, quantity and distribution of rains have also seen variations in the past few years.

The IMD also admits that while between 1988 and 2008 its forecasts were “qualitatively correct in 19 years” (90% accuracy), errors started creeping in later years. In some years (1994, 1997, 1999, 2002, 2004 and 2007) the forecast error (difference between actual rainfall and forecast rainfall) was more than 10%, it says. “It is not possible to have 100% success for forecasts based on statistical models. The problems with statistical models are inherent in this approach and are being faced by forecaster worldwide,” it adds.

There have been suggestions from experts that India should re-orient the schedule as changes in rainfall pattern not just upsets kharif but also the rabi season.

With more than 60 per cent of India’s agricultural lands being dependent on seasonal rains, it is a cause for worry, they say. Though as per ICAR Director General Tirlochan Mohapatra, India has planned adequately to deal with changes in the season. “We have plans in place, in case monsoon is delayed how to delay planting and sowing. This is how we have been able to get higher yields and not very significant negative impacts in production have been seen,” he says.

The IMD issues operational long range forecast for the monsoon in two stages. The first stage forecast is issued in mid-April and consists of quantitative forecast for the season. The second stage forecast is issued by the end of June. It consists of update for the forecast issued in April, a forecast for July rainfall over the country as whole and forecasts for seasonal rainfall over broad rainfall homogeneous regions of India.


All readers are invited to post comments responsibly. Any messages with foul language or inciting hatred will be deleted. Comments with all capital letters will also be deleted. Readers are encouraged to flag the comments they feel are inappropriate.
The views expressed in the Comments section are of the individuals writing the post. The Tribune does not endorse or support the views in these posts in any manner.
Share On