Science

What El Nino Has In Store For India: It’s Time To Scale-Up Long Term Weather Predictions

M R Subramani

Apr 23, 2019, 10:01 AM | Updated 10:01 AM IST


Indian monsoon (Representative image)
Indian monsoon (Representative image)
  • India has two supercomputers - Pratyush and Mihir - which were built for weather forecasting.
  • However, when it comes to El Nino, the country’s weather outlook or predictions are not considered on par with either the US, Australian or the Japanese meteorological agencies.
  • On 15 April, the India Meteorological Department (IMD) came out with its outlook on the south-west monsoon that begins on 1 June. The south-west monsoon is crucial to Indian agriculture and economy in many ways.

    The south-west monsoon accounts for 70 per cent of the country’s total rainfall, with the north-east monsoon, that begins on 1 October, making up the rest. While the south-west monsoon is crucial for almost all parts of the country, the north-east monsoon is more important for Tamil Nadu, parts of Karnataka, Andhra Pradesh, Orissa and Bengal.

    In its outlook, the IMD says rainfall during south-west monsoon is likely to be 96 per cent of the long period average. The IMD gave the outlook based on higher forecast probability of 39 per cent and 33 per cent of climatological probability.

    This means, there is a 40 per cent chance of the rainfall being 96 per cent of the long period average. The IMD statement also shows a 32 per cent forecast probability of below normal rainfall. This is an area of concern since there are still chances of rainfall being deficient during this monsoon.

    The Possibility Of The El Nino Effect

    The IMD has also forecast that weak El Nino conditions are likely to prevail during the monsoon with its effect tapering down as the season progresses. El Nino is a warm weather phenomenon caused by the warming up of the floor of the Pacific Ocean.

    El Nino leads to drought in the Indian Ocean region and in the past, the weather phenomenon has resulted in Indian monsoon being affected. El Nino is followed by La Nina, which results in torrential rains in the Indian Ocean region, leading to floods and other resultant damages.

    On 16 April, the Australian Meteorological Department said there was a 70 per cent chance of the El Nino setting in, though the atmosphere hasn’t showed a consistent response of the system springing up. The Australian agency said that the El Nino pressure pattern was yet to develop, which means that the phenomenon could be a little weak.

    On 10 April, the Japan Meteorological Agency said that El Nino conditions are persisting in the Pacific region and there was an 80 per cent chance for these weather conditions to continue until end of September.

    On 11 April, The National Ocean and Atmospheric Administration (NOAA) of the US said that there was a 65 per cent chance of a weak El Nino during summer, though the possibility could drop to 55 per cent.

    El Nino Concerns For India

    The forecast of El Nino possibility could not have come at a more testing time than this. This is because India has had deficient rainfall throughout 2018.

    Last year, rainfall deficiency during monsoon was 22 per cent, and post-monsoon, the rains were lower than normal by 44 per cent. Winter rains were the saving grace last year with the country receiving 24 per cent excess but this year’s pre-monsoon rains during 1 March to 18 April are 33 per cent deficient.

    Last year’s excess winter rains has helped West Bengal, Uttarakhand, Punjab, Bihar, Telangana, parts of Andhra Pradesh and south Karnataka. However, Madhya Pradesh, a key agrarian State, still reels from a prolonged dry period.

    Water Storage Status

    The water storage status in the 91 important reservoirs across the country is a little better than last year. The current storage level is 12 per cent more compared to the status last year. If the storage is compared with the last 10 years’ average, it is 3 per cent higher.

    However, the Central Water Commission data shows that the storage situation in Maharashtra (-39 per cent), Gujarat (-29 per cent), Uttar Pradesh (-34 per cent), Andhra Pradesh (-82 per cent) and Telangana (-29 per cent) is worrisome. The level of 70 of the major reservoirs is below 40 per cent - another area of concern.

    This week, rains lashed some parts of the country but one hopes that the country will receive some more good rainfall before the monsoon sets it. Such rainfall will help in improving soil moisture and create conducive conditions for sowing of kharif (summer) crops.

    However, if the deficiency continues, then there is a possibility of delayed kharif sowing as farmers prefer to wait for better soil moisture. The other aspect to consider is that the follow-up rains will also have to be on time.

    India’s Weather Predicting Capability

    One of the problems of the IMD outlook in the last couple of years is that it gives a general view of the monsoon than looking at specific regions. Like last year, Madhya Pradesh and Gujarat received deficient rainfall. The year before, it was Karnataka’s turn to receive below normal rains.

    Way back in 2009, the Indian government said it was making efforts to enhance its weather predicting abilities. The IMD has enhanced its short-term weather predicting capability but that cannot be said about long-term predictions.

    India and the US are involved in various programmes on the weather and ocean front. For example, Indian and US ocean experts are involved in examining the sea surface temperatures of the Bay of Bengal to find out if water coming from rivers and streams into the sea are affecting the weather phenomenon, especially with regard to north-east monsoon.

    India has two supercomputers - Pratyush and Mihir - which are among the 100 fastest computers in the world. These computers were built for weather forecasting. And recently, India has joined the exclusive club of countries that have produced anti-satellite weapons. However, when it comes to El Nino, the country’s weather outlook or predictions are not considered on par with either the US, Australian or the Japanese meteorological agencies.

    In Conclusion

    In the event of a poor monsoon, the Indian economy could suffer since most rural purchases depend on farm income following kharif and rabi harvests. In this context, it is important for the country to be well prepared for events like El Nino.

    In this regard, it would be good if India’s weather predicting abilities improve to match with the best in the world. This will not only help the country’s economy but perhaps aid other nations and, more importantly, help Indian agricultural exports too.

    M.R. Subramani is Executive Editor, Swarajya. He tweets @mrsubramani


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