September 2, 2015 1:15:50 am
In June, a rain-bearing weather phenomenon called Madden Julian Oscillation, or MJO, came to India’s rescue. July was bad, but a few timely interventions by convectional, or heat-induced, rainfall in some parts of the country ensured that the scarcity was not felt much. But August has not been able to escape the full force of El Niño, and it appears neither will September. The dire prediction of the India Meteorological Department (IMD) at the start of the monsoon season is finally coming true.
El Niño refers to a condition in the equatorial Pacific Ocean, off the coast of Ecuador and Peru in South America, in which ocean surface temperatures rise unusually. El Niño is known to have an impact on the Indian monsoon, besides affecting a lot of other weather events worldwide. There is a strong correlation between an El Niño event and a poor monsoon.
Over the last two months, the El Niño has gained in strength — the sea surface has become progressively warmer — according to information gathered by the Climate Prediction Centre (CPC) of the National Oceanic and Atmospheric Administration (NOAA) of the United States. The phenomenon was weaker at the beginning of the monsoon, but it was evident even then that it would have an adverse impact on rainfall.
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The IMD’s forecast reflected this. The first forecast on April 22 predicted 93 per cent of normal rainfall over the four-month monsoon season. In its updated forecast on June 2, IMD revised the figure downward to 88 per cent.
The surprisingly good rainfall in June was attributed to MJO, a moving system of wind, cloud and air pressure that brings rain as it circles the earth around the equator, and it seemed determined to prove forecasters wrong. But that was not to be. MJO is a temporary phenomenon and lasts barely a week or 10 days in any particular region.
July experienced a 17 per cent shortage, partly due to the fact that the Indian Ocean Dipole (IOD), a phenomenon similar to El Niño but which occurs in the Indian Ocean, did not turn favourable as expected. In its ‘positive’ phase, the IOD tends to neutralise the impact of El Niño. However, thanks to the good rainfall in June, the deficit did not hurt. The reservoirs, for example, were still filled to more than their normal storage levels for that time of the year.
That began changing in August. Rainfall in August was 22.54 per cent below normal. It was the driest month of this monsoon season. A similar deficiency in September, which is what weather scientists are expecting, will be in line with the forecast made by the IMD.
Prevailing El Niño conditions suggest it will remain strong for some more time, especially in the regions that are supposed to have the most impact on the Indian monsoon.
But what is more important is that the phenomenon is set to continue beyond this year. “There is a greater than 90 per cent chance that El Niño will continue through Northern Hemisphere winter 2015-16, and around an 85 per cent chance that it will last into early spring 2016,” the latest bulletin on El Niño by the Climate Prediction Centre, released on Monday, says.
Which means the El Niño can have an impact on next year’s monsoon as well, possibly on its first part.
In the last 60 years, the average duration of an El Niño has been 10 months. But there have been instances of prolonged El Niño, as in 1986-87, when it lasted 19 months, and in 1968-69, when it continued for 18 months. In both cases, India experienced droughts in consecutive years.
The silver lining to this situation is the IMD’s fairly accurate forecast. The possibility of a drought-like situation was flagged early, and in very clear terms. The Department was not afraid to state up front what the numbers indicated, as is believed to have happened in some previous years. It was important that IMD backed itself, especially since 2014 was also a drought year.
While IMD maintains that it just puts forward numbers thrown up by the models it runs, the fact is that 2015 was probably the first year ever in which it predicted below normal rainfall — below 96 per cent — in its first long-range forecast, made as early as in April. This was also the first time that the IMD warned of a possibility of below-90 per cent rainfall at the beginning of June.
The result has been that governments, both at the Centre and at the states, are fairly well prepared to deal with a drought. Water in the reservoirs has been used judiciously, farmers were advised in time to change the timing of sowing or to shift to alternative crops, and markets were not left to deal with uncertainties.
More than the MJO or any other weather phenomenon, it was the accurate forecast and the timely action of the governments that has cushioned the country against the impact of a bad monsoon so far.
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