The Pacific Ocean had shown a warming trend way back in the Indian summer of 2014. The Niño 3.4 index, which is directly associated with Indian Monsoon, kept on increasing gradually. The value had crossed 0.5°C by the beginning of 2015 and reached 0.6°C on January 26 and kept increasing thereafter. It had reached the highest value of 3.1°C on November 23, 2015.
India got a brief respite in 2016 as the Niño index started witnessing a rapid decline since March 2016 and reached the negative value of – 0.1 in May. The Pacific Ocean had also cooled down considerably. Thus, Southwest Monsoon 2016 ended with normal rainfall at 97% of long period average from June 1 to September 30.
According to Skymet Weather, El Niño has once again started showing signs of resurfacing in the coming months.
El- Niño and Southwest Monsoon 2017
Usually, an El Niño is followed by La Niña that is invariably related with good Monsoon rains. Back in December, all weather models were suggesting that weak La Niña conditions will continue during early 2017 and by April or May, neutral conditions may develop. Going by this prediction, India in 2017 would have witnessed either a normal Monsoon or above normal rains.
However, weather models took a U-turn and by mid-January, most of them have started indicating towards the resurfacing of El Niño. As per this latest outlook for Niño 3.4 Index, the sea surface temperatures (SST) in the tropical Pacific Ocean are likely to increase in a span of six months.
Another model is working on the same trend but it is just falling short of threshold neutral value. The table below will give clear picture of majority of dynamic and statistical models indicating towards the rising trend of the Niño index.
However, in contrary to El Niño conditions, there is another factor that influences the performance of Southwest Monsoon. The Indian Ocean Dipole (IOD) plays a vital role. According to meteorologists, the positive IOD is linked with good Monsoon rains, while the negative IOD has adverse effect on the same.
As of now, weather models are suggesting that IOD is likely to remain positive during the upcoming Monsoon season. But we have to wait and watch up to how much extent will IOD be able to neutralize the effect of the expected evolving El Niño. Here’s is a look at the current outlook of IOD.
Relation between El- Niño and drought in India
The most prominent droughts in India, eight of them, since 1871 have been El Niño triggered droughts, including the recent ones that occurred in 2002, 2009, 2014 and 2015. Nevertheless, it is important to note that all El Niño years do not lead to drought in India. The year 1997-98 is a stark reminder as it was a strong El Niño year. However, it did not cause drought in India, in fact, rainfall was in excess. On the other hand, a moderate El Niño in 2002 resulted in one of the worst droughts.
Going by historical data of 135 years from 1880 to 2015, about 90% of all evolving El Niño years have led to below normal rainfall and 65% of evolving El Niño years have brought droughts. From this fact, one thing is clear that El Niño years adversely affect the weather in India in terms of Monsoon rain, with very few exceptions. During an El Niño year, the rainfall is generally below the normal average, which has its negative bearing on crop production.
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