 "Image via Shutterstock")
It is that time of the year once again when India is pinning all its hopes on the rain god. Not surprising ofcourse, after two consecutive years of drought, the country desperately needs a good monsoon season to get the rural economy back on track.
And hence, it came as a big relief when private weather forecaster Skymet on Tuesday predicted above normal rainfall this year, with waning El Nino. Jatin Singh, chief executive officer, Skymet, said the El Niño would collapse after the onset of monsoon. "It is not likely to have an adverse impact on monsoon."
El Niño is a temperature anomaly and is scientifically known as the El Niño-Southern Oscillation cycle (ENSO). It is the warm phase of the ENSO, where the water temperature in the Pacific Ocean near the equator becomes abnormally warm. El Nino usually begins in the summer and peaks during the following winter.
The warm water in the Pacific Ocean interacts with the atmosphere, causing various weather events, ranging from drought to floods. An El Niño arrives on a cycle of every three to seven years.
Effect of El Nino on rain forecast
Indian monsoon — which impacts not just India, but also other regions of south and south-east Asia and Australia — is important because of its immense influence on the Indian economy and the neighboring nations. It is directly linked to the ENSO phenomenon. In summer months, temperatures over much of India rise to as high as 45 degree celsius, while the Indian Ocean is much cooler. This results in a rise in warm air over the land and cooler moisture-bearing air blows in from the sea, bringing heavy rains or drought in the region.
According to an analysis by the India Meteorological Department (IMD), of the 18 El Nino years between 1880 and 2006, twelve have coincided with deficient or below-normal rainfall in the country.
The Indian monsoon model is characterised by ENSO-induced warm zones in the Pacific, which causes the warm air over them to rise and initiate circulation cells. A circulation cell is defined as a circular path of air, in which warm air rises from the surface, moves to cooler areas, sinks back down to the surface, then moves back to near where it began. Such cells along northern Australia, Indonesia and the eastern edge of the Indian Ocean could have their downdraft (strong downward current of air) sides over a nascent monsoon circulation cell in the Indian Ocean, causing poor monsoon rains over the subcontinent.
This of course is the reason why India faced two consecutive years of drought.
According to Skymet, the prevailing El Niño this year has weakened, and is getting closer to neutrality. In fact, Niño 3.4 which is associated with the Southwest Monsoon has already attained the neutral value of 0.2°C. Much to the relief of economists and market watchers, for the first time since January 2015, Niño 3.4 levels have gone down.
But as the El Nino bows out, it is time for La Nina to set in. Based on the 26 El Nino events since 1900, about 50% have been followed by a neutral year with 40% by La Nina, according to Australia’s weather bureau.
La Nina
La Niña is defined as the positive phase of El Niño Southern Oscillation and is associated with cooler than average sea surface temperatures in the central and eastern tropical Pacific Ocean.
La Nina usually results in better than normal monsoon in India.
According to a report by Australia’s Bureau of Meteorology, there is a 50% probability that this year’s monsoon season will be characterised by La Nina and hence above normal rainfall.
This will have a far reaching effect on the Indian economy, considering that India continues to be primarily an agrarian one with more than half of India's population engaged directly or indirectly in agriculture and allied activities. Better returns on the produce will also mean more disposable income which will push consumption, a prospect India Inc is patiently waiting for since the last few years.
