What is El Nino? How does it affect India’s monsoon?

When ocean temperatures in the central and eastern Pacific Oceans rise above average, El Nino takes place

By Anoushka Caroline Williams  Published on  14 Jun 2023 10:33 AM GMT
What is El Nino? How does it affect India’s monsoon?

Hyderabad: Indian Meteorological Department has predicted typical monsoon rainfall in 2023.

However, a 90% chance of an El Nino weather pattern forming during the monsoon season of June to September boosts the potential of precipitation that is below average.

In the past, India had below-average rainfall during the majority of El Nino years, which occasionally caused severe droughts that damaged crops and necessitated restrictions on the export of some food grains.

"I can make out a weak low in Bay from the previous week. On the west coast and in the northeast, it rains the most. I was afraid about this. It occurs when El Nio is rapidly changing,” said Jatin Singh, founder of Skymet.

He warned that an El Nio that is developing is much more deadly than previous ones.

What is El Nino? How does it affect India’s monsoon?

El Nio is a band of unusually warm saltwater that develops in the equatorial Pacific Ocean and stretches from the International Date Line at 180° longitude to 120° west longitude, which includes the Pacific coast of South America, which includes Peru and Chile.

When ocean temperatures in the central and eastern Pacific Oceans rise above average, El Nino takes place. The monsoon circulation across the Indian subcontinent weakens as a result of changes in atmospheric patterns brought on by global warming. As a result, during El Nino years, the Indian monsoon is frequently weaker and less dependable.

El Nio has several significant effects, one of which is a weakening of the trade winds. The trade winds, which blow from east to west around the equator, got their name because commerce ships have historically exploited them to fill their sails.

How close is the correlation between El Nino and monsoon rain?

India has normal or above-normal rainfall during El Nino years. The El Nino weather pattern has happened 15 times during the previous 70 years, with India having normal or above-average rainfall six times. The previous four El Nino years, however, have shown a different pattern, with India routinely experiencing drought conditions and rainfall that is less than 90% of the long-term normal.

El Nio will undoubtedly affect the Indian monsoon since cloud-bearing trade winds that move inland are a major cause of the rainfall.

However, the trade winds are not the only factor affecting the monsoon. Due to the intense summer heat, the air above the landmass rises, creating a vacuum that allows humid air from above the sea to flood in. The Himalayan barrier acts as a barrier to this air, but when it does, the colder temperatures cause large rain clouds to form, providing relief to the dry country below.

El Nino occurrences are classified as moderate, medium, or strong depending on how much the temperature rises above average.

India's rainfall fell to 78.2% of the average in 2009 due to a mild El Nino, which was the lowest amount seen in 37 years. On the other hand, despite a severe El Nino in 1997, India got 102% of its usual rainfall. El Nino might be significant in 2023, according to weather models.

Sugata Hazra, a former director of oceanographic studies at Jadavpur University in Calcutta, claims that a positive IOD is what caused India to experience a regular monsoon in 1997 despite the presence of a severe El Nino.

Even though it was preceded by floods in Gujarat and Assam, Hazra continues, "the strong El Nio of 2015 led to a delayed, and ultimately insufficient monsoon and droughts on the east coast." He goes on to explain that the IOD was good but insufficient.

A strong positive indicates a one-degree temperature differential between the ocean's western and eastern regions. The most recent information available indicates that the change this year is 0.1 degrees.

Hazra continues, “The El Niño phenomenon is not active yet. We are in the neutral phase of Enso or El Niño/Southern Oscillation.” Enso is the cycle of warming and cooling that takes place in roughly 2-7 year intervals over the equatorial Pacific Ocean and the atmosphere above it. El Niño is its warm phase, while La Niña is its cool phase.

Why is Monsoon Important?

For India, the monsoon is crucial since it provides around 70% of the country's yearly precipitation and affects important crops including rice, wheat, sugarcane, soybeans, and peanuts. Over half of India's 1.4 billion people work in agriculture, which accounts for around 19% of the $3 trillion GDP.

Beyond agriculture, the monsoon has an impact on the overall economy. Enough rain encourages economic expansion generally and reduces the recent surge in food price inflation, which has increased borrowing costs.

A rise in agricultural output may potentially loosen limitations on the export of rice, wheat, and sugar. On the other hand, a drought necessitates maintaining export limits and importing food. India had to import sugar in 2009 due to insufficient rainfall, which led to record-high world sugar prices.

According to Rajat Chaudhuri, author of the cli-fi novel The Butterfly Effect, "El Nio will very definitely have wide-ranging repercussions even if it starts as a meteorological event. Droughts and decreased agricultural yields can have an impact on earnings, cause inflation, and encourage migration. Additionally, it will affect fish output, perhaps resulting in livelihood losses. On the other hand, some signs suggest El Nio may prevent the formation of tropical cyclones in the Bay of Bengal. El Nio may make this summer's heat waves more intense, according to climate models”.

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