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Introduction
El Nino is a climatic pattern that represents the unusual warming of the surface waters in the Eastern Pacific Ocean. It is a complex weather phenomenon that results from the differences in the oceanic temperature in the Pacific Region of the equator. It is termed as the warm phase of the “El Nino-Southern Oscillation” (ENSO).
The ENSO cycle represents the fluctuations in the temperature between the atmosphere and ocean in the East Pacific Region of the equator. El Nino can last from nine to ten months, but some El Nino events can last up to a year.
Some interesting facts of El Nino are as follows:
- El Ninos that occurred between 1982-1983 and 1997-1998 were among the most disastrous events of the 20th century.
- During the 1997-1998 event, drought conditions rose in Malaysia, Indonesia, and the Philippines. California and Peru experienced heavy rainfalls and flooding.
- In the 1982-1983 event, the surface level temperature in the sea was between 9 to 18° F, which was above normal.
- The 1997-1998 event was the first El Nino event that was scientifically monitored from the start to end.
El Nino climate change
The ‘El Nino’ term was recognised first by a few South American fishermen in the 17th century. El Nino refers to the extensive interaction of the oceans and the atmosphere, which is linked to the periodic warming of the surface temperature of the sea across the Equatorial Pacific Central and East-Central direction. El Nino has impacted agriculture and Indian monsoons.
El Nino effects
The cool-water surface of the Peruvian coast gets warm due to the El Nino ocean current. When the water gets warm, the stable winds reverse or lose their direction. So, the direction of the moisture-containing winds is driven towards Peru from the Western Pacific Region. This causes heavy rains in Peru during the El Nino event. If the temperature and pressure are extreme, there will be a larger deficit of monsoons in India.
La Nina
The ‘La Nina’ event is termed as the anti-El Nino, which means the opposite of El Nino. It is referred to as the cold event that has a temperature below average in sea surface across the Equatorial Pacific of East-Central. This temperature is considered as the lower pressure than normal over the Western Pacific Area. This lower pressure contributes to heavy rainfall, and so, there were hazardous floods in Australia. This results in lower cloud production and rainfall in Northern Australia. However, dryness was observed at the west coast of South America, the Pampas region of Southern South America, and the Gulf Coast of the United States.
El Nino and La Nina ocean current on India
Since 1950, India has faced 13 droughts due to El Nino and La Nina events because the El Nino year had average rains in India. India is highly dependent on the monsoon rains for agriculture; the lesser rainfall caused much damage to the crop yields.
ENSO and India
The strong El Nino event produces less monsoon rains and therefore results in droughts in Southeast Asia. India is occupied with a larger part of cold air than the El Nino cold air. Therefore, in the La Nina year, rainfall linked with the summer monsoon in Southeast Asia is greater than the normal, especially in Bangladesh and India. This generally benefits the Indian economy that is highly dependent on the monsoon for agriculture. As a result, India also faces a colder than the normal winter season.
Conclusion:
There is a consensus among climate scientists that El Nino events have become more frequent and progressively warmer over the past fifty years. Sea surface temperatures over the Pacific can warm by 1–3°F or more during an El Nino event, which can last anywhere from a few months to two years. El Nino has an impact on weather systems all across the world, causing predictable changes in temperature, rainfall, and winds.
