El Niño strengthens, could develop into strongest since 1950, says US agency, Pg15

Key Highlights:

• The National Oceanic and Atmospheric Administration (NOAA) predicts an 81% chance of a very strong El Niño from October to December.
• This El Niño event could rank among the largest recorded since 1950.
• The Niño 3.4 index has already surpassed 1.2°C, indicating a moderate El Niño.
• India is expected to experience below-normal monsoon rainfall this year due to the strengthening El Niño.
• The current El Niño began in June and is projected to intensify and continue into 2027.

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Detailed Insights:

• El Niño and La Niña are opposing phases of the El Niño Southern Oscillation (ENSO), which is a significant ocean-atmosphere interaction.
• ENSO phases are determined by the sea surface temperatures in the Niño 3.4 region of the Pacific Ocean.
• An El Niño is officially declared when the average sea surface temperature anomaly in the Niño 3.4 region exceeds 0.50°C.
• An El Niño is considered strong when the Niño 3.4 index crosses 1.5°C, and very strong when it goes beyond 2°C.
• The 2015-2016 El Niño, known as "Godzilla," was the strongest recent event, with the Niño 3.4 index remaining above 2°C for over four months.
• Other very strong El Niño phases occurred in 1982-83, 1991-92, and 1997-98.
• The rapid strengthening of the current El Niño is attributed to increased subsurface temperatures in the eastern Pacific and weakened trade winds.
• The India Meteorological Department (IMD) has forecast slightly below-normal rainfall across the country until July 22.
• Historically, 60% of El Niño years have resulted in either below-normal or deficient seasonal rainfall in India.

Key Concepts Involved:

• El Niño: A climate pattern characterized by the unusual warming of surface waters in the eastern equatorial Pacific Ocean.
• La Niña: A climate pattern characterized by the unusual cooling of surface waters in the eastern equatorial Pacific Ocean.
• El Niño Southern Oscillation (ENSO): A periodic fluctuation in sea surface temperature and the air pressure of the overlying atmosphere across the equatorial Pacific.
• Niño 3.4 region: A specific area in the equatorial Pacific Ocean (5°N-5°S, 120°-170°W) used to monitor and define El Niño and La Niña events.