T.N. May Encounter El Niño Differently From Rest Of India, Pg11

Key Highlights:

• A 'super' El Niño is currently being tracked, characterized by Pacific Ocean surface waters warming by 2°C, significantly above the typical 0.5°C rise.
• Unlike the rest of India, which typically experiences deficient rainfall during El Niño years, Tamil Nadu often receives increased rainfall and cyclones.
• The Indian Ocean Dipole (IOD) is currently neutral, while the northern Indian Ocean, particularly the southern Bay of Bengal, has shown unusual warming of about 1°C as of September 2026.
• Scientists predict that the current El Niño could intensify moisture inflow from the Bay of Bengal, potentially leading to heavy rains and cyclones along the Tamil Nadu coast from October to December 2026.
• The unique seasonal reversal of the East India Coastal Current (EICC) and anomalous equatorial currents contribute to sea surface temperature variations in the region.

Detailed Insights:

• The El Niño Southern Oscillation (ENSO) is a climate phenomenon in the Pacific Ocean that occurs every two to seven years, with global climatic effects.
• During strong El Niño years, pressure differences between the Bay of Bengal and the Arabian Sea create a "wind tunnel" effect, directing moist air into coastal Tamil Nadu.
• Warmer waters in the Bay of Bengal during El Niño years lead to increased evaporation, with cyclonic circulations releasing this stored heat as intense, localized rainfall.
• The 2015 El Niño, one of the strongest, caused devastating floods in Tamil Nadu, including 1,522 mm of rain in Chennai over four days, despite a weak southwest monsoon across India.
• Satellite data indicates that the entire Indian Ocean is warmer than usual, with the exception of the head Bay and the northern Arabian Sea.
• Weakened winds and clear skies during El Niño years allow more sunlight to heat the ocean, and the Bay of Bengal's shallow mixed layer traps this heat, accelerating warming.
• International initiatives like OceanEye, announced by the EU and Canada, aim to improve real-time ocean data collection for better monitoring and prediction of such events.

Scientific/Technical Concepts Involved:

• El Niño Southern Oscillation (ENSO): A periodic fluctuation in sea surface temperature and air pressure across the equatorial Pacific Ocean.
• Indian Ocean Dipole (IOD): An irregular oscillation of sea surface temperatures in the Indian Ocean, with alternating positive, neutral, and negative phases.
• Northeast Monsoon: The winter monsoon in India, bringing rainfall primarily to the southeastern peninsular region, including Tamil Nadu.
• East India Coastal Current (EICC): A seasonal ocean current along the east coast of India that undergoes a unique reversal between February and November.