NEW SUDY ON EL-NINO & LA-NINA (Syllabus: GS Paper 1 – Geogrpahy)

News-CRUX-10     20th February 2024        
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Context: Monsoon rainfall over India is known to be strongly influenced by El Nino and La Nina events, the alternating warming and cooling of the eastern Pacific Ocean that impacts weather across the world. 

oA new study by Indian researchers has now suggested that even air quality in the country could be influenced by the two weather events.

Key Points of Study

  • The study conducted by: National Institute of Advanced Studies in Bengaluru and the Indian Institute of Tropical Meteorology in Pune
  • It suggests: A correlation between the unusual air quality in select Indian cities during the winter of 2022 and the record-breaking La Nina event that occurred during that time.
  • First-Time Association with La Nina: This marks the first instance where the air quality in Indian cities has been linked to a La Nina event, thereby indirectly implicating climate change, which exacerbates the severity of both El Nino and La Nina phenomena.
  • PM2.5 Concentration Variations: According to the study, PM2.5 concentrations in Ghaziabad during that winter exhibited a reduction of approximately 33% from the norm, while Noida experienced a decrease of 28% below average.
  • Anomalous Behavior Prompting Study: The anomalous behavior of air quality in various Indian cities during the specified period prompted the researchers to investigate further, eventually leading them to explore the potential impacts of the La Nina phenomenon.

Wind Direction

  • Change in Wind Direction: The most crucial factor in explaining the anomaly of winter 2022 was a change in the normal wind direction.

oDuring typical winters, wind predominantly blows in the northwesterly direction, such as from Punjab towards Delhi and onward into the Gangetic plains.

  • North-South Wind Circulation in Winter 2022: In the winter of 2022, the wind circulation deviated from its usual north-westerly pattern.
  • Altered Pollution Route: Due to the north-south wind circulation pattern in winter 2022, pollutants from Punjab and Haryana took a different route.

oThey travelled over Rajasthan and Gujarat and extended into southern regions, altering the usual dispersion patterns of pollutants during the winter months.

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