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Effects of El Niño and Antarctic Oscillation On Air Pollution

Topics covered:

  1. Conservation, environmental pollution and degradation, environmental impact assessment.

 

Effects of El Niño and Antarctic Oscillation On Air Pollution

 

What to study?

For prelims and mains: Causes and effects of El Niño and Antarctic Oscillation on pollution levels.

 

Context: Team of researchers affiliated with various institutions in China and the U.S. has discovered that data from El Niño and Antarctic Oscillation events can be used to foretell air pollution levels in northern India.

 

Background:

In recent years, northern India has experienced poor air quality, significantly in the winter months, to the extent that the nation has some of the worst air quality in the world—surpassing even China. Researchers have additionally found that in some years, pollution ranges appear worse than regular because of weather conditions.

 

Key findings:

  1. El Niño occasions tend to end in lowered wind speeds within the area, which prevented airborne pollutants from moving out of densely populated areas.
  2. Antarctic Oscillation occasions create stronger winds in some components of northern India and weaken them in others, resulting in uneven impacts on pollution levels.

 

Significance:

  1. The model they have developed shows 75% accuracy in predicting pollution levels, and the prediction can be done even a season in advance. 
  2. India has been emerging as one of the world’s most polluted countries, with particulate matter PM 2.5 levels spiking more than 999 microgram per cubic metre in parts of Delhi last year.
  3. Studying a combination of El Nino, Antarctic Oscillation and the anomalies in sea surface temperature during autumn (September-November), can help forecast the pollution conditions in winter (December-February).
  4. The statistical model developed by the team can also help the government in adjusting policies and strategies for pollution control before winter comes, the paper published in Science Advances adds.

 

What is Antarctic Oscillation?

  • The Antarctic oscillation (AAO) is a low-frequency mode of atmospheric variability of the southern hemisphere.
  • It is also known as the Southern Annular Mode (SAM).
  • It is defined as a belt of westerly winds or low pressure surrounding Antarctica which moves north or south as its mode of variability.
  • In its positive phase, the westerly wind belt that drives the Antarctic Circumpolar Current intensifies and contracts towards Antarctica, while its negative phase involves this belt moving towards the Equator.
  • Effects: Winds associated with the Southern Annular Mode cause oceanic upwelling of warm circumpolar deep water along the Antarctic continental shelf, which has been linked to ice shelf basal melt, representing a possible wind-driven mechanism that could destabilize large portions of the Antarctic Ice Sheet.

 

Sources: the Hindu.