La Nina [UPSC Geography Notes]

Geography is an important part of General Studies I in the UPSC exam. In this article, you can read about the phenomenon of La Nina for the IAS exam.

El Niño and La Niña are opposite phases of what is known as the El Niño-Southern Oscillation (ENSO) cycle. The ENSO is a recurring climatic pattern involving temperature changes in the waters of the eastern and central tropical Pacific Ocean, and changes in the patterns of upper and lower level winds, sea level pressure, and tropical rainfall across the Pacific Basin. El Nino is often called the warm phase and La Nina is called the cold phase of ENSO. These deviations from the normal surface temperatures can have a large-scale impact on the global weather conditions and overall climate.

Read more about El Niño here.

La Nina

  • La Nina means ‘little girl’ in Spanish.
  • Also called El Viejo or ‘cold event’.
  • In this case, water temperature in the Eastern Pacific gets colder than normal.
  • Due to this, there is a strong high pressure over the eastern equatorial Pacific.
  • Hence, there is low pressure in the Western Pacific and off Asia.
  • Because of this, the following events take place:
    1. Droughts in Ecuador and Peru.
    2. Heavy floods in Australia.
    3. High temperatures in the Indian Ocean, Western Pacific, and off the coast of Somalia.
    4. Good monsoon rains in India. La Nina years experience better than normal monsoons in India.
  • La Nina is thus, beneficial for Indian Monsoons.

El Nino and La Nina, both occur every 4 to 5 years. The episodes last for 9 – 12 months generally. It has been observed that El Nino is more common than La Nina.

For more NCERT Geography Notes for IAS, click on the link below:

Geography Notes For UPSC Exam

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