Context– the Indian Meteorological Department forecasted a normal monsoon and the development of El Niño with a 4 % shortfall in monsoon rainfall.
Key highlights:
- The development of El Niño is the key factor affecting the diminished rainfall in certain parts of India.
- A possibility of below normal monsoon at 94% of the long period average(LPA) with Haryana, Uttar pradesh and Rajasthan to experience reduced rainfall.
- There is a possibility of development of a ‘positive phase’ in the Indian Ocean Dipole and reduced snow cover in Eurasia.
- The central india and southern indian as the key agricultural areas are likely to receive normal and slightly above normal rainfall.
What is El Niño?
Meaning little boy in Spanish . It refers to a cyclical phenomenon of the warming of the central pacific ocean . It is the warmer phase . It causes the pacific jet stream to move south and spread to the east. Severe El Niño can cause droughts, flooding, disease outbreaks , heat stress ,respiratory disorders, etc.
What is La Niña?
Meaning little girl in Spanish and is the opposite effect of El Niño .It is the cold phase .Here the trade winds are strong and they have a cooling effect. It causes the jet stream to move upward and weaken in the eastern pacific . During La Niña winters , the south sees warmer and drier conditions while the north see’s cooler and wetter conditions. La Niña can lead to severe hurricanes.
Together the El Niño andLa Niña are known as the El Niño -Southern oscillation cycle that are climatic patterns that affect the temperature of the central and eastern pacific ocean that have its effect on the worldwide weather conditions, ecosystems, wildfire, and economics .
The effects of these two last from 9 to 12 months or even years. The occurrence of El Niño is more frequent than La Niña.
Effect of El Niño and La Niña on India;
Since 1950, 10 out of 13 droughts have been due to El Niño and one due to La Niña. El Niño is responsible for causing dry seasons and lesser rainfall that severely affects the monsoon dependent agriculture in India causing below average crop yields.
What is the Indian Ocean Dipole (IOD)?
It refers to the difference in the surface temperatures between two areas or poles. Like the western people in the Arabian sea, the west of the Indian ocean and the eastern pole in the eastern ocean south of Indonesia. It plays a significant role in bringing rainfall.It is similar to the ENSO but occurs in the equatorial Indian ocean.
The positiveIOD is associated with El Niño- causing warm sea temperature in western indian ocean and less rainfall and the negative IOD with La Niña- causing cooler sea temperature and more rainfall.
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