Question

Q. With reference to the El Nino-Southern Oscillation (ENSO), which of the following statements are correct?

Select the correct answer using the code given below

• A.
  1 and 2 only
• B.
  2 and 3 only
• C.
  1 and 3 only
• D.
  1, 2 and 3

Answer 1

The correct option is B

2 and 3 only
Explanation:

Statement 1 is incorrect:

• El Niño is a climate pattern that describes the unusual warming of surface waters in the eastern equatorial Pacific Ocean.
• El Niño Modoki is characterized by changes in sea-surface temperatures in the central Pacific.

Statement 2 is correct:

• The thick layer of warm water accumulated due to unusual warming of surface waters does not allow normal upwelling to occur.
• Without an upwelling, the euphotic zone can no longer support its normally productive coastal ecosystem in the eastern equatorial Pacific Ocean.

Statement 3 is correct:

• During an El Niño event, westward-blowing trade winds weaken along the Equator along with the areas of the central pacific ocean.
• These changes in air pressure and wind speed cause warm surface water to move eastward along the Equator, from the western Pacific to the coast of northern South America.