Previous Year Question
A new type of El Nino called El Nino Modoki appeared in the news. In this context, consider the following statements.
Normal El Nino forms in the Central Pacific ocean whereas El Nino Modoki forms in Eastern Pacific ocean.
Normal El Nino results in diminished hurricanes in the Atlantic ocean but El Nino Modoki results in a greater number of hurricanes with greater frequency.
Which of the statements given above is/are correct?
Correct Answer: B
Detailed Solution
Statement 1 is incorrect: It reverses the principal warming locations of conventional El Niño and El Niño Modoki.
Normal or conventional El Niño: Anomalous sea-surface warming is most prominent in the eastern and east-central equatorial Pacific.
El Niño Modoki: Maximum warming is centred in the central equatorial Pacific, with relatively cooler sea-surface temperatures to its east and west.
The Japanese word Modoki approximately means “similar but different.”
Statement 2 was considered correct in the scientific context of the 2010 question:
Conventional El Niño increases vertical wind shear over the Atlantic.
Strong vertical wind shear disrupts the vertical structure of developing tropical cyclones and suppresses Atlantic hurricane activity.
Because El Niño Modoki warming is centred in the central Pacific, its effects on the Walker circulation and remote atmospheric conditions differ from those of conventional El Niño.
Studies available when the question was framed associated it with a less suppressive environment and greater Atlantic hurricane activity relative to conventional El Niño.
Current scientific clarification
Later NOAA research indicates that the influence of El Niño Modoki on Atlantic hurricane activity is not uniform across all events. Some analyses find it less suppressive than conventional El Niño, while others find its average effect to be approximately negligible.