UPSC Prelims 2010 Q4: Environment & Ecology – Ecosystems & Ecology Concepts
A new type of El Nino called El Nino Modoki appeared in the news. In this context, consider
the following statements:
1. Normal El Nino forms in the Central Pacific ocean whereas El Nino Modoki forms in Eastern
Pacific ocean.
2. 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?
- (a) 1 only
- (b) 2 only
- (c) Both 1 and 2
- (d) Neither 1 nor 2
Answer: (b) 2 only
Explanation
El Nino Modoki: checking both statements
El Nino Modoki is a variant of the classic El Nino phenomenon, distinguished by where ocean warming occurs.
| Statement | Verdict | Reason |
|---|---|---|
| 1. Normal El Nino forms in Central Pacific; Modoki forms in Eastern Pacific | Incorrect | This is reversed: the normal/classic El Nino warms the Eastern/Central-Eastern Pacific, while El Nino Modoki is characterized by warming concentrated in the Central Pacific, flanked by cooler water to the east and west |
| 2. Normal El Nino reduces Atlantic hurricanes; Modoki increases their frequency | Correct | Classic El Nino's wind-shear effects typically suppress Atlantic hurricane activity; El Nino Modoki's different wind patterns are linked to more frequent Atlantic hurricanes |
El Nino vs El Nino Modoki:
| Point | Normal El Nino | El Nino Modoki |
|---|---|---|
| Warming zone | Eastern/Central-Eastern Pacific | Central Pacific (flanked by cooler water) |
| Atlantic hurricanes | Suppressed | More frequent |
Answer: (b) 2 only.
Why each option is right or wrong
- (a) Incorrect. Statement 1 reverses the warming-zone locations of normal El Nino and El Nino Modoki.
- (b) CORRECT. Statement 2 accurately describes the contrasting hurricane effects of normal El Nino versus El Nino Modoki.
- (c) Incorrect. Statement 1 is factually reversed, so 'both' cannot be correct.
- (d) Incorrect. Statement 2 is accurate, so 'neither' is wrong.
Key point
El Nino Modoki warms the CENTRAL Pacific (not Eastern, which is normal El Nino's zone) and is linked to MORE Atlantic hurricanes, unlike normal El Nino which suppresses them.
Remember
El Nino Modoki: warms the Central Pacific and is linked to MORE frequent Atlantic hurricanes — the reverse of classic El Nino's effects.
Common mistakes
- Reversing the warming-zone locations of normal El Nino versus El Nino Modoki.
- Assuming all El Nino variants have the same effect on Atlantic hurricane activity.
- Not knowing the specific Central Pacific signature that defines 'Modoki' events.
Exam tip
El Nino Modoki = Central Pacific warming (not Eastern) + MORE Atlantic hurricanes (unlike normal El Nino's suppression).
Sources
- Karumuri Ashok et al. — "El Niño Modoki and its possible teleconnection", Journal of Geophysical Research, vol. 112 (2007)
- National Oceanic and Atmospheric Administration (NOAA) — El Niño/Southern Oscillation (ENSO) Diagnostic Discussion