Consider the following statements:

Statement I: El Niño events are generally associated with weakened monsoon winds, leading to below-normal rainfall over India.

Statement II: A positive Indian Ocean Dipole (IOD) weakens the monsoon, reducing moisture availability and disrupting monsoonal circulation over India.

Which one of the following is correct in respect of the above statements?

Question

Question

Both Statement I and Statement II are correct, and Statement II is the correct explanation for Statement I.
Both Statement I and Statement II are correct, but Statement II is not the correct explanation for Statement I.
Statement I is correct, but Statement II is incorrect.
Statement I is incorrect, but Statement II is correct.

Answer 1

The correct answer is option 3.

In News

The 2023 monsoon defied expectations by remaining normal despite a strong El Niño, which typically weakens the Indian monsoon.
This was attributed to the Indian Ocean Dipole (IOD), which helped counteract the drying effects of El Niño.

Key Points

El Niño weakens the Indian monsoon by warming the central and eastern Pacific Ocean, which disrupts global wind patterns.
- This weakens monsoon winds, reducing moisture transport to India and causing below-normal rainfall in most El Niño years.
  - Hence, Statement I is correct.
A positive IOD actually strengthens the monsoon, not weakens it.
- A positive IOD (warmer western Indian Ocean, cooler eastern Indian Ocean) enhances moisture inflow into India, improving monsoon performance.
- A negative IOD, on the other hand, weakens the monsoon.
  - Hence, Statement II is incorrect.

Additional Information

El Niño & Monsoon Relationship:
- El Niño has historically led to deficient monsoons in India, but this effect is not always guaranteed.
- The 2023 monsoon remained normal due to a strong positive IOD, which balanced El Niño’s drying effect.
Indian Ocean Dipole (IOD) Impact:
- Positive IOD (warm western Indian Ocean, cool eastern Indian Ocean) → Strengthens monsoon by increasing moisture transport.
- Negative IOD (cool western Indian Ocean, warm eastern Indian Ocean) → Weakens monsoon by reducing moisture availability.
Current Climate Trends:
- Climate change is altering the ENSO-Monsoon relationship, making monsoon forecasting more complex.
- Other factors like Arctic warming and jet stream shifts also influence monsoon patterns.