La Nina is suspected to have caused recent floods in Australia. How is La Nina different from EI Nino?

1. La Nina is characterised by unusually cold ocean temperature in the equatorial Indian ocean whereas EI Nino is characterised by unusually warm ocean temperature in the equatorial Pacific Ocean.
2. EI Nino has an adverse effect on the southwest monsoon of India, but La Nina has no effect on monsoon climate.

Which of the statements given above is/are correct?

1. 1 only
2. 2 only
3. Both 1 and 2
4. Neither 1 nor 2

Explanation

Statement 1 is incorrect

• La Niña is not associated with cold temperatures in the equatorial Indian Ocean. Instead, it is characterised by cooler-than-normal sea surface temperatures in the central and eastern equatorial Pacific Ocean, while El Niño is marked by warmer-than-normal sea surface temperatures in the same Pacific region.

Statement 2 is incorrect

• El Niño generally weakens the southwest monsoon in India, often leading to below-normal rainfall. However, La Niña does influence the monsoon, usually strengthening it and increasing the chances of above-normal rainfall. Hence, it is incorrect to say that La Niña has no effect on the monsoon climate.

Answer: (d) Neither 1 nor 2 | Difficulty Level: Hard