Source: The Hindu
From June to September, a “normal” monsoon is predicted by the private meteorological service Skymet meteorological. During that time, the monsoon rainfall will be 3% more than the historical average of 868.6 mm. Rainfall is regarded as typical when it falls within a window of 4% of the historical average.
This season, La Nina was short and feeble. El Nino events, which typically taint the monsoon, are deemed out. Increased monsoon rainfall is typically associated with a La Nina, while the converse is true for an El Nino.
There would be sufficient rainfall in the central monsoon rain-fed region of Madhya Pradesh and Maharashtra. There was probably too much rain in the Western Ghats, especially over Kerala, coastal Karnataka, and Goa. Rainfall in the hilly areas of North India and the northeast is probably going to be lower than usual.
June, the first month of the monsoon season, was expected to see 4% less rainfall than usual. The monsoon’s wettest months, July and August, are expected to get 2% and 8% more rainfall, respectively, while September will see 4% more. India ended up receiving 8% more rainfall last year.
Model Question:
“Discuss the impact of La Niña on the Indian Monsoon. How does it differ from El Niño in terms of monsoon behavior and associated weather patterns in India?”
Model Answer:
The Indian Monsoon is a complex climatic phenomenon influenced by various global oceanic-atmospheric interactions. Among them, the El Niño–Southern Oscillation (ENSO) plays a critical role, with La Niña and El Niño representing its cold and warm phases respectively.
Impact of La Niña on Indian Monsoon:
La Niña refers to the cooling of sea surface temperatures in the central and eastern Pacific Ocean, accompanied by strengthened trade winds. It typically leads to:
- Stronger Monsoon Winds: The pressure gradient across the Indian Ocean increases, enhancing the southwest monsoon flow.
- Above-normal Rainfall: La Niña years often correlate with surplus monsoon rainfall in India (e.g., 2020, 2021).
- Flooding Events: Increased precipitation can lead to localized or widespread floods.
- Favorable for Agriculture: Timely and adequate rainfall boosts Kharif crop production.
Comparison with El Niño:
Feature—La Niña—El Niño
Sea Surface Temp—Cooler than normal—Warmer than normal
Impact on Monsoon—Strengthens monsoon—Weakens monsoon
Rainfall—Above normal—Below normal (drought-prone)
Agricultural Output—Generally better—Often poor due to drought
Cyclones—Can enhance post-monsoon cyclones—Suppresses cyclone activity
While La Niña generally benefits the Indian monsoon and agriculture, its impact is not uniform across regions and years. The Indian monsoon is influenced by multiple factors such as the Indian Ocean Dipole (IOD), Madden-Julian Oscillation (MJO), and local weather systems. Hence, while La Niña creates favorable conditions, a holistic approach is essential for monsoon prediction and planning.
