WMO's 'Supersized' El Nino Forecast (Geography)
WMO's 'Supersized' El Nino Forecast (Geography)
Why In News:
The WMO has warned that a potentially “supersized” El Niño, possibly the strongest ever recorded, could persist until around February 2027.
El Niño and ENSO
ENSO (El Niño–Southern Oscillation) is a recurring climate phenomenon involving changes in sea-surface temperatures (SSTs) and atmospheric pressure over the tropical Pacific Ocean.
El Niño is the warm phase, characterised by unusually warm SSTs in the central and eastern equatorial Pacific.
La Niña is the cool phase, marked by unusually cold SSTs in the same region, while neutral conditions occur when neither phase dominates.
The Southern Oscillation refers to the associated atmospheric pressure fluctuation, commonly monitored through the Southern Oscillation Index (SOI).
The SOI is based on the sea-level pressure difference between Tahiti and Darwin, Australia; sustained negative values generally indicate El Niño conditions, while positive values favour La Niña.
El Niño, Indian Monsoon & Global Effects
Impact on Indian Monsoon: El Niño generally weakens the Indian Summer Monsoon, increasing the likelihood of below-normal rainfall and drought in parts of India.
Global Climate Impact: It causes warmer and wetter conditions along Peru and Ecuador, while parts of Australia and Southeast Asia may experience drier conditions; it can also temporarily raise global temperatures.
Role of IOD: The impact of El Niño on India is influenced by the Indian Ocean Dipole (IOD), with a positive IOD sometimes reducing its adverse effect on Indian monsoon rainfall.
Important Institutions
WMO is a specialised agency of the United Nations, headquartered in Geneva, dealing with international cooperation in weather, climate, hydrology and related environmental sciences.
In India, the India Meteorological Department (IMD) under the Ministry of Earth Sciences monitors and provides forecasts related to ENSO and its possible influence on the Indian monsoon.
The Monsoon Mission, undertaken by the Ministry of Earth Sciences, focuses on improving monsoon prediction through advanced coupled ocean-atmosphere models.
Indian Ocean Dipole (IOD)
IOD is an irregular fluctuation of sea-surface temperatures (SSTs) between the western and eastern Indian Ocean.
Positive IOD: Warmer waters in the western Indian Ocean and cooler waters near Indonesia → generally supports stronger Indian monsoon rainfall.
Negative IOD: Cooler western Indian Ocean and warmer eastern Indian Ocean → generally associated with weaker Indian monsoon conditions.
Significance for India: IOD influences monsoon variability, rainfall distribution, agriculture and extreme weather events, and can either strengthen or offset the effects of El Niño/La Niña.