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El-Nino
Context:
- The India Meteorological Department (IMD) has recorded unusually high temperatures, raising questions about the causes of these high temperatures and the requirements for classifying a heatwave.
- IMD reports heat waves in plains when maximum temperatures reach 40°C or 45°C above normal in at least two areas.
- Heatwaves are announced when temperatures deviate from normal by more than 6°C in hilly and coastal locations, where they begin at 30°C and 37°C, respectively.
El-Nino Influence:
The year 2024 marked the beginning of an El Niño event with unusually warm surface waters in the equatorial Pacific Ocean.
- El Nino years are associated with extreme heat, prolonged heat waves, and reduced pre-monsoon rainfall patterns.
- This scenario could have significant impacts on climate, agriculture, and ecosystems, drawing attention to potential impacts in different regions globally.
El-Nino vs La-Nino
El Ninño is characterised by warmer sea surface temperatures, high air pressure in the western Pacific, and weakened trade winds, resulting in drier and warmer conditions in India and wetter conditions in the southern US. Conversely, La Niña features cooler sea surface temperatures, high air pressure in the eastern Pacific, stronger trade winds, and brings wetter conditions to India and drier conditions to the southern US.
The Indian Ocean Dipole:
The IOD is a continuous variation of sea surface temperature in the Indian Ocean, characterised by positive, neutral, and negative phases.
- During the positive phase, the Indian Ocean is warming to the west, bringing drought to Indonesia and Australia.
- Conversely, during the negative phase, the eastern Indian Ocean heats up, bringing heavy rains and flooding to East Africa.
- This phenomenon greatly affects the strength of the Indian monsoon.
- Historical events included the positive IOD in 2007 coinciding with La Niña. Additionally, in 2010, strong negative IOD caused flooding in Queensland and Victoria.