Scientists make a breakthrough in ENSO forecasting with a new Recharge Oscillator model that simplifies predictions and accurately captures El Niño’s complex behavior.

What is ENSO ?

• El Niño is a climate pattern that emerges from fluctuating ocean temperatures in the tropical Pacific, affecting weather patterns worldwide, especially monsoons. 
• It’s characterized by warmer-than-average sea surface temperatures in the central and eastern tropical Pacific Ocean, weakening the typical easterly trade winds.
• It can last for several months and recur irregularly every 2 to 7 years with three phases:
  • El Niño (warm phase)
  • La Niña (cool phase)
  • Neutral phase
• It is monitored closely due to its global climate impact.

Why is ENSO hard to predict ?

• Late-emerging signals
• • Clear ENSO signals appear only in early summer.
  • Predictions made before that lose accuracy quickly, creating uncertainty.
• Unpredictable wind events
  • Westerly wind bursts can suddenly shift the system into a warm or cool phase.
  • These events inject chaos into the system, disrupting model forecasts.
• Influence of other oceans
  • Anomalies in the Indian Ocean or other basins can reinforce or counter ENSO.
• Experts differ on “Which ocean basin matters most.”

Recent scientific progress – Recharge Oscillator (RO) Model

• Developed by the CLIVAR Pacific Region Panel Working Group.
• Simplifies ENSO as a contest between two key variables:
  • Sea-surface temperature in the central-eastern Pacific.
  • Subsurface warm water volume in the western Pacific.
• The model successfully reproduces:
  • ENSO’s repeating cycle,
  • Its December peak,
  • The asymmetry in the strength of El Niño vs La Niña.

Further Reading: El Niño & La Nina

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