Enhanced multi-year predictability after El Niño and La Niña events

Area of Science:

• Climate Science
• Atmospheric Science
• Oceanography

Background:

• Regional climate variables like temperature and precipitation show interannual to decadal predictability.
• Previous decadal prediction studies often used diverse initial conditions, potentially masking state-dependent predictability.

Purpose of the Study:

• To assess multi-year climate predictability conditional on the El Niño-Southern Oscillation (ENSO) phase at initialization.
• To determine if ENSO phases influence the skill of decadal climate predictions.

Main Methods:

• Idealized prediction experiments using the Community Climate System Model Version 4.
• Real-world predictions using the Community Earth System Model.
• Analysis of hindcasts from the Coupled Model Intercomparison Project Phase 6 Decadal Climate Prediction Project.

Main Results:

• Predictions initialized during El Niño or La Niña conditions exhibit higher skill for near-surface air temperature and precipitation multiple years in advance.
• This enhanced predictability is superior to predictions initialized from neutral ENSO conditions.
• The findings are consistent across different climate models and prediction datasets.

Conclusions:

• ENSO phases significantly impact the skill of multi-year climate predictions.
• Predictability is enhanced following ENSO events due to phase transitions and associated teleconnections.
• Identifying specific initial states, like ENSO events, reveals opportunities for more skillful decadal climate forecasting.