Key findings

• The NAO is currently predictable on seasonal timescales of up to around a year in the future, and on decadal timescales of 10 years ahead.
• Studying eight different prediction systems, researchers found the differences in the accuracy of NAO prediction is linked to how the prediction systems represent interactions between the ocean and atmosphere in the North Atlantic.
• Interactions between the NAO, subpolar sea surface temperatures, and ocean circulation play a key role in NAO predictability. Improving how these processes are represented in prediction systems could help further improve NAO forecasts.
• Systems that include ocean initialization (the process of matching a climate model closely to an observed state of ocean conditions at the beginning of its simulation) generally produce more accurate decadal NAO predictions than uninitialized systems.

Background

The winter North Atlantic Oscillation (NAO) refers to variations in the north-south atmospheric pressure difference across the North Atlantic, between Iceland and the Azores. It strongly influences wind strength, the position of storm tracks across Europe, and temperature and rainfall changes in Europe and North America. 

Although it has long been viewed as unpredictable beyond short timescales, recent research suggests that the NAO is predictable on seasonal to decadal timescales, which could potentially provide significant benefits for society. However, the physical processes responsible for this decadal predictability, particularly the role of ocean-atmosphere interactions, have not yet been fully established. To address this knowledge gap, the researchers analysed eight different prediction systems to investigate the processes that underpin NAO decadal predictability.

What’s next?

While this study shows that feedback between the ocean and atmosphere are underestimated by models, and are key to understanding and predicting the NAO on decadal timescales, though some of the processes involved are still not fully understood. In addition to this, current prediction systems vary in how well they capture these processes highlighting a key area for future development and scientific focus. Addressing these challenges could improve our ability to forecast the NAO up to a decade ahead, helping society better prepare for future climate variability and change. 

Read the paper in npj Climate and Atmospheric Science

Reference: Patrizio, C.R., Athanasiadis, P.J., Smith, D.M. et al. (2025) Ocean-atmosphere feedbacks key to NAO decadal predictability. npj Clim Atmos Sci 8, 146. 

Keywords: North Atlantic oscillation, decadal predictions, ocean-atmosphere interactions, model comparison