Are the sources of NAO predictability stationary under climate change? Insights from interpretable machine learning 

Speaker:  Ioana colfescu

Chair(S): Scott Osprey, Maria Russo

wednesday 24th September, 13:00-14:00

ABSTRACT

The North Atlantic Oscillation (NAO) is the dominant mode of variability in the North Atlantic–European sector, but its predictability remains limited and its sensitivity to climate change poorly understood. Here we develop a convolutional neural network (CNN) to predict the NAO index two months in advance from lagged sea surface temperatures (SSTs). The model achieves correlations up to r≈0.40, competitive with statistical benchmarks. We introduce an interpretability framework based on SHAP (SHapley Additive exPlanations), using climatological and cluster-based background states, to attribute predictability to physical regions and teleconnections. Phase- and season-resolved analyses show that winter NAO+ skill is dominated by ENSO and tropical Atlantic teleconnections, while NAO− depends more on subpolar gyre and AMOC-related processes; summer NAO+ skill is linked to tropical drivers, while NAO− remains weaker and more noise-driven. Layer-wise probing reveals how predictability emerges hierarchically within the network, from noisy shallow features to robust teleconnections in deeper layers. Finally, by applying transfer learning to future scenario simulations (2070–2100), we assess the stationarity and transferability of NAO predictability pathways.

A regular series of streamed online seminars.  The aim of the seminar series is to offer easy-to-access and interactive online seminars designed to share latest thinking and good practice, and exchange ideas, tools and processes. We envisage the seminar series will become an exciting vehicle that helps to encourage free flowing dialogue and collaboration right across the NCAS community. Seminars can have a science focus or be used to share anything that may be of professional interest to the NCAS community.

Seminars will take place every other Wednesday at 13:00.  Seminars are hosted on Google Meet to join follow the link 

Google Meet joining info
Video call link: https://meet.google.com/xjf-eida-wch
Or dial: ‪(GB) +44 20 3956 5045‬ PIN: ‪936 128 191‬#
More phone numbers: https://tel.meet/xjf-eida-wch?pin=8321800743980

Please note these seminars are intended to be internal to NCAS.  Please do not share details of the link without prior permission.

Please follow these simple guidelines to help make our seminar successful.

1. Please put yourself on mute.

2. If you have a question add it to the chat.  At the end of the talk the Chair will give you the opportunity to ask your question.