Teleconnection Strength and Network Design Control Reconstruction Skill of North Atlantic Climate Modes

ABSTRACT

Reconstructing the North Atlantic Oscillation (NAO) and East Atlantic (EA) Pattern is crucial for understanding past climate variability and improving climate predictions. This study examines the impact of proxy network density and location on the reconstructability of these modes, using an idealised pseudo‐proxy approach based on ERA5 reanalysis temperature and precipitation. Results show that temperature proxies contribute more skill than precipitation and that the sign of the teleconnection matters. For NAO reconstruction from temperature, networks combining both dipole poles outperform single‐pole networks at small to moderate network sizes. EA reconstruction displays only small, variable‐dependent benefits from sampling both centres of action. A parallel analysis using the CESM1 Last Millennium Ensemble confirms these patterns hold over centennial timescales and under external forcing. Because our pseudo‐proxies are idealised and noise‐free, our results provide an upper ceiling on reconstruction skill and a lower bound on proxy‐network density for a given skill level, highlighting the importance of careful site selection.