NAO predictability from external forcing in the late 20th century

Abstract The North Atlantic Oscillation (NAO) is predictable in climate models at near-decadal timescales. Predictive skill derives from ocean initialization, which can capture variability internal to the system, and external radiative forcing. Herein, we show that predictive for NAO a very large uninitialized multi-model ensemble commensurate with previously reported state-of-the-art initialized prediction system. system produce similar levels of northern European precipitation SSTs. Identifying these components becomes possible ensemble, confirming erroneously low signal-to-noise ratio identified both models. Though results here imply forcing major source NAO, they also indicate initialization may be important particular events (the mid-1990s strong positive NAO), and, as suggested, certain regions such subpolar ocean. Overall, suggest improving models’ response help resolve known error