Predictable atmospheric circulation driver of Eurasian winter temperatures

Abstract In contrast to global warming trends, much of Eurasia experienced a winter cooling trend over 1990–2014. Some studies have proposed a causal link between this regional cooling, particularly strong over Siberia, to coincident reductions in Arctic sea-ice extent. However, free-running historical climate models overwhelmingly simulate a forced Eurasian warming signal, leading other studies to suggest that internal variability explains the observed cooling. Here, we use retrospective seasonal climate predictions to highlight a robust dynamical link between Siberian cooling and upstream north-east Atlantic atmospheric circulation changes. Examining the interannual predictability of these circulation patterns, we find spuriously weak but skilful model signals. When these weak dynamical signals are corrected, stronger low-frequency variability in downstream Siberian temperature also emerges, with half of the observed 1990–2014 cooling simulated. Our results suggest that Eurasian decadal climate variability is at least partly driven by a predictable atmospheric circulation response to slowly evolving boundary conditions.