Hidden potential in predicting wintertime temperature anomalies in the
Northern Hemisphere
Abstract
Variability of the North Atlantic Oscillation (NAO) drives wintertime
temperature anomalies in the Northern Hemisphere. Dynamical seasonal
prediction systems can skilfully predict the winter NAO. However,
prediction of the NAO-dependent air temperature anomalies remains
elusive, partially due to the low variability of predicted NAO. Here, we
demonstrate a hidden potential of a multi-model ensemble of operational
seasonal prediction systems for predicting wintertime temperature by
increasing the variability of predicted NAO. We identify and subsample
those ensemble members which are close to NAO index estimated from
initial autumn conditions. In our novel multi-model approach, the
correlation prediction skill for wintertime Central Europe temperature
is improved from 0.25 to 0.66, accompanied by an increased winter NAO
prediction skill of 0.9. Thereby, temperature anomalies can be skilfully
predicted for the upcoming winter over a large part of the Northern
Hemisphere through increased variability and skill of predicted NAO.