Metastable Regime Behavior and Prefered Transitions of the North Atlantic Jet Stream

Christian Franzke
Britain Antarctic Survey
Natural Complexity

The metastable regime behavior and the predictability characteristics of the eddy-driven jet stream over the North Atlantic ocean are investigated. A Hidden Markov Model (HMM) analysis shows that the jet stream exhibits 3 significant metastable regimes which correspond to northern and southern jet states and a blocking state. A simple Markov model for predicting the regimes has a prediction horizon of about 6 days which is comparable with the predictability of blockings in the ECMWF ensemble forecasting system and we find prefered transition routes between the regimes. The dynamical causes of the regime behavior will be discussed.

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