Noémie Le Carrer:
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Making Sense of Ensemble Predictions in Weather Forecasting: Can Possibility Theory Overcoe the Limitations of Standard Probabilistic Interpretations?
Ensemble forecasting is widely used in weather prediction to reflect uncertainty about high-dimensional, nonlinear systems with extreme sensitivity to initial conditions. Results are generally interpreted probabilistically but this interpretation is not reliable because of the chaotic nature of the dynamics of the atmospheric system as well as the fact that the ensembles were not actually generated probabilistically. We show that probability distributions are not the best way to extract the information contained in ensemble prediction systems. A more workable possibilistic interpretation of ensemble predictions takes inspiration from fuzzy and possibility theories. This framework also integrates other sources of information such as the insight on the local system’s dynamics provided by the analog method and provides more meaningful quantitative results.