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Fig8.2.7-4: An example of the accumulated cyclone energy (ACE) product.  This takes into account number, strength, and duration of all the tropical storms forecast by the sub-seasonal ensemble during the weekly period within each arbitrarily defined ocean basin, and totals their energy.  This value is compared with a similarly derived ACE from the sub-seasonal range climate (ERSUBS-M-climateClimate) for the same week to determine the significance level for the given basin.  If significance is greater than 90% the basin is shaded.  Green bars represent the forecast and orange bars the model climatology - these can be directly compared.

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• Strike probability chart.  This is the probability (in %) that a tropical cyclone will pass within a 300 km radius from a given location and within the 7-day time window.   The charts are based on the number of sub-seasonal range ensemble members that predict a tropical cyclone, each member having equal weight.   It is similar to the tropical cyclone activity charts produced for the medium-range forecasts.  
• Probability anomaly chart.  This shows whether the strike probabilities are higher (red shading) or lower (blue shading) than probabilities within a 20-year model climatology within the same 7-day time window.  They are computed by subtracting the model climatological probabilities from the real-time forecast probabilities.  Mean anomalies of probability are shown by the scale.
• Model sub-seasonal range climate charts (ERSUBS-M-climateClimate) show weekly mean strike probabilities (in %) within the same 7-day time window.

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