Probabilistic Solar Forecasts Evaluation Part I: Ensemble Prediction Systems (Eps)

This pair of articles proposes a framework to perform a comprehensive testing procedure on solar probabilistic forecasts. The evaluation framework is based on graphical diagnosis tools and quantitative scores initially designed by the weather forecasts verification community. To illustrate the application of the proposed verification framework, two sites, which experience very different climatic conditions, have been selected. First, Desert Rock, situated in the continental US, has high occurrence of clear skies. And second, Tampon, situated on the Reunion tropical island, presents highly variable sky conditions.Part I focuses on the assessment of ensemble forecasts commonly provided by meteorological utilities such as ECMWF or NCEP. The singular nature of this type of probabilistic forecasts requires to carefully indicate the assumptions used to define the associated CDF and to use suitable verification tools.