Model performance against Final Global TEC product provided by the Universitat Politècnica de Catalunya (UPC) for the period June 2017 to May 2018: (a) distribution of TEC difference (forecast-actual), statistical parameters are reported together with a red line indicating the mean; (b) map of the mean values of the TEC difference (forecast-actual); (c) time profile of the RGEC parameter, the black dashed line indicates the zero reference value; (d) map of the standard deviation of the TEC difference (forecast-actual).