Articles | Volume 13
27 Jul 2016
 | 27 Jul 2016

Validation of the new HelioClim-3 version 4 real-time and short-term forecast service using 14 BSRN stations

Claire Thomas, Laurent Saboret, Etienne Wey, Philippe Blanc, and Lucien Wald

Abstract. Meteosat Second Generation (MSG) satellite images acquired every 15 min during daytime are currently processed by the Heliosat-2 method every night to generate the HelioClim-3 (HC3) database of the surface solar irradiation for the day before. A new service is proposed based on version 4 of HC3 (HC3v4) that offers real-time and forecasted irradiation for horizons up to a few hours. The service is based on a local persistence of the clear-sky index. Its results were compared to coincident high quality 15 min global irradiations measured in fourteen stations belonging to the Baseline Surface Radiation Network (BSRN). For forecasts for a temporal horizon of 15 min ahead, the relative bias and root mean square error (RMSE) range respectively from 0 to 2 %, and 20 to 23 % for most stations. The correlation coefficient ranges from 0.94 to 0.95. These performances are similar to HC3v4 for the same stations. Expectedly, the quality of the forecasts degrades as the temporal horizon increases. For 1 h ahead forecasts of 15 min irradiation, the relative bias, root mean square error (RMSE) and correlation coefficient range respectively from −3 to 1 %, 30 to 37 %, and 0.90 to 0.91.

Short summary
HelioClim-3 (version 4) is a satellite-derived solar surface irradiance database available at d-1 until 2015. To fulfill the requirements of numerous users, a new service based on the principle of persistence has been developed; it provides solar data in real time and forecasts until the end of the current day. The service exhibits good performances for 15 min and 1 h ahead forecasts, and degrades as the temporal horizon increases. Several customers have so far purchased this service.