Calibration of long-term global horizontal irradiation estimated by HelioClim-3 through short-term local measurement campaigns: extending of the results to European and African sites

Abstract

International audienceThis paper proposes an adaptation of a recent ground-based short-term calibration algorithm applied to long-term time-series of global horizontal irradiation (GHI) provided by HelioClim-3 (HC3), a satellite-based surface solar irradiation database; it extends the initial conclusions for the South-East of France to a larger coverage. A first analysis of the long-term ground pyranometric measurements leads to the characterization of the clearness index error variability which confirms the systematic presence of, at least, a sinusoid component which period is equal to the astronomical year. On contrary of the first results based on the South-East of France, because the phasing of this sinusoid highly varies from one site to another, an adaptation of the original calibration procedure is proposed in order to have it applicable under different latitudes. The resulting mean bias error on the monthly GHI systematically goes below 3% when considering a 12-month local measurement campaign, while the seasonal variability of the error is drastically reduced