A computer implemented method of estimating at least one solar irradiance component, the method comprising: obtaining a sensor measurement from an instrument to provide a measured global horizontal irradiance (GHImeasured), wherein the measured global horizontal irradiance (GHImeasured) consists of at least an estimated diffuse horizontal irradiance (DHIestimated) and an estimated direct normal irradiance (DNIestimated); providing at least one modeled component, wherein at least one of the modeled components is a modeled global horizontal irradiance based on an atmospheric model (GHI model); calculating an irradiance estimate modifier (IMOD) in a computing device according to the measured global horizontal irradiance (GHImeasured) and the modeled global horizontal irradiance (GHI model); and providing at least one estimated solar irradiance component by a computing device according to the irradiance estimate modifier (IMOD) and at least one modeled component.