Physical and Statistical Analysis Procedure of Solar Irradiance Measurements Based on Sky Cover Conditions
Abstract
Global climate change has popularized investigations of solar resources, essentially through long-term series of solar irradiance measurements. This investigation presents a physical and statistical procedure for analysis of global (IG), sky-diffuse (ID) and direct-beam (IB) solar irradiance measurements in horizontal surfaces, acquired in 5-minute instantaneous average (Wm-2) by the Solar Radiometry Laboratory of the School of Agricultural Sciences (São Paulo State University - UNESP) in Botucatu/São Paulo/Brazil. The procedure was implemented based on quality control rules of the International Commission on Illumination (CIE) to detect physically impossible events and statistical ranges in function of sky coverage to identify questionable events. The use of this type of procedure can assist Brazilian governmental, academic and industrial institutions in providing a more reliable solar radiation database in different regions.