Method for Flagging Shaded Solar Data Using a Semi-Graphical Representation
Abstract
Solar radiation monitoring instruments should have unobstructed views to the sun at all times of the day and year as it moves in the local sky. If shading is identified, the measured data at those points should be quality-flagged automatically, as large amounts of data are to be processed, and excluded from the ‘usable’ data. To process the data, the shaded areas have to be expressed as equations or conditions that define them and allow to determine whether any measurement was taken inside the shaded area. There is no established method for identifying and flagging those shaded data when analysing solar radiation measurements. This work presents a method that uses CERN’s ROOT data analysis framework to define the shaded area graphically in an efficient and precise way, translating this into a region against which each measurement is easily checked.