Method for flagging shaded solar data using a semi-graphical representation

Sola r ra dia tion monitoring instruments should have unobstructed views to the sun at a ll times of the day and the yea r a s it moves across the local sky, and measured data should be quality-flagged automatically, a s large amounts of da ta are to be processed. If shading is identified, the data a t the shaded areas should be properly flagged and excluded from the 'usable' data; for this, the shaded areas have to be expressed in the data processing code as equa tions or conditions that define the areas a nd a llow to determine whether a ny measurement was ta ken inside the sha ded area. There is no established method for identifying and flagging those shaded data when analysing sola r ra dia tion measurements. This work presents a method that uses CERN's ROOT Da ta Analysis Fra mework to define the shaded area gra phically in a n efficient a nd precise wa y, tra nslating this into a region a ga inst which ea ch measurement is then easily checked in the code, a nd discarded or flagged accordingly.