Outdoor solar radiometer calibration under ISO-9847:1992 standard and alternative methods

An alternative method for outdoor calibration of horizontal pyranometers, based on ISO-9847:1992, is presented and tested for several different field pyranometers. The new method differs from the standard method in its robust data analysis and in a concrete set of clear-sky filters that are proposed. The proposal is better suited for the automated data acquisition which is commonly used for this task. As a first step towards its validation, results from this method are compared to those resulting from a direct application of the ISO-9847:1992 standard.