Summary
In 1922 monitoring of global irradiation started in Stockholm, Sweden. Over the years SMHI has been measuring this meteorological quantity with various instruments and at different sites within Stockholm. This type of changes of instruments and sites cause minor, but important systematic changes in the measured global irradiation. Therefore, it is not recommended to directly compare the results from different periods.
The report presents methods how this can be done and there is a final data set with long-term global radiation data for Stockholm. Daily and monthly final data are presented on a web-page at www.smhi.se
As a bi-product the sunshine duration was also digitized, controlled and corrected. These data can be found in Appendix 3.