Using reduced data sets ISCCP-B2 from the Meteosat satellites to assess surface solar irradiance

This paper explores the capabilities of a combination of the reduced data set ISCCP-B2 from the Meteosat satellites and the recently developed method Heliosat-2 to assess the daily mean of the surface solar irradiance at any geographical site in Europe and Africa. Firstly, we discuss the implementation of the method Heliosat-2. Secondly, B2-derived irradiances are compared to coincident measurements made in meteorological networks for 90 stations from 1994 to 1997. Bias is less than 1 W m−2 for the whole set. Larger bias may be observed at individual sites, ranging from −15 to +32 W m−2. For the whole set, the root mean square difference is 35 W m−2 (17%) for daily mean irradiance and 25 W m−2 (12%) for monthly mean irradiance. These accuracies are close to those of similar data sets of irradiance, such as Medias and NASA Surface Radiation Budget. It is concluded that B2 data can be used in a reliable way to produce long-term time-series of irradiance for Europe, Africa and the Atlantic Ocean.