Diffuse and direct components of solar radiation in ground-based and satellite-derived data

Many applications of solar radiation data require values for the separate diffuse (F) and direct (R) components of global radiation (G). Accurate measurement of these has been difficult, and beyond the scope of many meteorological and climate networks. Here I describe the use of high-quality data from a Baseline Surface Radiation Network (BSRN) site to assess and enhance the quality and utility of surface irradiance data, whether measured by ground-based networks or inferred from satellite data. Prediction of R and F from measured G is shown to be consistent from timescales of one minute to one hour, and accuracy is adequate for practical use in solar energy applications.