Inter-comparison of Solar Resource Data Sets: NASA-SRB/SSE versus DLR-ISIS Global and Beam Irradiance

摘要

Two satellite-derived solar irradiance data sets covering the full globe are compared against each other. One is NASA's SSE (Surface meteorology and Solar Energy) data set, the other DLR's ISIS (Irradiance at the Surface derived from ISCCP cloud data) Both consist of boxes with coarse spatial resolution: SSE has approximately 100 km wide boxes, ISIS 280 km. Both data sets are based on long-term archives: SSE so far covers 10 years, ISIS 21 years. Also both data sets offer information on global hemispherical irradiance and direct normal irradi?ance, required for planning of concentrating or tracking solar energy devices. The two satellite schemes use differ?ing cloud detection, aerosols and water vapor, and sepa?rate radiative transfer calculations. Comparing both data sets in 12 different regions worldwide allows analyzing effects of different climates and satellite viewing geome?tries on quality. It is found that both data sets agree rea?sonably well for global irradiance indicated by an RMS deviation below 9%. On average over all regions SSE reports approximately 6% less irradiance than ISIS, This bias is similar for direct normal irradiance, but RMS is much higher exceeding 20%.