Comparison of Historical Satellite Based Estimates of Solar Radiation Resources with Recent Rotating Shadowband Radiometer Measurements

摘要

Satellite based solar radiation estimates have recently been incorporated into the 1990 to 2005 update to the 1961-1990 U.S. National Solar Radiation Database (NSRDB). The National Aeronautics and Space Administration (NASA) also supplies satellite based estimates of solar radiation. The usefulness of such data with respect to solar resources for site selection and designing solar energy conversion systems is often questioned. The availability of rotating shadow band radiometer measurement data at several new stations provides an opportunity to compare historical satellite based estimates of solar resources with measurements. We compare mean monthly daily total (MMDT) solar radiation data from eight years of NSRDB and 22 years of NASA hourly global horizontal and direct beam solar estimates with measured data from three stations, collected after the end of the available resource estimates. We compare the most recent shadowband radiometer MMDT with a complement of thermopile "first class" solar radiometers at one of the sites. Quantitative analysis shows that in the majority of cases, the long term average MMDT and measured data are comparable, within 10% of each other for global, and 20% for direct radiation MMDT.