Uncertainty in monthly GHI due to daily data gaps. (15th November 2017)

• Record Type: Journal Article
• Authors: Peruchena, Carlos F.; Amores, Antonio F.
• Is Part Of: Solar energy. Volume 157(2017)
• Page Start: 827
• Page End: 829
• Publication Date: 2017-11-15
• Subjects: Global horizontal irradiance -- Uncertainty -- Gap -- Resource assessment; Solar energy -- Periodicals; Solar engines -- Periodicals; 621.47
• DOI: 10.1016/j.solener.2017.08.080
• Languages: English
• ISSNs: 0038-092X

Abstract

Highlights: Solar irradiation is analyzed on a daily basis in different climates. Uncertainties in the solar resource assessments associated with daily gaps are estimated. Sky clearness conditions highly influence the uncertainty levels found. Abstract: The common presence of gaps in solar irradiance series led to the development of new methods for quantifying uncertainty in evidence, and new schemes of inference from uncertain data. The uncertainty of monthly Global Horizontal solar Irradiation (GHI) averages is assessed in this study by investigating the impact of different amounts of daily data gaps. This paper quantifies the uncertainty in the calculation of monthly GHI values in the presence of daily gaps as a function of the monthly clearness index, ktm (ratio of the monthly GHI to its corresponding extraterrestrial solar irradiation at the same plane). The results indicate an inverse relation between ktm and GHI uncertainty due to daily data gaps: for the least clear skies (minimum ktm ), even just a single day missing introduces an uncertainty four times bigger than the best scenario. This difference increases with the number of missing days.