Validation of the Surface Downwelling Solar Irradiance Estimates of the HelioClim-3 Database in Egypt

Remote Sensing

Yehia Eissa⁸  Mohamed Korany³  Youva Aoun⁶  Mohamed Boraiy¹  Magdy M. Abdel Wahab⁹  Stephane C. Alfaro⁵  Philippe Blanc⁶  Mossad El-Metwally⁴  Hosni Ghedira⁸  Katja Hungershoefer⁷  Lucien Wald⁶  Richard Müller² 

[1] Physics and Mathematical Engineering Department, Faculty of Engineering, Port Said University, Port Said 42526, Egypt; E-Mail:;Masdar Institute, Research Center for Renewable Energy Mapping and Assessment, P.O. Box 54224 Abu Dhabi, UAE; E-Mail;Egyptian Meteorological Authority, Cairo 11599, Egypt; E-Mail:;Physics Department, Faculty of Science, Port Said University, Port Said 42526, Egypt; E-Mail:;Laboratoire Inter-universitaire des Systèmes Atmosphériques, Universités de Paris-Est Créteil et Paris-Diderot, Paris 94010, France; E-Mail:;MINES ParisTech, PSL Research University, O.I.E. – Centre Observation, Impacts, Energy, CS 10207 – 06904 Sophia Antipolis cedex, France; E-Mails:;Deutscher Wetterdienst, Offenbach 63067, Germany; E-Mail:;Masdar Institute, Research Center for Renewable Energy Mapping and Assessment, P.O. Box 54224 Abu Dhabi, UAE; E-Mail:;Astronomy and Meteorology Department, Faculty of Science, Cairo University, Giza 12613, Egypt; E-Mail:

关键词: atmosphere;    model;    solar radiation;    surface solar irradiance;   

DOI  :  10.3390/rs70709269

来源: mdpi

【 摘 要 】

HelioClim-3 (HC3) is a database providing time series of the surface downwelling solar irradiance that are computed from images of the Meteosat satellites. This paper presents the validation results of the hourly global horizontal irradiance (GHI) and direct normal irradiance (DNI), i.e., beam irradiance at normal incidence, of versions four and five of HC3 at seven Egyptian sites. The validation is performed for all-sky conditions, as well as cloud-free conditions. Both versions of HC3 provide similar performances whatever the conditions. Another comparison is made with the estimates provided by the McClear database that is restricted to cloud-free conditions. All databases capture well the temporal variability of the GHI in all conditions, McClear being superior for cloud-free cases. In cloud-free conditions for the GHI, the relative root mean square error (RMSE) are fairly similar, ranging from 6% to 15%; both HC3 databases exhibit a smaller bias than McClear. McClear offers an overall better performance for the cloud-free DNI estimates. For all-sky conditions, the relative RMSE for GHI ranges from 10% to 22%, except one station, while, for the DNI, the results are not so good for the two stations with DNI measurements.

【 授权许可】

CC BY   
© 2015 by the authors; licensee MDPI, Basel, Switzerland.