Validation of HelioClim-3 Version 4, HelioClim-3 Version 5 and MACC-RAD Using 14 BSRN Stations

Abstract

This communication presents the results of a comparison of three satellite-derived databases covering Africa, Europe, Middle East and part of South America, against corresponding 15min irradiations of very high quality measured by fourteen Baseline Surface Radiation Network (BSRN) stations. The three databases are accessible via the SoDa Service website, and are the two latest versions of HelioClim-3: versions 4 (HC3v4) and 5 (HC3v5), and the MACC-RAD database. The comparison was performed for durations of 15min, 1h, 1 day and 1 month for both the global irradiation received on a horizontal surface (GHI) and the direct irradiation received on a plane normal to sun rays (DNI).It is found that the three satellite-derived radiation databases exhibit satisfactory performances. For most of the fourteen locations, HC3v5 surpasses HC3v4 and MACC-RAD, with a bias ranging from -4 to 5% for the GHI and for all tested duration. The correlation coefficient is large for all databases and most often greater than 0.92 for 15min and 0.98 for daily irradiation for GHI. The RMSE is fairly constant for all locations for 15min and is approximately 20 kWh m-2 –slightly greater for MACC-RAD. -For daily irradiation, it ranges between 300 and 400 kWh m-2 for HC3v5, 300 and 500 kWh m-2 for HC3v4, and 400 and 550 kWh m-2 for MACC-RAD. Bias for the DNI is larger in absolute values than for GHI for all databases: -12 to 10% for HC3v5. The correlation coefficient is most often greater than 0.68 for 15min and 0.84 for daily irradiation. The RMSE for 15min ranges between 46 and 60 kWh m-2 for HC3v5, 46 and 63 kWh m-2 for HC3v4, and 48 and 66 kWh m-2 for MACC-RAD. For daily irradiation, it ranges between 1100 and 1600 kWh m-2 for HC3v5, between 1300 and 1700 kWh m-2 for HC3v4, and between 1000 and 1850 kWh m-2 for MACC-RAD. The MACC-RAD resource show promises provided the model for cloud properties is improved.