Comparative Assessment of Solar Radiation by Satellite-Based and Reanalysis Products Over Vietnam Regions

This study compares the daily solar irradiance estimated from Himawari-8 satellite and by the ERA-Interim reanalysis of the European Center for Medium-range Weather Forecasts (ECMWF) against qualified ground measurements in 5 stations in different regions of Vietnam. The result showed better agreement between satellite estimation and observed data with high correlation of values 0.92-0.94 compared to that of ERA-products which is 0.67-0.72. We compared satellite-based estimation with ERA-Interim reanalysis in the spatial scale of 7 climate zones and temporal scale of 4 seasons. The results showed that ERA-Interim products were well associated with satellite-based estimates in seasonal trends, but with different biases. The difference between two products was particularly pronounced in the months of DJF periods and in the north part of Vietnam because of unresolved cloud in ERA reanalysis. Thus, satellite estimation of solar irradiation could be used for producing reliable solar radiation maps for Vietnam in condition of limited surface observations.