Revision of solar radiation product ERA5 based on random forest algorithm.

This study performed a multi - scale error analysis of the mean surface downward shortwave radiation flux product ERA5 (0. 25° X 0. 25°) of the European Centre for Medium - Range Weather Forecasts ( ECMWF) using 93 pieces of solar radiation hourly data in 2013 of China. Subsequently, this study revised and analyzed the total radiation product ERA5 by training the random forest model using various relevant elements such as meteorological and geographic ones. Finally, the model was used to obtain the map of revised hourly radiation spatial distribution. As a result, the reanalyzed data can be beter applied in industries such as agriculture, electric power, and urban construction. The results are as follows. $ The MAE, RMSE, and R values between the ERA5 solar radiation and the measured values of stations in 2013 were 27.60 W/m2, 29. 87 W/m2, and 0. 97 respectively. Moreover, the ERA5 values were higher than the measured values of stations. % The accuracy was improved after the revision using the random forest model. After revision, the MAE, RMSE, and R values between the ERA5 solar radiation and the measured values of stations were 3. 34 W/m2, 3.85 W/m2, and 1. 00, respectively, indicating that correlation was significantly improved. © The spatial macroscopic distribution paUerns of radiation before and after revision were consistent, but the ERA5 radiation value significantly decreased in local areas. [ABSTRACT FROM AUTHOR]