A review and comparison of surface incident shortwave radiation from multiple data sources: satellite retrievals, reanalysis data and GCM simulations

Surface incident shortwave radiation (R-s) can promote the circulation of substance and energy, and the accuracy of its estimation is of great significance for climate studies. The R-s can be acquired from satellite retrievals, reanalysis predictions and general circulation model (GCM) simulations. Although R-s estimates have been evaluated and compared in previous studies, most of them focus on evaluating the R-s estimates over specific regions using ground measurements from limited stations. Therefore, it is essential to comprehensively validate R-s estimates from multiple data sources. In this study, ground measurements of 690 stations from BSRN, GEBA, CMA, GC-NET and buoys were employed to validate the R-s estimates from seven representative products (GLASS, GEWEX-SRB, CERES-EBAF, ERA5, MERRA2, CFSR and CMIP6). The validation results indicated that the selected products overestimated R-s globally, with biases ranged from 0.48 to 21.27 W/m(2). The satellite retrievals showed relatively better accuracy among seven datasets compared to ground measurements at the selected stations. Moreover, the selected seven products were all in poor accuracy at high-latitude regions with RMSEs greater than 50 W/m(2). The long-term variation trends were also analyzed in this study.

Automated summary

Surface incident shortwave radiation (R-s) is crucial for substance and energy circulation, and its accurate estimation is significant for climate studies. This study validates R-s estimates from seven representative products using ground measurements from multiple data sources. The results show that the selected products generally overestimate R-s globally, with biases ranging from 0.48 to 21.27 W/m(2). Satellite retrievals demonstrate relatively better accuracy compared to ground measurements, but all selected products perform poorly at high-latitude regions with RMSEs greater than 50 W/m(2).