- Frontier Science Center for Deep Ocean Multispheres and Earth System (FDOMES) and Physical Oceanography Laboratory, College of Oceanic and Atmospheric Sciences, Ocean University of China, Qingdao, China (wh1636@stu.ouc.edu.cn)
The global target of net-zero emissions and carbon neutrality by the mid-21st century is accelerating the transition to clean energy. Accurately assessing solar energy potential requires high-quality hourly surface solar radiation (SSR) and direct radiation (Rd) datasets. This study evaluates hourly SSR and Rd data from two reanalysis products (ERA5 and MERRA-2) and three satellite-derived products (CERES, SARAH-E, and Solcast) against 22 years of homogeneous surface observations in China. This validation utilizes data from 96 stations for SSR and 17 stations for Rd, and includes both accuracy and stability tests:
- According to the accuracy test, SSR and Rdare often overestimated, with lower accuracy observed during sunrise and sunset. SSR exhibits larger seasonal variations in accuracy than Rd, with accuracy declining in the cold season. SARAH-E and ERA5 demonstrate the least overestimation of the diurnal cycle of SSR, indicating the highest accuracy. CERES and SARAH-E demonstrate the highest accuracy for Rd, with CERES underestimating and SARAH-E overestimating throughout the day.
- Decadal trends of SSR and Rdare also overestimated by most products. SSR stability is lower in the cold season compared to the warm season. Rd stability decreases notably in cloudy and polluted MERRA-2 and CERES exhibit the highest stability for SSR, while ERA5 demonstrates the highest stability for Rd.
In summary, as highlighted by the bold lines in Figure 1, ERA5 excels in capturing the diurnal cycle of SSR, and CERES demonstrates superior performance for Rd across China.
Figure 1. Overall comparison of products over China for hourly surface solar radiation (a) and direct radiation (b), regarding accuracy index (nMABD, the normalized mean absolute bias deviation, %) and stability index (absolute decadal trend bias, % decadal–1). The performance of each product correlates positively with the size of its hexagon.
How to cite: Wang, H. and Wang, Y.: Evaluation of Hourly Solar Radiation Products for Solar Energy Applications over China, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-8062, https://doi.org/10.5194/egusphere-egu25-8062, 2025.
