Distributed simulation for solar radiation of all‐weather in Fujian Province based on <scp>SUNFLUX</scp>

Abstract Solar radiation is a critical parameter in surface energy balance systems, and it is essential for climate analysis and resource assessment to achieve high‐resolution spatial simulation. In this study, SUNFLUX, a physical model that incorporates a ray‐tracing algorithm to account for terrain masking, is used to simulate the spatial distribution of global solar radiation across the complex terrain of Fujian Province. Compared with European Centre for Medium‐Range Weather Forecasts Reanalysis v5 data, the simulated global solar radiation under clear‐sky conditions achieves a correlation coefficient of 0.9943, with mean absolute error and root‐mean‐square error (RMSE) values of 0.73 W·m −2 and 6.41 W·m −2 respectively. Under all‐weather conditions, the correlation coefficient remains high (0.9706) with an RMSE of 14.24 W·m −2 . Validation against observational data from three stations (Fuzhou, Jian'ou, and Yong'an) show a correlation coefficient exceeding 0.8 at hourly scales and improving to over 0.85 at daily scales. Temporally, radiation exhibits a seasonal pattern with higher values in summer and lower values in winter. Spatially, a “higher in the south and east, lower in the north and west” distribution pattern is observed, with local enhancements on sunlit slopes and reductions on shaded slopes—particularly pronounced in winter. The study ultimately generates high‐resolution spatial distribution maps of global solar radiation for Fujian, providing robust support for solar energy resource assessment in complex terrains.