Temporal and spatial trends of solar radiation in China

In recent years, due to environmental pollution such as smog and PM2.5, surface solar radiation has changed drastically. Analysing and studying the temporal and spatial variation of solar radiation is of great significance for the deployment and planning of solar energy resources. Based on 85 solar radiation data monitoring stations and solar radiation estimation models, this study completes the solar radiation data of 1 994 stations from 1970 to 2020, analyses the long-term change trend and mutation situation of each station by using innovation trend and M-K mutation detection, and obtains the spatial distribution of annual and seasonal total solar radiation temporal changes in China. The results show that from 1970 to 2020, the total annual solar radiation in China shows a downward trend, with an average variation of -4.26 MJ/(m2·a), an upward trend in western Tibet, western Gansu and central Shaanxi, with an average variation of about 30 to 105 MJ/(m2·a ),the fastest downward trend in Shanxi, Henan, and Shandong, about -100 to -45 MJ/(m2·a), an upward trend of 0.89 MJ/m2in spring, and the average decreasing trend of total solar radiation in summer is the most obvious, with an average variation of -2.40 MJ/m2.