Quantification of the urbanization impacts on solar dimming and brightening over China

Metropolis’ contribution (anthropogenic aerosols) to solar dimming and brightening remains a hot topic of special concern over the past several decades. However, urbanization effects on surface incident solar radiation (R s) have not been comprehensively investigated. In this study, the urbanization effects on solar dimming and brightening were addressed using the densely distributed reconstructed R s data at 375 stations and 92 urban–rural station pairs over the time period of 1960–2019 in China. The results indicate that the impacts of urbanization on the monthly mean R s is 0.86 ± 7.99 W m−2 during the study period, while the impact is 0.90 ± 8.30 W m−2 and 0.82 ± 8.26 W m−2 for the solar dimming (1960–1992) and brightening (1992–2019) phase, respectively. The urbanization effects on the trend of R s is −0.39 and 0.16 W m−2 per decade during dimming and brightening, respectively. It also found that urbanization effects on R s trend differs strikingly in magnitudes for specific regions in China. Generally, urbanization speeds up China’s dimming in the dimming phase and slows down China’s brightening in the brightening phase.