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.