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Keywords:

  • solar dimming;
  • urbanization;
  • atmospheric aerosols

[1] During the 25-year period (1964–1989), a noticeable decline in surface solar radiation, termed global dimming, over worldwide sites was essentially a local phenomenon associated with human activity as expressed by the sites' population density. Specifically, our findings indicate that solar dimming was observed only over a limited part (∼30%) of the total land area, restricted to highly-populated sites with population density higher than 10 person/km2. Dimming was dominated by anthropogenic aerosol emissions: the decline in surface solar radiation intensified from −0.05 W/m2/yr to −0.32 W/m2/yr, with population density increasing from 10 to 200 person/km2. At sites with population density >200 person/km2, a saturation effect was observed: declining trends were much less pronounced than those over sites with a lower population density. Overall, it is demonstrated that urban areas obtained less solar radiation, compared to rural areas, in the amount of ∼12 W/m2 which is equivalent to about 8%.