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Quantification of the effect of urbanization on solar dimming
Author(s) -
Alpert Pinhas,
Kishcha Pavel
Publication year - 2008
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/2007gl033012
Subject(s) - population density , population , atmospheric sciences , environmental science , urbanization , radiation , saturation (graph theory) , aerosol , geography , meteorology , physics , demography , ecology , biology , optics , mathematics , combinatorics , sociology
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/km 2 . Dimming was dominated by anthropogenic aerosol emissions: the decline in surface solar radiation intensified from −0.05 W/m 2 /yr to −0.32 W/m 2 /yr, with population density increasing from 10 to 200 person/km 2 . At sites with population density >200 person/km 2 , 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/m 2 which is equivalent to about 8%.