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Global dimming or local dimming?: Effect of urbanization on sunlight availability
Author(s) -
Alpert Pinhas,
Kishcha Pavel,
Kaufman Yoram J.,
Schwarzbard Rotem
Publication year - 2005
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 - 10.1029/2005gl023320
Subject(s) - sunlight , environmental science , urbanization , population , atmospheric sciences , climatology , meteorology , geography , geology , demography , physics , biology , astronomy , ecology , sociology
From the 1950s to the 1980s, a significant decrease of surface solar radiation has been observed at different locations throughout the world. Here we show that this phenomenon, widely termed global dimming, is dominated by the large urban sites. The global‐scale analysis of year‐to‐year variations of solar radiation fluxes shows a decline of 0.41 W/m 2 /yr for highly populated sites compared to only 0.16 W/m 2 /yr for sparsely populated sites (<0.1 million). Since most of the globe has sparse population, this suggests that solar dimming is of local or regional nature. The dimming is sharpest for the sites at 10°N to 40°N with great industrial activity. In the equatorial regions even the opposite trend to dimming is observed for sparsely populated sites.