Global dimming or local dimming?: Effect of urbanization on sunlight availability
Article first published online: 2 SEP 2005
Copyright 2005 by the American Geophysical Union.
Geophysical Research Letters
Volume 32, Issue 17, September 2005
How to Cite
2005), Global dimming or local dimming?: Effect of urbanization on sunlight availability, Geophys. Res. Lett., 32, L17802, doi:10.1029/2005GL023320., , , and (
- Issue published online: 2 SEP 2005
- Article first published online: 2 SEP 2005
- Manuscript Accepted: 22 JUL 2005
- Manuscript Revised: 4 JUL 2005
- Manuscript Received: 22 APR 2005
 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/m2/yr for highly populated sites compared to only 0.16 W/m2/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.