Worldwide variations in artificial skyglow
Davies, Thomas W.
Gaston, Kevin J.
Nature Publishing Group
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Despite constituting a widespread and significant environmental change, understanding of artificial nighttime skyglow is extremely limited. Until now, published monitoring studies have been local or regional in scope, and typically of short duration. In this first major international compilation of monitoring data we answer several key questions about skyglow properties. Skyglow is observed to vary over four orders of magnitude, a range hundreds of times larger than was the case before artificial light. Nearly all of the study sites were polluted by artificial light. A non-linear relationship is observed between the sky brightness on clear and overcast nights, with a change in behavior near the rural to urban landuse transition. Overcast skies ranged from a third darker to almost 18 times brighter than clear. Clear sky radiances estimated by the World Atlas of Artificial Night Sky Brightness were found to be overestimated by ~25%; our dataset will play an important role in the calibration and ground truthing of future skyglow models. Most of the brightly lit sites darkened as the night progressed, typically by ~5% per hour. The great variation in skyglow radiance observed from site-to-site and with changing meteorological conditions underlines the need for a long-term international monitoring program.
MILIEU (FU Berlin)
Federal Ministry of Education and Research, Germany
EU COST Action ES1204 (Loss of the Night Network)
European Research Council (ERC) under the EU's Seventh Framework Program (FP7/2007-2013)
panish Network for Light Pollution Studies
National Aeronautics and Space Administration (Goddard Space Flight Center)
Ohio State University
University of Iowa
The Adam Mickiewicz University
Open access journal
Vol. 5, article 8409
Place of publication