Worldwide variations in artificial skyglow

Abstract

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.

Out of the Dark: Establishing a Large-Scale Field Experiment to Assess the Effects of Artificial Light at Night on Species and Food Webs

“…To maximally utilize the setup and to gain as much information as possible on ecological changes in response to illumination, it should also serve as a nucleus for future experiments that may help to understand how ALAN affects natural ecosystems. Initial results from this experimental site about the skyglow level [44] and the impact of ALAN on microbial diversity and community respiration in freshwater sediments [12] have been recently published. Other researchers are explicitly invited to contact the corresponding authors if they would like to perform a study at the facility.…”

“…The SQM measures radiance in the astronomical units magSQM/arcsec 2 [44]. We report sky luminance relative to an assumed "natural night sky luminance" of 252 μcd/m 2 , following the convention of Cinzano et al [45].…”

Nutrition in the spotlight: metabolic effects of environmental light

“…socio-economic development, changes in LD environment may have adverse effects on human subjects and wildlife (4) . In animals, light pollution leads to behavioural and physiological adaptations, such as alterations in orientation, survivorship, reproductive success and visual communication (5,6) .…”

Measuring Light Pollution with Fisheye Lens Imagery from A Moving Boat – A Proof of Concept

“…NSB measurements with either single sensors or all-sky photometry are only sparsely done in an aquatic or even in a marine context [25]. We have recently quantified the NSB at a freshwater lake in Germany from a floating platform using both methods [16].…”

“…Ground based NSB measuring methods can provide information in overcast conditions. These include single sensors such as inexpensive handheld sky brightness meters [24] with the advantage of providing data from citizen scientists, hobby astronomers and researchers on a local to global scale [16,25,26]. The drawback of this method is that no spatial and no spectral information is available, and most devices only measure the NSB at zenith, potentially missing out higher fractions of LP near the horizon [16,21,27].…”