Physical behaviour of anthropogenic light propagation into the nocturnal environment

Abstract

Propagation of artificial light at night (ALAN) in the environment is now known to have non negligible consequences on fauna, flora and human health. These consequences depend on light levels and their spectral power distributions, which in turn rely on the efficiency of various physical processes involved in the radiative transfer of this light into the atmosphere and its interactions with the built and natural environment. ALAN can affect the living organisms by direct lighting and indirect lighting (scattered by the sky and clouds and/or reflected by local surfaces). This paper mainly focuses on the behaviour of the indirect light scattered under clear sky conditions. Various interaction processes between anthropogenic light sources and the natural environment are discussed. This work mostly relies on a sensitivity analysis conducted with the light pollution radiative transfer model, Illumina (Aubé et al . 2005 Light pollution modelling and detection in a heterogeneous environment: toward a night-time aerosol optical depth retrieval method. In Proc. SPIE 2005, vol. 5890, San Diego, California, USA). More specifically, the impact of (i) the molecular and aerosol scattering and absorption, (ii) the second order of scattering, (iii) the topography and obstacle blocking, (iv) the ground reflectance and (v) the spectrum of light devices and their angular emission functions are examined. This analysis considers different behaviour as a function of the distance from the city centre, along with different zenith viewing angles in the principal plane.

Evaluating the summer night sky brightness at a research field site on Lake Stechlin in northeastern Germany

“…Artificial skyglow is one type of LP that is mainly observed in densely populated areas where ALAN is scattered by atmospheric molecules or aerosols and returned to Earth [13]. Skyglow can be drastically amplified by several orders of magnitude due to the presence of clouds as shown by empirical [14,15] and theoretical [16] work.…”

Rapid assessment of lamp spectrum to quantify ecological effects of light at night

“…To evaluate the potential effect of each lamp on night sky pollution, we calculated the Star Light Index proposed by Aubé et al (2013) using the spreadsheet provided as an electronic supplement, which tracks human scotopic vision. We also calculated indices to evaluate the effect of spectrum on Rayleigh scattering, which would be prevalent near cities, and Mie scattering, which would predominate in indirect skyglow >80 km from city centers (Aubé, 2015;Luginbuhl, Boley, & Davis, 2014; see Figure 2).…”

The LED Paradox: How Light Pollution Challenges Experts to Reconsider Sustainable Lighting

“…This is not surprising, considering that the light spectrum plays a key role in ecological, medical, as well as astronomical research on artificial light at night [25]. Astronomers know that blue-rich lighting scatters more in the atmosphere (Rayleigh scattering) and thus contributes to undesirable sky glow, which is also reflected in the scientific literature [26][27][28]. Neuro-scientists and biologists show that blue-rich light at night has the greatest effects on the circadian rhythm of humans [29][30][31] and on a number of wildlife species [9,[32][33][34].…”