Artificial Light at Night (ALAN) Research Literature Database -- Query Results

Cox, D. T. C., Sánchez de Miguel, A., Dzurjak, S. A., Bennie, J., & Gaston, K. J. (2020). National Scale Spatial Variation in Artificial Light at Night. Remote Sensing, 12(10), 1591. Abstract: The disruption to natural light regimes caused by outdoor artificial nighttime lighting has significant impacts on human health and the natural world. Artificial light at night takes two forms, light emissions and skyglow (caused by the scattering of light by water, dust and gas molecules in the atmosphere). Key to determining where the biological impacts from each form are likely to be experienced is understanding their spatial occurrence, and how this varies with other landscape factors. To examine this, we used data from the Visible Infrared Imaging Radiometer Suite (VIIRS) day/night band and the World Atlas of Artificial Night Sky Brightness, to determine covariation in (a) light emissions, and (b) skyglow, with human population density, landcover, protected areas and roads in Britain. We demonstrate that, although artificial light at night increases with human density, the amount of light per person decreases with increasing urbanization (with per capita median direct emissions three times greater in rural than urban populations, and per capita median skyglow eleven times greater). There was significant variation in artificial light at night within different landcover types, emphasizing that light pollution is not a solely urban issue. Further, half of English National Parks have higher levels of skyglow than light emissions, indicating their failure to buffer biodiversity from pressures that artificial lighting poses. The higher per capita emissions in rural than urban areas provide different challenges and opportunities for mitigating the negative human health and environmental impacts of light pollution. Keywords: Remote Sensing; United Kingdom; National parks; skyglow; VIIRS-DNB; albedo; landcover; light emissions; light pollution; protected areas; skyglow; sky brightness; urbanization http://alandb.darksky.org/show.php?record=2920
Wallner, S., & Kocifaj, M. (2019). Impacts of surface albedo variations on the night sky brightness – A numerical and experimental analysis. Journal of Quantitative Spectroscopy and Radiative Transfer, 239, 106648. Abstract: The aim of this paper is to analyze surface albedo impacts on artificial night sky brightness at zenith. The way in which these parameters correlate with each other is analyzed numerically and then experimentally by Sky Quality Meters (SQMs) in the city of Linz, Austria between 2016 and 2018. Three SQMs are located in city areas that differ in ground type, while other two are installed outside but near the city. To eliminate systematic errors of different SQMs or a missing inter-calibration of all devices, we examine relative change in zenithal brightness instead of its absolute values. However, the ground albedo not only depends on the ground type, but also shows seasonal variation most often driven by vegetation and environmental change. To understand these changes, we use SkyGlow simulator to perform numerical experiments on four different albedo models. The results have proven that seasonal variations are clearly visible as green city parts become darker around autumn and ratios to urban located SQMs increase. We show that there is a major difference in simulation results if either conducting city parts with various surface albedos or using only one averaged value over the whole city. The latter produces worse fit to the observed SQM data, implying that a use of various surface albedos is a need when modelling zenithal brightness in artificially lit areas of a city or town. Also, the seasonal changes of surface albedo cannot be neglected and the parameter itself must be included in the modelling tools. Keywords: Skyglow; albedo; surface albedo; Sky Quality Meter; Austria; Europe http://alandb.darksky.org/show.php?record=2675

Abstract: The disruption to natural light regimes caused by outdoor artificial nighttime lighting has significant impacts on human health and the natural world. Artificial light at night takes two forms, light emissions and skyglow (caused by the scattering of light by water, dust and gas molecules in the atmosphere). Key to determining where the biological impacts from each form are likely to be experienced is understanding their spatial occurrence, and how this varies with other landscape factors. To examine this, we used data from the Visible Infrared Imaging Radiometer Suite (VIIRS) day/night band and the World Atlas of Artificial Night Sky Brightness, to determine covariation in (a) light emissions, and (b) skyglow, with human population density, landcover, protected areas and roads in Britain. We demonstrate that, although artificial light at night increases with human density, the amount of light per person decreases with increasing urbanization (with per capita median direct emissions three times greater in rural than urban populations, and per capita median skyglow eleven times greater). There was significant variation in artificial light at night within different landcover types, emphasizing that light pollution is not a solely urban issue. Further, half of English National Parks have higher levels of skyglow than light emissions, indicating their failure to buffer biodiversity from pressures that artificial lighting poses. The higher per capita emissions in rural than urban areas provide different challenges and opportunities for mitigating the negative human health and environmental impacts of light pollution.

Keywords: Remote Sensing; United Kingdom; National parks; skyglow; VIIRS-DNB; albedo; landcover; light emissions; light pollution; protected areas; skyglow; sky brightness; urbanization

http://alandb.darksky.org/show.php?record=2920

Abstract: The aim of this paper is to analyze surface albedo impacts on artificial night sky brightness at zenith. The way in which these parameters correlate with each other is analyzed numerically and then experimentally by Sky Quality Meters (SQMs) in the city of Linz, Austria between 2016 and 2018. Three SQMs are located in city areas that differ in ground type, while other two are installed outside but near the city. To eliminate systematic errors of different SQMs or a missing inter-calibration of all devices, we examine relative change in zenithal brightness instead of its absolute values. However, the ground albedo not only depends on the ground type, but also shows seasonal variation most often driven by vegetation and environmental change. To understand these changes, we use SkyGlow simulator to perform numerical experiments on four different albedo models. The results have proven that seasonal variations are clearly visible as green city parts become darker around autumn and ratios to urban located SQMs increase. We show that there is a major difference in simulation results if either conducting city parts with various surface albedos or using only one averaged value over the whole city. The latter produces worse fit to the observed SQM data, implying that a use of various surface albedos is a need when modelling zenithal brightness in artificially lit areas of a city or town. Also, the seasonal changes of surface albedo cannot be neglected and the parameter itself must be included in the modelling tools.