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Author Solano Lamphar, H.A.; Kocifaj, M.
Title Urban night-sky luminance due to different cloud types: A numerical experiment Type Journal Article
Year 2015 Publication Lighting Research and Technology Abbreviated Journal (up) Lighting Res. & Tech.
Volume 48 Issue 8 Pages 1017-1033
Keywords Skyglow; modeling; urban; clouds; radiative transfer
Abstract In this paper, we analyse theoretically and numerically the sky glow in urban and suburban areas, focusing on the zenith-normalised luminance of a cloudy sky. The results suggest that the altitude of a cloud imposes important changes in the luminance distribution. Peak values of sky luminance can be observed at a distance d = R + h tan (z), where R is the city radius, and h is the cloud altitude. Fluctuations of the zenith-normalised luminance over the city are dictated by three effects, specifically (i) extinction and backscatter in the undercloud atmosphere, (ii) the cloud properties and (iii) the radiant intensity function of the dominant ground-based light sources. For high clouds, the aerosol optical property is evident at moderate elevation angles. The light beams emitted from different parts of the city propagate along different inclined trajectories before they contribute to the elevated zenith luminance of low clouds. Then, multiple factors combine together to form the light field at the ground, city-size and city emission pattern being of specific importance.
Address Cátedras CONACYT, Instituto de investigaciones Dr José María Luis Mora, Programa Interdisciplinario de Estudios Metropolitanos (CentroMet), Plaza Valentín Gómez Farías #12 Col. San Juan Mixcoac, México D.F. C.P 03730. E-mail: lamphar(at)gmail.com
Corporate Author Thesis
Publisher SAGE Place of Publication Editor
Language English Summary Language English Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1477-0938 ISBN Medium
Area Expedition Conference
Notes Approved no
Call Number IDA @ john @ Serial 1225
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Author Bierman, A.
Title Will switching to LED outdoor lighting increase sky glow? Type Journal Article
Year 2012 Publication Lighting Research and Technology Abbreviated Journal (up) Lighting Research and Technology
Volume 44 Issue 4 Pages 449-458
Keywords LED; light emitting diode; skyglow; light pollution; modeling; Radiative transfer
Abstract As LED sources are increasingly being used for outdoor lighting, concerns are being raised about their impact on man-made sky glow. This paper compares the amount of light scattered back to Earth from a 6500 K phosphor-converted white LED light source to that from a 2050 K high pressure sodium (HPS) light source. Calculations based solely on molecular Rayleigh scattering provide an upper limit of 22% more scatter from the LED source, but are not realistic because the atmosphere has significant scatter from aerosol content. Adding in the effects of aerosols in the atmosphere, as derived from aerosol optical depth measurements and Mie scattering distributions, reduces the wavelength dependency of scattered light to where the LED source has roughly 10–20% more scattered light contributing to sky glow. Scattering ratios (LED:HPS) are calculated for different angles and atmospheric conditions.
Address Lighting Research Center, 21 Union Street, Troy, NY 12180-3352, USA; bierma2(at)rpi.edu
Corporate Author Thesis
Publisher SAGE Place of Publication Editor
Language English Summary Language English Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1477-1535 ISBN Medium
Area Expedition Conference
Notes Luginbuhl, Boley, and Davis (2013) dispute Bierman's thesis. Approved no
Call Number IDA @ john @ Serial 269
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Author Rabaza, O.; Aznar-Dols, F.; Mercado-Vargas, M.; Espin-Estrella, A.
Title A new method of measuring and monitoring light pollution in the night sky Type Journal Article
Year 2014 Publication Lighting Research and Technology Abbreviated Journal (up) Lighting Research and Technology
Volume 46 Issue 1 Pages 5-19
Keywords Instrumentation; all-sky; measurement; modeling; monitoring
Abstract This paper describes a method of measuring and monitoring light pollution in the night sky. This method is capable of instantly quantifying the levels of artificial radiance and monochromatic luminance of the sky glow by means of a system that includes an all-sky camera as well as several interference filters. The calibration is done with an integrating sphere where the measurement pattern used is obtained from the light reflected from the inner wall of the sphere which comes from radiation emitted by a calibration lamp with a known luminous flux. The inner wall of this sphere is a Lambertian surface, which ensures that the light reflected or falling on it is uniformly dispersed in all directions (i.e. the surface luminance is isotropic).
Address Ovidio Rabaza Castillo, E.T.S. de Ingenieros de Caminos, Canales y Puertos, Departamento de Ingenieria Civil, Campus de Fuentenueva, Universidad de Granada, 18071, Granada, Spain E-mail: ovidio(at)ugr.es
Corporate Author Thesis
Publisher SAGE Place of Publication Editor
Language English Summary Language English Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1477-1535 ISBN Medium
Area Expedition Conference
Notes Approved no
Call Number IDA @ john @ Serial 1347
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Author Kocifaj, M.
Title A numerical experiment on light pollution from distant sources: Light pollution from distant sources Type Journal Article
Year 2011 Publication Monthly Notices of the Royal Astronomical Society Abbreviated Journal (up) MNRAS
Volume 415 Issue 4 Pages 3609-3615
Keywords scattering; atmospheric effects; light pollution; methods: numerical; skyglow; modeling
Abstract To predict the light pollution of the night-time sky realistically over any location or measuring point on the ground presents quite a difficult calculation task. Light pollution of the local atmosphere is caused by stray light, light loss or reflection of artificially illuminated ground objects or surfaces such as streets, advertisement boards or building interiors. Thus it depends on the size, shape, spatial distribution, radiative pattern and spectral characteristics of many neighbouring light sources. The actual state of the atmospheric environment and the orography of the surrounding terrain are also relevant. All of these factors together influence the spectral sky radiance/luminance in a complex manner. Knowledge of the directional behaviour of light pollution is especially important for the correct interpretation of astronomical observations. From a mathematical point of view, the light noise or veil luminance of a specific sky element is given by a superposition of scattered light beams. Theoretical models that simulate light pollution typically take into account all ground-based light sources, thus imposing great requirements on CPU and MEM. As shown in this paper, a contribution of distant sources to the light pollution might be essential under specific conditions of low turbidity and/or Garstang-like radiative patterns. To evaluate the convergence of the theoretical model, numerical experiments are made for different light sources, spectral bands and atmospheric conditions. It is shown that in the worst case the integration limit is approximately 100 km, but it can be significantly shortened for light sources with cosine-like radiative patterns.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0035-8711 ISBN Medium
Area Expedition Conference
Notes Approved no
Call Number IDA @ john @ Serial 267
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Author Kocifaj, M.
Title Modelling the spectral behaviour of night skylight close to artificial light sources Type Journal Article
Year 2010 Publication Monthly Notices of the Royal Astronomical Society Abbreviated Journal (up) MNRAS
Volume 403 Issue 4 Pages 2105-2110
Keywords scattering; atmospheric effects; light pollution; methods: numerical; Modeling
Abstract Spectral features of the night sky are simulated under cloudless conditions. Numerical runs show that spectral composition of the diffuse light changes over the whole sky and sky radiances quickly respond to altering aerosol characteristics, such as the asymmetry parameter, single scattering albedo and total optical thickness. The general trend is a steep decrease of diffuse irradiance with a distance from the city centre. Powerstar HQI-NDL lamps produce more light at short wavelengths, thus implying the higher levels of light pollution. The red light may markedly contribute to the obtrusive light if Vialox NAV-4Y lamps are considered as a prevailing source of light in the model town. In a non-turbid atmosphere, the minimum radiance is notoriously observed close to the zenith. As aerosol loading increases, the minimum radiance is shifted to larger zenith angles at the opposite side of the light source. Obtained results may serve as corrections to spectrophotometry data, as the light pollution can be easily calculated for any sky element and for any spectral band.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0035-8711 ISBN Medium
Area Expedition Conference
Notes Approved no
Call Number IDA @ john @ Serial 276
Permanent link to this record