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Author Kocifaj, M. url  doi
openurl 
  Title Two-stream approximation for rapid modeling the light pollution levels in local atmosphere Type Journal Article
  Year 2012 Publication Astrophysics and Space Science Abbreviated Journal Astrophys Space Sci  
  Volume 341 Issue 2 Pages 301-307  
  Keywords (up) Light pollution; Atmospheric effects; Methods: numerical; Radiative transfer; Scattering; modeling; two-stream approximation  
  Abstract The two-stream concept is used for modeling the radiative transfer in Earth's atmosphere illuminated by ground-based light sources. The light pollution levels (illuminance and irradiance) are computed for various aerosol microphysical parameters, specifically the asymmetry parameter g A , single scattering albedo ω A , and optical thickness τ A . Two distinct size distributions of Junge's and gamma-type are employed. Rather then being a monotonic function of τ A , the diffuse illuminance/irradiance shows a local minimum at specific τ A, lim independent of size distribution taken into consideration. The existence of local minima has relation to the scattering and attenuation efficiencies both of which have opposite effects. The computational scheme introduced in this paper is advantageous especially if the entire set of calculations needs to be repeated with an aim to simulate diffuse light in various situations and when altering optical states of the atmospheric environment.  
  Address  
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  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 0004-640X ISBN Medium  
  Area Expedition Conference  
  Notes Approved no  
  Call Number IDA @ john @ Serial 273  
Permanent link to this record
 

 
Author Kocifaj, M. url  doi
openurl 
  Title Light-pollution model for cloudy and cloudless night skies with ground-based light sources Type Journal Article
  Year 2007 Publication Applied Optics Abbreviated Journal Appl. Opt.  
  Volume 46 Issue 15 Pages 3013  
  Keywords (up) light pollution; modeling  
  Abstract The scalable theoretical model of light pollution for ground sources is presented. The model is successfully employed for simulation of angular behavior of the spectral and integral sky radiance and∕or luminance during nighttime. There is no restriction on the number of ground-based light sources or on the spatial distribution of these sources in the vicinity of the measuring point (i.e., both distances and azimuth angles of the light sources are configurable). The model is applicable for real finite-dimensional surface sources with defined spectral and angular radiating properties contrary to frequently used point-source approximations. The influence of the atmosphere on the transmitted radiation is formulated in terms of aerosol and molecular optical properties. Altitude and spectral reflectance of a cloud layer are the main factors introduced for simulation of cloudy and∕or overcast conditions. The derived equations are translated into numerically fast code, and it is possible to repeat the entire set of calculations in real time. The parametric character of the model enables its efficient usage by illuminating engineers and∕or astronomers in the study of various light-pollution situations. Some examples of numerical runs in the form of graphical results are presented.  
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  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 0003-6935 ISBN Medium  
  Area Expedition Conference  
  Notes Approved no  
  Call Number IDA @ john @ Serial 277  
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Author Rea, M. S.; Bierman, A. url  openurl
  Title Spectral considerations for outdoor lighting: Consequences for sky glow Type Journal Article
  Year 2014 Publication Lighting Research and Technology Abbreviated Journal Lighting Res. & Tech.  
  Volume 47 Issue 8 Pages 920-930  
  Keywords (up) Lighting; skyglow; spectrum; scattering; aerosol; modeling  
  Abstract It is well known that the magnitude of sky glow on a clear night depends upon the aerosol content in the atmosphere and the spectral power distribution (amount and spectrum). Sources with a greater proportion of short-wavelength radiation produce more backscattered radiation, but as aerosol density increases, the differential effect of spectrum becomes smaller. Sky glow magnitude also depends upon the operating characteristics of the detector and will be greater when the spectrum of the backscattered radiation is tuned to the spectral band-pass characteristics of the detector. The human visual system is most often used to assess sky glow magnitude, but its spectral response is not limited to a single, univariate detector. Rather, the retina is composed of many neural channels, each with its own spectral and absolute sensitivities to optical radiation. Since we can use a different neural channel to see an individual star than we do to gain an overall impression of sky brightness, changes to the spectral power distribution of backscattered radiation differentially, and simultaneously, affect one’s ability to see a single star and to assess sky brightness. A general method for assessing sky glow based upon aerosol content, spectral power distribution and the specific operating characteristics of a detector, human or otherwise, is offered.  
  Address Lighting Research Center, Rensselaer Polytechnic Institute, Troy, New York, USA  
  Corporate Author Thesis  
  Publisher The Society of Light and Lighting Place of Publication Editor  
  Language Summary Language Original Title  
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  Notes Approved no  
  Call Number IDA @ john @ Serial 1065  
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Author Bará, S.; Nievas, M.; Sanchez de Miguel, A.; Zamorano, J. url  openurl
  Title Zernike analysis of all-sky night brightness maps Type Journal Article
  Year 2014 Publication Applied Optics Abbreviated Journal Appl Opt  
  Volume 53 Issue 12 Pages 2677-2686  
  Keywords (up) modeling; light at night; light pollution; all-sky; Zernike polynomials; image decomposition; sky brightness  
  Abstract All-sky night brightness maps (calibrated images of the night sky with hemispherical field-of-view (FOV) taken at standard photometric bands) provide useful data to assess the light pollution levels at any ground site. We show that these maps can be efficiently described and analyzed using Zernike circle polynomials. The relevant image information can be compressed into a low-dimensional coefficients vector, giving an analytical expression for the sky brightness and alleviating the effects of noise. Moreover, the Zernike expansions allow us to quantify in a straightforward way the average and zenithal sky brightness and its variation across the FOV, providing a convenient framework to study the time course of these magnitudes. We apply this framework to analyze the results of a one-year campaign of night sky brightness measurements made at the UCM observatory in Madrid.  
  Address Área de Óptica, Dept. de Física Aplicada, Fac. de Física, Universidade de Santiago de Compostela, 15782 Santiago de Compostela, Galicia, Spain  
  Corporate Author Thesis  
  Publisher Optical Society of America Place of Publication Editor  
  Language English Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 0003-6935 ISBN Medium  
  Area Expedition Conference  
  Notes PMID:24787595 Approved no  
  Call Number IDA @ john @ Serial 318  
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Author Kocifaj, M.; Solano Lamphar, H.A. url  doi
openurl 
  Title Skyglow: a retrieval of the approximate radiant intensity function of ground-based light sources Type Journal Article
  Year 2014 Publication Monthly Notices of the Royal Astronomical Society Abbreviated Journal Monthly Notices of the Royal Astronomical Society  
  Volume 439 Issue 4 Pages 3405-3413  
  Keywords (up) radiative transfer; atmospheric effects; light pollution; methods: observational; site testing; skyglow; modeling  
  Abstract The angular distribution of the light emitted from a city is an important source of information about public lighting systems and it also plays a key role in modelling the skyglow. Usually, the upwardly directed radiation is characterized through a parametrized emission function – a semi-empirical approach as a reasonable approximation that allows for fast computations. However, theoretical or experimental retrievals of emission characteristics are extremely difficult to obtain because of both the complexity of radiative transfer methods and/or the lack of highly specialized measuring devices.

Our research has been conducted with the specific objective to identify an efficient theoretical technique for retrieval of the emission pattern of ground-based light sources in order to determine the optimum values of the scaling parameters of the Garstang function. In particular, the input data involve the zenith luminance or radiance with horizontal illuminance or irradiance. Theoretical ratios of zenith luminance LV(0) to horizontal illuminance DV are calculated for a set of distances d that separate a hypothetical observer from the light source (a city or town). This approach is advantageous because inexpensive traditional equipment can be used to obtain the mean values of the Garstang parameters. Furthermore, it can also be applied to other parametrizable emission functions and to any measuring site, even one with a masked horizon.
 
  Address Department of Experimental Physics, Faculty of Mathematics, Physics and Informatics, Comenius University, Mlynská dolina, 842 48 Bratislava, Slovak Republic  
  Corporate Author Thesis  
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  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 326  
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