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Author Kocifaj, M.
Title Ground albedo impacts on higher-order scattering spectral radiances of night sky Type Journal Article
Year 2019 Publication Journal of Quantitative Spectroscopy and Radiative Transfer Abbreviated Journal Journal of Quantitative Spectroscopy and Radiative Transfer
Volume 239 Issue Pages (down) 106670
Keywords skyglow
Abstract The contribution from ground reflected light to the night sky radiance is of increased interest because of constant modernization of street lighting systems that now efficiently eliminate light emissions above the horizontal plane, so the appreciable fraction of artificial light directed upwards is from ground reflection. Diffuse light of a night sky shows a positive correlation with ground albedo (α), but it seems there is no linear trend between α and the night sky brightness (NSB), at least not for all sky elements, and, the mechanism of this relationship becomes even more complicated due to multiple scattering effects. The extent to which the ground reflectance influences the higher-order scattering radiance of night sky, and, the factors that initiate the crossover from single- to multiple-scattering dominance of the sky glow has been virtually unexplored until now.

We demonstrate here that albedo-induced effects in NSB exhibit an angular dependence, with amplitudes enhanced towards shorter wavelengths. For low values of ground reflectance and at short distances from a light source, the second-scattering radiance is found to be only a few percent of the first-order scattering radiance. However, the ratio of a higher- to the first-order scattering radiance gradually increases near horizon, specifically at the side opposite to the azimuthal position of the light source. Also the NSB in blue band has decreasing gradation tendency when increasing the altitude above sea level. The findings in this paper are significant in a proper incorporation of higher-order scattering in modeling the NSB under elevated reflectance conditions, and may be critical for saving computational time.
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 0022-4073 ISBN Medium
Area Expedition Conference
Notes Approved no
Call Number GFZ @ kyba @ Serial 2679
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Author Bará, S.; Falchi, F.; Furgoni, R.; Lima, R.C.
Title Fast Fourier-transform calculation of artificial night sky brightness maps Type Journal Article
Year 2020 Publication Journal of Quantitative Spectroscopy and Radiative Transfer Abbreviated Journal Journal of Quantitative Spectroscopy and Radiative Transfer
Volume 240 Issue Pages (down) 106658
Keywords Skyglow; Light pollution; Atmospheric optics; Photometry; Radiometry; Fourier transforms
Abstract Light pollution poses a growing threat to optical astronomy, in addition to its detrimental impacts on the natural environment, the intangible heritage of humankind related to the contemplation of the starry sky and, potentially, on human health. The computation of maps showing the spatial distribution of several light pollution related functions (e.g. the anthropogenic zenithal night sky brightness, or the average brightness of the celestial hemisphere) is a key tool for light pollution monitoring and control, providing the scientific rationale for the adoption of informed decisions on public lighting and astronomical site preservation. The calculation of such maps from satellite radiance data for wide regions of the planet with sub-kilometric spatial resolution often implies a huge amount of basic pixel operations, requiring in many cases extremely large computation times. In this paper we show that, using adequate geographical projections, a wide set of light pollution map calculations can be reframed in terms of two-dimensional convolutions that can be easily evaluated using conventional fast Fourier-transform (FFT) algorithms, with typical computation times smaller than 10^-6 s per output pixel.
Address Departamento de Física Aplicada, Universidade de Santiago de Compostela, 15782 Santiago de Compostela, Galicia, Spain; salva.bara(at)usc.es
Corporate Author Thesis
Publisher Elsevier Place of Publication Editor
Language English Summary Language English Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0022-4073 ISBN Medium
Area Expedition Conference
Notes Approved no
Call Number IDA @ john @ Serial 2782
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Author Wallner, S.; Kocifaj, M.
Title Impacts of surface albedo variations on the night sky brightness – A numerical and experimental analysis Type Journal Article
Year 2019 Publication Journal of Quantitative Spectroscopy and Radiative Transfer Abbreviated Journal Journal of Quantitative Spectroscopy and Radiative Transfer
Volume 239 Issue Pages (down) 106648
Keywords Skyglow; albedo; surface albedo; Sky Quality Meter; Austria; Europe
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.
Address Department of Astrophysics, University of Vienna, Türkenschanzstrasse 17, 1180 Vienna, Austria; stefan.wallner(at)univie.ac.at
Corporate Author Thesis
Publisher Elsevier Place of Publication Editor
Language English Summary Language English Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0022-4073 ISBN Medium
Area Expedition Conference
Notes Approved no
Call Number GFZ @ kyba @ Serial 2675
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Author Bará, S.; Rigueiro, I.; Lima, R.C.
Title Monitoring transition: Expected night sky brightness trends in different photometric bands Type Journal Article
Year 2019 Publication Journal of Quantitative Spectroscopy and Radiative Transfer Abbreviated Journal Journal of Quantitative Spectroscopy and Radiative Transfer
Volume 239 Issue Pages (down) 106644
Keywords Skyglow; Remote Sensing; Instrumentation
Abstract Several light pollution indicators are commonly used to monitor the effects of the transition from outdoor lighting systems based on traditional gas-discharge lamps to solid-state light sources. In this work we analyze a subset of these indicators, including the artificial zenithal night sky brightness in the visual photopic and scotopic bands, the brightness in the specific photometric band of the widely used Sky Quality Meter (SQM), and the top-of-atmosphere radiance detected by the VIIRS-DNB radiometer onboard the satellite Suomi-NPP. Using a single-scattering approximation in a layered atmosphere we quantitatively show that, depending on the transition scenarios, these indicators may show different, even opposite behaviors. This is mainly due to the combined effects of the changes in the sources' spectra and angular radiation patterns, the wavelength-dependent atmospheric propagation processes and the differences in the detector spectral sensitivity bands. It is suggested that the possible presence of this differential behavior should be taken into account when evaluating light pollution indicator datasets for assessing the outcomes of public policy decisions regarding the upgrading of outdoor lighting systems.
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 0022-4073 ISBN Medium
Area Expedition Conference
Notes Approved no
Call Number GFZ @ kyba @ Serial 2810
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Author Zhang, B.; Zhang, H.; Jing, Q.; Wang, J.
Title Light pollution on the growth, physiology and chlorophyll fluorescence response of landscape plant perennial ryegrass (Lolium perenne L.) Type Journal Article
Year 2020 Publication Ecological Indicators Abbreviated Journal Ecological Indicators
Volume 115 Issue Pages (down) 106448
Keywords Plants
Abstract Perennial ryegrass (Lolium perenne L.) was commonly used for urban green planting such as lawns, which was not only affected by sunlight, but also by light pollution caused by night artificial lighting. In order to see the ryegrass growth, physiological characters and chlorophyll fluorescence response to light pollution and provide the suitable lighting time, 6 different artificial lighting times (24/0 h, 22/2 h, 20/4 h, 18/6 h, 16/8 h and 14/10 h) were conducted in growth chambers. There were significant systematic differences in perennial ryegrass growth characters in seed germination rate, leaf length (LL) and leaf weight (LW) (F = 47.99, 28.34, 13.47, respectively; P < 0.01) while under 16/8h lighting time treatment which had the highest values and the increasing lighting time decreased the growth. It had the best effect under 16/8h lighting time treatment on leaf physiological reactions and also significant. The maximum curvature point temperature (TCC) was significant different (F = 28.08, P < 0.01). The relative variable fluorescence differences at 2 ms (VJ) was increased with the lighting time increased (F = 20.25, P < 0.01). The results of reaction center (RC) of PSII under 6 lighting times also had significant differences. For the result of the yield and efficiency of electron transport chain (ETC), Fv/Fm (φP0), ψ0 and φE0 showed the significantly increased trend with the lighting time decreased while the φD0 was decreased. The shape of the OJIP curves was sensitive to the lighting times which showed that with the increasing lighting times the chlorophyll fluorescence intensity changed and shifted the fluorescence curve lower. Leaf light-response curves (LC) were also significant under 6 lighting times. Significant positive correlations were found between leaf physiological characters (SP, SC, Chl a, Chl b, Chl a + b, WP and TCC) and J-I-P test chlorophyll fluorescence parameters (PIABS, ABS/RC and TR0/RC) except ET0/RC while the correlation with DI0/RC was significant negative. There were significant positive correlations between leaf physiological characters (SP, SC, Chl a, Chl b, Chl a + b, WP and TCC) and φP0, φE0, ψ0 while the relationships with φD0 were significantly negative. Nighttime artificial lighting acted as a depressor of the fitness of photosynthesis and growth characters, via the changing of the photosynthetic apparatus.
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 1470160X ISBN Medium
Area Expedition Conference
Notes Approved no
Call Number GFZ @ kyba @ Serial 2905
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