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Author Kocifaj, M.; Kómar, L.; Lamphar, H.; Wallner, S.
Title Are population-based models advantageous in estimating the lumen outputs from light-pollution sources? Type Journal Article
Year 2020 Publication Monthly Notices of the Royal Astronomical Society: Letters Abbreviated Journal
Volume (down) 496 Issue 1 Pages L138-L141
Keywords Remote Sensing
Abstract The total lumen output (TLO) from ground-based artificial light sources is required in a wide range of light-pollution models currently in use. No realistic assessment of diffuse light levels in the nocturnal environment is possible if the information on TLO is missing. Traditional approaches to skyglow modelling, if no lighting inventory is available, foresee to estimate TLO based on population and average amount of lumens per capita. However, we show in this letter that a model based on the area of artificially lit surfaces can reduce uncertainties in estimating TLO by 25 per cent for compact urban areas of defined centres and autonomous character and even 50 per cent for diffuse cities with small satellite towns interacting closely with the main city. The new model could be of great significance to the community of light-pollution researchers, especially astronomers, physicists, and modellers who use TLO routinely in light-pollution characterization.
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 1745-3925 ISBN Medium
Area Expedition Conference
Notes Approved no
Call Number UP @ altintas1 @ Serial 3181
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Author Kocifaj, M.; Bará, S.
Title Aerosol characterization using satellite remote sensing of light pollution sources at night Type Journal Article
Year 2020 Publication Monthly Notices of the Royal Astronomical Society: Letters Abbreviated Journal MNRAS
Volume (down) 495 Issue 1 Pages L76-L80
Keywords Skyglow; Radiative transfer; Light scattering; Aerosols
Abstract A demanding challenge in atmospheric research is the night-time characterization of aerosols using passive techniques, that is, by extracting information from scattered light that has not been emitted by the observer. Satellite observations of artificial night-time lights have been used to retrieve some basic integral parameters, like the aerosol optical depth. However, a thorough analysis of the scattering processes allows one to obtain substantially more detailed information on aerosol properties. In this letter, we demonstrate a practicable approach for determining the aerosol particle size number distribution function in the air column, based on the measurement of the angular radiance distribution of the scattered light emitted by night- time lights of cities and towns, recorded from low Earth orbit. The method is self-calibrating and does not require the knowledge of the absolute city emissions. The input radiance data are readily available from several spaceborne platforms, like the VIIRS-DNB radiometer onboard the Suomi-NPP satellite.
Address Faculty of Mathematics, Physics, and Informatics, Comenius University, Mlynska Dolina, 842 48 Bratislava, Slovakia; Miroslav.Kocifaj(at)savba.sk
Corporate Author Thesis
Publisher OUP Place of Publication Editor
Language English Summary Language English Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1745-3925 ISBN Medium
Area Expedition Conference
Notes Approved no
Call Number IDA @ john @ Serial 2910
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Author Wallner, S.; Kocifaj, M.; Komar, L.; Solano-Lamphar, H.A.
Title Night-sky imaging as a potential tool for characterization of total lumen output from small and medium-sized cities Type Journal Article
Year 2020 Publication Monthly Notices of the Royal Astronomical Society Abbreviated Journal
Volume (down) 494 Issue 4 Pages 5008-5017
Keywords Skyglow
Abstract In this article, the asymptotic formula developed in past work and applied to predict skyglow due to distant sources was evolved, with the objective of characterizing small and medium-sized cities in the observer's surroundings. To enable this, a combination of theoretical computations and in situ measurements is needed, aiming to distinguish between dominant and smaller light-emitting sources, with the latter usually being camouflaged when measuring the night sky. Furthermore, for numerical modelling of skyglow, few of the most important parameters, specifically the amount of total lumens installed and radiated to the upward hemisphere, can be derived. Astronomical observatories, in particular, can profit from this concept, since they are usually situated far away from large cities but can still be surrounded by smaller villages and towns. We present a detailed description of how theoretical computations are combined with all-sky photometry in order to obtain the properties mentioned. Results are compared with satellite data, showing that, regarding approximations undertaken for processing, they are comparable, underlining the functionality of our approach. The idea of including in situ observations enables us to quantify the impact of small and medium-sized cities globally and independent of location, as long as measurements were conducted outside light domes. In addition, the presented work may be of major interest to the light-pollution community if conducting long-term observations of cities, since the quality of commonly used satellite data is going to decrease in the future, due to blindness in short wavelengths and upcoming conversions of public lighting systems to blue-enlightened LEDs.
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 GFZ @ kyba @ Serial 2911
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Author Bará, S.; Aubé, M.; Barentine, J.; Zamorano, J.
Title Magnitude to luminance conversions and visual brightness of the night sky Type Journal Article
Year 2020 Publication Monthly Notices of the Royal Astronomical Society Abbreviated Journal MNRAS
Volume (down) 493 Issue 2 Pages 2429–2437
Keywords Skyglow; light pollution; atmospheric effects; techniques: photometric; methods: numerical; luminance
Abstract The visual brightness of the night sky is not a single-valued function of its brightness in other photometric bands, because the transformations between photometric systems depend on the spectral power distribution of the skyglow. We analyze the transformation between the night sky brightness in the Johnson-Cousins V band (mV, measured in magnitudes per square arcsecond, mpsas) and its visual luminance (L, in SI units cd m−2) for observers with photopic and scotopic adaptation, in terms of the spectral power distribution of the incident light. We calculate the zero-point luminances for a set of skyglow spectra recorded at different places in the world, including strongly light-polluted locations and sites with nearly pristine natural dark skies. The photopic skyglow luminance corresponding to mV = 0.00 mpsas is found to vary between 1.11–1.34 × 105 cd m−2 if mV is reported in the absolute (AB) magnitude scale, and between 1.18–1.43 × 105 cd m−2 if a Vega scale for mV is used instead. The photopic luminance for mV = 22.0 mpsas is correspondingly comprised between 176 and 213 μcd m−2 (AB), or 187 and 227 μcd m−2 (Vega). These constants tend to decrease for increasing correlated color temperatures (CCT). The photopic zero-point luminances are generally higher than the ones expected for blackbody radiation of comparable CCT. The scotopic-to-photopic luminance ratio (S/P) for our spectral dataset varies from 0.8 to 2.5. Under scotopic adaptation the dependence of the zero-point luminances with the CCT, and their values relative to blackbody radiation, are reversed with respect to photopic ones.
Address Departamento de Física Aplicada, Universidade de Santiago de Compostela, 15782 Santiago de Compostela, Galicia; salva.bara(at)usc.gal
Corporate Author Thesis
Publisher Oxford Academic Place of Publication Editor
Language English Summary Language English Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN ISBN Medium
Area Expedition Conference
Notes Approved no
Call Number IDA @ john @ Serial 2825
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Author Cavazzani, S.; Ortolani, S.; Bertolo, A.; Binotto, R.; Fiorentin, P.; Carraro, G.; Saviane, I.; Zitelli, V.
Title Sky Quality Meter and satellite correlation for night cloud-cover analysis at astronomical sites Type Journal Article
Year 2020 Publication Monthly Notices of the Royal Astronomical Society Abbreviated Journal
Volume (down) 493 Issue 2 Pages 2463-2471
Keywords Skyglow
Abstract The analysis of night cloud cover is very important for astronomical observations in real time, considering a typical observation time of about 15 minutes, and to provide statistics. In this article, we use the Sky Quality Meter (SQM) for high-resolution temporal analysis of the La Silla and Asiago (Ekar Observatory) sky: 3 and 5 minutes respectively. We investigate the annual temporal evolution of the natural contributions of the sky at a site not influenced by artificial light at night (ALAN) and at one highly influenced. We also make a correlation between GOES and Aqua satellite data and ground-based SQM data to confirm the relationship between the SQM data and cloud cover. We develop an algorithm that allows the use of the SQM for night cloud detection and reach correlations with the nighttime cloud cover detected by the GOES and Aqua satellites of 97.2 per cent at La Silla and 94.6 per cent at Asiago. Our algorithm also classifies photometric (PN) and spectroscopic nights (SN). We measure 59.1 per cent PN and 21.7 per cent SN for a total percentage of clear nights of 80.8 per cent at La Silla in 2018. The respective Ekar Observatory values are 31.1 per cent PN, 24.0 per cent SN and 55.1 per cent of total clear night time. Application to the SQM network would involve the development of long-term statistics and large data forecasting models for site testing and real-time astronomical observation.
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 GFZ @ kyba @ Serial 2842
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