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Author Li, X.; Levin, N.; Xie, J.; Li, D.
Title Monitoring hourly night-time light by an unmanned aerial vehicle and its implications to satellite remote sensing Type Journal Article
Year 2020 Publication Remote Sensing of Environment Abbreviated Journal Remote Sensing of Environment
Volume 247 Issue Pages in press
Keywords (up) Remote Sensing; Skyglow; Instrumentation
Abstract Satellite-observed night-time light in urban areas has been widely used as an indicator for socioeconomic development and light pollution. Up to present, the diurnal dynamics of city light during the night, which are important to understand the nature of human activity and the underlying variables explaining night-time brightness, have hardly been investigated by remote sensing techniques due to limitation of the revisit time and spatial resolution of available satellites. In this study, we employed a consumer-grade unmanned aerial vehicle (UAV) to monitor city light in a study area located in Wuhan City, China, from 8:08 PM, April 15, 2019 to 5:08 AM, April 16, 2019, with an hourly temporal resolution. By using three ground-based Sky Quality Meters (SQMs), we found that the UAV-recorded light brightness was consistent with the ground luminous intensity measured by the SQMs in both the spatial (R2 = 0.72) and temporal dimensions (R2 > 0.94), and that the average city light brightness was consistent with the sky brightness in the temporal dimension (R2 = 0.98), indicating that UAV images can reliably monitor the city's night-time brightness. The temporal analysis showed that different locations had different patterns of temporal changes in their night-time brightness, implying that inter-calibration of two kinds of satellite images with different overpass times would be a challenge. Combining an urban function map of 18 classes and the hourly UAV images, we found that urban functions differed in their temporal light dynamics. For example, the outdoor sports field lost 97.28% of its measured brightness between 8: 08 PM – 4:05 AM, while an administrative building only lost 4.56%, and the entire study area lost 61.86% of its total brightness. Within our study area, the period between 9:06 PM and 10:05 PM was the period with largest amount of light loss. The spectral analysis we conducted showed that city light colors were different in some urban functions, with the major road being the reddest region at 8:08 PM and becoming even redder at 4:05 AM. This preliminary study indicates that UAVs are a good tool to investigate city light at night, and that city light is very complex in both of the temporal and spatial dimensions, requiring comprehensive investigation using more advanced UAV techniques, and emphasizing the need for geostationary platforms for night-time light sensors.
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Series Volume Series Issue Edition
ISSN 0034-4257 ISBN Medium
Area Expedition Conference
Notes Approved no
Call Number GFZ @ kyba @ Serial 3014
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Author Kyba, C.C.M.; Bouroussis, C.; Canal-Domingo, R.; Falchi, F.; Giacomelli, A.; Hänel, A.; Kolláth, Z.; Massetti, L.; Ribas, S.J.; Spoelstra, H.; Tong, K.P.; Wuchterl, G.
Title Report of the 2015 LoNNe Intercomparison Campaign Type Journal Article
Year 2015 Publication Abbreviated Journal
Volume Issue Pages
Keywords (up) skyglow; instrumentation
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Notes Approved no
Call Number LoNNe @ kyba @; IDA @ john @; GFZ @ kyba @ Serial 1255
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Author Duriscoe, D.M.
Title Photometric indicators of visual night sky quality derived from all-sky brightness maps Type Journal Article
Year 2016 Publication Journal of Quantitative Spectroscopy and Radiative Transfer Abbreviated Journal JQSRT
Volume 181 Issue Pages 33-45
Keywords (up) Skyglow; Instrumentation
Abstract Wide angle or fisheye cameras provide a high resolution record of artificial sky glow, which results from the scattering of escaped anthropogenic light by the atmosphere, over the sky vault in the moonless nocturnal environment. Analysis of this record yields important indicators of the extent and severity of light pollution. The following indicators were derived through numerical analysis of all-sky brightness maps: zenithal, average all-sky, median, brightest, and darkest sky brightness. In addition, horizontal and vertical illuminance, resulting from sky brightness were computed. A natural reference condition to which the anthropogenic component may be compared is proposed for each indicator, based upon an iterative analysis of a high resolution natural sky model. All-sky brightness data, calibrated in the V band by photometry of standard stars and converted to luminance, from 406 separate data sets were included in an exploratory analysis. Of these, six locations representing a wide range of severity of impact from artificial sky brightness were selected as examples and examined in detail. All-sky average brightness is the most unbiased indicator of impact to the environment, and is more sensitive and accurate in areas of slight to moderate light pollution impact than zenith brightness. Maximum vertical illuminance provides an excellent indicator of impacts to wilderness character, as does measures of the brightest portions of the sky. Zenith brightness, the workhorse of field campaigns, is compared to the other indicators and found to correlate well with horizontal illuminance, especially at relatively bright sites. The median sky brightness describes a brightness threshold for the upper half of the sky, of importance to telescopic optical astronomy. Numeric indicators, in concert with all-sky brightness maps, provide a complete assessment of visual sky quality at a site.
Address U.S. National Park Service, Natural Sounds and Night Skies Division, 351 Pacu Lane, Bishop, CA 93514, USA; dan_duriscoe(at)nps.gov
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 LoNNe @ kyba @ ; IDA @ john @ Serial 1376
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Author Jechow, A.; Ribas, S.J.; Domingo, R.C.; Hölker, F.; Kolláth, Z.; Kyba, C.C.M.
Title Tracking the dynamics of skyglow with differential photometry using a digital camera with fisheye lens Type Journal Article
Year 2018 Publication Journal of Quantitative Spectroscopy and Radiative Transfer Abbreviated Journal Journal of Quantitative Spectroscopy and Radiative Transfer
Volume 209 Issue Pages 212-223
Keywords (up) Skyglow; Instrumentation
Abstract rtificial skyglow is dynamic due to changing atmospheric conditions and the switching on and off of artificial lights throughout the night. Street lights as well as the ornamental illumination of historical sites and buildings are sometimes switched off at a certain time to save energy. Ornamental lights in particular are often directed upwards, and can therefore have a major contribution towards brightening of the night sky. Here we use differential photometry to investigate the change in night sky brightness and illuminance during an automated regular switch-off of ornamental light in the town of Balaguer and an organized switch-off of all public lights in the village of Àger, both near Montsec Astronomical Park in Spain. The sites were observed during two nights with clear and cloudy conditions using a DSLR camera and a fisheye lens. A time series of images makes it possible to track changes in lighting conditions and sky brightness simultaneously. During the clear night, the ornamental lights in Balaguer contribute over 20% of the skyglow at zenith at the observational site. Furthermore, we are able to track very small changes in the ground illuminance on a cloudy night near Àger.
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ISSN 0022-4073 ISBN Medium
Area Expedition Conference
Notes Approved no
Call Number LoNNe @ kyba @ Serial 1807
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Author Bouroussis, C.A.; Topalis, F.V.
Title The effect of the spectral response of measurement instruments in the assessment of night sky brightness Type Journal Article
Year 2018 Publication Journal of Quantitative Spectroscopy and Radiative Transfer Abbreviated Journal Journal of Quantitative Spectroscopy and Radiative Transfer
Volume 216 Issue Pages 56-69
Keywords (up) Skyglow; Instrumentation
Abstract This paper deals with the errors and uncertainties in skyglow measurements caused by the variation of sky's spectrum. It considers the theoretical spectral response of common instruments that are used for light pollution assessment. Various types of light sources were used in this investigation. This study calculates the spectral mismatch errors and the corresponding correction factors for each combination of instrument and light source. The calculation method is described and the results are presented in multiple figures. Calculated data show a big variation in potential errors that can be introduced when comparing readings of diverse instruments without considering the sky spectrum variation. This makes the spectral data of the sky a mandatory input to the dark sky assessment. Useful conclusions, related to instruments with better or worse behaviour, are derived from the calculations. The paper also includes suggestions on how to conduct multi-instrument measurements with or without spectral data.
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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 1908
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