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Author Lamphar, H. url  doi
openurl 
  Title Spatio-temporal association of light pollution and urban sprawl using remote sensing imagery and GIS: A simple method based in Otsu's algorithm Type Journal Article
  Year 2020 Publication Journal of Quantitative Spectroscopy and Radiative Transfer Abbreviated Journal Journal of Quantitative Spectroscopy and Radiative Transfer  
  Volume 251 Issue Pages (down) 107060  
  Keywords Remote Sensing  
  Abstract Automatic thresholding methods are used to detect spatio-temporal changes in the land subject to different natural and anthropogenic processes. Image segmentation plays an important role in this analysis, where urban sprawl detection take place with daylight images. However, recently some investigators have used nocturnal images in remote sensing imagery research. Such georeferenced data represent a good tool for analysis of the light pollution and urban sprawl. There are various physical processes involved in the radiative transfer of the light projected from the cities. Though, with a correct method based on background subtraction, any satellite remotely sensed nocturnal image can be useful in detecting urban sprawl. We base this work on thresholding processes of georeferenced nocturnal satellite images. We used a method combining digital classification techniques, geographic information systems and statistical analyzes. The proposed method is helpful because of a simple implementation and time saving. The pixel intensity of nocturnal images can offer a tool to calculate aspects related to electricity consumption and the efficiency of public lighting. We hope the results motivates other authors to study relationships with other social, natural and economic issues.  
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  Corporate Author Thesis  
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  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 2990  
Permanent link to this record
 

 
Author Kocifaj, M.; Kundracik, F. url  doi
openurl 
  Title Multi-wavelength radiometry of aerosols designed for more accurate night sky brightness predictions Type Journal Article
  Year 2020 Publication Journal of Quantitative Spectroscopy and Radiative Transfer Abbreviated Journal Journal of Quantitative Spectroscopy and Radiative Transfer  
  Volume 250 Issue Pages (down) 106998  
  Keywords Skyglow; Remote Sensing  
  Abstract Scattering by aerosols and gases cause a certain fraction of artificial light emitted upwards is redirected to the ground. Of all atmospheric constituents just the aerosols are most important modulators of night-sky brightness under cloudless conditions. Unlike most of the previous we highlight a crucial role of solar radiometry for determining the atmospheric optical depth before night-time observation is to be made. Aerosol optical depth at visible wavelengths extracted from the data measured provides then the information on size distribution or mean refractive index of aerosol particles that in turn are both necessary to make night sky brightness prediction more accurate. Therefore, combining daytime and night-time radiometry we can achieve accuracy much higher than ever before. This is due to significantly reduced uncertainty in aerosol properties.

The aerosol data are retrieved from a new portable multi-wavelength optical analyzer that operates Ocean Optics spectrometer. The equipment provides the radiance data from 350 nm to 1000 nm with spectral resolution of 1 nm. Due to high sun radiance levels we use a system of mirrors each reducing the signal to about 4%, while keeping the integration time short. The minimum integration time of 3 ms allows for detection of direct sunlight. The system developed is sensitive to small changes in the aerosol system, while showing a good detection limit even under low turbidity conditions. The system performance is demonstrated in field experiment conducted shortly after front passage when most of aerosol particles is effectively removed by rain.
 
  Address  
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  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 2906  
Permanent link to this record
 

 
Author Min, M.; Zheng, J.; Zhang, P.; Hu, X.; Chen, L.; Li, X.; Huang, Y.; Zhu, L. url  doi
openurl 
  Title A low-light radiative transfer model for satellite observations of moonlight and earth surface light at night Type Journal Article
  Year 2020 Publication Journal of Quantitative Spectroscopy and Radiative Transfer Abbreviated Journal Journal of Quantitative Spectroscopy and Radiative Transfer  
  Volume in press Issue Pages (down) 106954  
  Keywords Remote Sensing; Instrumentation  
  Abstract Lunar sun-reflected light can be effectively measured through a low-light band or a day/night band (DNB) implemented on space-based optical sensors. Based on moonlight, nocturnal observations for artificial light sources at night can be achieved. However, to date, an open-sourced and mature Low-Light Radiative Transfer Model (LLRTM) for the further understanding of the radiative transfer problem at night is still unavailable. Therefore, this study develops a new LLRTM at night with the correction of the lunar and active surface light sources. First, the radiative transfer equations with an active surface light source are derived for the calculation based on the lunar spectral irradiance (LSI) model. The simulation from this new LLRTM shows a minimal bias when compared with the discrete ordinates radiative transfer (DISORT) model. The simulated results of radiance and reflectance at the top of the atmosphere (TOA) also show that the surface light source has a remarkable impact on the radiative transfer process. In contrast, the change in the lunar phase angle has minimal influence. Also, comparing with space-based DNB radiance observations, LLRTM shows the potential to simulate space-based low-light imager observations under an effective surface light source condition during the night.  
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  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 2850  
Permanent link to this record
 

 
Author Bará, S.; Rigueiro, I.; Lima, R.C. url  doi
openurl 
  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.  
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  Corporate Author Thesis  
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  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  
Permanent link to this record
 

 
Author Beresford, A.E.; Donald, P.F.; Buchanan, G.M. url  doi
openurl 
  Title Repeatable and standardised monitoring of threats to Key Biodiversity Areas in Africa using Google Earth Engine Type Journal Article
  Year 2020 Publication Ecological Indicators Abbreviated Journal Ecological Indicators  
  Volume 109 Issue Pages (down) 105763  
  Keywords Remote Sensing  
  Abstract Key Biodiversity Areas (KBAs) are sites that make significant contributions to the global persistence of biodiversity, but identification of sites alone is not sufficient to ensure their conservation. Monitoring is essential if pressures on these sites are to be identified, priorities set and appropriate responses developed. Here, we describe how analysis of freely available data on a cloud-processing platform (Google Earth Engine) can be used to assess changes in three example remotely sensed threat indicators (fire frequency, tree loss and night-time lights) over time on KBAs in Africa. We develop easily repeatable methods with shared code that could be applied across any geographic area and could be adapted and applied to other datasets as they become available. Fire frequency was found to have increased significantly on 12.4% of KBAs and 15.9% of ecoregions, whilst rates of forest loss increased significantly on 24.3% of KBAs and 22.6% of ecoregions. There was also evidence of significant increases in night-time lights on over half (53.3%) of KBAs and 39.6% of ecoregions between 1992 and 2013, and on 11.6% of KBAs and 53.0% of ecoregions between 2014 and 2018.  
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  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 2707  
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