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Author Puschnig, J.; Wallner, S.; Posch, T.
Title Circalunar variations of the night sky brightness – an FFT perspective on the impact of light pollution Type Journal Article
Year 2020 Publication Monthly Notices of the Royal Astronomical Society Abbreviated Journal
Volume 492 Issue 2 Pages (down) 2622-2637
Keywords Skyglow; Moonlight
Abstract Circa-monthly activity conducted by moonlight is observed in many species on Earth. Given the vast amount of artificial light at night (ALAN) that pollutes large areas around the globe, the synchronization to the circalunar cycle is often strongly perturbed. Using 2-yr data from a network of 23 photometers (Sky Quality Meters; SQM) in Austria (latitude ∼48°), we quantify how light pollution impacts the recognition of the circalunar periodicity. We do so via frequency analysis of nightly mean sky brightnesses using Fast Fourier Transforms. A very tight linear relation between the mean zenithal night sky brightness (NSB) given in magSQMarcsec−2 and the amplitude of the circalunar signal is found, indicating that for sites with a mean zenithal NSB brighter than 16.5 magSQMarcsec−2 the lunar rhythm practically vanishes. This finding implies that the circalunar rhythm is still detectable (within the broad bandpass of the SQM) at most places around the globe, but its amplitude against the light polluted sky is strongly reduced. We find that the circalunar contrast in zenith is reduced compared to ALAN-free sites by factors of 19 in the state capital of Linz (∼200 000 inhabitants) and 13 in small towns, e.g. Freistadt and Mattighofen, with less than 10 000 inhabitants. Only two of our sites, both situated in national parks (Bodinggraben and Zöblboden), show natural circalunar amplitudes. At our urban sites, we further detect a strong seasonal signal that is linked to the amplification of anthropogenic skyglow during the winter months due to climatological conditions.
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ISSN 0035-8711 ISBN Medium
Area Expedition Conference
Notes Approved no
Call Number GFZ @ kyba @ Serial 2838
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Author Singhal, R. K., Kumar, V., Kumar, M., & Bose, B.
Title Responses of different light intensities and continue light during dark period on rice (Oryza sativa L.) seed germination and seedling development Type Journal Article
Year 2019 Publication Journal of Pharmacognosy and Phytochemistry Abbreviated Journal
Volume 8 Issue 4 Pages (down) 2602-2609
Keywords Plants
Abstract Temperature, humidity and moisture content are the important abiotic component regulating seedling establishment in plants including rice. Light factor intensity and duration are also important environmental factors regulating rice growth and development. In the growth and development of rice crop germination followed by seedling establishment is the foremost and very important growth stages. Light component such as intensity, direction and duration are the regulating factor for several physiological, biochemical and molecular processes in plants. To consider these facts, in the present piece of work rice seed of HUR-105 grown under different light regimes, from T1 (2000 lux for 12 h during day time + 12 h dark period) (lower light intensity), T2 (4000 lux for 12 h during day time+ 12 h dark period), T3 (6000 lux for 12 h during day time + 12 h dark period) (moderate), T4 (9000 lux for 12 h during day time + 12 h dark period) (optimum) and to T5 (9000 lux for 12h during day time + 200 lux for 12 h during night time). Germination, seedling growth and biochemical parameters were observed at different time intervals. It was observed that germination %, germination index (GI), germination rate index (GRI), coefficient of velocity of germination (CVG), mean germination rate (MGR), seedling vigour (SV), α-amylase activity and soluble sugar content significantly reduced in both the treatments T1 and T5. Further, the mean time germination and insoluble sugar content were increased in T1 and T5 treatment. The present experiment concluded that both lower light intensity (T1) and addition of low light during dark period (considered as night light pollution) causes stress condition and reduce germination and seedling establishment potential of rice crop.
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Notes Approved no
Call Number IDA @ intern @ Serial 2738
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Author Crumey, A.
Title Human Contrast Threshold and Astronomical Visibility. Type Journal Article
Year 2014 Publication Monthly Notices of the Royal Astronomical Society Abbreviated Journal MNRAS
Volume 422 Issue 3 Pages (down) 2600-2619
Keywords Vision; visibility; skyglow; sky brightness; modeling
Abstract The standard visibility model in light-pollution studies is the formula of Hecht, as used e.g. by Schaefer. However, it is applicable only to point sources and is shown to be of limited accuracy. A new visibility model is presented for uniform achromatic targets of any size against background luminances ranging from zero to full daylight, produced by a systematic procedure applicable to any appropriate data set (e.g. Blackwell's), and based on a simple but previously unrecognized empirical relation between contrast threshold and adaptation luminance. The scotopic luminance correction for variable spectral radiance (colour index) is calculated. For point sources, the model is more accurate than Hecht's formula and is verified using telescopic data collected at Mount Wilson in 1947, enabling the sky brightness at that time to be determined. The result is darker than the calculation by Garstang, implying that light pollution grew more rapidly in subsequent decades than has been supposed. The model is applied to the nebular observations of William Herschel, enabling his visual performance to be quantified. Proposals are made regarding sky quality indicators for public use.
Address Department of Humanities, Northumbria University, Newcastle upon Tyne NE1 8ST, UK; andrew.crumey(at)northumbria.ac.uk
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Publisher Oxford Journals Place of Publication Editor
Language English Summary Language English 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 LoNNe @ christopher.kyba @ Serial 536
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Author Yeh, C.; Perez, A.; Driscoll, A.; Azzari, G.; Tang, Z.; Lobell, D.; Ermon, S.; Burke, M.
Title Using publicly available satellite imagery and deep learning to understand economic well-being in Africa Type Journal Article
Year 2020 Publication Nature Communications Abbreviated Journal Nat Commun
Volume 11 Issue 1 Pages (down) 2583
Keywords Remote Sensing
Abstract Accurate and comprehensive measurements of economic well-being are fundamental inputs into both research and policy, but such measures are unavailable at a local level in many parts of the world. Here we train deep learning models to predict survey-based estimates of asset wealth across ~ 20,000 African villages from publicly-available multispectral satellite imagery. Models can explain 70% of the variation in ground-measured village wealth in countries where the model was not trained, outperforming previous benchmarks from high-resolution imagery, and comparison with independent wealth measurements from censuses suggests that errors in satellite estimates are comparable to errors in existing ground data. Satellite-based estimates can also explain up to 50% of the variation in district-aggregated changes in wealth over time, with daytime imagery particularly useful in this task. We demonstrate the utility of satellite-based estimates for research and policy, and demonstrate their scalability by creating a wealth map for Africa's most populous country.
Address National Bureau of Economic Research, 1050 Massachusetts Avenue, Cambridge, MA, 02138-5398, USA. mburke@stanford.edu
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ISSN 2041-1723 ISBN Medium
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Notes PMID:32444658 Approved no
Call Number GFZ @ kyba @ Serial 2939
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Author Kuffer, M.; Pfeffer, K.; Sliuzas, R.; Taubenbock, H.; Baud, I.; van Maarseveen, M.
Title Capturing the Urban Divide in Nighttime Light Images From the International Space Station Type Journal Article
Year 2018 Publication IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing Abbreviated Journal IEEE J. Sel. Top. Appl. Earth Observations Remote Sensing
Volume 11 Issue 8 Pages (down) 2578-2586
Keywords Remote Sensing
Abstract Earlier studies utilizing coarse resolution DMSP-OLS nighttime light (NTL) imagery suggest a negative correlation between the amount of NTL and urban deprivation. The International Space Station (ISS) NTL images offer higher resolution images compared to DMSP-OLS or VIIRS images, allowing an analysis of intraurban NTL variations. The aim of this study is to examine the capacity of ISS images for analyzing the intraurban divide. NTL images of four cities (one African, two Asian, and one South American) have been processed and analyzed. The results show that deprived areas are generally the darker spots of built-up areas within cities, illustrating the urban divide in terms of access to street lighting. However, differences exist between cities: Deprived areas in the African city (Dar es Salaam) generally feature lower NTL emissions compared to the examined cities in South America (Belo Horizonte) and Asia (Mumbai and Ahmedabad). Beyond, variations exist in NTL emissions across deprived areas within cities. Deprived areas at the periphery show less NTL compared to central areas. Edges of deprived areas have higher NTL emissions compared to internal areas. NTL emission differences between types of deprived areas were detected. The correlation between ISS NTL images and population densities is weak; this can be explained by densely built-up deprived areas having less NTL compared to lower density formal areas. Our findings show ISS data complement other data to capture the urban divide between deprived and better-off areas and the need to consider socioeconomic conditions in estimating populations.
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Language Summary Language Original Title
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Series Volume Series Issue Edition
ISSN 1939-1404 ISBN Medium
Area Expedition Conference
Notes Approved no
Call Number GFZ @ kyba @ Serial 2178
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