| Records |
| Author |
Jechow, A.; Hölker, F. |
| Title |
Snowglow—The Amplification of Skyglow by Snow and Clouds can Exceed Full Moon Illuminance in Suburban Areas |
Type |
Journal Article |
| Year |
2019 |
Publication |
Journal of Imaging |
Abbreviated Journal |
J. Imaging |
| Volume |
5 |
Issue |
8 |
Pages |
69 |
| Keywords |
Skyglow |
| Abstract |
Artificial skyglow, the fraction of artificial light at night that is emitted upwards from Earth and subsequently scattered back within the atmosphere, depends on atmospheric conditions but also on the ground albedo. One effect that has not gained much attention so far is the amplification of skyglow by snow, particularly in combination with clouds. Snow, however, has a very high albedo and can become important when the direct upward emission is reduced when using shielded luminaires. In this work, first results of skyglow amplification by fresh snow and clouds measured with all-sky photometry in a suburban area are presented. Amplification factors for the zenith luminance of 188 for snow and clouds in combination and 33 for snow alone were found at this site. The maximum zenith luminance of nearly 250 mcd/m2 measured with snow and clouds is a factor of 1000 higher than the commonly used clear sky reference of 0.25 mcd/m2. Compared with our darkest zenith luminance of 0.07 mcd/m2 measured for overcast conditions in a very remote area, this leads to an overall amplification factor of ca. 3500. Horizontal illuminance measurements show values of up to 0.79 lx, exceeding maximum possible full-moon illuminance levels by more than a factor of two. Additional measurements near the Arctic Circle for clear and overcast conditions are presented and strategies for further studies are discussed. We propose the term “snowglow” to describe the amplification of skyglow by snow with and without clouds. |
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2313-433X |
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GFZ @ kyba @ |
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2699 |
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| Author |
Craggs, J.; Guest, J.R.; Davis, M.; Simmons, J.; Dashti, E.; Sweet, M. |
| Title |
Inducing broadcast coral spawning ex situ: Closed system mesocosm design and husbandry protocol |
Type |
Journal Article |
| Year |
2017 |
Publication |
Ecology and Evolution |
Abbreviated Journal |
Ecol Evol |
| Volume |
7 |
Issue |
24 |
Pages |
11066-11078 |
| Keywords |
Moonlight; Animals; *Acropora; *gametogenic cycle ex situ; *insolation; *lunar cycle; *photoperiod |
| Abstract |
For many corals, the timing of broadcast spawning correlates strongly with a number of environmental signals (seasonal temperature, lunar, and diel cycles). Robust experimental studies examining the role of these putative cues in triggering spawning have been lacking until recently because it has not been possible to predictably induce spawning in fully closed artificial mesocosms. Here, we present a closed system mesocosm aquarium design that utilizes microprocessor technology to accurately replicate environmental conditions, including photoperiod, seasonal insolation, lunar cycles, and seasonal temperature from Singapore and the Great Barrier Reef (GBR), Australia. Coupled with appropriate coral husbandry, these mesocosms were successful in inducing, for the first time, broadcast coral spawning in a fully closed artificial ex situ environment. Four Acropora species (A. hyacinthus, A. tenuis, A. millepora, and A. microclados) from two geographical locations, kept for over 1 year, completed full gametogenic cycles ex situ. The percentage of colonies developing oocytes varied from ~29% for A. hyacinthus to 100% for A. millepora and A. microclados. Within the Singapore mesocosm, A. hyacinthus exhibited the closest synchronization to wild spawning, with all four gravid colonies releasing gametes in the same lunar month as wild predicted dates. Spawning within the GBR mesocosm commenced at the predicted wild spawn date but extended over a period of 3 months. Gamete release in relation to the time postsunset for A. hyacinthus, A. millepora, and A. tenuis was consistent with time windows previously described in the wild. Spawn date in relation to full moon, however, was delayed in all species, possibly as a result of external light pollution. The system described here could broaden the number of institutions on a global scale, that can access material for broadcast coral spawning research, providing opportunities for institutions distant from coral reefs to produce large numbers of coral larvae and juveniles for research purposes and reef restoration efforts. |
| Address |
Aquatic Research Facility Environmental Sustainability Research Centre College of Life and Natural Sciences University of Derby Derby UK |
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English |
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2045-7758 |
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PMID:29299282; PMCID:PMC5743687 |
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GFZ @ kyba @ |
Serial |
2698 |
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| Author |
Xia, C.; Yeh, A.G.-O.; Zhang, A. |
| Title |
Analyzing spatial relationships between urban land use intensity and urban vitality at street block level: A case study of five Chinese megacities |
Type |
Journal Article |
| Year |
2020 |
Publication |
Landscape and Urban Planning |
Abbreviated Journal |
Landscape and Urban Planning |
| Volume |
193 |
Issue |
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Pages |
103669 |
| Keywords |
Remote Sensing |
| Abstract |
Urban sprawl in urbanizing China has resulted in a series of ecological and environmental problems. Urban planners have been committed to promoting compact development through high-density and mixed land use. However, a problem brought by such compact urban form is the mismatch between physical spaces and socio-economic activities. To date, minimal research has been conducted using spatial statistics to study this issue at the local scales. Moreover, urban night-time vitality has been consistently ignored in existing studies. In the current work, urban land use intensity was analyzed on the basis of street block density and typology, and urban daytime and night-time vitality were measured using small catering business and night-time light data, respectively. The spatial relationships between urban land use intensity and urban vitality were investigated using a local indicator of spatial association (LISA), and five megacities in China were taken as a case study to examine whether variations exist between different cities. Results showed a significant positive spatial autocorrelation between urban land use intensity and urban vitality according to global statistics. Therefore, socio-economic activities are more likely to be abundant in densely developed urban areas. However, local spatial mismatches were found in the five megacities, indicating overcrowded or underutilized urban spaces in all the cities. These relationships were associated with different urban areas (urbanized before 1995 and during 1995–2015), land use conditions (function and mixture) and time periods (day and night). The results of this work will provide a comprehensive understanding of compact city and sustainability. |
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0169-2046 |
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GFZ @ kyba @ |
Serial |
2697 |
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| Author |
Grauer, A.D.; Grauer, P.A.; Davies, N.; Davies, G. |
| Title |
Impact of Space Weather on the Natural Night Sky |
Type |
Journal Article |
| Year |
2019 |
Publication |
Publications of the Astronomical Society of the Pacific |
Abbreviated Journal |
PASP |
| Volume |
131 |
Issue |
1005 |
Pages |
114508 |
| Keywords |
Darkness; night sky brightness; United States; New Zealand; Sun; space weather; solar wind |
| Abstract |
In 2018, Solar Cycle 24 entered a deep solar minimum. During this period, we collected night sky brightness data at Cosmic Campground International Dark Sky Sanctuary (CCIDSS) in the USA (2018 September 4–2019 January 4) and at Aotea/Great Barrier Island International Dark Sky Sanctuary (AGBIIDSS) in New Zealand (2018 March 26–August 31. These sites have artificial-light-pollution-free natural night skies. The equipment employed are identical Unihedron SQM-LU-DL meters, used as single-channel differential photometers, to scan the sky as Earth rotates on its axis. We have developed new analysis techniques which select those data points which are uninfluenced by Sun, Moon, or clouds to follow brightness changes at selected points on the celestial sphere and to measure the brightness of the airglow above its quiescent level. The 2018 natural night sky was measured to change in brightness by approximately 0.9 mag arcsec−2 at both locations. Preliminary results indicate the modulations of the light curves (brightness versus R.A.) we observed are related in complex ways to elements of space weather conditions in the near-Earth environment. In particular, episodes of increased night sky brightness are observed to be contemporaneous with geomagnetic activity, increases in mean solar wind speed, and some solar proton/electron fluence events. Charged particles in the solar wind take days to reach near-Earth environment after a coronal hole is observed to be facing in our direction. Use of this information could make it possible to predict increases in Earth’s natural night sky brightness several days in advance. What we have learned during this solar minimum leads us to search for other solar driven changes in night sky brightness as the Sun begins to move into solar maximum conditions. |
| Address |
Catalina Sky Survey, Lunar and Planetary Laboratory, University of Arizona, USA; algrauer(at)me.com |
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Astronomical Society of the Pacific |
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English |
Summary Language |
English |
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0004-6280 |
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IDA @ john @ |
Serial |
2696 |
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| Author |
Kumar, P.; Ashawat, M.S.; Pandit, V.; Sharma, D.K. |
| Title |
Artificial Light Pollution at Night: A Risk for Normal Circadian Rhythm and Physiological Functions in Humans |
Type |
Journal Article |
| Year |
2019 |
Publication |
Current Environmental Engineering |
Abbreviated Journal |
Cee |
| Volume |
6 |
Issue |
2 |
Pages |
111-125 |
| Keywords |
Human Health; Review |
| Abstract |
From the past three to four decades, ecologists and scientists have exhaustively studied the effect of increased artificial light pollution at night on the ecological and physiological behavior of mammals. The Suprachiasmatic Nuclei (SCN) or master clock in the brain of mammals including humans synchronizes the physiological functions with the light: dark cycle. The prolongation of light period in the light: dark cycle disrupts the circadian rhythm of mammals causing several negative or modified physiological consequences. Changed physiological level of melatonin, an important endocrine hormone, had been identified as an important factor causing different consequences such as cancer, diabetes mellitus, metabolic disturbances, oxidative stress, and depression. The presence of artificial light at night is the demand of the era but thoughts must be given to the prevention of consequences due to artificial light pollution and ‘how much is needed’. The review paper discusses the effect of artificial light pollution on the biological clock of humans and associated negative physiological consequences. Further, the paper also briefly discusses the economics of light pollution and measures needed to prevent physiological disorders in humans. |
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2212-7178 |
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GFZ @ kyba @ |
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2695 |
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